WorldWideScience

Sample records for haplodiploid sex determination

  1. Complementary sex determination substantially increases extinction proneness of haplodiploid populations.

    Science.gov (United States)

    Zayed, Amro; Packer, Laurence

    2005-07-26

    The role of genetic factors in extinction is firmly established for diploid organisms, but haplodiploids have been considered immune to genetic load impacts because deleterious alleles are readily purged in haploid males. However, we show that single-locus complementary sex determination ancestral to the haplodiploid Hymenoptera (ants, bees, and wasps) imposes a substantial genetic load through homozygosity at the sex locus that results in the production of inviable or sterile diploid males. Using stochastic modeling, we have discovered that diploid male production (DMP) can initiate a rapid and previously uncharacterized extinction vortex. The extinction rate in haplodiploid populations with DMP is an order of magnitude greater than in its absence under realistic but conservative demographic parameter values. Furthermore, DMP alone can elevate the base extinction risk in haplodiploids by over an order of magnitude higher than that caused by inbreeding depression in threatened diploids. Thus, contrary to previous expectations, haplodiploids are more, rather than less, prone to extinction for genetic reasons. Our findings necessitate a fundamental shift in approaches to the conservation and population biology of these ecologically and economically crucial insects.

  2. Genetics of sex determination in the haplodiploid wasp Nasonia ...

    Indian Academy of Sciences (India)

    2010-09-06

    Sep 6, 2010 ... How gender is determined under haplodiploidy in the ab- sence of heteromorphic sex ... determination (see below). Sex-determination mutants ... not others (Nöthiger and Steinmann-Zwicky 1985; Wilkins. 1995; Saccone et al.

  3. Sex determination in the haplodiploid wasp Nasonia vitripennis (Hymenoptera Chalcidoidea) : A critical consideration of models and evidence

    NARCIS (Netherlands)

    Beukeboom, Leo W.; Kamping, Albert; van de Zande, Louis

    Sex determining mechanisms are highly diverse. Like all Hymenoptera, the parasitic wasp Nasonia vitripennis reproduces by haplodiploidy: males are haploid and females are diploid. Sex in Nasonia is not determined by complementary alleles at sex loci. Evidence for several alternative models is

  4. Single locus complementary sex determination in Hymenoptera : an "unintelligent" design?

    NARCIS (Netherlands)

    Wilgenburg, Ellen van; Driessen, Gerard; Beukeboom, Leo W.

    2006-01-01

    The haplodiploid sex determining mechanism in Hymenoptera (males are haploid, females are diploid) has played an important role in the evolution of this insect order. In Hymenoptera sex is usually determined by a single locus, heterozygotes are female and hemizygotes are male. Under inbreeding,

  5. Single locus complementary sex determination in Hymenoptera: an "unintelligent" design?

    NARCIS (Netherlands)

    van Wilgenburg, E.; Driessen, G.J.J.; Beukeboom, L.W.

    2006-01-01

    The haplodiploid sex determining mechanism in Hymenoptera (males are haploid, females are diploid) has played an important role in the evolution of this insect order. In Hymenoptera sex is usually determined by a single locus, heterozygotes are female and hemizygotes are male. Under inbreeding,

  6. Mosaicism may explain the evolution of social characters in haplodiploid Hymenoptera with female workers.

    Science.gov (United States)

    Morpurgo, Giorgio; Babudri, Nora; Fioretti, Bernard; Catacuzzeno, Luigi

    2010-12-01

    The role of haplodiploidy in the evolution of eusocial insects and why in Hymenoptera males do not perform any work is presently unknown. We show here that within-colony conflict caused by the coexistence of individuals of the same caste expressing the same character in different ways can be fundamental in the evolution of social characters in species that have already reached the eusocial condition. Mosaic colonies, composed by individuals expressing either the wild-type or a mutant phenotype, inevitably occurs during the evolution of advantageous social traits in insects. We simulated the evolution of an advantageous social trait increasing colony fitness in haplodiploid and diplodiploid species considering all possible conditions, i.e. dominance/recessivity of the allele determining the new social character, sex of the castes, and influence of mosaicism on the colony fitness. When mosaicism lowered colony fitness below that of the colony homogeneous for the wild type allele, the fixation of an advantageous social character was possible only in haplodiploids with female castes. When mosaicism caused smaller reductions in colony fitness, reaching frequencies of 90% was much faster in haplodiploids with female castes and dominant mutations. Our results suggest that the evolution of social characters is easier in haplodiploid than in diplodiploid species, provided that workers are females.

  7. Sex determination

    Indian Academy of Sciences (India)

    The sex-determining system differs considerably among organisms. Even among insect species, the genetic system for sex-determination is highly diversified. In Drosophila melanogaster, somatic sexual differentiation is regulated by a well characterized genetic hierarchy X : A > Sxl > tra/tra2 > dsx and fru. This cascade ...

  8. Sex Determination, Sex Chromosomes, and Karyotype Evolution in Insects.

    Science.gov (United States)

    Blackmon, Heath; Ross, Laura; Bachtrog, Doris

    2017-01-01

    Insects harbor a tremendous diversity of sex determining mechanisms both within and between groups. For example, in some orders such as Hymenoptera, all members are haplodiploid, whereas Diptera contain species with homomorphic as well as male and female heterogametic sex chromosome systems or paternal genome elimination. We have established a large database on karyotypes and sex chromosomes in insects, containing information on over 13000 species covering 29 orders of insects. This database constitutes a unique starting point to report phylogenetic patterns on the distribution of sex determination mechanisms, sex chromosomes, and karyotypes among insects and allows us to test general theories on the evolutionary dynamics of karyotypes, sex chromosomes, and sex determination systems in a comparative framework. Phylogenetic analysis reveals that male heterogamety is the ancestral mode of sex determination in insects, and transitions to female heterogamety are extremely rare. Many insect orders harbor species with complex sex chromosomes, and gains and losses of the sex-limited chromosome are frequent in some groups. Haplodiploidy originated several times within insects, and parthenogenesis is rare but evolves frequently. Providing a single source to electronically access data previously distributed among more than 500 articles and books will not only accelerate analyses of the assembled data, but also provide a unique resource to guide research on which taxa are likely to be informative to address specific questions, for example, for genome sequencing projects or large-scale comparative studies. © The American Genetic Association 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Maternal provision of non-sex-specific transformer messenger RNA in sex determination of the wasp Asobara tabida.

    Science.gov (United States)

    Geuverink, E; Verhulst, E C; van Leussen, M; van de Zande, L; Beukeboom, L W

    2018-02-01

    In many insect species maternal provision of sex-specifically spliced messenger RNA (mRNA) of sex determination genes is an essential component of the sex determination mechanism. In haplodiploid Hymenoptera, maternal provision in combination with genomic imprinting has been shown for the parasitoid Nasonia vitripennis, known as maternal effect genomic imprinting sex determination (MEGISD). Here, we characterize the sex determination cascade of Asobara tabida, another hymenopteran parasitoid. We show the presence of the conserved sex determination genes doublesex (dsx), transformer (tra) and transformer-2 (tra2) orthologues in As. tabida. Of these, At-dsx and At-tra are sex-specifically spliced, indicating a conserved function in sex determination. At-tra and At-tra2 mRNA is maternally provided to embryos but, in contrast to most studied insects, As. tabida females transmit a non-sex-specific splice form of At-tra mRNA to the eggs. In this respect, As. tabida sex determination differs from the MEGISD mechanism. How the paternal genome can induce female development in the absence of maternal provision of sex-specifically spliced mRNA remains an open question. Our study reports a hitherto unknown variant of maternal effect sex determination and accentuates the diversity of insect sex determination mechanisms. © 2017 The Authors. Insect Molecular Biology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society.

  10. Commentary Sex determination

    Indian Academy of Sciences (India)

    PRAKASH KUMAR G

    2008-01-31

    ZW is reserved for female heterogamety.) The Radder et al study used lab incubation regimes that mimic temperature profiles of cool natural nests, so temperature probably determines sex at least occasionally in nature.

  11. Single locus complementary sex determination in Hymenoptera: an "unintelligent" design?

    Directory of Open Access Journals (Sweden)

    Driessen Gerard

    2006-01-01

    Full Text Available Abstract The haplodiploid sex determining mechanism in Hymenoptera (males are haploid, females are diploid has played an important role in the evolution of this insect order. In Hymenoptera sex is usually determined by a single locus, heterozygotes are female and hemizygotes are male. Under inbreeding, homozygous diploid and sterile males occur which form a genetic burden for a population. We review life history and genetical traits that may overcome the disadvantages of single locus complementary sex determination (sl-CSD. Behavioural adaptations to avoid matings between relatives include active dispersal from natal patches and mating preferences for non-relatives. In non-social species, temporal and spatial segregation of male and female offspring reduces the burden of sl-CSD. In social species, diploid males are produced at the expense of workers and female reproductives. In some social species, diploid males and diploid male producing queens are killed by workers. Diploid male production may have played a role in the evolution or maintenance of polygyny (multiple queens and polyandry (multiple mating. Some forms of thelytoky (parthenogenetic female production increase homozygosity and are therefore incompatible with sl-CSD. We discuss a number of hypothetical adaptations to sl-CSD which should be considered in future studies of this insect order.

  12. A new component of the Nasonia sex determining cascade is maternally silenced and regulates transformer expression.

    Science.gov (United States)

    Verhulst, Eveline C; Lynch, Jeremy A; Bopp, Daniel; Beukeboom, Leo W; van de Zande, Louis

    2013-01-01

    Although sex determination is a universal process in sexually reproducing organisms, sex determination pathways are among the most highly variable genetic systems found in nature. Nevertheless, general principles can be identified among the diversity, like the central role of transformer (tra) in insects. When a functional TRA protein is produced in early embryogenesis, the female sex determining route is activated, while prevention of TRA production leads to male development. In dipterans, male development is achieved by prevention of female-specific splicing of tra mRNA, either mediated by X-chromosome dose or masculinizing factors. In Hymenoptera, which have haplodiploid sex determination, complementary sex determination and maternal imprinting have been identified to regulate timely TRA production. In the parasitoid Nasonia, zygotic transformer (Nvtra) expression and splicing is regulated by a combination of maternal provision of Nvtra mRNA and silencing of Nvtra expression in unfertilized eggs. It is unclear, however, if this silencing is directly on the tra locus or whether it is mediated through maternal silencing of a trans-acting factor. Here we show that in Nasonia, female sex determination is dependent on zygotic activation of Nvtra expression by an as yet unknown factor. This factor, which we propose to term womanizer (wom), is maternally silenced during oogenesis to ensure male development in unfertilized eggs. This finding implicates the upstream recruitment of a novel gene in the Nasonia sex determining cascade and supports the notion that sex determining cascades can rapidly change by adding new components on top of existing regulators.

  13. Comparative AFLP reveals paternal sex ratio chromosome specific DNA sequences in the parasitoid wasp Trichogramma kaykai

    NARCIS (Netherlands)

    Vugt, van J.J.F.A.; Hulst, van der R.G.M.; Pruijssers, A.; Verbaarschot, P.G.H.; Stouthamer, R.; Jong, de H.

    2009-01-01

    The parasitoid wasp Trichogramma kaykai with a haplo-diploid sex determination has a B chromosome called the paternal sex ratio (PSR) chromosome that confers paternal genome loss during early embryogenesis, resulting in male offspring. So far, it is not well known whether the PSR chromosome has

  14. COMPLEMENTARY SEX DETERMINATION IN HYMENOPTERAN PARASITOIDS AND ITS IMPLICATIONS FOR BIOLOGICAL CONTROL

    Institute of Scientific and Technical Information of China (English)

    WUZhishan; KeithR.Hopper; PaulJ.Ode; RogerW.Fuester; CHENJia-hua; GeorgeE.Heimpel

    2003-01-01

    In haplodiploid Hymenoptera, unfertilized eggs produce haploid males while fertilized eggs lead to diploid females under most circumstances. Diploid males can also be produced from fertilization under a system of sex determination known as complementary sex determination (CSD). Under single-locus CSD, sex is determined by multiple alleles at a single sex locus. Individuals heterozygous at the sex locus are female while hemizygous and homozygous individuals develop as haploid and diploid males, respectively. In multiple-locus CSD, two or more loci, each with two or more alleles, determine sex. Diploid individuals are female if one or more sex loci are het-erozygous, while a diploid is male only if homozygous at all sex loci. Diploid males are known to occur in 43 hym-enopteran species and single-locus CSD has been demonstrated in 22 of these species. Diploid males are either developmentally inviable or sterile, so their production constitutes a genetic load. Because diploid male production is more likely under inbreeding, CSD is a form of inbreeding depression. It is crucial to preserve the diversity of sex alleles and reduce the loss of genetic variation in biological control. In the parasitoid species with single-locus CSD, certain precautionary procedures can prevent negative effects of single-locus CSD on biological control.

  15. Insect Sex Determination Manipulated by Their Endosymbionts: Incidences, Mechanisms and Implications.

    Science.gov (United States)

    Kageyama, Daisuke; Narita, Satoko; Watanabe, Masaya

    2012-02-10

    The sex-determining systems of arthropods are surprisingly diverse. Some species have male or female heterogametic sex chromosomes while other species do not have sex chromosomes. Most species are diploids but some species, including wasps, ants, thrips and mites, are haplodiploids (n in males; 2n in females). Many of the sexual aberrations, such as sexual mosaics, sex-specific lethality and conversion of sexuality, can be explained by developmental defects including double fertilization of a binucleate egg, loss of a sex chromosome or perturbation of sex-determining gene expression, which occur accidentally or are induced by certain environmental conditions. However, recent studies have revealed that such sexual aberrations can be caused by various groups of vertically-transmitted endosymbiotic microbes such as bacteria of the genera Wolbachia, Rickettsia, Arsenophonus, Spiroplasma and Cardinium, as well as microsporidian protists. In this review, we first summarize the accumulated data on endosymbiont-induced sexual aberrations, and then discuss how such endosymbionts affect the developmental system of their hosts and what kinds of ecological and evolutionary effects these endosymbionts have on their host populations.

  16. Sex Determination, Sex Ratios, and Genetic Conflict

    NARCIS (Netherlands)

    Werren, John H.; Beukeboom, Leo W.

    1998-01-01

    Genetic mechanisms of sex determination are unexpectedly diverse and change rapidly during evolution. We review the role of genetic conflict as the driving force behind this diversity and turnover. Genetic conflict occurs when different components of a genetic system are subject to selection in

  17. Commentary Sex determination

    Indian Academy of Sciences (India)

    PRAKASH KUMAR G

    2008-01-31

    Jan 31, 2008 ... years old (Charnier 1966 reported it in an African agamid lizard), although it was ... people's attention in Susumu Ohno's now famous book on .... If they do enhance male and female fitness, sex chromosomes would then be.

  18. A New Component of the Nasonia Sex Determining Cascade Is Maternally Silenced and Regulates Transformer Expression

    Science.gov (United States)

    Bopp, Daniel; Beukeboom, Leo W.; van de Zande, Louis

    2013-01-01

    Although sex determination is a universal process in sexually reproducing organisms, sex determination pathways are among the most highly variable genetic systems found in nature. Nevertheless, general principles can be identified among the diversity, like the central role of transformer (tra) in insects. When a functional TRA protein is produced in early embryogenesis, the female sex determining route is activated, while prevention of TRA production leads to male development. In dipterans, male development is achieved by prevention of female-specific splicing of tra mRNA, either mediated by X-chromosome dose or masculinizing factors. In Hymenoptera, which have haplodiploid sex determination, complementary sex determination and maternal imprinting have been identified to regulate timely TRA production. In the parasitoid Nasonia, zygotic transformer (Nvtra) expression and splicing is regulated by a combination of maternal provision of Nvtra mRNA and silencing of Nvtra expression in unfertilized eggs. It is unclear, however, if this silencing is directly on the tra locus or whether it is mediated through maternal silencing of a trans-acting factor. Here we show that in Nasonia, female sex determination is dependent on zygotic activation of Nvtra expression by an as yet unknown factor. This factor, which we propose to term womanizer (wom), is maternally silenced during oogenesis to ensure male development in unfertilized eggs. This finding implicates the upstream recruitment of a novel gene in the Nasonia sex determining cascade and supports the notion that sex determining cascades can rapidly change by adding new components on top of existing regulators. PMID:23717455

  19. Phylogenetic distribution and evolutionary dynamics of the sex determination genes doublesex and transformer in insects.

    Science.gov (United States)

    Geuverink, E; Beukeboom, L W

    2014-01-01

    Sex determination in insects is characterized by a gene cascade that is conserved at the bottom but contains diverse primary signals at the top. The bottom master switch gene doublesex is found in all insects. Its upstream regulator transformer is present in the orders Hymenoptera, Coleoptera and Diptera, but has thus far not been found in Lepidoptera and in the basal lineages of Diptera. transformer is presumed to be ancestral to the holometabolous insects based on its shared domains and conserved features of autoregulation and sex-specific splicing. We interpret that its absence in basal lineages of Diptera and its order-specific conserved domains indicate multiple independent losses or recruitments into the sex determination cascade. Duplications of transformer are found in derived families within the Hymenoptera, characterized by their complementary sex determination mechanism. As duplications are not found in any other insect order, they appear linked to the haplodiploid reproduction of the Hymenoptera. Further phylogenetic analyses combined with functional studies are needed to understand the evolutionary history of the transformer gene among insects. © 2013 S. Karger AG, Basel.

  20. The evolution of sex ratios and sex-determining systems

    NARCIS (Netherlands)

    Uller, Tobias; Pen, Ido; Wapstra, Erik; Beukeboom, Leo W.; Komdeur, Jan

    Sex determination is a fundamental process governed by diverse mechanisms. Sex ratio selection is commonly implicated in the evolution of sex-determining systems, although formal models are rare. Here, we argue that, although sex ratio selection can induce shifts in sex determination, genomic

  1. Hybrid incompatibilities are affected by dominance and dosage in the haplodiploid wasp Nasonia

    Science.gov (United States)

    Beukeboom, Leo W.; Koevoets, Tosca; Morales, Hernán E.; Ferber, Steven; van de Zande, Louis

    2015-01-01

    Study of genome incompatibilities in species hybrids is important for understanding the genetic basis of reproductive isolation and speciation. According to Haldane's rule hybridization affects the heterogametic sex more than the homogametic sex. Several theories have been proposed that attribute asymmetry in hybridization effects to either phenotype (sex) or genotype (heterogamety). Here we investigate the genetic basis of hybrid genome incompatibility in the haplodiploid wasp Nasonia using the powerful features of haploid males and sex reversal. We separately investigate the effects of heterozygosity (ploidy level) and sex by generating sex reversed diploid hybrid males and comparing them to genotypically similar haploid hybrid males and diploid hybrid females. Hybrid effects of sterility were more pronounced than of inviability, and were particularly strong in haploid males, but weak to absent in diploid males and females, indicating a strong ploidy level but no sex specific effect. Molecular markers identified a number of genomic regions associated with hybrid inviability in haploid males that disappeared under diploidy in both hybrid males and females. Hybrid inviability was rescued by dominance effects at some genomic regions, but aggravated or alleviated by dosage effects at other regions, consistent with cytonuclear incompatibilities. Dosage effects underlying Bateson–Dobzhansky–Muller (BDM) incompatibilities need more consideration in explaining Haldane's rule in diploid systems. PMID:25926847

  2. Apomictic parthenogenesis in a parasitoid wasp Meteorus pulchricornis, uncommon in the haplodiploid order Hymenoptera.

    Science.gov (United States)

    Tsutsui, Y; Maeto, K; Hamaguchi, K; Isaki, Y; Takami, Y; Naito, T; Miura, K

    2014-06-01

    Although apomixis is the most common form of parthenogenesis in diplodiploid arthropods, it is uncommon in the haplodiploid insect order Hymenoptera. We found a new type of spontaneous apomixis in the Hymenoptera, completely lacking meiosis and the expulsion of polar bodies in egg maturation division, on the thelytokous strain of a parasitoid wasp Meteorus pulchricornis (Wesmael) (Braconidae, Euphorinae) on pest lepidopteran larvae Spodoptera litura (Fabricius) (Noctuidae). The absence of the meiotic process was consistent with a non-segregation pattern in the offspring of heterozygous females, and no positive evidence was obtained for the induction of thelytoky by any bacterial symbionts. We discuss the conditions that enable the occurrence of such rare cases of apomictic thelytoky in the Hymenoptera, suggesting the significance of fixed heterosis caused by hybridization or polyploidization, symbiosis with bacterial agents, and occasional sex. Our finding will encourage further genetic studies on parasitoid wasps to use asexual lines more wisely for biological control.

  3. Sex determination in the Hymenoptera

    NARCIS (Netherlands)

    Heimpel, George E.; de Boer, Jetske G.

    2008-01-01

    The dominant and ancestral mode of sex determination in the Hymenoptera is arrhenotokous parthenogenesis, in which diploid females develop from fertilized eggs and haploid males develop from unfertilized eggs. We discuss recent progress in the understanding of the genetic and cytoplasmic mechanisms

  4. Genetic sex determination and extinction.

    Science.gov (United States)

    Hedrick, Philip W; Gadau, Jürgen; Page, Robert E

    2006-02-01

    Genetic factors can affect the probability of extinction either by increasing the effect of detrimental variants or by decreasing the potential for future adaptive responses. In a recent paper, Zayed and Packer demonstrate that low variation at a specific locus, the complementary sex determination (csd) locus in Hymenoptera (ants, bees and wasps), can result in a sharply increased probability of extinction. Their findings illustrate situations in which there is a feedback process between decreased genetic variation at the csd locus owing to genetic drift and decreased population growth, resulting in an extreme type of extinction vortex for these ecologically important organisms.

  5. SEX DETERMINATION FROM FEMORAL HEAD DIAMETERS IN ...

    African Journals Online (AJOL)

    hi-tech

    2000-03-01

    Mar 1, 2000 ... In medico-legal cases where sophisticated methods of sex determination is lacking, these ... scientific methods(3). Using the visual method ... between the sexes and the values of the right and left femoral head diameters.

  6. Sex selection and restricting abortion and sex determination.

    Science.gov (United States)

    Zilberberg, Julie

    2007-11-01

    Sex selection in India and China is fostered by a limiting social structure that disallows women from performing the roles that men perform, and relegates women to a lower status level. Individual parents and individual families benefit concretely from having a son born into the family, while society, and girls and women as a group, are harmed by the widespread practice of sex selection. Sex selection reinforces oppression of women and girls. Sex selection is best addressed by ameliorating the situations of women and girls, increasing their autonomy, and elevating their status in society. One might argue that restricting or prohibiting abortion, prohibiting sex selection, and prohibiting sex determination would eliminate sex selective abortion. But this decreases women's autonomy rather than increases it. Such practices will turn underground. Sex selective infanticide, and slower death by long term neglect, could increase. If abortion is restricted, the burden is placed on women seeking abortions to show that they have a legally acceptable or legitimate reason for a desired abortion, and this seriously limits women's autonomy. Instead of restricting abortion, banning sex selection, and sex determination, it is better to address the practice of sex selection by elevating the status of women and empowering women so that giving birth to a girl is a real and positive option, instead of a detriment to the parents and family as it is currently. But, if a ban on sex selective abortion or a ban on sex determination is indeed instituted, then wider social change promoting women's status in society should be instituted simultaneously.

  7. Inbreeding Depression and Purging in a Haplodiploid: Gender-Related Effects

    NARCIS (Netherlands)

    Tien, N.S.H.; Sabelis, M.W.; Egas, M.

    2015-01-01

    Compared with diploid species, haplodiploids suffer less inbreeding depression because male haploidy imposes purifying selection on recessive deleterious alleles. However, alleles of genes only expressed in the diploid females are protected in heterozygous individuals. This leads to the prediction

  8. Microbial manipulation of host sex determination

    NARCIS (Netherlands)

    Beukeboom, Leo W.

    A recent study in the lepidopteran Ostrinia scapulalis shows that endosymbionts can actively manipulate the sex determination mechanism of their host. Wolbachia bacteria alter the sex-specific splicing of the doublesex master switch gene. In ZZ males of this female heterogametic system, the female

  9. Occupational Segregation by Sex: Determinants and Changes.

    Science.gov (United States)

    Beller, Andrea H.

    1982-01-01

    This study found that occupational sex segregation began to diminish during the 1970s, in conjunction with enforcement of the equal employment opportunity laws against sex discrimination in employment. The success of these laws suggests that discrimination was originally a determinant of occupational segregation. (Author/SK)

  10. Sex determination: insights from the silkworm

    Indian Academy of Sciences (India)

    2010-09-06

    determination pathway that controls most sex-specific phenotypes, is a .... Sports and Culture, Government of Japan, grant-in-aid for Young. Scientists ... Berghammer A. J., Klingler M. and Wimmer E. A. 1999 A universal marker for ...

  11. Sex determination: ways to evolve a hermaphrodite.

    OpenAIRE

    Braendle , Christian; Félix , Marie-Anne

    2006-01-01

    Most species of the nematode genus Caenorhabditis reproduce through males and females; C. elegans and C. briggsae, however, produce self-fertile hermaphrodites instead of females. These transitions to hermaphroditism evolved convergently through distinct modifications of germline sex determination mechanisms.

  12. Sex determination in mythology and history.

    Science.gov (United States)

    Mittwoch, Ursula

    2005-02-01

    The history of ideas on how the sexes became divided spans at least three thousand years. The biblical account of the origin of Eve, and the opinions of the philosophers of classical Greece, have unexpected bearings on present-day ideas. The scientific study of sex determination can be said to have begun in the 17th century with the discovery of spermatozoa, but the origin and function of the "spermatic animalcules" eluded investigators until 1841. The mammalian egg was discovered in 1827, and in the last quarter of the century fertilization was observed. The view current at that time, that sex determination was under environmental control, gave way to the idea of chromosomal determination in the first quarter of the 20th century. The study of human and other mammalian chromosomes during the third quarter of the century, and the discovery of sex-chromosome abnormalities, emphasized the importance of the Y chromosome for male sex determination. The last quarter of the century witnessed a hunt for the "testis-determining" gene, thought to be responsible for the differentiation of Sertoli cells, and culminating in the isolation of SRY (Sry in the mouse). However, an increasing number of additional genes and growth factors were found to be required for the establishment of male sex. During the same period evidence emerged that male development was accompanied by enhanced growth, both of gonads and whole embryos. An unexpected finding was the demonstration of temperature-dependent sex determination in reptiles. With the advent of the 21st century, it was shown that Sry induces cell proliferation in fetal mouse gonads, and it has been suggested that male sex differentiation in mammals requires a higher metabolic rate. These insights could lead to a better understanding and improved treatment of abnormalities of sexual development.

  13. Determination of sex by armbone dimensions.

    Science.gov (United States)

    Aye, Victor Omakoji

    2010-06-15

    Sex determination is a vital part of the medico-legal system but can be difficult in cases where the body is damaged. The purpose of this study was to develop a technique for sex determination from three arm-bone dimensions (wrist circumference, arm length and arm span). This knowledge can be applied in cases of mass disaster, homicide and events such as sports. Data were collected for 95 Nigerian male students and 90 Nigerian female students using physical anthropometry. Discriminant function presented the wrist dimension as the dominant contributor in this study. Combination equations for both the wrist and arm-span dimensions correctly classified sex (male/female) with an accuracy rate of 84.9%. On cross-validation, sex was also established with the same 84.9% accuracy rate. Sex determination was higher in males. Sexual dimorphism was established in this study, although the wrist circumference was more distinct than arm span; a combination of both generated sex with an accuracy prediction rate of 84.9%. (c) 2010 Elsevier Ireland Ltd. All rights reserved.

  14. Longevity enhances selection of environmental sex determination.

    Science.gov (United States)

    Bull, J J; Bulmer, M G

    1989-12-01

    Environmental sex determination (ESD) is a mechanism in which an individual develops as male or female largely in response to some environmental effect experienced early in life. Its forms range from sex determination by egg incubation temperature in reptiles to sex determination of photoperiod in amphipods. Previous theoretical work as suggested that ESD is favored by natural selection if the fitness consequences of the early environmental experience differ for males and females, so that an individual benefits by being male under some conditions and female under others. A drawback of ESD is that it enables climatic changes to influence the population sex ratio, and such fluctuations select against ESD. This study employed numerical analyses to investigate the balance between these two opposing forces. The negative impact of climatic fluctuations appears to depend greatly on species longevity: substantial between-year fluctuations are of little consequence in selecting against ESD in long-lived species because annual sex ratio fluctuations tend to cancel and thus alter the total population sex ratio only slightly. Thus, if a species is sufficiently long-lived, extreme ESD can be maintained despite only a weak advantage. This result offers one explanation for the failure to demonstrate an advantage for the extreme forms of ESD observed in reptiles.

  15. How is sex determined in insects?

    Indian Academy of Sciences (India)

    gan's student Calvin Bridges formulated his classic balance theory of sex determination in ... affect not only specific traits but also the entire sexual fate of an individual. ... the decision whether to become male or female is conveyed very early in ...

  16. The accuracy of 2D ultrasound prenatal sex determination ...

    African Journals Online (AJOL)

    Most of the women were happy even when the sex differed from that which they desired. Conclusion: Prenatal sonographic sex determination has a high sensitivity index. Consequently we advocate its use prior to more invasive sex tests. Keywords: Accuracy, gender determination, prenatal gender, prenatal sex, sex ...

  17. A Review of Sex Determining Mechanisms in Geckos (Gekkota: Squamata)

    OpenAIRE

    Gamble, T.

    2010-01-01

    Geckos are a species-rich clade of reptiles possessing diverse sex determining mechanisms. Some species possess genetic sex determination, with both male and female heterogamety, while other species have temperature-dependent sex determination. I compiled information from the literature on the taxonomic distribution of these sex determining mechanisms in geckos. Using phylogenetic data from the literature, I reconstructed the minimum number of transitions among these sex determining mechanism...

  18. Sex Determination by Morphometry of Lips

    Directory of Open Access Journals (Sweden)

    B. Senthil Kumar

    2018-04-01

    Full Text Available Background: Facial anthropometric parameters are affected by various factors including age, sex, ethnicity, socioeconomic status, environment and region. The lips become thinner as age increases and the wet line moves caudally, in addition oral commissure begins to downturn. Aim and Objectives: The purpose of this study was to create a baseline data in determining the sex of the people from India and Malaysia depending on morphometry of lips. Materials and Methods:Atotal of 100 Malaysians and 100 South Indians were enrolled for the study. Various morphometric measurements of lips were taken using Vernier caliper. The data were analyzed by one way ANOVAto find out the significance among the sex and population. Results: All the measurements of upper and lower lips were higher in males as compared to females and thus sexual dimorphism exists. Mouth width and height were found to be more in Indian males followed by Malaysian males whereas in females it's vice versa. Vermilion upper lip occupied less than half of total upper lip height, whereas vermilion lower lip occupied more than half of total lower lip height in both the population. Indian males and females differed significantly in lip parameters from those of Malaysian males and females. Conclusion: It can be concluded from the study that same standards cannot be used on each other's populations for identification and cosmetic surgery. The study highlights the applied significance of observations to forensic medicine namely, personal identification, racial and sex dimorphic criteria of identification.

  19. Sex ratio variation and sex determination in Urtica dioica

    NARCIS (Netherlands)

    Glawe, Grit Anja

    2006-01-01

    This thesis will first document on variation in progeny sex ratios among individual female plants of Urtica dioica at our field site in Meijendel (Chapter 2). Next, we show that there is also considerable sex ratio variation among male and female flowering shoots in 26 natural populations studied

  20. Sex differences in adolescent depression: do sex hormones determine vulnerability?

    NARCIS (Netherlands)

    Naninck, E.F.G.; Lucassen, P.J.; Bakker, J.

    2011-01-01

    Depression is one of the most common, costly and severe psychopathologies worldwide. Its incidence, however, differs significantly between the sexes, and depression rates in women are twice those of men. Interestingly, this sex difference emerges during adolescence. Although the adolescent period is

  1. Guardian small RNAs and sex determination.

    Science.gov (United States)

    Katsuma, Susumu; Kawamoto, Munetaka; Kiuchi, Takashi

    2014-01-01

    The W chromosome of the silkworm Bombyx mori has been known to determine femaleness for more than 80 years. However, the feminizing gene has not been molecularly identified, because the B. mori W chromosome is almost fully occupied by a large number of transposable elements. The W chromosome-derived feminizing factor of B. mori was recently shown to be a female-specific PIWI-interacting RNA (piRNA). piRNAs are small RNAs that potentially repress invading "non-self" elements (e.g., transposons and virus-like elements) by associating with PIWI proteins. Our results revealed that female-specific piRNA precursors, which we named Fem, are transcribed from the sex-determining region of the W chromosome at the early embryonic stage and are processed into a single mature piRNA (Fem piRNA). Fem piRNA forms a complex with Siwi (silkworm Piwi), which cleaves a protein-coding mRNA transcribed from the Z chromosome. RNA interference of this Z-linked gene, which we named Masc, revealed that this gene encodes a protein required for masculinization and dosage compensation. Fem and Masc both participate in the ping-pong cycle of the piRNA amplification loop by associating with the 2 B. mori PIWI proteins Siwi and BmAgo3 (silkworm Ago3), respectively, indicating that the piRNA-mediated interaction between the 2 sex chromosomes is the primary signal for the B. mori sex determination cascade. Fem is a non-transposable repetitive sequence on the W chromosome, whereas Masc is a single-copy protein-coding gene. It is of great interest how the piRNA system recognizes "self "Masc mRNA as "non-self" RNA.

  2. The sex and sex determination in Pyropia haitanensis (Bangiales, Rhodophyta).

    Science.gov (United States)

    Zhang, Yuan; Yan, Xing-hong; Aruga, Yusho

    2013-01-01

    Pyropia haitanensis has a biphasic life cycle with macroscopic gametophytic blade (n) and microscopic filamentous conchocelis (2n) phase. Its gametophytic blades have long been believed to be mainly dioecious. However, when crossing the red mutant (R, ♀) with the wild type (W, ♂), the parental colors were segregated in F1 blades, of which 96.1% were linearly sectored with 2-4 color sectors. When color sectors were excised from the color-sectored blades and cultured singly, 99.7% of the color sectors appeared to be unisexual with an equal sex ratio. Although the sex of color sector did not genetically link with its color, the boundaries of both sex and color sectors coincided precisely. About 87.9% of the examined color-sectored blades were monoecious and the percentage increased with the number of color sectors of a blade. The gametophytic blades from each conchocelis strain produced by parthenogenesis of the excised color sectors were unisexual and unicolor, showing the same sex and color as their original sectors. These results indicate that most of the sexually reproduced Py. haitanensis blades are monoecious, and their sex is controlled by segregation of a pair of alleles during meiosis of conchospore, forming a sex-sectored tetrad. During the subsequent development of blades, one or two lower cell(s) of the tetrad contribute mainly to rhizoid formation, and rarely show their sexual phenotype, leading to reduced frequency of full sex phenotype of the meiotic blades. Moreover, the aberrant segregations of sex genes or color genes in a few of F1 blades were probably due to gene conversions, but there was no sex transfer in Py. haitanensis.

  3. A Review of Sex Determining Mechanisms in Geckos (Gekkota: Squamata)

    Science.gov (United States)

    Gamble, T.

    2010-01-01

    Geckos are a species-rich clade of reptiles possessing diverse sex determining mechanisms. Some species possess genetic sex determination, with both male and female heterogamety, while other species have temperature-dependent sex determination. I compiled information from the literature on the taxonomic distribution of these sex determining mechanisms in geckos. Using phylogenetic data from the literature, I reconstructed the minimum number of transitions among these sex determining mechanisms with parsimony-based ancestral state reconstruction. While only a small number of gecko species have been characterized, numerous changes among sex determining mechanisms were inferred. This diversity, coupled with the high frequency of transitions, makes geckos excellent candidates as a model clade for the study of vertebrate sex determination and evolution. PMID:20234154

  4. [Elucidation of key genes in sex determination in genetics teaching].

    Science.gov (United States)

    Li, Meng; He, Zhumei

    2014-06-01

    Sex is an important and complex feature of organisms, which is controlled by the genetic and environmental factors. The genetic factors, i.e., genes, are vital in sex determination. However, not all the related genes play the same roles, and some key genes play a vital role in the sex determination and differentiation. With the development of the modern genetics, a great progress on the key genes has been made in sex determination. In this review, we summarize the mechanism of sex determination and the strategy of how to study the key genes in sex determination. It will help us to understand the mechanism of sex determination better in the teaching of genetics.

  5. Conflict over condition-dependent sex allocation can lead to mixed sex-determination systems

    NARCIS (Netherlands)

    Kuijper, Bram; Pen, Ido

    Theory suggests that genetic conflicts drive turnovers between sex-determining mechanisms, yet these studies only apply to cases where sex allocation is independent of environment or condition. Here, we model parent-offspring conflict in the presence of condition-dependent sex allocation, where the

  6. Sex ratio selection and multi-factorial sex determination in the housefly : A dynamic model

    NARCIS (Netherlands)

    Kozielska, M.A.; Pen, I.R.; Beukeboom, L.W.; Weissing, F.J.

    Sex determining (SD) mechanisms are highly variable between different taxonomic groups and appear to change relatively quickly during evolution. Sex ratio selection could be a dominant force causing such changes. We investigate theoretically the effect of sex ratio selection on the dynamics of a

  7. Conflict over condition-dependent sex allocation can lead to mixed sex-determination systems

    NARCIS (Netherlands)

    Kuijper, Bram; Pen, Ido

    2014-01-01

    Theory suggests that genetic conflicts drive turnovers between sex-determining mechanisms, yet these studies only apply to cases where sex allocation is independent of environment or condition. Here, we model parent-offspring conflict in the presence of condition-dependent sex allocation, where the

  8. Sex Determination: Why So Many Ways of Doing It?

    Science.gov (United States)

    Bachtrog, Doris; Mank, Judith E.; Peichel, Catherine L.; Kirkpatrick, Mark; Otto, Sarah P.; Ashman, Tia-Lynn; Hahn, Matthew W.; Kitano, Jun; Mayrose, Itay; Ming, Ray; Perrin, Nicolas; Ross, Laura; Valenzuela, Nicole; Vamosi, Jana C.

    2014-01-01

    Sexual reproduction is an ancient feature of life on earth, and the familiar X and Y chromosomes in humans and other model species have led to the impression that sex determination mechanisms are old and conserved. In fact, males and females are determined by diverse mechanisms that evolve rapidly in many taxa. Yet this diversity in primary sex-determining signals is coupled with conserved molecular pathways that trigger male or female development. Conflicting selection on different parts of the genome and on the two sexes may drive many of these transitions, but few systems with rapid turnover of sex determination mechanisms have been rigorously studied. Here we survey our current understanding of how and why sex determination evolves in animals and plants and identify important gaps in our knowledge that present exciting research opportunities to characterize the evolutionary forces and molecular pathways underlying the evolution of sex determination. PMID:24983465

  9. Determining sex ratios of turtle hatchlings

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Previous status assessments of marine turtles have assumed that the natural sex ratio of a marine turtle population is 1:1 (e.g. Conant et al. 2009). However, this...

  10. Sex-determination systems and their evolution: Mammals

    International Nuclear Information System (INIS)

    Colorado Garzon, Fredy A; Matta Camacho, Nubia E; Sanchez, Antonio

    2012-01-01

    Sex-determination methods are very diverse as they have become an enduring research field, understanding the causes of gonadal development and elucidating the main factors involved in sex-determination of offspring required relating information from far-ranging areas such as cytology, embryology, morphology, molecular biology and even ecology and evolution. This article presents an overview of sex-determination in placental mammals, encompassing several levels of biological organization. The importance of the underlying molecular tools in the context of sex-determination assays and their implications in conservation genetics is also discussed.

  11. Transitions between sex-determining systems in reptiles and amphibians.

    Science.gov (United States)

    Sarre, Stephen D; Ezaz, Tariq; Georges, Arthur

    2011-01-01

    Important technological advances in genomics are driving a new understanding of the evolution of sex determination in vertebrates. In particular, comparative chromosome mapping in reptiles has shown an intriguing distribution of homology in sex chromosomes across reptile groups. When this new understanding is combined with the widespread distribution of genetic and temperature-dependent sex-determination mechanisms among reptiles, it is apparent that transitions between modes have occurred many times, as they have for amphibians (particularly between male and female heterogamety). It is also likely that thermosensitivity in sex determination is a key factor in those transitions in reptiles, and possibly in amphibians too. New models of sex determination involving temperature thresholds are providing the framework for the investigation of transitions and making possible key predictions about the homologies and sex-determination patterns expected among taxa in these groups. Molecular cytogenetics and other genomic approaches are essential to providing the fundamental material necessary to make advances in this field.

  12. Personal identification and sex determination using cheiloscopy

    Directory of Open Access Journals (Sweden)

    Ravindra Naik Gugulothu

    2015-01-01

    Full Text Available Introduction: Identification of an individual is a prerequisite for certification of death and for personal, social, and legal reasons. The study of lip prints (cheiloscopy was thought of as a method of identification of a person. It is safe to assume that cheiloscopy, in its present stage of development, has become a means of criminal identification dealing with lip prints. Aims and Objectives: To evaluate the lip prints of different individuals in various parts of the lip, to find out the incidence of any particular pattern in relation to specific gender, to ascertain the authenticity of lip prints as a tool for identification of an individual and establish its evidentiary value. Materials and Methods: The study was conducted on 500 subjects, which included 250 males (4 twins and 250 females, in the age group of 18-30 years. After application of lipstick evenly, the lip print of each subject was obtained on a simple bond paper. The lip prints of each individual were scanned using an image scanner set at a resolution of 600 dpi for better interpretation. Results: We had correctly matched the gender of 487 individuals out of 500 samples taken. We also found that no lip prints were similar among the 500 subjects and even in twins. Interpretation and Conclusion: Along with other traditional methods, cheiloscopy can also serve as a very important tool in the identification of a person based on the characteristic arrangement of lines and grooves appearing on the red portion of the lips. It can be used for sex determination and personal identification for forensic purposes.

  13. Sex determination: ciliates' self-censorship.

    Science.gov (United States)

    Bloomfield, Gareth

    2014-07-07

    Differentiation involves the expression of certain latent cellular characteristics and the repression of others. A new study has revealed how Paramecium uses short RNAs to delete information from the somatic genome of one of its two sexes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Sex determination of baleen whale artefacts

    DEFF Research Database (Denmark)

    Sinding, Mikkel Holger Strander; Tervo, Outi M.; Grønnow, Bjarne

    2016-01-01

    to 4500 years old bowhead whale samples, and for comparison on dilution series from modern bowhead whales of known sex. DNA sequencing of PCR products obtained from the ancient material confirmed a higher proportion of successful PCR amplifications of the X homologue over the Y homologue. This potentially...

  15. Sex Determination from Fingerprint Ridge Density | Gungadin ...

    African Journals Online (AJOL)

    This study was conducted with an aim to establish a relationship between sex and fingerprint ridge density. The fingerprints were taken from 500 subjects (250 males and 250 females) in the age group of 18-60 years. After taking fingerprints, the ridges were counted in the upper portion of the radial border of each print for all ...

  16. Climate-driven population divergence in sex-determining systems

    NARCIS (Netherlands)

    Pen, Ido; Uller, Tobias; Feldmeyer, Barbara; Harts, Anna; While, Geoffrey M.; Wapstra, Erik

    2010-01-01

    Sex determination is a fundamental biological process, yet its mechanisms are remarkably diverse(1,2). In vertebrates, sex can be determined by inherited genetic factors or by the temperature experienced during embryonic development(2,3). However, the evolutionary causes of this diversity remain

  17. Genotypic sex determination enabled adaptive radiations of extinct marine reptiles.

    Science.gov (United States)

    Organ, Chris L; Janes, Daniel E; Meade, Andrew; Pagel, Mark

    2009-09-17

    Adaptive radiations often follow the evolution of key traits, such as the origin of the amniotic egg and the subsequent radiation of terrestrial vertebrates. The mechanism by which a species determines the sex of its offspring has been linked to critical ecological and life-history traits but not to major adaptive radiations, in part because sex-determining mechanisms do not fossilize. Here we establish a previously unknown coevolutionary relationship in 94 amniote species between sex-determining mechanism and whether a species bears live young or lays eggs. We use that relationship to predict the sex-determining mechanism in three independent lineages of extinct Mesozoic marine reptiles (mosasaurs, sauropterygians and ichthyosaurs), each of which is known from fossils to have evolved live birth. Our results indicate that each lineage evolved genotypic sex determination before acquiring live birth. This enabled their pelagic radiations, where the relatively stable temperatures of the open ocean constrain temperature-dependent sex determination in amniote species. Freed from the need to move and nest on land, extreme physical adaptations to a pelagic lifestyle evolved in each group, such as the fluked tails, dorsal fins and wing-shaped limbs of ichthyosaurs. With the inclusion of ichthyosaurs, mosasaurs and sauropterygians, genotypic sex determination is present in all known fully pelagic amniote groups (sea snakes, sirenians and cetaceans), suggesting that this mode of sex determination and the subsequent evolution of live birth are key traits required for marine adaptive radiations in amniote lineages.

  18. Insect sex determination : It all evolves around transformer

    NARCIS (Netherlands)

    Verhulst, Eveline C.; van de Zande, Louis; Beukeboom, Leo W.

    Insects exhibit a variety of sex determining mechanisms including male or female heterogamety and haplodiploidy. The primary signal that starts sex determination is processed by a cascade of genes ending with the conserved switch doublesex that controls sexual differentiation. Transformer is the

  19. Insect sex determination: it all evolves around transformer.

    Science.gov (United States)

    Verhulst, Eveline C; van de Zande, Louis; Beukeboom, Leo W

    2010-08-01

    Insects exhibit a variety of sex determining mechanisms including male or female heterogamety and haplodiploidy. The primary signal that starts sex determination is processed by a cascade of genes ending with the conserved switch doublesex that controls sexual differentiation. Transformer is the doublesex splicing regulator and has been found in all examined insects, indicating its ancestral function as a sex-determining gene. Despite this conserved function, the variation in transformer nucleotide sequence, amino acid composition and protein structure can accommodate a multitude of upstream sex determining signals. Transformer regulation of doublesex and its taxonomic distribution indicate that the doublesex-transformer axis is conserved among all insects and that transformer is the key gene around which variation in sex determining mechanisms has evolved.

  20. Using technology, choosing sex. The campaign against sex determination and the question of choice.

    Science.gov (United States)

    1992-01-01

    Women's groups and people's science and health groups formed the Forum Against Sex Determination and Sex Pre-Selection in November 1985 in Bombay, India, to prevent sex determination and sex preselection tests. The Forum considered sex determination and sex preselection to be an abuse of science and technology against people, especially women. Between 1901 and 1991, the sex ratio fell from 972 females/1000 males to 929/1000. The Forum saw the issue of sex determination and sex preselection as a link to oppression of and discrimination against females in all sectors of society. It also believed this to be a human rights issue. The Forum lobbied for a law regulating diagnostic techniques without banning them, since determining chromosomal abnormalities is important. The State of Maharashtra passed such a law in June 1988. It had some provisions which were counter-productive, however. For example, women undergoing a sex determination test must pay a fine of Rs 5 if found guilty of planning to terminate a pregnancy of a female fetus. Yet, neither the husband nor parents-in-law are liable, even though they often pressure women to undergo sex determination tests. The Forum's efforts and enactment of the law in Maharashtra have prompted other state governments and the central government to propose similar legislation. These state governments include Goa, Gujarat, and Orissa. The central government has met with organizations and individuals lobbying against misuse of diagnostic tests to obtain their counsel. The Forum does not feel comfortable with state control, however, since it tends to consider government to be against the people. Yet, the Forum did want the state to protect women's interests. It has raised important questions about technology, particularly concerning criteria to determine desirable and appropriate technologies.

  1. Complementary sex determination in the parasitic wasp Diachasmimorpha longicaudata.

    Directory of Open Access Journals (Sweden)

    Leonela Carabajal Paladino

    Full Text Available We studied the sex determination in Diachasmimorpha longicaudata, a parasitoid braconid wasp widely used as biological control agent of fruit pest tephritid flies. We tested the complementary sex determination hypothesis (CSD known in at least 60 species of Hymenoptera. According to CSD, male or female development depends on the allelic composition of one sex locus (single-locus CSD or multiple sex loci (multiple-locus CSD. Hemizygote individuals are normal haploid males, and heterozygotes for at least one sex locus are normal diploid females, but homozygotes for all the sex loci are diploid males. In order to force the occurrence of diploid males in D. longicaudata, we established highly inbred lines and examined their offspring using chromosome counting, flow cytometry, and sex ratio analysis. We found that when mother-son crosses were studied, this wasp produced about 20% of diploid males out of the total male progeny. Our results suggest that this parasitoid may represent the second genus with multiple-locus CSD in Hymenoptera. Knowledge about the sex determination system in D. longicaudata is relevant for the improvement of mass rearing protocols of this species. This information also provides the necessary background for further investigations on the underlying molecular mechanisms of sex determination in this species, and a better insight into the evolution of this pathway in Hymenoptera in particular and insects in general.

  2. Vertebrate sex-determining genes play musical chairs.

    Science.gov (United States)

    Pan, Qiaowei; Anderson, Jennifer; Bertho, Sylvain; Herpin, Amaury; Wilson, Catherine; Postlethwait, John H; Schartl, Manfred; Guiguen, Yann

    2016-01-01

    Sexual reproduction is one of the most highly conserved processes in evolution. However, the genetic and cellular mechanisms making the decision of whether the undifferentiated gonad of animal embryos develops either towards male or female are manifold and quite diverse. In vertebrates, sex-determining mechanisms range from environmental to simple or complex genetic mechanisms and different mechanisms have evolved repeatedly and independently. In species with simple genetic sex-determination, master sex-determining genes lying on sex chromosomes drive the gonadal differentiation process by switching on a developmental program, which ultimately leads to testicular or ovarian differentiation. So far, very few sex-determining genes have been identified in vertebrates and apart from mammals and birds, these genes are apparently not conserved over a larger number of related orders, families, genera, or even species. To fill this knowledge gap and to better explore genetic sex-determination, we propose a strategy (RAD-Sex) that makes use of next-generation sequencing technology to identify genetic markers that define sex-specific segments of the male or female genome. Copyright © 2016 Académie des sciences. All rights reserved.

  3. Some progress in sexual reproduction and sex determination of ...

    African Journals Online (AJOL)

    As a result of this, elucidating the basic physiological mechanisms of algae becomes even more urgent. Of all the fields, sexual reproduction and sex determination are basic and essential aspects. In this review, we summarized the advances of sex in several typical algae which are of great economic importance and often ...

  4. Altering the sex determination pathway in Drosophila fat body modifies sex-specific stress responses.

    Science.gov (United States)

    Argue, Kathryn J; Neckameyer, Wendi S

    2014-07-01

    The stress response in Drosophila melanogaster reveals sex differences in behavior, similar to what has been observed in mammals. However, unlike mammals, the sex determination pathway in Drosophila is well established, making this an ideal system to identify factors involved in the modulation of sex-specific responses to stress. In this study, we show that the Drosophila fat body, which has been shown to be important for energy homeostasis and sex determination, is a dynamic tissue that is altered in response to stress in a sex and time-dependent manner. We manipulated the sex determination pathway in the fat body via targeted expression of transformer and transformer-2 and analyzed these animals for changes in their response to stress. In the majority of cases, manipulation of transformer or transformer-2 was able to change the physiological output in response to starvation and oxidative stress to that of the opposite sex. Our data also uncover the possibility of additional downstream targets for transformer and transformer-2 that are separate from the sex determination pathway and can influence behavioral and physiological responses. Copyright © 2014 the American Physiological Society.

  5. Cretaceous park of sex determination: sex chromosomes are conserved across iguanas.

    Science.gov (United States)

    Rovatsos, Michail; Pokorná, Martina; Altmanová, Marie; Kratochvíl, Lukáš

    2014-03-01

    Many poikilothermic vertebrate lineages, especially among amphibians and fishes, possess a rapid turnover of sex chromosomes, while in endotherms there is a notable stability of sex chromosomes. Reptiles in general exhibit variability in sex-determining systems; as typical poikilotherms, they might be expected to have a rapid turnover of sex chromosomes. However, molecular data which would enable the testing of the stability of sex chromosomes are lacking in most lineages. Here, we provide molecular evidence that sex chromosomes are highly conserved across iguanas, one of the most species-rich clade of reptiles. We demonstrate that members of the New World families Iguanidae, Tropiduridae, Leiocephalidae, Phrynosomatidae, Dactyloidae and Crotaphytidae, as well as of the family Opluridae which is restricted to Madagascar, all share homologous sex chromosomes. As our sampling represents the majority of the phylogenetic diversity of iguanas, the origin of iguana sex chromosomes can be traced back in history to the basal splitting of this group which occurred during the Cretaceous period. Iguanas thus show a stability of sex chromosomes comparable to mammals and birds and represent the group with the oldest sex chromosomes currently known among amniotic poikilothermic vertebrates.

  6. Heritable Variation for Sex Ratio under Environmental Sex Determination in the Common Snapping Turtle (Chelydra Serpentina)

    Science.gov (United States)

    Janzen, F. J.

    1992-01-01

    The magnitude of quantitative genetic variation for primary sex ratio was measured in families extracted from a natural population of the common snapping turtle (Chelydra serpentina), which possesses temperature-dependent sex determination (TSD). Eggs were incubated at three temperatures that produced mixed sex ratios. This experimental design provided estimates of the heritability of sex ratio in multiple environments and a test of the hypothesis that genotype X environment (G X E) interactions may be maintaining genetic variation for sex ratio in this population of C. serpentina. Substantial quantitative genetic variation for primary sex ratio was detected in all experimental treatments. These results in conjunction with the occurrence of TSD in this species provide support for three critical assumptions of Fisher's theory for the microevolution of sex ratio. There were statistically significant effects of family and incubation temperature on sex ratio, but no significant interaction was observed. Estimates of the genetic correlations of sex ratio across environments were highly positive and essentially indistinguishable from +1. These latter two findings suggest that G X E interaction is not the mechanism maintaining genetic variation for sex ratio in this system. Finally, although substantial heritable variation exists for primary sex ratio of C. serpentina under constant temperatures, estimates of the effective heritability of primary sex ratio in nature are approximately an order of magnitude smaller. Small effective heritability and a long generation time in C. serpentina imply that evolution of sex ratios would be slow even in response to strong selection by, among other potential agents, any rapid and/or substantial shifts in local temperatures, including those produced by changes in the global climate. PMID:1592234

  7. Does the mechanism of sex determination constrain the potential for sex manipulation? A test in geckos with contrasting sex-determining systems

    Science.gov (United States)

    Kratochvíl, Lukáš; Kubička, Lukáš; Landová, Eva

    2008-03-01

    The concentration of yolk steroids was suggested to influence offspring gender in oviparous animals subject to both temperature-dependent sex determination (TSD) and genotypic sex determination (GSD). However, the proposed mechanisms of steroid effects are thought to differ between TSD and GSD: a direct effect of oestrogens on gonad feminisation in TSD species vs a differential induction of male-producing or female-producing gametes in GSD species. Geckos offer an ideal opportunity for testing these suggested mechanisms. Closely related gecko species differ in their modes of sex determination. They lay clutches of two synchronously formed eggs; both eggs share equal steroid levels. If identical hormonal composition and environment during vitellogenesis, gravidity and incubation determine the sex of the progeny, siblings should share the same gender in both TSD and GSD geckos. We found strong support for this prediction in a TSD gecko species. Among clutches that were incubated at the temperature that produced both sexes, there were no clutches with siblings of the opposite sex. On the other hand, about half of the clutches yielded siblings of the opposite sex in four GSD species. These results suggest that sex-determining systems constrain the ability of the female to produce single-sex siblings and, hence, it seems that the GSD mechanism constrains the opportunities for sex ratio manipulation in geckos via yolk steroid manipulation.

  8. How is sex determined in insects? An epilogue

    Indian Academy of Sciences (India)

    transcriptional factors, which bring about sexual dimorphism in adult flies. ... sex determination, in response to both internal and external selection forces. ... such as in the control of pests (e.g. C. capitata) and vectors of human diseases.

  9. Sex determination in Medfly: A molecular approach

    International Nuclear Information System (INIS)

    Saccone, G.; Pane, A.; Testa, G.; Santoro, M.; De Martino, G.; Di Paola, F.; Polito, L.C.; Louis, C.

    2000-01-01

    With the aim of developing new strategies of control to limit the damages inflicted on fruit crops by Ceratitis capitata (Wied.) (Medfly), a biotechnological approach is undertaken whereby female viability would be impaired or male viability would be improved following the introduction of specific genes into the genome of C. capitata. Only males will then be mass produced and released in the infested areas after sterilisation (Louis et al. 1987). Such conditional lethal or 'advantageous' genes could be expressed in transgenic flies either female-specifically or male-specifically by using cis regulative sequences obtained from previously isolated endogenous Ceratitis genes (Saccone et al. 1996, 1998). By using molecular strategies based on a subtractive technique, we have recently isolated male-specifically expressed genes in the Medfly. Furthermore, we present the current status of the research on the Ceratitis dsx gene, showing sex-specific alternative splicing as in Drosophila, and on the tra-inaZ strategy to induce in Drosophila flies female-specific conditional lethality

  10. Sex determination strategies in 2012: towards a common regulatory model?

    Science.gov (United States)

    2012-01-01

    Sex determination is a complicated process involving large-scale modifications in gene expression affecting virtually every tissue in the body. Although the evolutionary origin of sex remains controversial, there is little doubt that it has developed as a process of optimizing metabolic control, as well as developmental and reproductive functions within a given setting of limited resources and environmental pressure. Evidence from various model organisms supports the view that sex determination may occur as a result of direct environmental induction or genetic regulation. The first process has been well documented in reptiles and fish, while the second is the classic case for avian species and mammals. Both of the latter have developed a variety of sex-specific/sex-related genes, which ultimately form a complete chromosome pair (sex chromosomes/gonosomes). Interestingly, combinations of environmental and genetic mechanisms have been described among different classes of animals, thus rendering the possibility of a unidirectional continuous evolutionary process from the one type of mechanism to the other unlikely. On the other hand, common elements appear throughout the animal kingdom, with regard to a) conserved key genes and b) a central role of sex steroid control as a prerequisite for ultimately normal sex differentiation. Studies in invertebrates also indicate a role of epigenetic chromatin modification, particularly with regard to alternative splicing options. This review summarizes current evidence from research in this hot field and signifies the need for further study of both normal hormonal regulators of sexual phenotype and patterns of environmental disruption. PMID:22357269

  11. Sex determination mechanisms in the Calliphoridae (blow flies).

    Science.gov (United States)

    Scott, M J; Pimsler, M L; Tarone, A M

    2014-01-01

    The Calliphoridae or blow flies are a family of insects that occupy diverse habitats and perform important ecological roles, particularly the decomposition of animal remains. Some Calliphoridae species are also important in the forensic sciences, in agriculture (e.g. as livestock pests) and in medicine (e.g. maggot therapy). Calliphoridae provide striking examples in support of the hypothesis that sex determination regulatory gene hierarchies evolve in the reverse order, with the gene at the top being the most recently added. Unlike the model fly Drosophila melanogaster, where sex is determined by the number of X chromosomes, in the Australian sheep blow fly (Lucilia cuprina) sex is determined by a Y-linked male-determining gene (M). A different regulatory system appears to operate in the hairy maggot blow fly (Chrysomya rufifacies) where the maternal genotype determines sex. It is hypothesized that females heterozygous for a dominant female-determining factor (F/f) produce only female offspring and homozygous f/f females produce only sons. The bottom of the regulatory hierarchy appears to be the same in D. melanogaster and L. cuprina, with sex-specific splicing of doublesex transcripts being controlled by the female-specific Transformer (TRA) protein. We discuss a model that has been proposed for how tra transcripts are sex-specifically spliced in calliphorids, which is very different from D. melanogaster. © 2013 S. Karger AG, Basel.

  12. Sex determination using the Probabilistic Sex Diagnosis (DSP: Diagnose Sexuelle Probabiliste) tool in a virtual environment.

    Science.gov (United States)

    Chapman, Tara; Lefevre, Philippe; Semal, Patrick; Moiseev, Fedor; Sholukha, Victor; Louryan, Stéphane; Rooze, Marcel; Van Sint Jan, Serge

    2014-01-01

    The hip bone is one of the most reliable indicators of sex in the human body due to the fact it is the most dimorphic bone. Probabilistic Sex Diagnosis (DSP: Diagnose Sexuelle Probabiliste) developed by Murail et al., in 2005, is a sex determination method based on a worldwide hip bone metrical database. Sex is determined by comparing specific measurements taken from each specimen using sliding callipers and computing the probability of specimens being female or male. In forensic science it is sometimes not possible to sex a body due to corpse decay or injury. Skeletalization and dissection of a body is a laborious process and desecrates the body. There were two aims to this study. The first aim was to examine the accuracy of the DSP method in comparison with a current visual sexing method on sex determination. A further aim was to see if it was possible to virtually utilise the DSP method on both the hip bone and the pelvic girdle in order to utilise this method for forensic sciences. For the first part of the study, forty-nine dry hip bones of unknown sex were obtained from the Body Donation Programme of the Université Libre de Bruxelles (ULB). A comparison was made between DSP analysis and visual sexing on dry bone by two researchers. CT scans of bones were then analysed to obtain three-dimensional (3D) virtual models and the method of DSP was analysed virtually by importing the models into a customised software programme called lhpFusionBox which was developed at ULB. The software enables DSP distances to be measured via virtually-palpated bony landmarks. There was found to be 100% agreement of sex between the manual and virtual DSP method. The second part of the study aimed to further validate the method by analysing thirty-nine supplementary pelvic girdles of known sex blind. There was found to be a 100% accuracy rate further demonstrating that the virtual DSP method is robust. Statistically significant differences were found in the identification of sex

  13. Kin discrimination and sex ratios in a parasitoid wasp

    NARCIS (Netherlands)

    Reece, S.E.; Shuker, D.M.; Pen, I.R.; Duncan, A.B.; Choudhary, A.; Batchelor, C.M.; West, S.A.

    Sex ratio theory provides a clear and simple way to test if nonsocial haplodiploid wasps can discriminate between kin and nonkin. Specifically, if females can discriminate siblings from nonrelatives, then they are expected to produce a higher proportion of daughters if they mate with a sibling. This

  14. Rapid quantification and sex determination of forensic evidence materials.

    Science.gov (United States)

    Andréasson, Hanna; Allen, Marie

    2003-11-01

    DNA quantification of forensic evidence is very valuable for an optimal use of the available biological material. Moreover, sex determination is of great importance as additional information in criminal investigations as well as in identification of missing persons, no suspect cases, and ancient DNA studies. While routine forensic DNA analysis based on short tandem repeat markers includes a marker for sex determination, analysis of samples containing scarce amounts of DNA is often based on mitochondrial DNA, and sex determination is not performed. In order to allow quantification and simultaneous sex determination on minute amounts of DNA, an assay based on real-time PCR analysis of a marker within the human amelogenin gene has been developed. The sex determination is based on melting curve analysis, while an externally standardized kinetic analysis allows quantification of the nuclear DNA copy number in the sample. This real-time DNA quantification assay has proven to be highly sensitive, enabling quantification of single DNA copies. Although certain limitations were apparent, the system is a rapid, cost-effective, and flexible assay for analysis of forensic casework samples.

  15. Sex-specific determinants of fitness in a social mammal.

    Science.gov (United States)

    Lardy, Sophie; Allainé, Dominique; Bonenfant, Christophe; Cohas, Aurélie

    2015-11-01

    Sociality should evolve when the fitness benefits of group living outweigh the costs. Theoretical models predict an optimal group size maximizing individual fitness. However, beyond the number of individuals present in a group, the characteristics of these individuals, like their sex, are likely to affect the fitness payoffs of group living. Using 20 years of individually based data on a social mammal, the Alpine marmot (Marmota marmota), we tested for the occurrence of an optimal group size and composition, and for sex-specific effects of group characteristics on fitness. Based on lifetime data of 52 males and 39 females, our findings support the existence of an optimal group size maximizing male fitness and an optimal group composition maximizing fitness of males and females. Additionally, although group characteristics (i.e., size, composition and instability) affecting male and female fitness differed, fitness depended strongly on the number of same-sex subordinates within the social group in the two sexes. By comparing multiple measures of social group characteristics and of fitness in both sexes, we highlighted the sex-specific determinants of fitness in the two sexes and revealed the crucial role of intrasexual competition in shaping social group composition.

  16. Efficacy of cheiloscopy in determination of sex among South indians.

    Science.gov (United States)

    Kautilya D, Vijay; Bodkha, Pravir; Rajamohan, Naveen

    2013-10-01

    Human identification plays a vital role in any crime investigation. Along with the various other established methods, cheiloscopy also plays a key role in linking the criminal with the crime. The ability of a technique in differentiating the sex of a person in the field can help in screening a large number of suspects. This study evaluated the efficacy of cheiloscopy in determination of sex among South Indians. It also studied the pattern of dimorphism in the lips and lip prints of south Indians. Lip prints from 100 medical students (50 males and 50 females) were obtained and were analyzed, based on Tsuchihashi and Suzuki classification, to check for dimorphism. Lip dimensions were studied by using standard sliding calipers for dimorphism. The most common pattern of lip print among males was Type III as compared to Type I in females. The outer four portions of the lip showed statistically significant differences in males and females. Middle portion of the lip was statistically insignificant in sex determination, based on lip print patterns. Thickness of the lip was significantly larger in males as compared to that in females and this criterion could be used to establish a logistic regression for determination of sex of a person. Lips not only significantly differ among the males and females in the pattern of the lip print that they present, but they also differ in their size. These features can effectively be used to determine the sex of a person accurately.

  17. Sex determination in the Lesser Flamingo ( Phoenicopterus minor ...

    African Journals Online (AJOL)

    PCR amplification of the CHD-Z and CHD-W genes using DNA extracted from the blood samples was used to determine the sex of each bird. There were significant differences in mass and tarsus length among the three age groups, indicating that Lesser Flamingos continue to grow in skeletal size and mass between ...

  18. Sex and PRNP genotype determination in preimplantation caprine embryos.

    Science.gov (United States)

    Guignot, F; Perreau, C; Cavarroc, C; Touzé, J-L; Pougnard, J-L; Dupont, F; Beckers, J-F; Rémy, B; Babilliot, J-M; Bed'Hom, B; Lamorinière, J M; Mermillod, P; Baril, G

    2011-08-01

    The objective of this study was to test the accuracy of genotype diagnosis after whole amplification of DNA extracted from biopsies obtained by trimming goat embryos and to evaluate the viability of biopsied embryos after vitrification/warming and transfer. Whole genome amplification (WGA) was performed using Multiple Displacement Amplification (MDA). Sex and prion protein (PRNP) genotypes were determined. Sex diagnosis was carried out by PCR amplification of ZFX/ZFY and Y chromosome-specific sequences. Prion protein genotype determination was performed on codons 142, 154, 211, 222 and 240. Embryos were collected at day 7 after oestrus and biopsied either immediately after collection (blastocysts and expanded blastocysts) or after 24 h of in vitro culture (compacted morulae). Biopsied embryos were frozen by vitrification. Vitrified whole embryos were kept as control. DNA of biopsies was extracted and amplified using MDA. Sex diagnosis was efficient for 97.4% of biopsies and PRNP genotyping was determined in 78.7% of biopsies. After embryo transfer, no significant difference was observed in kidding rate between biopsied and vitrified control embryos, whereas embryo survival rate was different between biopsied and whole vitrified embryos (p = 0.032). At birth, 100% of diagnosed sex and 98.2% of predetermined codons were correct. Offspring PRNP profiles were in agreement with parental genotype. Whole genome amplification with MDA kit coupled with sex diagnosis and PRNP genotype predetermination are very accurate techniques to genotype goat embryos before transfer. These novel results allow us to plan selection of scrapie-resistant genotypes and kid sex before transfer of cryopreserved embryo. © 2010 Blackwell Verlag GmbH.

  19. Interactions of Socioeconomic Determinants, Offspring Sex Preference and Fertility Behavior

    Directory of Open Access Journals (Sweden)

    Paul M. Sharp

    2011-01-01

    Full Text Available Using path anaysis and the 5% PUMS data of the 1990 and 2000 censuses, this study examines 1 the correlation between Chinese-American sex preference for children and their fertility behavior, and 2 the interaction between the sex preference and its socioeconomic determinants. Of normative and non-normative factors investegated in this study, offspring sex preference is the greatest stimulus to Chinese fertility. Of socioeconomic variables, women’s educational attainment plays a primary role in depressing the impact of son preference in addition to their increasing stay in the host society. However, these two factors do not work on their husbands in the same way, demonstrating men’s inflexible attitudes toward gender roles in the family and in society. Son preference exerts positive impact on American-Chinese fertility and prevent from further decline. Yet, the influence has been diminishing since 1990 as observed in this study.

  20. Pulp tissue in sex determination: A fluorescent microscopic study

    Science.gov (United States)

    Nayar, Amit; Singh, Harkanwal Preet; Leekha, Swati

    2014-01-01

    Aims: To determine and compare the reliability of pulp tissue in determination of sex and to analyze whether caries have any effect on fluorescent body test. Materials and Methods: This study was carried on 50 maxillary and mandibular teeth (25 male teeth and 25 female teeth), which were indicated for extraction. The teeth are categorized into 5 groups, 10 each (5 from males and 5 from females) on the basis of caries progression. The pulp cells are stained with quinacrine hydrochloride and observed with fluorescent microscope for fluorescent body. Gender is determined by identification of Y chromosome fluorescence in dental pulp. Results: Fluorescent bodies were found to be more in sound teeth in males as the caries increase the mean percentage of fluorescent bodies observed decreases in males. We also observed the fluorescent spots in females, and the value of the spot increases in female as the caries progresses, thereby giving false positive results in females. Conclusion: Sex determination by fluorescent staining of the Y chromosome is a reliable technique in teeth with healthy pulps or caries with enamel or up to half way of dentin. Teeth with caries involving pulp cannot be used for sex determination. PMID:25125912

  1. Genetic architecture of sex determination in fish: Applications to sex ratio control in aquaculture

    Directory of Open Access Journals (Sweden)

    Paulino eMartínez

    2014-09-01

    Full Text Available Controlling the sex ratio is essential in finfish farming. A balanced sex ratio is usually good for broodstock management, since it enables to develop appropriate breeding schemes. However, in some species the production of monosex populations is desirable because the existence of sexual dimorphism, primarily in growth or first time of sexual maturation, but also in color or shape, can render one sex more valuable. The knowledge of the genetic architecture of sex determination (SD is convenient for controlling sex ratio and for the implementation of breeding programs. Unlike mammals and birds, which show highly conserved master genes that control a conserved genetic network responsible for gonad differentiation (GD, a huge diversity of SD mechanisms has been reported in fish. Despite theory predictions, more than one gene is in many cases involved in fish SD and genetic differences have been observed in the GD network. Environmental factors also play a relevant role and epigenetic mechanisms are becoming increasingly recognized for the establishment and maintenance of the GD pathways. Although major genetic factors are frequently involved in fish SD, these observations strongly suggest that SD in this group resembles a complex trait. Accordingly, the application of quantitative genetics combined with genomic tools is desirable to address its study and in fact, when applied, it has frequently demonstrated a multigene trait interacting with environmental factors in model and cultured fish species. This scenario has notable implications for aquaculture and, depending upon the species, from chromosome manipulation or environmental control techniques up to classical selection or marker assisted selection programs, are being applied. In this review, we selected four relevant species or fish groups to illustrate this diversity and hence the technologies that can be used by the industry for the control of sex ratio: turbot and European sea bass, two

  2. Recombination and its impact on the genome of the haplodiploid parasitoid wasp Nasonia.

    Directory of Open Access Journals (Sweden)

    Oliver Niehuis

    2010-01-01

    that the genomes of haplodiploid and of diploid higher eukaryotes do not differ systematically in their recombination rates and associated parameters.

  3. Sex Determination in Insects: a binary decision based on alternative splicing

    OpenAIRE

    Salz, Helen K.

    2011-01-01

    The gene regulatory networks that control sex determination vary between species. Despite these differences, comparative studies in insects have found that alternative splicing is reiteratively used in evolution to control expression of the key sex determining genes. Sex determination is best understood in Drosophila where activation of the RNA binding protein encoding gene Sex-lethal is the central female-determining event. Sex-lethal serves as a genetic switch because once activated it cont...

  4. The paternal-sex-ratio (PSR) chromosome in natural populations of Nasonia (Hymenoptera Chalcidoidea)

    NARCIS (Netherlands)

    Beukeboom, L.W.; Werren, J.H.

    2000-01-01

    Selfish genetic elements may be important in promoting evolutionary change. Paternal sex ratio (PSR) is a selfish B chromosome that causes all-male families in the haplodiploid parasitic wasp Nasonia vitripennis, by inducing paternal genome loss in fertilized eggs. The natural distribution and

  5. Gender/Sex as a Social Determinant of Cardiovascular Risk.

    Science.gov (United States)

    O'Neil, Adrienne; Scovelle, Anna J; Milner, Allison J; Kavanagh, Anne

    2018-02-20

    The social gradient for cardiovascular disease (CVD) onset and outcomes is well established. The American Heart Association's Social Determinants of Risk and Outcomes of Cardiovascular Disease Scientific Statement advocates looking beyond breakthroughs in biological science toward a social determinants approach that focuses on socioeconomic position, race and ethnicity, social support, culture and access to medical care, and residential environments to curb the burden of CVD going forward. Indeed, the benefits of this approach are likely to be far reaching, enhancing the positive effects of advances in CVD related to prevention and treatment while reducing health inequities that contribute to CVD onset and outcomes. It is disappointing that the role of gender has been largely neglected despite being a critical determinant of cardiovascular health. It is clear that trajectories and outcomes of CVD differ by biological sex, yet the tendency for sex and gender to be conflated has contributed to the idea that both are constant or fixed with little room for intervention. Rather, as distinct from biological sex, gender is socially produced. Overlaid on biological sex, gender is a broad term that shapes and interacts with one's cognition to guide norms, roles, behaviors, and social relations. It is a fluid construct that varies across time, place, and life stage. Gender can interact with biological sex and, indeed, other social determinants, such as ethnicity and socioeconomic position, to shape cardiovascular health from conception, through early life when health behaviors and risk factors are shaped, into adolescence and adulthood. This article will illustrate how gender shapes the early adoption of health behaviors in childhood, adolescence, and young adulthood by focusing on physical activity, drinking, and smoking behaviors (including the influence of role modeling). We will also discuss the role of gender in psychosocial stress with a focus on trauma from life

  6. Canine index – A tool for sex determination

    Directory of Open Access Journals (Sweden)

    Shankar M. Bakkannavar

    2015-12-01

    Full Text Available Teeth are most useful tools in victim identification in the living as well as the dead in the field of forensic investigations. Their ability to survive in situations like mass disasters makes them constructive devices. Many authors have measured crowns of teeth in both males and females and found certain variations. Canines, reported to survive in air crash and hurricane disasters, are perhaps the most stable teeth in the oral cavity because of the labiolingual thickness of the crown and the root anchorage in the alveolar process of jaws. Measurement of mesiodistal width of the mandibular canines and inter-canine distance of the mandible provides good evidence of sex identification due to dimorphism. This study was undertaken to evaluate the effectiveness of canine index (CI in the determination of sex.

  7. MORPHOMETRIC EVALUATION OF FORAMEN MAGNUM FOR SEX DETERMINATION IN A DOCUMENTED NORTH INDIAN SAMPLE

    OpenAIRE

    Jain; Alok Kumar; Pankaj

    2013-01-01

    ABSTRACT: Sex determination is used in anthropology, forensic medicine and medic o - legal cases. It is (1) remarked that “next to the pelvis, the skull is the most easily sexed portion of the skeleton”. It has been suggested (2 - 5) that the measurements of the foramen magnum are useful for determining the sex. There are two osteological techniques used to determine the sex of an individual; the first is visual assessment to evaluate the morphological sex tra...

  8. When daughters are unwanted. Sex determination tests in India.

    Science.gov (United States)

    Kishwar, M

    1995-01-01

    Amniocentesis and ultrasound have been used for detecting fetal abnormalities, but in India they have been used for sex determination, leading to the abortion of hundreds of thousands of female fetuses. As a result, by 1991 the sex ratio had declined to 929 females per 1000 males from 972 females per 1000 males in 1901. This amounts to a deficit of almost 30 million females in the whole population. The regional prevalence of sex preferences has spread horizontally and vertically in the south and the northeast, where the ratios used to be more favorable. A ban on such prenatal diagnosis was passed in several states, but it proved to be ineffective and unenforceable. The result was only that the fees charged soared. Finally, in August 1994 the Indian Parliament enacted the Prenatal Diagnostics Techniques Act that prohibited genetic counseling centers to perform such procedures unless strict criteria were observed (age over 35 years, two or more previous abortions, exposure to drugs, infections, and mental or physical retardation). However, the emergence of a police-doctor nexus is dangerous for the well-being of any society and could lead to criminalization of the medical profession. Some doctors also rationalize this practice as a means of controlling population, because the custom continues to have children until the desired number of sons are born. In low sex ratio regions seclusion, disinheritance of women from property, low female literacy, poor health, greater incidence of domestic violence, and low employment rates are typical. The aversion to female infants is a culturally conditioned choice which materializes in the pervasive dread of daughters. Women themselves perpetuate the dread because of their own misery, low status, abuse, and the burden of the dowry. The devaluation of women is rooted in history, particularly in the northwest where constant wars favored a martial society for males (with strict purdah for females), and in addition British colonialism

  9. Hybrid incompatibilities are affected by dominance and dosage in the haplodiploid wasp Nasonia

    NARCIS (Netherlands)

    Beukeboom, Leo W; Koevoets, Tosca; Morales, Hernán E; Ferber, Steven; van de Zande, Louis

    2015-01-01

    Study of genome incompatibilities in species hybrids is important for understanding the genetic basis of reproductive isolation and speciation. According to Haldane's rule hybridization affects the heterogametic sex more than the homogametic sex. Several theories have been proposed that attribute

  10. [Molecular mechanisms in sex determination: from gene regulation to pathology].

    Science.gov (United States)

    Ravel, C; Chantot-Bastaraud, S; Siffroi, J-P

    2004-01-01

    Testis determination is the complex process by which the bipotential gonad becomes a normal testis during embryo development. As a consequence, this process leads to sexual differentiation corresponding to the masculinization of both genital track and external genitalia. The whole phenomenon is under genetic control and is particularly driven by the presence of the Y chromosome and by the SRY gene, which acts as the key initiator of the early steps of testis determination. However, many other autosomal genes, present in both males and females, are expressed during testis formation in a gene activation pathway, which is far to be totally elucidated. All these genes act in a dosage-sensitive manner by which quantitative gene abnormalities, due to chromosomal deletions, duplications or mosaicism, may lead to testis determination failure and sex reversal.

  11. Species identification and sex determination of the genus Nepenthes (Nepenthaceae).

    Science.gov (United States)

    Mokkamul, Piya; Chaveerach, Arunrat; Sudmoon, Runglawan; Tanee, Tawatchai

    2007-02-15

    Nepenthes species are well known for their ornamentally attractive pitchers. The species diversity was randomly surveyed in some conservation areas of Thailand and three species were found, namely N. gracilis Korth., N. mirabilis Druce. and N. smilesii Hemsl. Young plants as unknown species from Chatuchak market were added in plant sampled set. Thirty two Inter Simple Sequence Repeat (ISSR) primers were screened and 13 successful primers were used to produce DNA banding patterns for constructing a dendrogram. The dendrogram is potentially power tool to identify unknown species from Chatuchak market, differentiate species population, population by geographical areas and sex determination. The geographical area of N. mirabilis was specified to Southern and Northeastern regions and finally, subdivided into exact areas according to province. Male and female plants of N. gracilis at Phu Wua Wildlife Sanctuary and N. mirabilis at Bung Khonglong non-hunting area were determined. Two unknown species from Chatuchak market were analyzed to be N. mirabilis with the genetic similarities (S) 77.2 to 84.7. Be more sex specific in all sample studied, 37 Random Amplified Polymorphic DNA (RAPD) primers were investigated. The result shows that only one RAPD primer show high resolution results at about 750 bp specific male-related marker.

  12. Maintenance of polygenic sex determination in a fluctuating environment: an individual-based model.

    Science.gov (United States)

    Bateman, A W; Anholt, B R

    2017-05-01

    R. A. Fisher predicted that individuals should invest equally in offspring of both sexes, and that the proportion of males and females produced (the primary sex ratio) should evolve towards 1:1 when unconstrained. For many species, sex determination is dependent on sex chromosomes, creating a strong tendency for balanced sex ratios, but in other cases, multiple autosomal genes interact to determine sex. In such cases, the maintenance of multiple sex-determining alleles at multiple loci and the consequent among-family variability in sex ratios presents a puzzle, as theory predicts that such systems should be unstable. Theory also predicts that environmental influences on sex can complicate outcomes of genetic sex determination, and that population structure may play a role. Tigriopus californicus, a copepod that lives in splash-pool metapopulations and exhibits polygenic and environment-dependent sex determination, presents a test case for relevant theory. We use this species as a model for parameterizing an individual-based simulation to investigate conditions that could maintain polygenic sex determination. We find that metapopulation structure can delay the degradation of polygenic sex determination and that periods of alternating frequency-dependent selection, imposed by seasonal fluctuations in environmental conditions, can maintain polygenic sex determination indefinitely. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  13. Comparative In silico Study of Sex-Determining Region Y (SRY) Protein Sequences Involved in Sex-Determining.

    Science.gov (United States)

    Vakili Azghandi, Masoume; Nasiri, Mohammadreza; Shamsa, Ali; Jalali, Mohsen; Shariati, Mohammad Mahdi

    2016-04-01

    The SRY gene (SRY) provides instructions for making a transcription factor called the sex-determining region Y protein. The sex-determining region Y protein causes a fetus to develop as a male. In this study, SRY of 15 spices included of human, chimpanzee, dog, pig, rat, cattle, buffalo, goat, sheep, horse, zebra, frog, urial, dolphin and killer whale were used for determine of bioinformatic differences. Nucleotide sequences of SRY were retrieved from the NCBI databank. Bioinformatic analysis of SRY is done by CLC Main Workbench version 5.5 and ClustalW (http:/www.ebi.ac.uk/clustalw/) and MEGA6 softwares. The multiple sequence alignment results indicated that SRY protein sequences from Orcinus orca (killer whale) and Tursiopsaduncus (dolphin) have least genetic distance of 0.33 in these 15 species and are 99.67% identical at the amino acid level. Homosapiens and Pantroglodytes (chimpanzee) have the next lowest genetic distance of 1.35 and are 98.65% identical at the amino acid level. These findings indicate that the SRY proteins are conserved in the 15 species, and their evolutionary relationships are similar.

  14. Comparative In silico Study of Sex-Determining Region Y (SRY Protein Sequences Involved in Sex-Determining

    Directory of Open Access Journals (Sweden)

    Masoume Vakili Azghandi

    2016-05-01

    Full Text Available Background: The SRY gene (SRY provides instructions for making a transcription factor called the sex-determining region Y protein. The sex-determining region Y protein causes a fetus to develop as a male. In this study, SRY of 15 spices included of human, chimpanzee, dog, pig, rat, cattle, buffalo, goat, sheep, horse, zebra, frog, urial, dolphin and killer whale were used for determine of bioinformatic differences. Methods: Nucleotide sequences of SRY were retrieved from the NCBI databank. Bioinformatic analysis of SRY is done by CLC Main Workbench version 5.5 and ClustalW (http:/www.ebi.ac.uk/clustalw/ and MEGA6 softwares. Results: The multiple sequence alignment results indicated that SRY protein sequences from Orcinus orca (killer whale and Tursiopsaduncus (dolphin have least genetic distance of 0.33 in these 15 species and are 99.67% identical at the amino acid level. Homosapiens and Pantroglodytes (chimpanzee have the next lowest genetic distance of 1.35 and are 98.65% identical at the amino acid level. Conclusion: These findings indicate that the SRY proteins are conserved in the 15 species, and their evolutionary relationships are similar.

  15. Influence of postzygotic reproductive isolation on the interspecific transmission of the paternal sex ratio chromosome in Trichogramma

    NARCIS (Netherlands)

    Jeong, G.S.; Stouthamer, R.

    2006-01-01

    The paternal sex ratio (PSR) chromosome is a supernumerary chromosome that causes the destruction of the paternal chromosome set in the first mitosis in a fertilized egg. It is known from parasitoid wasps in the genera Nasonia and Trichogramma (Hymenoptera). In these haplodiploids, the egg

  16. Sex determination in Madagascar geckos of the genus Paroedura (Squamata: Gekkonidae): are differentiated sex chromosomes indeed so evolutionary stable?

    Czech Academy of Sciences Publication Activity Database

    Koubová, M.; Johnson Pokorná, Martina; Rovatsos, M.; Farkačová, K.; Altmanová, M.; Kratochvíl, L.

    2014-01-01

    Roč. 22, č. 4 (2014), s. 441-452 ISSN 0967-3849 R&D Projects: GA ČR GAP506/10/0718 Institutional support: RVO:67985904 Keywords : sex chromosomes * heterochromatin * reptiles * sex determination * FISH * ITSs Subject RIV: EG - Zoology Impact factor: 2.478, year: 2014

  17. Genes involved in sex determination and the influence of ...

    African Journals Online (AJOL)

    As the sex reversal is a highly desired process in fish farming aiming at obtaining male mono-sexual populations (due to weight gain of males), several techniques based on direct and indirect manipulation of phenotypic sex are being tested. Recent surveys show the use of temperature as alternative to the process of sex ...

  18. Sex determination in insects: a binary decision based on alternative splicing.

    Science.gov (United States)

    Salz, Helen K

    2011-08-01

    The gene regulatory networks that control sex determination vary between species. Despite these differences, comparative studies in insects have found that alternative splicing is reiteratively used in evolution to control expression of the key sex-determining genes. Sex determination is best understood in Drosophila where activation of the RNA binding protein-encoding gene Sex-lethal is the central female-determining event. Sex-lethal serves as a genetic switch because once activated it controls its own expression by a positive feedback splicing mechanism. Sex fate choice in is also maintained by self-sustaining positive feedback splicing mechanisms in other dipteran and hymenopteran insects, although different RNA binding protein-encoding genes function as the binary switch. Studies exploring the mechanisms of sex-specific splicing have revealed the extent to which sex determination is integrated with other developmental regulatory networks. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Distance and sex determine host plant choice by herbivorous beetles.

    Directory of Open Access Journals (Sweden)

    Daniel J Ballhorn

    Full Text Available Plants respond to herbivore damage with the release of volatile organic compounds (VOCs. This indirect defense can cause ecological costs when herbivores themselves use VOCs as cues to localize suitable host plants. Can VOCs reliably indicate food plant quality to herbivores?We determined the choice behavior of herbivorous beetles (Chrysomelidae: Gynandrobrotica guerreroensis and Cerotoma ruficornis when facing lima bean plants (Fabaceae: Phaseolus lunatus with different cyanogenic potential, which is an important constitutive direct defense. Expression of inducible indirect defenses was experimentally manipulated by jasmonic acid treatment at different concentrations. The long-distance responses of male and female beetles to the resulting induced plant volatiles were investigated in olfactometer and free-flight experiments and compared to the short-distance decisions of the same beetles in feeding trials.Female beetles of both species were repelled by VOCs released from all induced plants independent of the level of induction. In contrast, male beetles were repelled by strongly induced plants, showed no significant differences in choice behavior towards moderately induced plants, but responded positively to VOCs released from little induced plants. Thus, beetle sex and plant VOCs had a significant effect on host searching behavior. By contrast, feeding behavior of both sexes was strongly determined by the cyanogenic potential of leaves, although females again responded more sensitively than males. Apparently, VOCs mainly provide information to these beetles that are not directly related to food quality. Being induced by herbivory and involved in indirect plant defense, such VOCs might indicate the presence of competitors and predators to herbivores. We conclude that plant quality as a food source and finding a potentially enemy-free space is more important for female than for male insect herbivores, whereas the presence of a slightly damaged

  20. Birth order, individual sex and sex of competitors determine the outcome of conflict among siblings over parental care

    Science.gov (United States)

    Bonisoli-Alquati, Andrea; Boncoraglio, Giuseppe; Caprioli, Manuela; Saino, Nicola

    2011-01-01

    Success in competition for limiting parental resources depends on the interplay between parental decisions over allocation of care and offspring traits. Birth order, individual sex and sex of competing siblings are major candidates as determinants of success in sib–sib competition, but experimental studies focusing on the combined effect of these factors on parent–offspring communication and within-brood competitive dynamics are rare. Here, we assessed individual food intake and body mass gain during feeding trials in barn swallow chicks differing for seniority and sex, and compared the intensity of their acoustic and postural solicitation (begging) displays. Begging intensity and success in competition depended on seniority in combination with individual sex and sex of the opponent. Junior chicks begged more than seniors, independently of satiation level (which was also experimentally manipulated), and obtained greater access to food. Females were generally weaker competitors than males. Individual sex and sex of the opponent also affected duration of begging bouts. Present results thus show that competition with siblings can make the rearing environment variably harsh for developing chicks, depending on individual sex, sex of competing broodmates and age ranking within the nest. They also suggest that parental decisions on the allocation of care and response of kin to signalling siblings may further contribute to the outcome of sibling competition. PMID:20943688

  1. Fish with thermolabile sex determination (TSD) as models to study brain sex differentiation.

    Science.gov (United States)

    Blázquez, Mercedes; Somoza, Gustavo M

    2010-05-01

    As fish are ectothermic animals, water temperature can affect their basic biological processes such as larval development, growth and reproduction. Similar to reptiles, the incubation temperature during early phases of development is capable to modify sex ratios in a large number of fish species. This phenomenon, known as thermolabile sex determination (TSD) was first reported in Menidia menidia, a species belonging to the family Atherinopsidae. Since then, an increasing number of fish have also been found to exhibit TSD. Traditionally, likewise in reptiles, several TSD patterns have been described in fish, however it has been recently postulated that only one, females at low temperatures and males at high temperatures, may represent the "real" or "true" TSD. Many studies regarding the influence of temperature on the final sex ratios have been focused on the expression and activity of gonadal aromatase, the enzyme involved in the conversion of androgens into estrogens and encoded by the cyp19a1a gene. In this regard, teleost fish, may be due to a whole genome duplication event, produce another aromatase enzyme, commonly named brain aromatase, encoded by the cyp19a1b gene. Contrary to what has been described in other vertebrates, fish exhibit very high levels of aromatase activity in the brain and therefore they synthesize high amounts of neuroestrogens. However, its biological significance is still not understood. In addition, the mechanism whereby temperature can induce the development of a testis or an ovary still remains elusive. In this context the present review is aimed to discuss several theories about the possible role of brain aromatase using fish as models. The relevance of brain aromatase and therefore of neuroestrogens as the possible cue for gonadal differentiation is raised. In addition, the possible role of brain aromatase as the way to keep the high levels of neurogenesis in fish is also considered. Several key examples of how teleosts and aromatase

  2. Evolutionary diversity and turn-over of sex determination in teleost fishes.

    Science.gov (United States)

    Mank, J E; Avise, J C

    2009-01-01

    Sex determination, due to the obvious association with reproduction and Darwinian fitness, has been traditionally assumed to be a relatively conserved trait. However, research on teleost fishes has shown that this need not be the case, as these animals display a remarkable diversity in the ways that they determine sex. These different mechanisms, which include constitutive genetic mechanisms on sex chromosomes, polygenic constitutive mechanisms, environmental influences, hermaphroditism, and unisexuality have each originated numerous independent times in the teleosts. The evolutionary lability of sex determination, and the corresponding rapid rate of turn-over among different modes, makes the teleost clade an excellent model with which to test theories regarding the evolution of sex determining adaptations. Much of the plasticity in sex determination likely results from the dynamic teleost genome, and recent advances in fish genetics and genomics have revealed the role of gene and genome duplication in fostering emergence and turn-over of sex determining mechanisms. 2009 S. Karger AG, Basel.

  3. Sex determination in honeybees: two separate mechanisms induce and maintain the female pathway

    DEFF Research Database (Denmark)

    Gempe, Tanja; Hasselmann, Martin; Schiøtt, Morten

    2009-01-01

    Organisms have evolved a bewildering diversity of mechanisms to generate the two sexes. The honeybee (Apis mellifera) employs an interesting system in which sex is determined by heterozygosity at a single locus (the Sex Determination Locus) harbouring the complementary sex determiner (csd) gene....... Bees heterozygous at Sex Determination Locus are females, whereas bees homozygous or hemizygous are males. Little is known, however, about the regulation that links sex determination to sexual differentiation. To investigate the control of sexual development in honeybees, we analyzed the functions...... and the regulatory interactions of genes involved in the sex determination pathway. We show that heterozygous csd is only required to induce the female pathway, while the feminizer (fem) gene maintains this decision throughout development. By RNAi induced knockdown we show that the fem gene is essential for entire...

  4. Sex determination in Madagascar geckos of the genus Paroedura (Squamata: Gekkonidae): are differentiated sex chromosomes indeed so evolutionary stable?

    Science.gov (United States)

    Koubová, Martina; Johnson Pokorná, Martina; Rovatsos, Michail; Farkačová, Klára; Altmanová, Marie; Kratochvíl, Lukáš

    2014-12-01

    Among amniote vertebrates, geckos represent a clade with exceptional variability in sex determination; however, only a minority of species of this highly diverse group has been studied in this respect. Here, we describe for the first time a female heterogamety in the genus Paroedura, the group radiated in Madagascar and adjacent islands. We identified homomorphic ZZ/ZW sex chromosomes with a highly heterochromatic W chromosome in Paroedura masobe, Paroedura oviceps, Paroedura karstophila, Paroedura stumpffi, and Paroedura lohatsara. Comparative genomic hybridization (CGH) revealed that female-specific sequences are greatly amplified in the W chromosome of P. lohatsara and that P. gracilis seems to possess a derived system of multiple sex chromosomes. Contrastingly, neither CGH nor heterochromatin visualization revealed differentiated sex chromosomes in the members of the Paroedura picta-Paroedura bastardi-Paroedura ibityensis clade, which is phylogenetically nested within lineages with a heterochromatic W chromosome. As a sex ratio consistent with genotypic sex determination has been reported in P. picta, it appears that the members of the P. picta-P. bastardi-P. ibityensis clade possess homomorphic, poorly differentiated sex chromosomes and may represent a rare example of evolutionary loss of highly differentiated sex chromosomes. Fluorescent in situ hybridization (FISH) with a telomeric probe revealed a telomere-typical pattern in all species and an accumulation of telomeric sequences in the centromeric region of autosomes in P. stumpffi and P. bastardi. Our study adds important information for the greater understanding of the variability and evolution of sex determination in geckos and demonstrates how the geckos of the genus Paroedura provide an interesting model for studying the evolution of the sex chromosomes.

  5. Impact and determinants of sex preference in Nepal.

    Science.gov (United States)

    Leone, Tiziana; Matthews, Zoë; Dalla Zuanna, Gianpiero

    2003-06-01

    Gender discrimination and son preference are key demographic features of South Asia and are well documented for India. However, gender bias and sex preference in Nepal have received little attention. 1996 Nepal Demographic and Health Survey data on ever-married women aged 15-49 who did not desire any more children were used to investigate levels of gender bias and sex preference. The level of contraceptive use and the total fertility rate in the absence of sex preference were estimated, and logistic regression was performed to analyze the association between socioeconomic and demographic variables and stopping childbearing after the birth of a son. Commonly used indicators of gender bias, such as sex ratio at birth and sex-specific immunization rates, do not suggest a high level of gender discrimination in Nepal. However, sex preference decreases contraceptive use by 24% and increases the total fertility rate by more than 6%. Women's contraceptive use, exposure to the media, parity, last birth interval, educational level and religion are linked to stopping childbearing after the birth of a boy, as is the ethnic makeup of the local area. The level of sex preference in Nepal is substantial. Sex preference is an important barrier to the increase of contraceptive use and decline of fertility in the country; its impact will be greater as desired family size declines.

  6. What was the ancestral sex-determining mechanism in amniote vertebrates?

    Science.gov (United States)

    Johnson Pokorná, Martina; Kratochvíl, Lukáš

    2016-02-01

    Amniote vertebrates, the group consisting of mammals and reptiles including birds, possess various mechanisms of sex determination. Under environmental sex determination (ESD), the sex of individuals depends on the environmental conditions occurring during their development and therefore there are no sexual differences present in their genotypes. Alternatively, through the mode of genotypic sex determination (GSD), sex is determined by a sex-specific genotype, i.e. by the combination of sex chromosomes at various stages of differentiation at conception. As well as influencing sex determination, sex-specific parts of genomes may, and often do, develop specific reproductive or ecological roles in their bearers. Accordingly, an individual with a mismatch between phenotypic (gonadal) and genotypic sex, for example an individual sex-reversed by environmental effects, should have a lower fitness due to the lack of specialized, sex-specific parts of their genome. In this case, evolutionary transitions from GSD to ESD should be less likely than transitions in the opposite direction. This prediction contrasts with the view that GSD was the ancestral sex-determining mechanism for amniote vertebrates. Ancestral GSD would require several transitions from GSD to ESD associated with an independent dedifferentiation of sex chromosomes, at least in the ancestors of crocodiles, turtles, and lepidosaurs (tuataras and squamate reptiles). In this review, we argue that the alternative theory postulating ESD as ancestral in amniotes is more parsimonious and is largely concordant with the theoretical expectations and current knowledge of the phylogenetic distribution and homology of sex-determining mechanisms. © 2014 Cambridge Philosophical Society.

  7. Evidence of oligogenic sex determination in the apple snail Pomacea canaliculata.

    Science.gov (United States)

    Yusa, Yoichi; Kumagai, Natsumi

    2018-02-26

    A small number of genes may interact to determine sex, but few such examples have been demonstrated in animals, especially through comprehensive mating experiments. The highly invasive apple snail Pomacea canaliculata is gonochoristic and shows a large variation in brood sex ratio, and the involvement of multiple genes has been suggested for this phenomenon. We conducted mating experiments to determine whether their sex determination involves a few or many genes (i.e., oligogenic or polygenic sex determination, respectively). Full-sib females or males that were born from the same parents were mated to an adult of the opposite sex, and the brood sex ratios of the parents and their offspring were investigated. Analysis of a total of 4288 offspring showed that the sex ratios of offspring from the full-sib females were variable but clustered into only a few values. Similar patterns were observed for the full-sib males, although the effect was less clear because fewer offspring were used (n = 747). Notably, the offspring sex ratios of all full-sib females in some families were nearly 0.5 (proportion of males) with little variation. These results indicate that the number of genotypes of the full-sibs, and hence genes involved in sex determination, is small in this snail. Such oligogenic systems may be a major sex-determining system among animals, especially those with variable sex ratios.

  8. Feedback Control of Sex Determination by Dosage Compensation Revealed through Caenorhabditis Elegans Sdc-3 Mutations

    OpenAIRE

    DeLong, L.; Plenefisch, J. D.; Klein, R. D.; Meyer, B. J.

    1993-01-01

    In Caenorhabditis elegans, sex determination and dosage compensation are coordinately controlled through a group of genes that respond to the primary sex determination signal. Here we describe a new gene, sdc-3, that also controls these processes. In contrast to previously described genes, the sex determination and dosage compensation activities of sdc-3 are separately mutable, indicating that they function independently. Paradoxically, the sdc-3 null phenotype fails to reveal the role of sdc...

  9. Sex determination using free fetal DNA in early pregnancy: With the approach to sex linked recessive disorders

    Directory of Open Access Journals (Sweden)

    Amir Monfaredan

    2017-03-01

    Full Text Available Introduction: Prenatal diagnosis is testing for detection of diseases or conditions in a fetus or embryo before it is born. Most of prenatal diagnostic (PD techniques are invasive and done in late stages of pregnancy. Using fetal DNA in maternal blood for fetal sex determination in early pregnancy might help in management of X-linked genetic diseases. This study aimed to investigate the accuracy of sex determination using fetal DNA in maternal blood at 8-12 weeks of gestation. Methods: In this cross-sectional study, 30 pregnant women at 8-12 weeks of gestation were enrolled. The sex-determining region Y (SRY gene expression with the internal control (IC glyceraldehyde 3-phosphate dehydrogenase (GAPDH was investigated with quantitative real-time polymerase chain reaction (PCR using specific primers and probes. Results: Accuracy of sex determination with SRY gene expression in 8-12 weeks of pregnancy were 85%, 85%, 90% and 100% respectively. Conclusion: It seems that fetal sex determining using fetal DNA in maternal blood is a reliable method for early stage of pregnancy.

  10. Sex determination of duck embryos: observations on syrinx development

    Science.gov (United States)

    Wilson, Robert E.; Sonsthagen, Sarah A.; Franson, J. Christian

    2013-01-01

    Ducks exhibit sexual dimorphism in vocal anatomy. Asymmetrical ossification of the syrinx (bulla syringealis) is discernable at about 10 days of age in male Pekin duck (Anas platyrhynchos domestica) embryos, but information is lacking on the early development of the bulla in wild ducks. To evaluate the reliability of this characteristic for sexing developing embryos, we examined the syrinx of dead embryos and compared results with molecular sexing techniques in high arctic nesting Common Eiders (Somateria mollissima). Embryos 8 days or older were accurately (100%) sexed based on the presence/absence of a bulla, 2 days earlier than Pekin duck. The use of the tracheal bulla can be a valuable technique when sex identification of embryos or young ducklings is required.

  11. Sex and ancestry determine the free-running circadian period.

    Science.gov (United States)

    Eastman, Charmane I; Tomaka, Victoria A; Crowley, Stephanie J

    2017-10-01

    The endogenous, free-running circadian period (τ) determines the phase relationship that an organism assumes when entrained to the 24-h day. We found a shorter circadian period in African Americans compared to non-Hispanic European Americans (24.07 versus 24.33 h). We speculate that a short circadian period, closer to 24 h, was advantageous to humans living around the equator, but when humans migrated North out of Africa, where the photoperiod changes with seasons, natural selection favoured people with longer circadian periods. Recently, in evolutionary terms, immigrants came from Europe and Africa to America ('the New World'). The Europeans were descendents of people who had lived in Europe for thousands of years with changing photoperiods (and presumably longer periods), whereas Africans had ancestors who had always lived around the equator (with shorter periods). It may have been advantageous to have a longer circadian period while living in Europe early in the evolution of humans. In our modern world, however, it is better to have a shorter period, because it helps make our circadian rhythms earlier, which is adaptive in our early-bird-dominated society. European American women had a shorter circadian period than men (24.24 versus 24.41), but there was no sex difference in African Americans (24.07 for both men and women). We speculate that selection pressures in Europe made men develop a slightly longer period than women to help them track dawn which could be useful for hunters, but less important for women as gatherers. © 2017 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.

  12. Determinants of Heterosexual Adolescents Having Sex with Female Sex Workers in Singapore.

    Directory of Open Access Journals (Sweden)

    Junice Y S Ng

    Full Text Available We assessed the proportion of and socio-ecological factors associated with ever having had sex with female sex workers (FSWs among heterosexual adolescents. We also described the characteristics of the adolescents who reported inconsistent condom use with FSWs.This is a cross-sectional study (response rate: 73% of 300 heterosexually active male adolescents of 16 to 19 years attending a national STI clinic in Singapore between 2009 and 2014. We assessed the ecological factors (individual, parental, peer, school and medial influences and sexual risk behaviors using a self-reported questionnaire. Poisson regression was used to obtain the adjusted prevalence ratios (aPR and confidence intervals (CI.The proportion of heterosexual male adolescents who had ever had sex with FSWs was 39%. Multivariate analysis showed that significant factors associated with ever having had sex with FSWs were sex initiation before 16 years old (aPR 1.79 CI: 1.30-2.46, never had a sexually active girlfriend (aPR 1.75 CI 1.28-2.38, reported lower self-esteem score (aPR 0.96 CI: 0.93-0.98, higher rebelliousness score (aPR 1.03 CI: 1.00-1.07 and more frequent viewing of pornography (aPR 1.47 CI: 1.04-2.09. Lifetime inconsistent condom use with FSWs was 30%.A significant proportion of heterosexual male adolescents attending the public STI clinic had ever had sex with FSWs. A targeted intervention that addresses different levels of influence to this behavior is needed. This is even more so because a considerable proportion of adolescents reported inconsistent condom use with FSWs, who may serve as a bridge of STI transmission to the community. National surveys on adolescent health should include the assessment of frequency of commercial sex visits and condom use with FSWs for long-term monitoring and surveillance.

  13. Sex determination from the frontal bone: a geometric morphometric study.

    Science.gov (United States)

    Perlaza, Néstor A

    2014-09-01

    Sex estimation in human skeletal remains when using the cranium through traditional methods is a fundamental pillar in human identification; however, it may be possible to incur in a margin of error due because of the state of preservation in incomplete or fragmented remains. The aim of this investigation was sex estimation through the geometric morphometric analysis of the frontal bone. The sample employed 60 lateral radiographs of adult subjects of both sexes (30 males and 30 females), aged between 18 and 40 years, with mean age for males of 28 ± 4 and 30 ± 6 years for females. Thin-plate splines evidenced strong expansion of the glabellar region in males and contraction in females. No significant differences were found between sexes with respect to size. The findings suggest differences in shape and size in the glabellar region, besides reaffirming the use of geometric morphometrics as a quantitative method in sex estimation. © 2014 American Academy of Forensic Sciences.

  14. Exploring the envelope. Systematic alteration in the sex-determination system of the nematode caenorhabditis elegans.

    OpenAIRE

    Hodgkin, Jonathan

    2002-01-01

    The natural sexes of the nematode Caenorhabditis elegans are the self-fertilizing hermaphrodite (XX) and the male (XO). The underlying genetic pathway controlling sexual phenotype has been extensively investigated. Mutations in key regulatory genes have been used to create a series of stable populations in which sex is determined not by X chromosome dosage, but in a variety of other ways, many of which mimic the diverse sex-determination systems found in different animal species. Most of thes...

  15. Children's Physical Attractiveness and Sex as Determinants of Adult Punitiveness

    Science.gov (United States)

    Dion, Karen K.

    1974-01-01

    Two studies investigated the influence of a child's physical attractiveness and sex as potential elicitors of differential adult punitiveness. Assessed were the reactions of 40 women and 44 men. Results reveal differences in men's and women's reactions and suggest differences in their orientation towards children's task behavior. (Author/SDH)

  16. Determinant Factors of Attitude towards Quantitative Subjects: Differences between Sexes

    Science.gov (United States)

    Mondejar-Jimenez, Jose; Vargas-Vargas, Manuel

    2010-01-01

    Nowadays, almost all curricula in the social sciences contain at least one course in statistics, given the importance of this discipline as an analytical tool. This work identifies the latent factors relating to students' motivation and attitude towards statistics, tests their covariance structure for samples of both sexes, and identifies the…

  17. Finding clues to the riddle of sex determination in zebrafish

    Indian Academy of Sciences (India)

    ... to instruct retention of the ovarian fate. The mechanism and identity of this instructive signal remain unknown. We hypothesize that sex in zebrafish is a culmination of combinatorial effects of the genome, germ cells and the environment with inputs from epigenetic factors translating the biological meaning of this interaction.

  18. Genes involved in sex determination process and the influence of ...

    African Journals Online (AJOL)

    DR. & MRS. TONY A. NLEWADIM

    2013-04-24

    Apr 24, 2013 ... sex reversal from females to males in many fish species is the use of steroid ...... functional males under 18°C (between 42 and 151 dpf). Craig et al. (1996) ..... Ecology meets endocrinology: ..... Phylogeny, expression and ...

  19. Absence of complementary sex determination in the parasitoid wasp genus asobara (hymenoptera: braconidae)

    NARCIS (Netherlands)

    Ma, W.J.; Kuijper, B.; Boer, de J.G.; Zande, van de L.; Beukeboom, L.W.; Wertheim, B.; Pannebakker, B.A.

    2013-01-01

    An attractive way to improve our understanding of sex determination evolution is to study the underlying mechanisms in closely related species and in a phylogenetic perspective. Hymenopterans are well suited owing to the diverse sex determination mechanisms, including different types of

  20. Absence of complementary sex determination in the parasitoid wasp genus Asobara (Hymenoptera: Braconidae)

    NARCIS (Netherlands)

    Ma, Wen-Juan; Kuijper, Bram; de Boer, Jetske G.; van de Zande, Louis; Beukeboom, Leo W.; Wertheim, Bregje; Pannebakker, Bart A.

    2013-01-01

    An attractive way to improve our understanding of sex determination evolution is to study the underlying mechanisms in closely related species and in a phylogenetic perspective. Hymenopterans are well suited owing to the diverse sex determination mechanisms, including different types of

  1. Gonadal expression of Sf1 and aromatase during sex determination in the red-eared slider turtle (Trachemys scripta), a reptile with temperature-dependent sex determination.

    Science.gov (United States)

    Ramsey, Mary; Shoemaker, Christina; Crews, David

    2007-12-01

    Many egg-laying reptiles have temperature-dependent sex determination (TSD), where the offspring sex is determined by incubation temperature during a temperature-sensitive period (TSP) in the middle third of development. The underlying mechanism transducing a temperature cue into an ovary or testis is unknown, but it is known that steroid hormones play an important role. During the TSP, exogenous application of estrogen can override a temperature cue and produce females, while blocking the activity of aromatase (Cyp19a1), the enzyme that converts testosterone to estradiol, produces males from a female-biased temperature. The production of estrogen is a key step in ovarian differentiation for many vertebrates, including TSD reptiles, and temperature-based differences in aromatase expression during the TSP may be a critical step in ovarian determination. Steroidogenic factor-1 (Sf1) is a key gene in vertebrate sex determination and regulates many steroidogenic enzymes, including aromatase. We find that Sf1 and aromatase are differentially expressed during sex determination in the red-eared slider turtle, Trachemys scripta elegans. Sf1 is expressed at higher levels during testis development while aromatase expression increases during ovary determination. We also assayed Sf1 and aromatase response to sex-reversing treatments via temperature or the modulation of estrogen availability. Sf1 expression was redirected to low-level female-specific patterns with feminizing temperature shift or exogenous estradiol application and redirected to more intense male-specific patterns with male-producing temperature shift or inhibition of aromatase activity. Conversely, aromatase expression was redirected to more intense female-specific patterns with female-producing treatment and redirected toward diffuse low-level male-specific patterns with masculinizing sex reversal. Our data do not lend support to a role for Sf1 in the regulation of aromatase expression during slider turtle sex

  2. Single-locus complementary sex determination in the inbreeding wasp Euodynerus foraminatus Saussure (Hymenoptera: Vespidae).

    Science.gov (United States)

    Stahlhut, J K; Cowan, D P

    2004-03-01

    The Hymenoptera have arrhenotokous haplodiploidy in which males normally develop from unfertilized eggs and are haploid, while females develop from fertilized eggs and are diploid. Multiple sex determination systems are known to underlie haplodiploidy, and the best understood is single-locus complementary sex determination (sl-CSD) in which sex is determined at a single polymorphic locus. Individuals heterozygous at the sex locus develop as females; individuals that are hemizygous (haploid) or homozygous (diploid) at the sex locus develop as males. sl-CSD can be detected with inbreeding experiments that produce diploid males in predictable proportions as well as sex ratio shifts due to diploid male production. This sex determination system is considered incompatible with inbreeding because the ensuing increase in homozygosity increases the production of diploid males that are inviable or infertile, imposing a high cost on matings between close relatives. However, in the solitary hunting wasp Euodynerus foraminatus, a species suspected of having sl-CSD, inbreeding may be common due to a high incidence of sibling matings at natal nests. In laboratory crosses with E. foraminatus, we find that sex ratios and diploid male production (detected as microsatellite heterozygosity) are consistent with sl-CSD, but not with other sex determination systems. This is the first documented example of sl-CSD in a hymenopteran with an apparent natural history of inbreeding, and thus presents a paradox for our understanding of hymenopteran genetics.

  3. Sex differences in depression and anxiety disorders: potential biological determinants.

    Science.gov (United States)

    Altemus, Margaret

    2006-11-01

    The phenomenon of higher rates of affective disorders in women illustrates many of the difficulties as well as promises of translating preclinical models to human disorders. Abnormalities in the regulation of the hypothalamic-pituitary adrenal axis and the sympathoadrenomedullary system have been identified in depression and anxiety disorders, and these disorders are clearly precipitated and exacerbated by stress. Despite the striking sex difference in the prevalence of depression and anxiety disorders, attempts to identify corresponding sex differences in stress response reactivity in animal models have met with limited success. Processes which may contribute to increased rates of affective disorders in women are greater fluxes in reproductive hormones across the life span, and increased sensitivity to catecholamine augmentation of emotional memory consolidation.

  4. Conservation of Sex-Linked Markers among Conspecific Populations of a Viviparous Skink, Niveoscincus ocellatus, Exhibiting Genetic and Temperature-Dependent Sex Determination

    Science.gov (United States)

    Burridge, Christopher P; Ezaz, Tariq; Wapstra, Erik

    2018-01-01

    Abstract Sex determination systems are exceptionally diverse and have undergone multiple and independent evolutionary transitions among species, particularly reptiles. However, the mechanisms underlying these transitions have not been established. Here, we tested for differences in sex-linked markers in the only known reptile that is polymorphic for sex determination system, the spotted snow skink, Niveoscincus ocellatus, to quantify the genomic differences that have accompanied this transition. In a highland population, sex is determined genetically, whereas in a lowland population, offspring sex ratio is influenced by temperature. We found a similar number of sex-linked loci in each population, including shared loci, with genotypes consistent with male heterogamety (XY). However, population-specific linkage disequilibrium suggests greater differentiation of sex chromosomes in the highland population. Our results suggest that transitions between sex determination systems can be facilitated by subtle genetic differences. PMID:29659810

  5. Abortion and sex determination: conflicting messages in information materials in a District of Rajasthan, India.

    Science.gov (United States)

    Nidadavolu, Vijaya; Bracken, Hillary

    2006-05-01

    Public information campaigns are an integral component of reproductive health programmes, including on abortion. In India, where sex selective abortion is increasing, public information is being disseminated on the illegality of sex determination. This paper presents findings from a study undertaken in 2003 in one district in Rajasthan to analyse the content of information materials on abortion and sex determination and people's perceptions of them. Most of the informational material about abortion was produced by one abortion service provider, but none by the public or private sector. The public sector had produced materials on the illegality of sex determination, some of which failed to distinguish between sex selection and other reasons for abortion. In the absence of knowledge of the legal status of abortion, the negative messages and strong language of these materials may have contributed to the perception that abortion is illegal in India. Future materials should address abortion and sex determination, including the legal status of abortion, availability of providers and social norms that shape decision-making. Married and unmarried women should be addressed and the participation of family members acknowledged, while supporting independent decisions by women. Sex determination should also be addressed, and the conditions under which a woman can and cannot seek an abortion clarified, using media and materials accessible to low-literate audiences. Based on what we learned in this research, a pictorial booklet and educator's manual were produced, covering both abortion and sex determination, and are being distributed in India.

  6. Prevalence and determinants of online-sex use in the German population.

    Directory of Open Access Journals (Sweden)

    Manfred E Beutel

    Full Text Available The unlimited access to sexual features in the World Wide Web has raised concerns about excessive and problematic online-sex use. However, little is known about antecedents of internet-sex use of different intensity. Based on a representative German sample of 2,522 participants between the ages of 14 and 97 years, the aims of the present study were (1 to determine the prevalence rates of online-sex users with the short version (ISSTGSV of the Internet Sex Screening Test and (2 to associate online-sex use with anxious vs. avoidant partner attachment patterns and "Big Five" personality traits as potential antecedents.The ISST is a brief, one-dimensional and reliable measure of online-sex activities (rtt = .69. Overall, 14.7% of respondents reported occasional and 4.2% intensive online-sex use. In multivariate analysis, online-sex use was significantly positively associated with male sex, younger age, unemployment and an anxious partner attachment pattern and negatively with conscientiousness and agreeableness.Arousal and satisfaction by virtual enactment of sexual phantasies may be attractive for anxiously attached persons who find it difficult to commit to a real life relationship due to fear of rejection or low self-esteem. More knowledge about the individual antecedents of intensive online-sex use may also be helpful for the development of consultation and treatment strategies for excessive and addictive online-sex use.

  7. Prevalence and determinants of online-sex use in the German population.

    Science.gov (United States)

    Beutel, Manfred E; Giralt, Sebastian; Wölfling, Klaus; Stöbel-Richter, Yve; Subic-Wrana, Claudia; Reiner, Iris; Tibubos, Ana Nanette; Brähler, Elmar

    2017-01-01

    The unlimited access to sexual features in the World Wide Web has raised concerns about excessive and problematic online-sex use. However, little is known about antecedents of internet-sex use of different intensity. Based on a representative German sample of 2,522 participants between the ages of 14 and 97 years, the aims of the present study were (1) to determine the prevalence rates of online-sex users with the short version (ISSTGSV) of the Internet Sex Screening Test and (2) to associate online-sex use with anxious vs. avoidant partner attachment patterns and "Big Five" personality traits as potential antecedents. The ISST is a brief, one-dimensional and reliable measure of online-sex activities (rtt = .69). Overall, 14.7% of respondents reported occasional and 4.2% intensive online-sex use. In multivariate analysis, online-sex use was significantly positively associated with male sex, younger age, unemployment and an anxious partner attachment pattern and negatively with conscientiousness and agreeableness. Arousal and satisfaction by virtual enactment of sexual phantasies may be attractive for anxiously attached persons who find it difficult to commit to a real life relationship due to fear of rejection or low self-esteem. More knowledge about the individual antecedents of intensive online-sex use may also be helpful for the development of consultation and treatment strategies for excessive and addictive online-sex use.

  8. Validation and use of DNA markers for sex determination in papaya (Carica papaya)

    International Nuclear Information System (INIS)

    Ejaz, M.; Iqbal, M.; Ahmed, I.

    2015-01-01

    Profitable papaya production requires female and hermaphrodite plants in higher number than male plants. This is only possible if sex of plants is determined at an early growth stage. The present study was conducted to validate sex-linked DNA markers using plants from two Pakistani papaya varieties and subsequently utilize them for determination of sex in juvenile papaya plants. One hundred and five plants (including 49 male and 56 female) of two Pakistani Papaya varieties at flowering stage were screened with six DNA markers viz., W-11, T12, SDP, Napf-76Napf-76, PKBT4 and PKBT5. All male plants exhibited amplification of sex-linked alleles with markers T12 and W11, whereas, 96% and 95% of female plants showed the absence of sex-linked allele with these markers, respectively. Markers SDP, PKBT5 and Napf-76 showed the presence of sex-linked alleles in 98%, 96% and 93% of male plants, respectively, whereas the same markers showed the absence of sex-linked alleles in 100%, 96% and 94% of female plants. One marker, PKBT4 could not produce expected PCR amplification reported previously. The five DNA markers were further used to screen 171 papaya seedlings. These markers clearly differentiated male and female sex types in the studied papaya plants. Results of our study are likely to facilitate Pakistani papaya breeders and growers to incorporate DNA based screening at juvenile stage to determine sex at early stage and to ensure profitable papaya production. (author)

  9. A heritable component in sex ratio and caste determination in a Cardiocondyla ant

    Directory of Open Access Journals (Sweden)

    Heinze Jürgen

    2009-10-01

    Full Text Available Abstract Studies on sex ratios in social insects provide among the most compelling evidence for the importance of kin selection in social evolution. The elegant synthesis of Fisher's sex ratio principle and Hamilton's inclusive fitness theory predicts that colony-level sex ratios vary with the colonies' social and genetic structures. Numerous empirical studies in ants, bees, and wasps have corroborated these predictions. However, the evolutionary optimization of sex ratios requires genetic variation, but one fundamental determinant of sex ratios - the propensity of female larvae to develop into young queens or workers ("queen bias" - is thought to be largely controlled by the environment. Evidence for a genetic influence on sex ratio and queen bias is as yet restricted to a few taxa, in particular hybrids. Because of the very short lifetime of their queens, ants of the genus Cardiocondyla are ideal model systems for the study of complete lifetime reproductive success, queen bias, and sex ratios. We found that lifetime sex ratios of the ant Cardiocondyla kagutsuchi have a heritable component. In experimental single-queen colonies, 22 queens from a genetic lineage with a highly female-biased sex ratio produced significantly more female-biased offspring sex ratios than 16 queens from a lineage with a more male-biased sex ratio (median 91.5% vs. 58.5% female sexuals. Sex ratio variation resulted from different likelihood of female larvae developing into sexuals (median 50% vs. 22.6% female sexuals even when uniformly nursed by workers from another colony. Consistent differences in lifetime sex ratios and queen bias among queens of C. kagutsuchi suggest that heritable, genetic or maternal effects strongly affect caste determination. Such variation might provide the basis for adaptive evolution of queen and worker strategies, though it momentarily constrains the power of workers and queens to optimize caste ratios.

  10. A heritable component in sex ratio and caste determination in a Cardiocondyla ant.

    Science.gov (United States)

    Frohschammer, Sabine; Heinze, Jürgen

    2009-10-28

    Studies on sex ratios in social insects provide among the most compelling evidence for the importance of kin selection in social evolution. The elegant synthesis of Fisher's sex ratio principle and Hamilton's inclusive fitness theory predicts that colony-level sex ratios vary with the colonies' social and genetic structures. Numerous empirical studies in ants, bees, and wasps have corroborated these predictions. However, the evolutionary optimization of sex ratios requires genetic variation, but one fundamental determinant of sex ratios - the propensity of female larvae to develop into young queens or workers ("queen bias") - is thought to be largely controlled by the environment. Evidence for a genetic influence on sex ratio and queen bias is as yet restricted to a few taxa, in particular hybrids.Because of the very short lifetime of their queens, ants of the genus Cardiocondyla are ideal model systems for the study of complete lifetime reproductive success, queen bias, and sex ratios. We found that lifetime sex ratios of the ant Cardiocondyla kagutsuchi have a heritable component. In experimental single-queen colonies, 22 queens from a genetic lineage with a highly female-biased sex ratio produced significantly more female-biased offspring sex ratios than 16 queens from a lineage with a more male-biased sex ratio (median 91.5% vs. 58.5% female sexuals). Sex ratio variation resulted from different likelihood of female larvae developing into sexuals (median 50% vs. 22.6% female sexuals) even when uniformly nursed by workers from another colony.Consistent differences in lifetime sex ratios and queen bias among queens of C. kagutsuchi suggest that heritable, genetic or maternal effects strongly affect caste determination. Such variation might provide the basis for adaptive evolution of queen and worker strategies, though it momentarily constrains the power of workers and queens to optimize caste ratios.

  11. Chromosome Banding in Amphibia. XXXVI. Multimorphic Sex Chromosomes and an Enigmatic Sex Determination in Eleutherodactylus johnstonei (Anura, Eleutherodactylidae).

    Science.gov (United States)

    Schmid, Michael; Steinlein, Claus

    2018-01-01

    A detailed cytogenetic study on the leaf litter frog Eleutherodactylus johnstonei from 14 different Caribbean islands and the mainlands of Venezuela and Guyana revealed the existence of multimorphic XY♂/XX♀ sex chromosomes 14. Their male sex determination and development depends either on the presence of 2 telocentric chromosomes 14 (XtYt), or on 1 submetacentric chromosome 14 (Xsm) plus 1 telocentric chromosome 14 (Yt), or on the presence of 2 submetacentric chromosomes 14 (XsmYsm). The female sex determination and development requires either the presence of 2 telocentric chromosomes 14 (XtXt) or 2 submetacentric chromosomes 14 (XsmXsm). In all individuals analyzed, the sex chromosomes 14 carry a prominent nucleolus organizer region in their long arms. An explanation is given for the origin of the (XtYt)♂, (XsmYt)♂, (XsmYsm)♂, (XtXt)♀, and (XsmXsm)♀ in the different populations of E. johnstonei. Furthermore, the present study gives detailed data on the chromosome banding patterns, in situ hybridization experiments, and the genome size of E. johnstonei. © 2018 S. Karger AG, Basel.

  12. Convergent evolution of chromosomal sex-determining regions in the animal and fungal kingdoms.

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    James A Fraser

    2004-12-01

    Full Text Available Sexual identity is governed by sex chromosomes in plants and animals, and by mating type (MAT loci in fungi. Comparative analysis of the MAT locus from a species cluster of the human fungal pathogen Cryptococcus revealed sequential evolutionary events that fashioned this large, highly unusual region. We hypothesize that MAT evolved via four main steps, beginning with acquisition of genes into two unlinked sex-determining regions, forming independent gene clusters that then fused via chromosomal translocation. A transitional tripolar intermediate state then converted to a bipolar system via gene conversion or recombination between the linked and unlinked sex-determining regions. MAT was subsequently subjected to intra- and interallelic gene conversion and inversions that suppress recombination. These events resemble those that shaped mammalian sex chromosomes, illustrating convergent evolution in sex-determining structures in the animal and fungal kingdoms.

  13. Ocean acidification but not warming alters sex determination in the Sydney rock oyster, Saccostrea glomerata.

    Science.gov (United States)

    Parker, Laura M; O'Connor, Wayne A; Byrne, Maria; Dove, Michael; Coleman, Ross A; Pörtner, Hans-O; Scanes, Elliot; Virtue, Patti; Gibbs, Mitchell; Ross, Pauline M

    2018-02-14

    Whether sex determination of marine organisms can be altered by ocean acidification and warming during this century remains a significant, unanswered question. Here, we show that exposure of the protandric hermaphrodite oyster, Saccostrea glomerata to ocean acidification, but not warming, alters sex determination resulting in changes in sex ratios. After just one reproductive cycle there were 16% more females than males. The rate of gametogenesis, gonad area, fecundity, shell length, extracellular pH and survival decreased in response to ocean acidification. Warming as a sole stressor slightly increased the rate of gametogenesis, gonad area and fecundity, but this increase was masked by the impact of ocean acidification at a level predicted for this century. Alterations to sex determination, sex ratios and reproductive capacity will have flow on effects to reduce larval supply and population size of oysters and potentially other marine organisms. © 2018 The Author(s).

  14. Physical Attractiveness, Age, and Sex as Determinants of Reactions to Resumes.

    Science.gov (United States)

    Quereshi, M. Y.; Kay, Janet P.

    1986-01-01

    Physical attractiveness, age, and sex were manipulated to determine their effect on the evaluation of 54 hypothetical applicants' resumes for three different jobs by 60 Master's in Business Administration students. Physical attractiveness favorably influenced the suitability ratings for all jobs; raters' sex and age were not significant but…

  15. Genetic sex determination in Astatotilapia calliptera, a prototype species for the Lake Malawi cichlid radiation

    Science.gov (United States)

    Peterson, Erin N.; Cline, Maggie E.; Moore, Emily C.; Roberts, Natalie B.; Roberts, Reade B.

    2017-06-01

    East African cichlids display extensive variation in sex determination systems. The species Astatotilapia calliptera is one of the few cichlids that reside both in Lake Malawi and in surrounding waterways. A. calliptera is of interest in evolutionary studies as a putative immediate outgroup species for the Lake Malawi species flock and possibly as a prototype ancestor-like species for the radiation. Here, we use linkage mapping to test association of sex in A. calliptera with loci that have been previously associated with genetic sex determination in East African cichlid species. We identify a male heterogametic XY system segregating at linkage group (LG) 7 in an A. calliptera line that originated from Lake Malawi, at a locus previously shown to act as an XY sex determination system in multiple species of Lake Malawi cichlids. Significant association of genetic markers and sex produce a broad genetic interval of approximately 26 megabases (Mb) using the Nile tilapia genome to orient markers; however, we note that the marker with the strongest association with sex is near a gene that acts as a master sex determiner in other fish species. We demonstrate that alleles of the marker are perfectly associated with sex in Metriaclima mbenjii, a species from the rock-dwelling clade of Lake Malawi. While we do not rule out the possibility of other sex determination loci in A. calliptera, this study provides a foundation for fine mapping of the cichlid sex determination gene on LG7 and evolutionary context regarding the origin and persistence of the LG7 XY across diverse, rapidly evolving lineages.

  16. Sexy splicing: regulatory interplays governing sex determination from Drosophila to mammals.

    Science.gov (United States)

    Lalli, Enzo; Ohe, Kenji; Latorre, Elisa; Bianchi, Marco E; Sassone-Corsi, Paolo

    2003-02-01

    A remarkable array of strategies is used to produce sexual differentiation in different species. Complex gene hierarchies govern sex determination pathways, as exemplified by the classic D. melanogaster paradigm, where an interplay of transcriptional, splicing and translational mechanisms operate. Molecular studies support the hypothesis that genetic sex determination pathways evolved in reverse order, from downstream to upstream genes, in the cascade. The recent identification of a role for the key regulatory factors SRY and WT1(+KTS) in pre-mRNA splicing indicates that important steps in the mammalian sex determination process are likely to operate at the post-transcriptional level.

  17. Mating Frequency and Effects on Sex Ratio in Female Parasitoids of xanthopimpla Stemmator (Thunberg). Implications in biological control Programmes

    International Nuclear Information System (INIS)

    Gitau, C.W.

    2002-01-01

    Cereals, especially maize and sorghum are the most important field crops in Africa. classical biological Control is a management strategy that employs natural enemies against exotic pests on cereal crops. The method has been used against Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), an introduced pest of maize, using the larval parasitoid cotesia flavipes (Cameron). However, C. flavipes is not able to attack all stem borer species in targeted areas. to complement its work, Xanthopimpla stemmator has successfully been established in Mauritius on Chilo sacchariphagus (Bojer). It is a common phenomenon for haplo-diploid parasitoids to give rise to male progeny when insemination does not take place. Mating becomes important to the parasitoid population since a male biased sex ratio can bring about collapse of the population. The aim of this study was to determine wether xanthopimpla stemmator females mat more than once and wether sex ratio of progeny is affected by multiple mating in female X. stemmator. The female showed a tendency to mate once. Multiple mating did not have any significant effect on either sex ratio or longevity. More males were produced in multiple mated females than once mated females.The effect of multiple mating in X. stemmator on sex ratio in relation to biocontrol programmes are discussed

  18. Sex Determination in Sea Cucumbers: Holothuria forskali and Stichopus regalis

    Directory of Open Access Journals (Sweden)

    Filipa Pinheiro Santos

    2014-06-01

    Full Text Available Sea cucumber aquaculture is underexploited in temperate regions, and it is inexistent in Portugal. However, there are some species with a large potential for this sector, namely Stichopus regalis and Holothuria forskali, as it their nutritional value. S. regalis is a common sea cucumber that is found in a wide depth range and is currently consumed all over the world, majority in Asia, with a high commercial value. On the other hand, H. forskali is the most plentiful specie of the Portuguese coast. The purpose of this study is to evaluate sex ratio on both species through biopsy method, using biopsy needle to collect a piece of gonad. Holothurian specimens were sampled coastwise in Peniche, Portugal (39° 21′ 32″ N, 9° 22′ 40″ W. A total of 45 H. forskali were collected in the low tide and 48 S. regalis were caught by trawl method. Both species were kept in captivity during 8 months, the rearing conditions are maintained close as possible to the natural habitat, and they were placed in a sand bottom. Mortality was evaluated during conditioning period, and it was verified approximately 19% of mortality in S. regalis, although in H. forskali it was not observed. Sex identification was performed with success only in H. forskali, and sexual ratio found was 1:1. All S. regalis specimens arrived eviscerated to the Aquaculture Laboratory and it was caused by the trawl capture method. For that reason, it was not possible to assess the sexual ratio. The possibility to distinguish holothurian genre is essential to realize sexual behavior, and to ease the understanding of reproductive cycle in attempt to introduce these new species for aquaculture rearing.

  19. Sex determination in gibbons of genus Nomascus using non-invasive method

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    Petra Bolechová

    2016-01-01

    Full Text Available Gibbons of the genus Nomascus have a strong sexual dimorphism and dichromatism. As they mature, both sexes develop sex-specific pelage colour. In combination with physical similarities in the genitalia with both sexes, there are problems with determining the sex of young individuals compared to other genus of gibbons. This is a pilot study applying a multiplex polymerase chain reactions based on a non-invasive method for sex determination of gibbons. The study was conducted on 22 faecal samples from gibbons of the genus Nomascus. The animals were monitored by staff so that the samples were identified correctly and each sample was collected immediately after the defecation. Results confirmed the sex in all adult and juvenile animals with known sex; and 2 females and 5 males in juveniles were determined with unknown sex. The results of direct examination completely corresponded with the PCR results. The PCR reaction with template DNA isolated from faecal material required BSA usage, however, we observed the occurrence of nonspecific fragments. This did not affect the reliability of our results and we confirmed the usability of this method for this genus.

  20. Sex determination of a Tunisian population by CT scan analysis of the skull.

    Science.gov (United States)

    Zaafrane, Malek; Ben Khelil, Mehdi; Naccache, Ines; Ezzedine, Ekbel; Savall, Frédéric; Telmon, Norbert; Mnif, Najla; Hamdoun, Moncef

    2018-05-01

    It is widely accepted that the estimation of biological attributes in the human skeleton is more accurate when population-specific standards are applied. With the shortage of such data for contemporary North African populations, it is duly required to establish population-specific standards. We present here the first craniometric standards for sex determination of a contemporary Tunisian population. The aim of this study was to analyze the correlation between sex and metric parameters of the skull in this population using CT scan analysis and to generate proper reliable standards for sex determination of a complete or fragmented skull. The study sample comprised cranial multislice computed tomography scans of 510 individuals equally distributed by sex. ASIR TM software in a General Electric TM workstation was used to position 37 landmarks along the volume-rendered images and the multiplanar slices, defining 27 inter-landmark distances. Frontal and parietal bone thickness was also measured for each case. The data were analyzed using basic descriptive statistics and logistic regression with cross-validation of classification results. All of the measurements were sexually dimorphic with male values being higher than female values. A nine-variable model achieved the maximum classification accuracy of 90% with -2.9% sex bias and a six-variable model yielded 85.9% sexing accuracy with -0.97% sex bias. We conclude that the skull is highly dimorphic and represents a reliable bone for sex determination in contemporary Tunisian individuals.

  1. Absence of complementary sex determination in the parasitoid wasp genus Asobara (Hymenoptera: Braconidae.

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    Wen-Juan Ma

    Full Text Available An attractive way to improve our understanding of sex determination evolution is to study the underlying mechanisms in closely related species and in a phylogenetic perspective. Hymenopterans are well suited owing to the diverse sex determination mechanisms, including different types of Complementary Sex Determination (CSD and maternal control sex determination. We investigated different types of CSD in four species within the braconid wasp genus Asobara that exhibit diverse life-history traits. Nine to thirteen generations of inbreeding were monitored for diploid male production, brood size, offspring sex ratio, and pupal mortality as indicators for CSD. In addition, simulation models were developed to compare these observations to predicted patterns for multilocus CSD with up to ten loci. The inbreeding regime did not result in diploid male production, decreased brood sizes, substantially increased offspring sex ratios nor in increased pupal mortality. The simulations further allowed us to reject CSD with up to ten loci, which is a strong refutation of the multilocus CSD model. We discuss how the absence of CSD can be reconciled with the variation in life-history traits among Asobara species, and the ramifications for the phylogenetic distribution of sex determination mechanisms in the Hymenoptera.

  2. Fgf9 and Wnt4 act as antagonistic signals to regulate mammalian sex determination.

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    Yuna Kim

    2006-06-01

    Full Text Available The genes encoding members of the wingless-related MMTV integration site (WNT and fibroblast growth factor (FGF families coordinate growth, morphogenesis, and differentiation in many fields of cells during development. In the mouse, Fgf9 and Wnt4 are expressed in gonads of both sexes prior to sex determination. Loss of Fgf9 leads to XY sex reversal, whereas loss of Wnt4 results in partial testis development in XX gonads. However, the relationship between these signals and the male sex-determining gene, Sry, was unknown. We show through gain- and loss-of-function experiments that fibroblast growth factor 9 (FGF9 and WNT4 act as opposing signals to regulate sex determination. In the mouse XY gonad, Sry normally initiates a feed-forward loop between Sox9 and Fgf9, which up-regulates Fgf9 and represses Wnt4 to establish the testis pathway. Surprisingly, loss of Wnt4 in XX gonads is sufficient to up-regulate Fgf9 and Sox9 in the absence of Sry. These data suggest that the fate of the gonad is controlled by antagonism between Fgf9 and Wnt4. The role of the male sex-determining switch--Sry in the case of mammals--is to tip the balance between these underlying patterning signals. In principle, sex determination in other vertebrates may operate through any switch that introduces an imbalance between these two signaling pathways.

  3. Manipulation of arthropod sex determination by endosymbionts : Diversity and molecular mechanisms

    NARCIS (Netherlands)

    Ma, W. -J.; Vavre, F.; Beukeboom, L. W.

    2014-01-01

    Arthropods exhibit a large variety of sex determination systems both at the chromosomal and molecular level. Male heterogamety, female heterogamety, and haplodiploidy occur frequently, but partially different genes are involved. Endosymbionts, such as Wolbachia, Cardinium, Rickettsia, and

  4. Three loci on mouse chromosome 5 and 10 modulate sex determination in XX Ods/+ mice.

    Science.gov (United States)

    Poirier, Christophe; Moran, Jennifer L; Kovanci, Ertug; Petit, Deborah C; Beier, David R; Bishop, Colin E

    2007-07-01

    In mouse, XY embryos are committed to the male sex determination pathway after the transient expression of the Y-linked Sry gene in the Sertoli cell lineage between 10.5 and 12.5 dpc. In the C57BL/6J strain, male sex determination program can be modulated by some autosomal genes. The C57BL/6J alleles at these autosomal loci can antagonize male sex determination in combination with specific Sry alleles. In this report, the authors have identified an effect of these C57BL/6J specific alleles in combination with a mutated Sox9 allele, Sox9(Ods). Authors report the mapping of three of these genetic loci on mouse chromosome 5 and 10 in a backcross of the Ods mutation to the C57BL/6J background. Our study confirms the importance of the strain C57BL/6J for the investigation of the genetic mechanisms that control sex determination.

  5. Sex determination based on a thoracic vertebra and ribs evaluation using clinical chest radiography.

    Science.gov (United States)

    Tsubaki, Shun; Morishita, Junji; Usumoto, Yosuke; Sakaguchi, Kyoko; Matsunobu, Yusuke; Kawazoe, Yusuke; Okumura, Miki; Ikeda, Noriaki

    2017-07-01

    Our aim was to investigate whether sex can be determined from a combination of geometric features obtained from the 10th thoracic vertebra, 6th rib, and 7th rib. Six hundred chest radiographs (300 males and 300 females) were randomly selected to include patients of six age groups (20s, 30s, 40s, 50s, 60s, and 70s). Each group included 100 images (50 males and 50 females). A total of 14 features, including 7 lengths, 5 indices for the vertebra, and 2 types of widths for ribs, were utilized and analyzed for sex determination. Dominant features contributing to sex determination were selected by stepwise discriminant analysis after checking the variance inflation factors for multicollinearity. The accuracy of sex determination using a combination of the vertebra and ribs was evaluated from the selected features by the stepwise discriminant analysis. The accuracies in each age group were also evaluated in this study. The accuracy of sex determination based on a combination of features of the vertebra and ribs was 88.8% (533/600). This performance was superior to that of the vertebra or ribs only. Moreover, sex determination of subjects in their 20s demonstrated the highest accuracy (96.0%, 96/100). The features selected in the stepwise discriminant analysis included some features in both the vertebra and ribs. These results indicate the usefulness of combined information obtained from the vertebra and ribs for sex determination. We conclude that a combination of geometric characteristics obtained from the vertebra and ribs could be useful for determining sex. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Environmental sex determination in the branchiopod crustacean Daphnia magna: deep conservation of a Doublesex gene in the sex-determining pathway.

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    Yasuhiko Kato

    2011-03-01

    Full Text Available Sex-determining mechanisms are diverse among animal lineages and can be broadly divided into two major categories: genetic and environmental. In contrast to genetic sex determination (GSD, little is known about the molecular mechanisms underlying environmental sex determination (ESD. The Doublesex (Dsx genes play an important role in controlling sexual dimorphism in genetic sex-determining organisms such as nematodes, insects, and vertebrates. Here we report the identification of two Dsx genes from Daphnia magna, a freshwater branchiopod crustacean that parthenogenetically produces males in response to environmental cues. One of these genes, designated DapmaDsx1, is responsible for the male trait development when expressed during environmental sex determination. The domain organization of DapmaDsx1 was similar to that of Dsx from insects, which are thought to be the sister group of branchiopod crustaceans. Intriguingly, the molecular basis for sexually dimorphic expression of DapmaDsx1 is different from that of insects. Rather than being regulated sex-specifically at the level of pre-mRNA splicing in the coding region, DapmaDsx1 exhibits sexually dimorphic differences in the abundance of its transcripts. During embryogenesis, expression of DapmaDsx1 was increased only in males and its transcripts were primarily detected in male-specific structures. Knock-down of DapmaDsx1 in male embryos resulted in the production of female traits including ovarian maturation, whereas ectopic expression of DapmaDsx1 in female embryos resulted in the development of male-like phenotypes. Expression patterns of another D. magna Dsx gene, DapmaDsx2, were similar to those of DapmaDsx1, but silencing and overexpression of this gene did not induce any clear phenotypic changes. These results establish DapmaDsx1 as a key regulator of the male phenotype. Our findings reveal how ESD is implemented by selective expression of a fundamental genetic component that is

  7. Sex determination and differentiation in Aurelia sp.1: the absence of temperature dependence

    Science.gov (United States)

    Liu, Chunsheng; Gu, Zhifeng; Xing, Mengxin; Sun, Yun; Chen, Siqing; Chen, Zhaoting

    2018-03-01

    Cnidarians, being regarded as `basal' metazoan animals, are considered to have relatively high plasticity in terms of sex reversal. In this study we used an experimental approach to demonstrate sexual differentiation and plasticity in benthic polyps and pelagic medusae of Aurelia sp.1 maintained at different temperatures. Results indicated that in Aurelia sp.1, sex differentiation has been determined at the polyp stage and that all medusae originating from a given polyp are, phenotypically, of the same sex. In addition, the sex of polyps budding from the same clone (either male or female) at different temperatures appears to be the same as that of the parent. The sex of medusae that had originated from a known-sex polyp was observed to remain the same as that of the parent, irrespective of differences in strobilation or rearing temperatures. These results indicate that the mechanism of sex determination of Aurelia sp.1. is not influenced by prevailing temperature regimes. A comparison of variability in terms of sexual plasticity of Aurelia sp.1 with that of Hydrozoa and Anthozoa suggests that species characterized by a free-swimming medusa life stage have a high dispersal potential, which probably results in a lower rate of sex reversal.

  8. Sex determination using cheiloscopy and mandibular canine index as a tool in forensic dentistry

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    B Bhagyashree

    2018-01-01

    Full Text Available Identification of a person′s individuality and sex determination are important for legal as well as identification purposes. The aim of the present study was to check the reliability of cheiloscopy and mandibular canine index (MCI in the determination of sex in an individual. The aim of this study is to analyze different lip patterns reproduced by the natural dye (vermilion and lysochrome (Sudan Black II dyes and to compare the MCI in males and females for the determination of sex and to check the reliability of cheiloscopy and MCI for the same. Latent lip prints were developed using natural dye (vermilion and lysochrome (Sudan Black II dyes and their patterns categorized according to Tsuchihashi′s classification. MCI were calculated. Analysis of the two was performed. According to discriminant functional analysis, percentage accuracy for cheiloscopy in the determination of sex was found to be 55% while for MCI, the same value was 85%. Natural dye (vermilion was found as an efficient dye compared to lysochrome (Sudan Black II dyes for the development of latent lip prints. Both the dyes showed Type I lip print pattern to be common in males and females. Furthermore, all the parameters in MCI were found to be significant in the determination of sex in an individual. The results of the present study revealed MCI to be more reliable in the determination of sex than cheiloscopy.

  9. Karyotype analysis and sex determination in Australian Brush-turkeys (Alectura lathami.

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    Madison T Ortega

    Full Text Available Sexual differentiation across taxa may be due to genetic sex determination (GSD and/or temperature sex determination (TSD. In many mammals, males are heterogametic (XY; whereas females are homogametic (XX. In most birds, the opposite is the case with females being heterogametic (ZW and males the homogametic sex (ZZ. Many reptile species lack sex chromosomes, and instead, sexual differentiation is influenced by temperature with specific temperatures promoting males or females varying across species possessing this form of sexual differentiation, although TSD has recently been shown to override GSD in Australian central beaded dragons (Pogona vitticeps. There has been speculation that Australian Brush-turkeys (Alectura lathami exhibit TSD alone and/or in combination with GSD. Thus, we sought to determine if this species possesses sex chromosomes. Blood was collected from one sexually mature female and two sexually mature males residing at Sylvan Heights Bird Park (SHBP and shipped for karyotype analysis. Karyotype analysis revealed that contrary to speculation, Australian Brush-turkeys possess the classic avian ZW/ZZ sex chromosomes. It remains a possibility that a biased primary sex ratio of Australian Brush-turkeys might be influenced by maternal condition prior to ovulation that result in her laying predominantly Z- or W-bearing eggs and/or sex-biased mortality due to higher sensitivity of one sex in environmental conditions. A better understanding of how maternal and extrinsic factors might differentially modulate ovulation of Z- or W-bearing eggs and hatching of developing chicks possessing ZW or ZZ sex chromosomes could be essential in conservation strategies used to save endangered members of Megapodiidae.

  10. A NEW HYPOTHESIS ON THE EVOLUTION OF SEX DETERMINATION IN VERTEBRATES - BIG FEMALES ZW, BIG MALES XY

    NARCIS (Netherlands)

    KRAAK, SBM; DELOOZE, EMA

    1993-01-01

    Why are there two chromosomal sex-determining mechanisms in vertebrates; ZW/ZZ, meaning female heterogamety, and XX/XY, meaning male heterogamety? We propose an evolutionary explanation. Transition from environmental sex determination to genetic sex determination can result when an allele that

  11. Mapping of five candidate sex-determining loci in rainbow trout (Oncorhynchus mykiss

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    Drew Robert E

    2009-01-01

    Full Text Available Abstract Background Rainbow trout have an XX/XY genetic mechanism of sex determination where males are the heterogametic sex. The homology of the sex-determining gene (SDG in medaka to Dmrt1 suggested that SDGs evolve from downstream genes by gene duplication. Orthologous sequences of the major genes of the mammalian sex determination pathway have been reported in the rainbow trout but the map position for the majority of these genes has not been assigned. Results Five loci of four candidate genes (Amh, Dax1, Dmrt1 and Sox6 were tested for linkage to the Y chromosome of rainbow trout. We exclude the role of all these loci as candidates for the primary SDG in this species. Sox6i and Sox6ii, duplicated copies of Sox6, mapped to homeologous linkage groups 10 and 18 respectively. Genotyping fishes of the OSU × Arlee mapping family for Sox6i and Sox6ii alleles indicated that Sox6i locus might be deleted in the Arlee lineage. Conclusion Additional candidate genes should be tested for their linkage to the Y chromosome. Mapping data of duplicated Sox6 loci supports previously suggested homeology between linkage groups 10 and 18. Enrichment of the rainbow trout genomic map with known gene markers allows map comparisons with other salmonids. Mapping of candidate sex-determining loci is important for analyses of potential autosomal modifiers of sex-determination in rainbow trout.

  12. Identification of the sex-determining locus in grass puffer (Takifugu niphobles) provides evidence for sex-chromosome turnover in a subset of Takifugu species

    Science.gov (United States)

    Atsumi, Kazufumi; Kamiya, Takashi; Nozawa, Aoi; Aoki, Yuma; Tasumi, Satoshi; Koyama, Takashi; Nakamura, Osamu; Suzuki, Yuzuru

    2018-01-01

    There is increasing evidence for frequent turnover in sex chromosomes in vertebrates. Yet experimental systems suitable for tracing the detailed process of turnover are rare. In theory, homologous turnover is possible if the new sex-determining locus is established on the existing sex-chromosome. However, there is no empirical evidence for such an event. The genus Takifugu includes fugu (Takifugu rubripes) and its two closely-related species whose sex is most likely determined by a SNP at the Amhr2 locus. In these species, males are heterozygous, with G and C alleles at the SNP site, while females are homozygous for the C allele. To determine if a shift in the sex-determining locus occurred in another member of this genus, we used genetic mapping to characterize the sex-chromosome systems of Takifugu niphobles. We found that the G allele of Amhr2 is absent in T. niphobles. Nevertheless, our initial mapping suggests a linkage between the phenotypic sex and the chromosome 19, which harbors the Amhr2 locus. Subsequent high-resolution analysis using a sex-reversed fish demonstrated that the sex-determining locus maps to the proximal end of chromosome 19, far from the Amhr2 locus. Thus, it is likely that homologous turnover involving these species has occurred. The data also showed that there is a male-specific reduction of recombination around the sex-determining locus. Nevertheless, no evidence for sex-chromosome differentiation was detected: the reduced recombination depended on phenotypic sex rather than genotypic sex; no X- or Y-specific maker was obtained; the YY individual was viable. Furthermore, fine-scale mapping narrowed down the new sex-determining locus to the interval corresponding to approximately 300-kb of sequence in the fugu genome. Thus, T. niphobles is determined to have a young and small sex-determining region that is suitable for studying an early phase of sex-chromosome evolution and the mechanisms underlying turnover of sex chromosome. PMID

  13. B chromosomes have a functional effect on female sex determination in Lake Victoria cichlid fishes.

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    Kohta Yoshida

    2011-08-01

    Full Text Available The endemic cichlid fishes in Lake Victoria are a model system for speciation through adaptive radiation. Although the evolution of the sex-determination system may also play a role in speciation, little is known about the sex-determination system of Lake Victoria cichlids. To understand the evolution of the sex-determination system in these fish, we performed cytogenetic analysis in 11 cichlid species from Lake Victoria. B chromosomes, which are present in addition to standard chromosomes, were found at a high prevalence rate (85% in these cichlids. In one species, B chromosomes were female-specific. Cross-breeding using females with and without the B chromosomes demonstrated that the presence of the B chromosomes leads to a female-biased sex ratio in this species. Although B chromosomes were believed to be selfish genetic elements with little effect on phenotype and to lack protein-coding genes, the present study provides evidence that B chromosomes have a functional effect on female sex determination. FISH analysis using a BAC clone containing B chromosome DNA suggested that the B chromosomes are derived from sex chromosomes. Determination of the nucleotide sequences of this clone (104.5 kb revealed the presence of several protein-coding genes in the B chromosome, suggesting that B chromosomes have the potential to contain functional genes. Because some sex chromosomes in amphibians and arthropods are thought to be derived from B chromosomes, the B chromosomes in Lake Victoria cichlids may represent an evolutionary transition toward the generation of sex chromosomes.

  14. Direct LAMP Assay without Prior DNA Purification for Sex Determination of Papaya

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    Chi-Chu Tsai

    2016-09-01

    Full Text Available Papaya (Carica papaya L. is an economically important tropical fruit tree with hermaphrodite, male and female sex types. Hermaphroditic plants are the major type used for papaya production because their fruits have more commercial advantages than those of female plants. Sex determination of the seedlings, or during the early growth stages, is very important for the papaya seedling industry. Thus far, the only method for determining the sex type of a papaya at the seedling stage has been DNA analysis. In this study, a molecular technique—based on DNA analysis—was developed for detecting male-hermaphrodite-specific markers to examine the papaya’s sex type. This method is based on the loop-mediated isothermal amplification (LAMP and does not require prior DNA purification. The results show that the method is an easy, efficient, and inexpensive way to determine a papaya’s sex. This is the first report on the LAMP assay, using intact plant materials-without DNA purification-as samples for the analysis of sex determination of papaya. We found that using high-efficiency DNA polymerase was essential for successful DNA amplification, using trace intact plant material as a template DNA source.

  15. Drosophila as a model for the study of sex determination in anopheline and aedine mosquitoes

    International Nuclear Information System (INIS)

    Pannuti, A.; Kocacitak, T.; Lucchesi, J.C.

    2000-01-01

    Sterile insect technique control strategies consist of releasing laboratory produced male insects that have been sterilised by irradiation. These strategies require the production of massive quantities of males. Population-replacement strategies rely on the genetically engineered interruption of that portion of the malaria parasite's life cycle that occurs in the mosquito. This could be achieved by the inundative introduction of transformed males or the more limited introduction of males carrying an infective agent capable of driving a parasite-inhibiting transgene into the vector population. Once again, the release of genetically engineered males would require genetic systems for their mass production. Mass production of males can be accomplished most effectively through genetic sexing techniques. Genetic sexing can be achieved by identifying the key steps in the genetic regulation of sex differentiation and by modifying one or more of these steps so that their execution would result in sex-specific lethality. As the necessary and seminal first step towards this goal, we set out to identify and isolate a gene whose primary transcript is processed differently in males and females of Anopheles gambiae Giles. A survey of sex determination among insects reveals a vast array of different mechanisms. Our understanding of these mechanisms consists only of information derived from classical cytological and genetic studies. Using the knowledge derived from the study of Drosophila, it has been possible to discern a fundamental pattern in the sex determining mechanisms of many diverse insect species (Noethiger and Steinmann-Zwicky 1985). The challenge now, is to determine if there has been an evolutionary conservation of the genes responsible for the fundamental pattern, i.e., if the molecular mechanisms that underlie sex determination in Drosophila are the same in other insects of interest or if in these insects, the apparent fundamental pattern is achieved by completely

  16. Use of radioimmunoassay procedures for the determination of sex hormones in animal tissues

    International Nuclear Information System (INIS)

    Hoffmann, B.

    1983-01-01

    Radioimmunoassay methods for the determination of sex steroids and other compounds with sex hormone-like activities in various edible animal tissues and endocrine glands have been developed. Reliability of these methods, allowing quantification in a range of 10 -11 M, has been adequately demonstrated. When applied to monitoring residues of anabolic sex hormones in edible tissues of veal calves, physiological baseline levels of some endogenous ''anabolic'' steroids (like testosterone, oestrogens) were established; in the case of xenobiotics residues at the scheduled time of slaughter could be quantified (trenbolone) and a regulatory method to implement the ban of diethylstilbestrol was introduced. (author)

  17. Use of radioimmunoassay procedures for the determination of sex hormones in animal tissues

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, B. (Institut fuer Veterinaermedizin des Bundesgesundheitsamtes (Robert von Ostertag-Institut), Berlin (Germany, F.R.))

    1983-07-01

    Radioimmunoassay methods for the determination of sex steroids and other compounds with sex hormone-like activities in various edible animal tissues and endocrine glands have been developed. Reliability of these methods, allowing quantification in a range of 10/sup -11/ M, has been adequately demonstrated. When applied to monitoring residues of anabolic sex hormones in edible tissues of veal calves, physiological baseline levels of some endogenous ''anabolic'' steroids (like testosterone, oestrogens) were established; in the case of xenobiotics residues at the scheduled time of slaughter could be quantified (trenbolone) and a regulatory method to implement the ban of diethylstilbestrol was introduced.

  18. Identification of Sex-determining Loci in Pacific White Shrimp Litopeneaus vannamei Using Linkage and Association Analysis.

    Science.gov (United States)

    Yu, Yang; Zhang, Xiaojun; Yuan, Jianbo; Wang, Quanchao; Li, Shihao; Huang, Hao; Li, Fuhua; Xiang, Jianhai

    2017-06-01

    The Pacific white shrimp Litopenaeus vannamei is a predominant aquaculture shrimp species in the world. Like other animals, the L. vannamei exhibited sexual dimorphism in growth trait. Mapping of the sex-determining locus will be very helpful to clarify the sex determination system and further benefit the shrimp aquaculture industry towards the production of mono-sex stocks. Based on the data used for high-density linkage map construction, linkage-mapping analysis was conducted. The sex determination region was mapped in linkage group (LG) 18. A large region from 0 to 21.205 cM in LG18 showed significant association with sex. However, none of the markers in this region showed complete association with sex in the other populations. So an association analysis was designed using the female parent, pool of female progenies, male parent, and pool of male progenies. Markers were de novo developed and those showing significant differences between female and male pools were identified. Among them, three sex-associated markers including one fully associated marker were identified. Integration of linkage and association analysis showed that the sex determination region was fine-mapped in a small region along LG18. The identified sex-associated marker can be used for the sex detection of this species at genetic level. The fine-mapped sex-determining region will contribute to the mapping of sex-determining gene and help to clarify sex determination system for L. vannamei.

  19. QTL Mapping of Sex Determination Loci Supports an Ancient Pathway in Ants and Honey Bees.

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    Misato O Miyakawa

    2015-11-01

    Full Text Available Sex determination mechanisms play a central role in life-history characteristics, affecting mating systems, sex ratios, inbreeding tolerance, etc. Downstream components of sex determination pathways are highly conserved, but upstream components evolve rapidly. Evolutionary dynamics of sex determination remain poorly understood, particularly because mechanisms appear so diverse. Here we investigate the origins and evolution of complementary sex determination (CSD in ants and bees. The honey bee has a well-characterized CSD locus, containing tandemly arranged homologs of the transformer gene [complementary sex determiner (csd and feminizer (fem]. Such tandem paralogs appear frequently in aculeate hymenopteran genomes. However, only comparative genomic, but not functional, data support a broader role for csd/fem in sex determination, and whether species other than the honey bee use this pathway remains controversial. Here we used a backcross to test whether csd/fem acts as a CSD locus in an ant (Vollenhovia emeryi. After sequencing and assembling the genome, we computed a linkage map, and conducted a quantitative trait locus (QTL analysis of diploid male production using 68 diploid males and 171 workers. We found two QTLs on separate linkage groups (CsdQTL1 and CsdQTL2 that jointly explained 98.0% of the phenotypic variance. CsdQTL1 included two tandem transformer homologs. These data support the prediction that the same CSD mechanism has indeed been conserved for over 100 million years. CsdQTL2 had no similarity to CsdQTL1 and included a 236-kb region with no obvious CSD gene candidates, making it impossible to conclusively characterize it using our data. The sequence of this locus was conserved in at least one other ant genome that diverged >75 million years ago. By applying QTL analysis to ants for the first time, we support the hypothesis that elements of hymenopteran CSD are ancient, but also show that more remains to be learned about the

  20. Molecular mechanisms of temperature-dependent sex determination in the context of ecological developmental biology.

    Science.gov (United States)

    Matsumoto, Yuiko; Crews, David

    2012-05-06

    Temperature-dependent sex determination (TSD) is a prime example of phenotypic plasticity in that gonadal sex is determined by the temperature of the incubating egg. In the red-eared slider turtle (Trachemys scripta), the effect of temperature can be overridden by exogenous ligands, i.e., sex steroid hormones and steroid metabolism enzyme inhibitors, during the temperature-sensitive period (TSP) of development. Precisely how the physical signal of temperature is transduced into a biological signal that ultimately results in sex determination remains unknown. In this review, we discuss the sex determining pathway underlying TSD by focusing on two candidate sex determining genes, Forkhead box protein L2 (FoxL2) and Doublesex mab3- related transcription factor 1 (Dmrt1). They appear to be involved in transducing the environmental temperature signal into a biological signal that subsequently determines gonadal sex. FoxL2 and Dmrt1 exhibit gonad-typical patterns of expression in response to temperature during the TSP in the red-eared slider turtle. Further, the biologically active ligands regulate the expression of FoxL2 and Dmrt1 during development to modify gonad trajectory. The precise regulatory mechanisms of expression of these genes by temperature or exogenous ligands are not clear. However, the environment often influences developmental gene expression by altering the epigenetic status in regulatory regions. Here, we will discuss if the regulation of FoxL2 and Dmrt1 expression by environment is mediated through epigenetic mechanisms during development in species with TSD. Published by Elsevier Ireland Ltd.

  1. Sex Determination of Japanese Quails (Coturnix Coturnix Japonica using with Zoometric Measurements

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    Tülin Çiçek Rathert

    2017-09-01

    Full Text Available The difficulty of sex determination in most poultry species causes significant financial losses for poultry production as birds cannot be separated at early stages of growth for meat or egg production. Therefore it is important to determine bird’s sex with zoometric parameters. This study was carried out to determine the sex of Japanese quails with zoometric measurements, such as live weight, body length, chest depth and chest width. Eighty-eight male and female Japanese quail chicks were used individually for live weight, chest depth (mm, chest width (mm and body length (mm with using digital scaled balance and caliper for every week over a period of six weeks. The weekly collected data were applied to t test for estimating the sex discrimination. The Pearson’s correlation was applied for examining the interrelationship between sex and biometric traits. The results indicated that there was a significant positive correlation between live weight and body length beginning with the 2nd week. Therefore, zoometric measurement of these body traits is suitable for discriminating the sex of Japanese quails in early phase of life.

  2. Sex determination using facial linear dimensions and angles among Hausa population of Kano State, Nigeria

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    Lawan H. Adamu

    2016-12-01

    Full Text Available The aim of the study was to determine sexual dimorphism as well as to predict sex using facial linear dimensions and angles among Hausas of Kano state Nigeria. A total of 283 subjects comprising 147 males and 136 females age range 18–25 years participated. Photographs methods were used to capture the face. Independent sample t-test was used to test for sex differences in the variables. Binary logistic regression was applied to obtain a predicting equation (BLR model for sex. The predicted probabilities of BLR were analyzed using receiver operating characteristic curve. The results showed that all the facial linear dimensions showed significance sexual dimorphism except interocular distance, upper facial width, philtrum length, lower vermilion width, left and right orbital width. With regards to sex prediction, upper facial height was the single best predictor of sex with an accuracy of 76.2% and 24–33% contribution to the prediction. However, the percentage accuracy increased to 91% when six variables were pooled together in the equations. For facial angles, only nasion and aperture modified angle did not show significant gender differences. However, in the variables with significant sexual dimorphism only nasomental angle showed a significant level of sex prediction with an accuracy of 70.3%. In conclusion, sex discrimination using facial linear dimensions and angles was well established in this study. The sex of an individual of Hausa ethnic group can be determined using facial linear dimensions. Dispite sexual dimorphsm shown by facial angles, only nasomental angle was good discriminator of sex.

  3. Sex determination in femurs of modern Egyptians: A comparative study between metric measurements and SRY gene detection

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    Iman F. Gaballah

    2014-12-01

    Conclusion: The SRY gene detection method for sex determination is quick and simple, requiring only one PCR reaction. It corroborates the results obtained from anatomical measurements and further confirms the sex of the femur bone in question.

  4. Missing female fetus: a micro level investigation of sex determination in a periurban area of Northern India.

    Science.gov (United States)

    Ghosh, Rohini; Sharma, Arun Kumar

    2012-01-01

    A micro-level investigation of 983 pregnant women (aged 15-49 years) regarding sex determination and associated factors was carried out in a periurban region of Northern India. Among the women surveyed, 183 chose to use sex determination. The highest percentage of sex determination was among 30-39-year-old women, and general caste and family size were two risk factors associated with sex determination. Correcting imbalances in sex ratios at birth is a complex issue without easy answers, especially in patriarchal societies. Apart from raising awareness among decisionmakers, property rights in favor of women and strict vigilance and record of registration of ultrasound machines are necessary.

  5. Determination of sex-ratio by birth order in an urban community in Manipur.

    Science.gov (United States)

    Brogen, Akoijam S; Shantibala, K; Rajkumari, Bishwalata; Laishram, Jalina

    2009-01-01

    To determine the sex ratio by birth order and to assess the sex preference of the couples in an urban community. A cross sectional study, in an urban community in Manipur, was conducted among the currently married couples. Data on background characteristics of the couple, family pedigree chart (of the offspring) including history of abortion, stillbirth, death of child of the couple, sex preference and Pre-natal Diagnostic Techniques (Regulation and Prevention of Misuse) Act [PNDT Act] were collected through a structured interview. Data were analyzed using descriptive and chi-square statistics. There were a total of 1777 births to the 855 couples interviewed. There were 900 females per 1000 males for the 1st birth order but the sex ratio was favorable towards females in the 2nd, 3rd and 4th birth orders. Among both the husbands and wives, being more educated was significantly associated (p<0.05) with preferring lesser number of children, using new technology for sex selection and having heard of the PNDT Act. Majority of those who wanted to use new technology for sex selection (128, 56.6%) preferred to have male child. Sex ratio in this community was favorable towards females, though it was less among the first born babies.

  6. Sex determination and disorders of sex development according to the revised nomenclature and classification in 46,XX individuals.

    Science.gov (United States)

    Kousta, Eleni; Papathanasiou, Asteroula; Skordis, Nicos

    2010-01-01

    There have been considerable advances concerning understanding of the early and later stages of ovarian development; a number of genes have been implicated and their mutations have been associated with developmental abnormalities. The most important genes controlling the initial phase of gonadal development, identical in females and males, are Wilms' tumor suppressor 1 (WT1) and steroidogenic factor 1 (SF1). Four genes are likely to be involved in the subsequent stages of ovarian development (WNT4, DAX1, FOXL2 and RSPO1), but none is yet proven to be the ovarian determining factor. Changes in nomenclature and classification were recently proposed in order to incorporate genetic advances and substitute gender-based diagnostic labels in terminology. The term "disorders of sex development" (DSD) is proposed to substitute the previous term "intersex disorders". Three main categories have been used to describe DSD in the 46,XX individual: 1) disorders of gonadal (ovarian) development: ovotesticular DSD, previously named true hermaphroditism, testicular DSD, previously named XX males, and gonadal dysgenesis; 2) disorders related to androgen excess (congenital adrenal hyperplasia, aromatase deficiency and P450 oxidoreductase deficiency); and 3) other rare disorders. In this mini-review, recent advances concerning development of the genital system in 46,XX individuals and related abnormalities are discussed. Basic embryology of the ovary and molecular pathways determining ovarian development are reviewed, focusing on mutations disrupting normal ovarian development. Disorders of sex development according to the revised nomenclature and classification in 46,XX individuals are summarized, including genetic progress in the field.

  7. Computer-assisted sperm morphometry fluorescence-based analysis has potential to determine progeny sex

    Directory of Open Access Journals (Sweden)

    Pilar Santolaria

    2016-01-01

    Full Text Available This study was designed to determine the ability of computer-assisted sperm morphometry analysis (CASA-Morph with fluorescence to discriminate between spermatozoa carrying different sex chromosomes from the nuclear morphometrics generated and different statistical procedures in the bovine species. The study was divided into two experiments. The first was to study the morphometric differences between X- and Y-chromosome-bearing spermatozoa (SX and SY, respectively. Spermatozoa from eight bulls were processed to assess simultaneously the sex chromosome by FISH and sperm morphometry by fluorescence-based CASA-Morph. SX cells were larger than SY cells on average (P < 0.001 although with important differences between bulls. A simultaneous evaluation of all the measured features by discriminant analysis revealed that nuclear area and average fluorescence intensity were the variables selected by stepwise discriminant function analysis as the best discriminators between SX and SY. In the second experiment, the sperm nuclear morphometric results from CASA-Morph in nonsexed (mixed SX and SY and sexed (SX semen samples from four bulls were compared. FISH allowed a successful classification of spermatozoa according to their sex chromosome content. X-sexed spermatozoa displayed a larger size and fluorescence intensity than nonsexed spermatozoa (P < 0.05. We conclude that the CASA-Morph fluorescence-based method has the potential to find differences between X- and Y-chromosome-bearing spermatozoa in bovine species although more studies are needed to increase the precision of sex determination by this technique.

  8. Sex determination from scapular length measurements by CT scans images in a Caucasian population.

    Science.gov (United States)

    Giurazza, F; Schena, E; Del Vescovo, R; Cazzato, R L; Mortato, L; Saccomandi, P; Paternostro, F; Onofri, L; Zobel, B Beomonte

    2013-01-01

    Together with race, stature and age, sex is a main component of the biological identity. Thanks to its proportional correlation with parts of the human body, sex can be evaluated form the skeleton. The most accurate approach to determine sex by bone size is based on os coxae or skull. After natural disaster their presence can never be guaranteed, therefore the development of methods of sex determination using other skeletal elements can result crucial. Herein, sexual dimorphism in the human scapula is used to develop a two-variable discriminant function for sex estimation. We have enrolled 100 males and 100 females who underwent thoracic CT scan evaluation and we have estimated two scapular diameters. The estimation has been carried out by analyzing images of the scapulae of each patient after three dimensional post-processing reconstructions. The two-variable function allows to obtain an overall accuracy of 88% on the calibration sample. Furthermore, we have employed the mentioned function on a collection of 10 individual test sample from the collection of the "Museo di Anatomia Umana di Firenze" of the Università degli Studi di Firenze; sex has been correctly predicted on 9 skeletons.

  9. Yolk-albumen testosterone in a lizard with temperature-dependent sex determination: relation with development.

    Science.gov (United States)

    Huang, Victoria; Bowden, Rachel M; Crews, David

    2013-06-01

    The leopard gecko (Eublepharis macularius) exhibits temperature-dependent sex determination as well as temperature-influenced polymorphisms. Research suggests that in oviparous reptiles with temperature-dependent sex determination, steroid hormones in the yolk might influence sex determination and sexual differentiation. From captive leopard geckos that were all from the same incubation temperature regime, we gathered freshly laid eggs, incubated them at one of two female-biased incubation temperatures (26 or 34°C), and measured testosterone content in the yolk-albumen at early or late development. No differences in the concentration of testosterone were detected in eggs from different incubation temperatures. We report testosterone concentrations in the yolk-albumen were higher in eggs of late development than early development at 26°C incubation temperatures, a finding opposite that reported in other TSD reptiles studied to date. Copyright © 2013. Published by Elsevier Inc.

  10. Possibility of Morphometrical Determining of Sex of Steppe Eagle Nestlings from Western and Eastern Populations?

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    Igor V. Karyakin

    2018-03-01

    Full Text Available Sexual dimorphism among nestlings of the Steppe Eagle (Aquila nipalensis is poorly manifested. Thus, determining of sex by morphometric methods encountered many difficulties and could be completed only by the most experienced ornithologists who knows the species very well. This article presents a morphometric method for determining sex of nestlings of the Steppe Eagles from different breeding populations that belongs to different size classes. The method is based on classification formula obtained via linear discriminant analysis conducted for the data set of measurements of Steppe Eagle’s nestlings from Central Kazakhstan and Altai Republic in 2017. To control the sex determination of nestlings a molecular-genetics method was used.

  11. Segregating variation for temperature-dependent sex determination in a lizard.

    Science.gov (United States)

    Rhen, T; Schroeder, A; Sakata, J T; Huang, V; Crews, D

    2011-04-01

    Temperature-dependent sex determination (TSD) was first reported in 1966 in an African lizard. It has since been shown that TSD occurs in some fish, several lizards, tuataras, numerous turtles and all crocodilians. Extreme temperatures can also cause sex reversal in several amphibians and lizards with genotypic sex determination. Research in TSD species indicates that estrogen signaling is important for ovary development and that orthologs of mammalian genes have a function in gonad differentiation. Nevertheless, the mechanism that actually transduces temperature into a biological signal for ovary versus testis development is not known in any species. Classical genetics could be used to identify the loci underlying TSD, but only if there is segregating variation for TSD. Here, we use the 'animal model' to analyze inheritance of sexual phenotype in a 13-generation pedigree of captive leopard geckos, Eublepharis macularius, a TSD reptile. We directly show genetic variance and genotype-by-temperature interactions for sex determination. Additive genetic variation was significant at a temperature that produces a female-biased sex ratio (30°C), but not at a temperature that produces a male-biased sex ratio (32.5°C). Conversely, dominance variance was significant at the male-biased temperature (32.5°C), but not at the female-biased temperature (30°C). Non-genetic maternal effects on sex determination were negligible in comparison with additive genetic variance, dominance variance and the primary effect of temperature. These data show for the first time that there is segregating variation for TSD in a reptile and consequently that a quantitative trait locus analysis would be practicable for identifying the genes underlying TSD.

  12. Patterns of reproductive isolation in a haplodiploid - strong post-mating, prezygotic barriers among three forms of a social spider mite.

    Science.gov (United States)

    Sato, Yukie; Sakamoto, Hironori; Gotoh, Tetsuo; Saito, Yutaka; Chao, Jung-Tai; Egas, Martijn; Mochizuki, Atsushi

    2018-03-22

    In speciation research, much attention is paid to the evolution of reproductive barriers, preventing diverging groups from hybridizing back into one gene pool. The prevalent view is that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection and genetic drift in groups that are segregated spatially and/or temporally. Reproductive barriers, however, can also be reinforced by natural selection against maladaptive hybridization. These mutually compatible theories are both empirically supported by studies, analysing relationships between intensity of reproductive isolation and genetic distance in sympatric taxa and allopatric taxa. Here, we present the - to our knowledge - first comparative study in a haplodiploid organism, the social spider mite Stigmaeopsis miscanthi, by measuring premating and post-mating, pre- and post-zygotic components of reproductive isolation, using three recently diverged forms of the mite that partly overlap in home range. We carried out cross-experiments and measured genetic distances (mitochondrial DNA and nuclear DNA) among parapatric and allopatric populations of the three forms. Our results show that the three forms are reproductively isolated, despite the absence of premating barriers, and that the post-mating, prezygotic component contributes most to reproductive isolation. As expected, the strength of post-mating reproductive barriers positively correlated with genetic distance. We did not find a clear pattern of prezygotic barriers evolving faster in parapatry than in allopatry, although one form did show a trend in line with the ecological and behavioural relationships between the forms. Our study advocates the versatility of haplodiploid animals for investigating the evolution of reproductive barriers. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

  13. Methyl farnesoate synthesis is necessary for the environmental sex determination in the water flea Daphnia pulex.

    Science.gov (United States)

    Toyota, Kenji; Miyakawa, Hitoshi; Hiruta, Chizue; Furuta, Kenjiro; Ogino, Yukiko; Shinoda, Tetsuro; Tatarazako, Norihisa; Miyagawa, Shinichi; Shaw, Joseph R; Iguchi, Taisen

    2015-09-01

    Sex-determination systems can be divided into two groups: genotypic sex determination (GSD) and environmental sex determination (ESD). ESD is an adaptive life-history strategy that allows control of sex in response to environmental cues in order to optimize fitness. However, the molecular basis of ESD remains largely unknown. The micro crustacean Daphnia pulex exhibits ESD in response to various external stimuli. Although methyl farnesoate (MF: putative juvenile hormone, JH, in daphnids) has been reported to induce male production in daphnids, the role of MF as a sex-determining factor remains elusive due to the lack of a suitable model system for its study. Here, we establish such a system for ESD studies in D. pulex. The WTN6 strain switches from producing females to producing males in response to the shortened day condition, while the MFP strain only produces females, irrespective of day-length. To clarify whether MF has a novel physiological role as a sex-determining factor in D. pulex, we demonstrate that a MF/JH biosynthesis inhibitor suppressed male production in WTN6 strain reared under the male-inducible condition, shortened day-length. Moreover, we show that juvenile hormone acid O-methyltransferase (JHAMT), a critical enzyme of MF/JH biosynthesis, displays MF-generating activity by catalyzing farnesoic acid. Expression of the JHAMT gene increased significantly just before the MF-sensitive period for male production in the WTN6 strain, but not in the MFP strain, when maintained under male-inducible conditions. These results suggest that MF synthesis regulated by JHAMT is necessary for male offspring production in D. pulex. Our findings provide novel insights into the genetic underpinnings of ESD and they begin to shed light on the physiological function of MF as a male-fate determiner in D. pulex. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Differentiation of sex chromosomes and karyotypic evolution in the eye-lid geckos (Squamata: Gekkota: Eublepharidae), a group with different modes of sex determination.

    Science.gov (United States)

    Pokorná, Martina; Rábová, Marie; Ráb, Petr; Ferguson-Smith, Malcolm A; Rens, Willem; Kratochvíl, Lukáš

    2010-11-01

    The eyelid geckos (family Eublepharidae) include both species with temperature-dependent sex determination and species where genotypic sex determination (GSD) was suggested based on the observation of equal sex ratios at several incubation temperatures. In this study, we present data on karyotypes and chromosomal characteristics in 12 species (Aeluroscalabotes felinus, Coleonyx brevis, Coleonyx elegans, Coleonyx variegatus, Eublepharis angramainyu, Eublepharis macularius, Goniurosaurus araneus, Goniurosaurus lichtenfelderi, Goniurosaurus luii, Goniurosaurus splendens, Hemitheconyx caudicinctus, and Holodactylus africanus) covering all genera of the family, and search for the presence of heteromorphic sex chromosomes. Phylogenetic mapping of chromosomal changes showed a long evolutionary stasis of karyotypes with all acrocentric chromosomes followed by numerous chromosomal rearrangements in the ancestors of two lineages. We have found heteromorphic sex chromosomes in only one species, which suggests that sex chromosomes in most GSD species of the eyelid geckos are not morphologically differentiated. The sexual difference in karyotype was detected only in C. elegans which has a multiple sex chromosome system (X(1)X(2)Y). The metacentric Y chromosome evolved most likely via centric fusion of two acrocentric chromosomes involving loss of interstitial telomeric sequences. We conclude that the eyelid geckos exhibit diversity in sex determination ranging from the absence of any sexual differences to heteromorphic sex chromosomes, which makes them an interesting system for exploring the evolutionary origin of sexually dimorphic genomes.

  15. Prenatal sex determination by radioimmunoassay of testosterone with and without chromatography of the amniotic fluid

    International Nuclear Information System (INIS)

    Distler, W.; Boniver-Ollmann, U.; Tigges, J.; Terinde, R.; Claussen, U.

    1979-01-01

    Amniotic fluid testosterone measured by radioimmunoassay (RIA) without chromatography (immunoreactive testosterone) seems not to be a definitive test for prenatal sex determination in all cases. In this study testosterone (T) levels measured by RIA with chromatography of the amniotic fluid samples were compared with immunoreactive testosterone (iT) values, to determine the predictive accuracy of the two methods. In 111 amniotic fluid samples between 15 and 19 weeks of gestation iT and T were measured parallelly. There are significant differences between iT- and T-means of both sexes (p [de

  16. Multilocus Sex Determination Revealed in Two Populations of Gynodioecious Wild Strawberry, Fragaria vesca subsp. bracteata.

    Science.gov (United States)

    Ashman, Tia-Lynn; Tennessen, Jacob A; Dalton, Rebecca M; Govindarajulu, Rajanikanth; Koski, Matthew H; Liston, Aaron

    2015-10-19

    Gynodioecy, the coexistence of females and hermaphrodites, occurs in 20% of angiosperm families and often enables transitions between hermaphroditism and dioecy. Clarifying mechanisms of sex determination in gynodioecious species can thus illuminate sexual system evolution. Genetic determination of gynodioecy, however, can be complex and is not fully characterized in any wild species. We used targeted sequence capture to genetically map a novel nuclear contributor to male sterility in a self-pollinated hermaphrodite of Fragaria vesca subsp. bracteata from the southern portion of its range. To understand its interaction with another identified locus and possibly additional loci, we performed crosses within and between two populations separated by 2000 km, phenotyped the progeny and sequenced candidate markers at both sex-determining loci. The newly mapped locus contains a high density of pentatricopeptide repeat genes, a class commonly involved in restoration of fertility caused by cytoplasmic male sterility. Examination of all crosses revealed three unlinked epistatically interacting loci that determine sexual phenotype and vary in frequency between populations. Fragaria vesca subsp. bracteata represents the first wild gynodioecious species with genomic evidence of both cytoplasmic and nuclear genes in sex determination. We propose a model for the interactions between these loci and new hypotheses for the evolution of sex determining chromosomes in the subdioecious and dioecious Fragaria. Copyright © 2015 Ashman et al.

  17. Formal and informal sex education as determinants of premarital sexual behavior.

    Science.gov (United States)

    Spanier, G B

    1976-01-01

    Controversies exist regarding the effects of sex education in the schools and informal sex education obtained from parents, peers, the mass media, and other sources. Similarly, there is widespread interest in premarital sexual behavior, especially its determinants. This study presents several issues reflecting these concerns which have been the subject of much speculation but which have received little attention by researchers. The purpose of this study was to investigate--through the use of respondent reports--how formal and informal sex education influences premarital sexual behavior during college. A national probability sample of 1177 college students was studied using face-to-face interviews with approximately equal numbers of males and females. These interviews, which were conducted for the Institute for Sex Research, included questions about past and present sexual involvement and other attitudinal, behavioral and background variables. Accordingly, the data about sexual behavior and attitudes are based on the interviewees' self-reports. Indices were created which operationalized independent variables such as familial sexual conservatism, exposure to eroticism, perceived sex knowledge, and sexual exposure and assault during childhood and adolescence. Individual items reflecting childhood sex play, masturbation, current religiosity, religiosity while growing up, social class, sources of sex information, sex education in classrooms, and high school and college dating were used. The dependent variable, premarital sociosexual involvement, is a composite measure of incidence and prevalence of premarital heterosexual involvement which meets Guttman scaling criteria. An Automatic Interaction Detector analysis was used to determine the relative influences of reported sexualization variables on premarital sexual behavior. Major findings can be summarized as follows: Heterosexual behavior progresses in stepwise fashion from elementary to advanced levels of involvement

  18. Tribolium castaneum Transformer-2 regulates sex determination and development in both males and females.

    Science.gov (United States)

    Shukla, Jayendra Nath; Palli, Subba Reddy

    2013-12-01

    Tribolium castaneum Transformer (TcTra) is essential for female sex determination and maintenance through the regulation of sex-specific splicing of doublesex (dsx) pre-mRNA. In females, TcTra also regulates the sex-specific splicing of its own pre-mRNA to ensure continuous production of functional Tra protein. Transformer protein is absent in males and hence dsx pre-mRNA is spliced in a default mode. The mechanisms by which males inhibit the production of functional Tra protein are not known. Here, we report on functional characterization of transformer-2 (tra-2) gene (an ortholog of Drosophila transformer-2) in T. castaneum. RNA interference-mediated knockdown in the expression of gene coding for tra-2 in female pupae or adults resulted in the production of male-specific isoform of dsx and both female and male isoforms of tra suggesting that Tra-2 is essential for the female-specific splicing of tra and dsx pre-mRNAs. Interestingly, knockdown of tra-2 in males did not affect the splicing of dsx but resulted in the production of both female and male isoforms of tra suggesting that Tra-2 suppresses female-specific splicing of tra pre-mRNA in males. This dual regulation of sex-specific splicing of tra pre-mRNA ensures a tight regulation of sex determination and maintenance. These data suggest a critical role for Tra-2 in suppression of female sex determination cascade in males. In addition, RNAi studies showed that Tra-2 is also required for successful embryonic and larval development in both sexes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Sex determination of Pohnpei Micronesian kingfishers using morphological and molecular genetic techniques

    Science.gov (United States)

    Kesler, Dylan C.; Lopes, I.F.; Haig, Susan M.

    2006-01-01

    Conservation-oriented studies of Micronesian Kingfishers (Todiramphus cinnamominus) have been hindered by a lack of basic natural history information, despite the status of the Guam subspecies (T. c. cinnamominus) as one of the most endangered species in the world. We used tissue samples and morphometric measures from museum specimens and wild-captured Pohnpei Micronesian Kingfishers (T. c. reichenbachii) to develop methods for sex determination. We present a modified molecular protocol and a discriminant function that yields the probability that a particular individual is male or female. Our results revealed that females were significantly larger than males, and the discriminant function correctly predicted sex in 73% (30/41) of the individuals. The sex of 86% (18/21) of individuals was correctly assigned when a moderate reliability threshold was set. Sex determination using molecular genetic techniques was more reliable than methods based on morphology. Our results will facilitate recovery efforts for the critically endangered Guam Micronesian Kingfisher and provide a basis for sex determination in the 11 other endangered congeners in the Pacific Basin.

  20. The evolution of environmental and genetic sex determination in fluctuating environments.

    Science.gov (United States)

    Van Dooren, Tom J M; Leimar, Olof

    2003-12-01

    Twenty years ago, Bulmer and Bull suggested that disruptive selection, produced by environmental fluctuations, can result in an evolutionary transition from environmental sex determination (ESD) to genetic sex determination (GSD). We investigated the feasibility of such a process, using mutation-limited adaptive dynamics and individual-based computer simulations. Our model describes the evolution of a reaction norm for sex determination in a metapopulation setting with partial migration and variation in an environmental variable both within and between local patches. The reaction norm represents the probability of becoming a female as a function of environmental state and was modeled as a sigmoid function with two parameters, one giving the location (i.e., the value of the environmental variable for which an individual has equal chance of becoming either sex) and the other giving the slope of the reaction norm for that environment. The slope can be interpreted as being set by the level of developmental noise in morph determination, with less noise giving a steeper slope and a more switchlike reaction norm. We found convergence stable reaction norms with intermediate to large amounts of developmental noise for conditions characterized by low migration rates, small differential competitive advantages between the sexes over environments, and little variation between individual environments within patches compared to variation between patches. We also considered reaction norms with the slope parameter constrained to a high value, corresponding to little developmental noise. For these we found evolutionary branching in the location parameter and a transition from ESD toward GSD, analogous to the original analysis by Bulmer and Bull. Further evolutionary change, including dominance evolution, produced a polymorphism acting as a GSD system with heterogamety. Our results point to the role of developmental noise in the evolution of sex determination.

  1. Computer-assisted sperm morphometry fluorescence-based analysis has potential to determine progeny sex.

    Science.gov (United States)

    Santolaria, Pilar; Pauciullo, Alfredo; Silvestre, Miguel A; Vicente-Fiel, Sandra; Villanova, Leyre; Pinton, Alain; Viruel, Juan; Sales, Ester; Yániz, Jesús L

    2016-01-01

    This study was designed to determine the ability of computer-assisted sperm morphometry analysis (CASA-Morph) with fluorescence to discriminate between spermatozoa carrying different sex chromosomes from the nuclear morphometrics generated and different statistical procedures in the bovine species. The study was divided into two experiments. The first was to study the morphometric differences between X- and Y-chromosome-bearing spermatozoa (SX and SY, respectively). Spermatozoa from eight bulls were processed to assess simultaneously the sex chromosome by FISH and sperm morphometry by fluorescence-based CASA-Morph. SX cells were larger than SY cells on average (P potential to find differences between X- and Y-chromosome-bearing spermatozoa in bovine species although more studies are needed to increase the precision of sex determination by this technique.

  2. Applying iPSCs for Preserving Endangered Species and Elucidating the Evolution of Mammalian Sex Determination.

    Science.gov (United States)

    Honda, Arata

    2018-04-06

    The endangered species Tokudaia osimensis has the unique chromosome constitution of 2n = 25, with an XO/XO sex chromosome configuration (2n = 25; XO). There is urgency to preserve this species and to elucidate the regulator(s) that can discriminate the males and females arising from the indistinguishable sex chromosome constitution. However, it is not realistic to examine this rare animal species by sacrificing individuals. Recently, true naïve induced pluripotent stem cells were successfully generated from a female T. osimensis, and the sexual plasticity of its germ cells was elucidated. This achievement constitutes the basis of an attractive research area, including embryonic fate determination, sex determination, and factor(s) that can replace the Y chromosome. In this essay, concrete strategies to conserve rare animal species and to reveal their specific characteristics using other compatible and abundant animals are proposed. © 2018 WILEY Periodicals, Inc.

  3. Determination of Sperm Sex Ratio in Bovine Semen Using Multiplex Real-time Polymerase Chain Reaction

    Directory of Open Access Journals (Sweden)

    Trisadee Khamlor

    2014-10-01

    Full Text Available Gender selection is important in livestock industries; for example, female calves are required in the dairy industry. Sex-sorted semen is commonly used for the production of calves of the desired gender. However, assessment of the sex ratio of the sorted semen is tedious and expensive. In this study, a rapid, cost effective and reliable method for determining the sex ratio was developed using a multiplex real-time polymerase chain reaction (PCR assay. In this assay, the X and Y chromosome-specific markers, i.e., bovine proteolipid protein (PLP gene and sex-determining region Y (SRY were simultaneously quantified in a single tube. The multiplex real-time PCR assay was shown to have high amplification efficiencies (97% to 99% comparable to the separated-tube simplex real-time PCR assay. The results obtained from both assays were not significantly different (p>0.05. The multiplex assay was validated using reference DNA of known X ratio (10%, 50%, and 90% as templates. The measured %X in semen samples were the same within 95% confidence intervals as the expected values, i.e., >90% in X-sorted semen, <10% in Y-sorted semen and close to 50% in the unsorted semen. The multiplex real-time PCR assay as shown in this study can thus be used to assess purity of sex-sorted semen.

  4. The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size.

    Science.gov (United States)

    Rideout, Elizabeth J; Narsaiya, Marcus S; Grewal, Savraj S

    2015-12-01

    Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.

  5. The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size.

    Directory of Open Access Journals (Sweden)

    Elizabeth J Rideout

    2015-12-01

    Full Text Available Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.

  6. Label-free detection of sex determining region Y (SRY) via capacitive biosensor

    KAUST Repository

    Sivashankar, Shilpa; Sapsanis, Christos; Agambayev, Sumeyra; Buttner, Ulrich; Salama, Khaled N.

    2016-01-01

    In this work, we present for the first time, the use of a simple fractal capacitive biosensor for the quantification and detection of sex-determining region Y (SRY) genes. This section of genetic code, which is found on the Y chromosome, finds

  7. Observation of a ZZW female in a natural population: implications for avian sex determination.

    Science.gov (United States)

    Arit, D; Bensch, S; Hansson, B; Hasselquist, D; Westerdahl, H

    2004-01-01

    Avian sex determination is chromosomal; however, the underlying mechanisms are not yet understood. There is no conclusive evidence for either of two proposed mechanisms: a dominant genetic switch or a dosage mechanism. No dominant sex-determining gene on the female-specific W chromosome has been found. Birds lack inactivation of one of the Z chromosomes in males, but seem to compensate for a double dose of Z-linked genes by other mechanisms. Recent studies showing female-specific expression of two genes may support an active role of the W chromosome. To resolve the question of avian sex determination the investigation of birds with a 2A: ZZW or 2A: ZO genotype would be decisive. Here, we report the case of an apparent 2A: ZZW great reed warbler (Acrocephalus arundinaceus) female breeding in a natural population, which was detected using Z-linked microsatellites. Our data strongly suggest a role of W-linked genes in avian sex determination. PMID:15252998

  8. Determinants of Human Papillomavirus Vaccination Intention Among Female Sex Workers in Amsterdam, the Netherlands

    NARCIS (Netherlands)

    Marra, E.; Dam, L. van; Kroone, N.; Alberts, C.J.; Craanen, M.; Zimet, G.D.; Heijmam, T.; Hogewoning, A.A.; Sonder, G.J.B.; Vries, H.J.C. de; Alberts, C.J.; Paulussen, T.G.W.M.; Schim van der Loeff, M.F.

    2017-01-01

    Introduction: Female sex workers (FSWs) are at risk for human papillomavirus (HPV)-induced diseases but are currently not targeted by the HPV vaccination program in the Netherlands. We explored determinants of their intention to get vaccinated against HPV in case vaccination would be offered to

  9. What was the ancestral sex-determining mechanism in amniote vertebrates?

    Czech Academy of Sciences Publication Activity Database

    Johnson Pokorná, Martina; Kratochvíl, L.

    2016-01-01

    Roč. 91, č. 1 (2016), s. 1-12 ISSN 1464-7931 R&D Projects: GA ČR GAP506/10/0718 Institutional support: RVO:67985904 Keywords : environmental sex determination * phylogeny * polyphenism Subject RIV: EG - Zoology Impact factor: 11.615, year: 2016

  10. Application of three-dimensional reconstruction technology in establishment of atlas space model and sex determination

    International Nuclear Information System (INIS)

    Zhou Jianying; Tian Yong; He Qing; Li Youqiong; Han Qing; Cheng Kailiang

    2013-01-01

    Objective: To establish the method of using the atlas morphological indexes for sex determination in Jilin province and to evaluate its effect. Methods: The clinic neck CT images were used to reconstruct the 3D image of atlas. A total of 27 linear measurement on 8 aspects of the atlas were measured and the ratios were calculated. The 14 items were selected. Results: Of the total 27 linear measurements, 14 were sexually dimorphic (P<0.05), and the accuracies of sex determination of 27 indexes were 52.0% -89.3% . The highest accuracy was width of vertebral body (86.7% ). A function with variables predicting sex with 96.8% accuracy was derived by using stepwise method of discriminant function analysis: Y=1.308W - 0.409CDF - 0.469LTPSD - 0.849LUACD + 0.478RUACD + 0.332RDACD + 0.363ATH - 0.334PTH - 0.236PAL. Conclusion: The method of using atlas traits for sex determination in Jilin province is practicable. (authors)

  11. Sex determination from the radius and ulna in a modern South African sample.

    Science.gov (United States)

    Barrier, I L O; L'Abbé, E N

    2008-07-18

    With a large number of unidentified skeletal remains found in South Africa, the development of population specific osteometric standards is imperative. Forensic anthropologists need to have access to a variety of techniques to establish accurate demographic profiles from complete, fragmentary and/or commingled remains. No research has been done on the forearm of African samples, even though these bones have been shown to exhibit sexual dimorphism. The purpose of this paper is to develop discriminant function formulae to determine sex from the radius and ulna in a South African population. The sample consisted of 200 male and 200 female skeletons from the Pretoria Bone (University of Pretoria) and Raymond A. Dart (Witwatersrand University) collections. Sixteen standard anthropometric measurements were taken from the radius (9) and ulna (7) and subjected to stepwise and direct discriminant function analysis. Distal breadth, minimum mid-shaft diameter and maximum head diameter were the best discriminators of sex for the radius, while minimum mid-shaft diameter and olecranon breadth were selected for the ulna. Classification accuracy for the forearm ranged from 76 to 86%. The radius and ulna can be considered moderate discriminators for determining sex in a South African group. However, it is advised that these formulae are used in conjunction with additional methods to determine sex.

  12. Analysis of genes involved in sex determination of fishes by phenol-emulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Ichiro; Nagoya, Hiroyuki; Okamoto, Hiroyuki; Araki, Kazuo [National Research Inst. of Aquaculture, Mie (Japan)

    1998-02-01

    With an aim to clarify the mechanism of sex determination common to vertebrates, the genes presumed to mediate the sex determination were analyzed through cDNA subtraction by phenol-emulsion method. A total RNA was extracted from male juvenile Amago, a kind of oncorhynchus and cDNA was synthesized using mRNA fractionated by oligo-dT column. The male-specific genes expressed in the stage of sex determination was isolated through incorporation to PVC-derived vector. Thus obtained genes were confirmed to be male-specific by Southern hybridization. The results of the screening for the subtracted products indicate that neither of the male-specific clones detected in this study was novel. Previous studies on sex discrimination based on mitochondrial DNA suggested that Sakuramasu and Amago belong in the same species, Oncorhynchus masou masou and the present results show that DNA sequence for male-derived GH pseudo-gene is partially different between the two fishes. (M.N.)

  13. Heel–Ball index: An analysis of footprint dimensions for determination of sex

    Directory of Open Access Journals (Sweden)

    Tanuj Kanchan

    2014-06-01

    Full Text Available Determination of sex from the footprints recovered at crime scenes can help the investigation by narrowing down the pool of possible suspects. The present research studies the dimensions of the heel and the ball in footprints, and derives the Heel–Ball (HB index from these foot dimensions with the aim to find out if the foot dimensions and the HB index exhibit sexual dimorphisms. The study was carried out on 100 individuals (50 males, 50 females of Indian origin. Footprints were obtained from both feet of the study participants using standard techniques. Thus, a total of 200 footprints were obtained. The breadth of the footprint at ball (BBAL and the breadth of the footprint at heel (BHEL were measured on the footprints. The HB index was derived as (BHEL ÷ BBAL × 100. The footprint measurements at the ball and heel were significantly larger in males on both the sides. Likewise, the derived HB index was larger in males in both feet, but the sex differences were not statistically significant. The study concludes that though footprint dimensions can be used in the determination of sex, the HB index may not be utilized in sex determination from footprints.

  14. Sex determination from hand and foot dimensions in a North Indian population.

    Science.gov (United States)

    Krishan, Kewal; Kanchan, Tanuj; Sharma, Abhilasha

    2011-03-01

    Hands and feet are often recovered from the site of natural as well as man-made disasters because of bomb blasts, train accidents, plane crashes, or mass homicides. This study is intended to establish standards for determination of sex from the dimensions of hands and feet in a North Indian population. The data for this study comprise 123 men and 123 women aged between 17 and 20 years from the "Rajput" population of Himachal Pradesh in North India. Four anthropometric measurements viz. hand length, hand breadth, foot length, and foot breadth have been taken on both sides of each subject following international anthropometric standards. The hand index (hand breadth/hand length × 100) and the foot index (foot breadth/foot length × 100) were calculated. Sectioning points and regression models are derived for the hand and foot dimensions and the derived indices. The hand and foot dimensions show a higher accuracy in sex determination by sectioning point analysis when compared to hand and foot index. Of the hand and the foot dimensions, hand breadth and foot breadth showed better accuracy in sex determination. Hand index and foot index remain poor sex discriminators in the study. © 2011 American Academy of Forensic Sciences.

  15. Sex-specific markers developed by next-generation sequencing confirmed an XX/XY sex determination system in bighead carp (Hypophthalmichehys nobilis) and silver carp (Hypophthalmichthys molitrix).

    Science.gov (United States)

    Liu, Haiyang; Pang, Meixia; Yu, Xiaomu; Zhou, Ying; Tong, Jingou; Fu, Beide

    2018-01-05

    Sex-specific markers are powerful tools for identifying sex-determination system in various animals. Bighead carp (Hypophthalmichehys nobilis) and silver carp (Hypophthalmichthys molitrix) are two of the most important edible fish in Asia, which have a long juvenility period that can lasts for 4-5 years. In this study, we found one sex-specific marker by next-generation sequencing together with bioinformatics analysis in bighead carp. The male-specific markers were used to perform molecular sexing in the progenies of artificial gynogenetic diploids and found all progenies (n = 160) were females. Meanwhile, around 1 : 1 sex ratio was observed in a total of 579 juvenile offspring from three other families. To further extend the male-specific region, we performed genome walking and got a male-specific sequence of 8,661 bp. Five pairs of primers were designed and could be used to efficiently distinguish males from females in bighead carp and silver carp. The development of these male-specific markers and results of their molecular sexing in different populations provide strong evidence for a sex determination system of female homogametry or male heterogametry (XX/XY) in bighead carp and silver carp. To the best of our knowledge, this is the first report of effective sex-specific markers in these two large carp species. © The Author(s) 2018. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

  16. Clinical significance of serum sex hormones protein and lipid determination in patients with ulcerative colitis

    International Nuclear Information System (INIS)

    Song Qingzhang; Zhang Min

    2010-01-01

    Objective: To investigate the relationships between changes of serum sex hormones levels and protein-lipid metabolism in patients with ulcerative colitis. Methods: Serum levels of estradiol (E 2 ) pregnenedione (P), prolactin(PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH) (with CLIA), sree testos (T, with RIA) and total-protein (TP), albumin (Alb), globulin (G), albumin/globulinratio (A/G) total-cholesterd (TC), high density lipoprotein cholesterols (LDL-C) (with biochemistry were determined in 72 patients) with ulcerative colitis and 72 controls. Results: The serum levels of T, LH, FSH, TP, Alb, A/G, TC, LDL-C in patients with ulcerative colitis were significantly lower than those in controls (P 2 , PRL in patients with ulcerative colitis were significantly higher than those in controls (P 2 were negatively correlated with TP, A/G and TC (P 2 levels in the female sex (P>0.05) as well as between LH, FSH and T levels in the male sex (P>0.05). Conclusion: The abnormal serum levels of sex hormone might contribute to the development of hypoproteinaemia and lowered lipid levels in patients with ulcerative colitis. Treatment with correction of serum sex hormones levels might be beneficial to the patients. (authors)

  17. Temperature-dependent sex determination modulates cardiovascular maturation in embryonic snapping turtles Chelydra serpentina.

    Science.gov (United States)

    Alvine, Travis; Rhen, Turk; Crossley, Dane A

    2013-03-01

    We investigated sex differences in cardiovascular maturation in embryos of the snapping turtle Chelydra serpentina, a species with temperature-dependent sex determination. One group of eggs was incubated at 26.5°C to produce males. Another group of eggs was incubated at 26.5°C until embryos reached stage 17; eggs were then shifted to 31°C for 6 days to produce females, and returned to 26.5°C for the rest of embryogenesis. Thus, males and females were at the same temperature when autonomic tone was determined and for most of development. Cholinergic blockade increased resting blood pressure (P(m)) and heart rate (f(H)) in both sexes at 75% and 90% of incubation. However, the magnitude of the f(H) response was enhanced in males compared with females at 90% of incubation. β-adrenergic blockade increased P(m) at 75% of incubation in both sexes but had no effect at 90% of incubation. β-adrenergic blockade reduced f(H) at both time points but produced a stronger response at 90% versus 75% of incubation. We found that α-adrenergic blockade decreased P(m) in both sexes at 75% and 90% of incubation and decreased f(H) at 75% of incubation in both sexes. At 90% of incubation, f(H) decreased in females but not males. Although these data clearly demonstrate sexual dimorphism in the autonomic regulation of cardiovascular physiology in embryos, further studies are needed to test whether differences are caused by endocrine signals from gonads or by a hormone-independent temperature effect.

  18. A Novel Candidate Gene for Temperature-Dependent Sex Determination in the Common Snapping Turtle

    Science.gov (United States)

    Schroeder, Anthony L.; Metzger, Kelsey J.; Miller, Alexandra; Rhen, Turk

    2016-01-01

    Temperature-dependent sex determination (TSD) was described nearly 50 years ago. Researchers have since identified many genes that display differential expression at male- vs. female-producing temperatures. Yet, it is unclear whether these genes (1) are involved in sex determination per se, (2) are downstream effectors involved in differentiation of ovaries and testes, or (3) are thermo-sensitive but unrelated to gonad development. Here we present multiple lines of evidence linking CIRBP to sex determination in the snapping turtle, Chelydra serpentina. We demonstrate significant associations between a single nucleotide polymorphism (SNP) (c63A > C) in CIRBP, transcript levels in embryonic gonads during specification of gonad fate, and sex in hatchlings from a thermal regime that produces mixed sex ratios. The A allele was induced in embryos exposed to a female-producing temperature, while expression of the C allele did not differ between female- and male-producing temperatures. In accord with this pattern of temperature-dependent, allele-specific expression, AA homozygotes were more likely to develop ovaries than AC heterozygotes, which, in turn, were more likely to develop ovaries than CC homozygotes. Multiple regression using SNPs in CIRBP and adjacent loci suggests that c63A > C may be the causal variant or closely linked to it. Differences in CIRBP allele frequencies among turtles from northern Minnesota, southern Minnesota, and Texas reflect small and large-scale latitudinal differences in TSD pattern. Finally, analysis of CIRBP protein localization reveals that CIRBP is in a position to mediate temperature effects on the developing gonads. Together, these studies strongly suggest that CIRBP is involved in determining the fate of the bipotential gonad. PMID:26936926

  19. Sex determination in Turdus amaurochalinus (Passeriformes: Muscicapidae: morphometrical analysis supported by CHD gene

    Directory of Open Access Journals (Sweden)

    Katyucha Von Kossel de Andrade Silva

    2011-06-01

    Full Text Available Sex determination is important for conservation and population studies, particularly for reproduction programs of threatened species and behavioural ecology. Turdus amaurochalinus, Creamy-bellied Thrush, only exhibits sexual dimorphism during the breeding season, when males are considered to show intense yellow bills, and females and immature males show dark brown bills. The objectives of this study were: 1 to determine the sex of individuals using genetic techniques, and 2 to test the hypothesis that sex dimorphism can be detected by morphometry. This study was carried out at Parque Nacional da Restinga de Jurubatiba, a preserved area located on the North coast of Rio de Janeiro State. The birds were captured using ornithological nets, singly marked with metal rings, weighed, measured and had blood samples collected before being released. The sex of 42 T. amaurochalinus individuals was determined using the CHD gene marker. A total of 20 males and 22 females were identified from June to August, with peak capture frequency in June. Turdus amaurochalinus females and males differed significantly in morphometrical measures. The most important traits to distinguish males from females were wing length (Student t-test=4.34, df=40, p=0.0001 and weight (Student t-test=2.08,df=40, p=0.044: females were heavier and had significantly shorter wing length than males. Females and males were correctly classified in 86% and 75% of cases, respectively, using Discriminant Analysis. The molecular analysis was the most secure method for sex determination in the studied species. Rev. Biol. Trop. 59 (2: 789- 794. Epub 2011 June 01.

  20. PRECONCEPTION AND PRENATAL DIAGNOSTIC TECHNIQUES ACT 1994 AND ITS MAIN ROLE TO CURB SEX DETERMINATION AND SEX SELECTION

    OpenAIRE

    Adv. Vaishali V. Waghmare; Dr. (Mrs) Hema Menon

    2016-01-01

    India has a male dominated culture where women are treated like a commodity and slave. Our Indian society gives preference only to the Son not to female because of which girls' child is not heartily welcomed and discrimination against girl child still prevails. Sex selective abortion is one of major issue in recent era in relation to violence against women under which the Ultrasonography machine plays an important role of sex detection. Main cause for sex selection are Patriarchal system, Do...

  1. Delimitation of the embryonic thermosensitive period for sex determination using an embryo growth model reveals a potential bias for sex ratio prediction in turtles.

    Science.gov (United States)

    Girondot, Marc; Monsinjon, Jonathan; Guillon, Jean-Michel

    2018-04-01

    The sexual phenotype of the gonad is dependent on incubation temperature in many turtles, all crocodilians, and some lepidosaurians. At hatching, identification of sexual phenotype is impossible without sacrificing the neonates. For this reason, a general method to infer sexual phenotype from incubation temperatures is needed. Temperature influences sex determination during a specific period of the embryonic development, starting when the gonad begins to form. At constant incubation temperatures, this thermosensitive period for sex determination (TSP) is located at the middle third of incubation duration (MTID). When temperature fluctuates, the position of the thermosensitive period for sex determination can be shifted from the MTID because embryo growth is affected by temperature. A method is proposed to locate the thermosensitive period for sex determination based on modelling the embryo growth, allowing its precise identification from a natural regime of temperatures. Results from natural nests and simulations show that the approximation of the thermosensitive period for sex determination to the middle third of incubation duration may create a quasi-systematic bias to lower temperatures when computing the average incubation temperature during this period and thus a male-bias for sex ratio estimate. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Sex determination using humeral dimensions in a sample from KwaZulu-Natal: an osteometric study.

    Science.gov (United States)

    Ogedengbe, Oluwatosin Olalekan; Ajayi, Sunday Adelaja; Komolafe, Omobola Aderibigbe; Zaw, Aung Khaing; Naidu, Edwin Coleridge Stephen; Okpara Azu, Onyemaechi

    2017-09-01

    The morphological characteristics of the humeral bone has been investigated in recent times with studies showing varying degrees of sexual dimorphism. Osteologists and forensic scientists have shown that sex determination methods based on skeletal measurements are population specific, and these population-specific variations are present in many body dimensions. The present study aims to establish sex identification using osteometric standards for the humerus in a contemporary KwaZulu-Natal population. A total of 11 parameters were measured in a sample of n=211 humeri (males, 113; females, 98) from the osteological collection in the Discipline of Clinical Anatomy, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa. The difference in means for nearly all variables were found to be significantly higher in males compared to females ( P <0.01) with the most effective single parameter for predicting sex being the vertical head diameter having an accuracy of 82.5%. Stepwise discriminant analysis increased the overall accuracy rate to 87.7% when all measurements were jointly applied. We conclude that the humerus is an important bone which can be reliably used for sex determination based on standard metric methods despite minor tribal or ancestral differences amongst an otherwise homogenous population.

  3. Phenotypic differences in teeth dimensions among Chennai population: An aid in sex determination

    Directory of Open Access Journals (Sweden)

    Sreedevi Dharman

    2015-01-01

    Full Text Available Objective: To investigate the presence of sexual dimorphism by studying the size of the teeth among males and females in Chennai population, which aids in sex determination. Materials and Methods: Incisocervical length, mesiodistal and buccolingual diameters were measured in teeth of 60 subjects (30 males, 30 females in the age group of 18-22 years from Chennai population. The differences in the mean values of parameters in males and females were calculated using independent t-test. Discriminant functional analysis was performed to determine the accuracy of sex. Results: Significant differences were found in mean incisocervical length which were found to be larger in males with P < 0.05 in 11, 12, 14, 17, 21, 22, 24, 26, 27, 31, 32, 33, 34, 41, 43, and 45 and with P < 0.001 in 13, 23, 32, 42, 43, and 44, with the exception of 37 and 47 which were larger in females. Mean mesiodistal diameter was larger in males with P < 0.05 in 11, 12, and 21 and with P < 0.001 in 13, 23, 33, and 43. Mean buccolingual diameter was larger in males with P < 0.05 in 12, 21, 31, 33, and 41 and with P < 0.001 in 11, 13, 23, and 43. Accuracy rate of predicting sex based on incisocervical length (17, 23, 47 and mesiodistal diameter (13, 33 was 78.3% and based on buccolingual diameter (13 was 76.7%. Conclusion: Males showed greater sexual dimorphism than females. Application of incisocervical, mesiodistal, and buccolingual dimensional variability among males and females in the Chennai population can aid in sex determination in forensic odontology, as the results showed moderate extent of dimorphism with an overall accuracy rate of predicting sex to be 78%.

  4. Gadd45g is essential for primary sex determination, male fertility and testis development.

    Directory of Open Access Journals (Sweden)

    Heiko Johnen

    Full Text Available In humans and most mammals, differentiation of the embryonic gonad into ovaries or testes is controlled by the Y-linked gene SRY. Here we show a role for the Gadd45g protein in this primary sex differentiation. We characterized mice deficient in Gadd45a, Gadd45b and Gadd45g, as well as double-knockout mice for Gadd45ab, Gadd45ag and Gadd45bg, and found a specific role for Gadd45g in male fertility and testis development. Gadd45g-deficient XY mice on a mixed 129/C57BL/6 background showed varying degrees of disorders of sexual development (DSD, ranging from male infertility to an intersex phenotype or complete gonadal dysgenesis (CGD. On a pure C57BL/6 (B6 background, all Gadd45g(-/- XY mice were born as completely sex-reversed XY-females, whereas lack of Gadd45a and/or Gadd45b did not affect primary sex determination or testis development. Gadd45g expression was similar in female and male embryonic gonads, and peaked around the time of sex differentiation at 11.5 days post-coitum (dpc. The molecular cause of the sex reversal was the failure of Gadd45g(-/- XY gonads to achieve the SRY expression threshold necessary for testes differentiation, resulting in ovary and Müllerian duct development. These results identify Gadd45g as a candidate gene for male infertility and 46,XY sex reversal in humans.

  5. Constraints on temperature-dependent sex determination in the leopard gecko (Eublepharis macularius): response to Kratochvil et al.

    Science.gov (United States)

    Huang, Victoria; Sakata, Jon T; Rhen, Turk; Coomber, Patricia; Simmonds, Sarah; Crews, David

    2008-12-01

    Kratochvil et al. (Naturwissenschaften 95:209-215, 2008) reported recently that in the leopard gecko (Eublepharis macularius) of the family Eublepharidae with temperature-dependent sex determination (TSD), clutches in which eggs were incubated at the same temperature produce only same-sex siblings. Interpreting this result in light of studies of sex steroid hormone involvement in sex determination, they suggested that maternally derived yolk steroid hormones could constrain sex-determining mechanisms in TSD reptiles. We have worked extensively with this species and have routinely incubated clutches at constant temperatures. To test the consistency of high frequency same-sex clutches across different incubation temperatures, we examined our records of clutches at the University of Texas at Austin from 1992 to 2001. We observed that clutches in which eggs were incubated at the same incubation temperature produced mixed-sex clutches as well as same-sex clutches. Furthermore, cases in which eggs within a clutch were separated and incubated at different temperatures produced the expected number of mixed-sex clutches. These results suggest that maternal influences on sex determination are secondary relative to incubation temperature effects.

  6. Suitability of foramen magnum measurements in sex determination and their clinical significance.

    Science.gov (United States)

    Tellioglu, A Metin; Durum, Y; Gok, M; Karakas, S; Polat, A G; Karaman, C Z

    2018-01-01

    The foramen magnum provides a transition between fossa cranii posterior and canalis vertebralis. Medulla oblongata, arteria vertebralis and nervus accessorius spinal part pass through the foramen magnum. In this study, we aimed to make the morphometric measurements of the foramen magnum on computed tomography (CT) and to determine the feasibility of sex determination based on these measurements. Besides sex determination, from a clinical aspect, it is important to know the measurements of the foramen magnum in the normal population in terms of diseases characterised by displacement of the posterior fossa structures through foramen magnum to upper cervical spinal canal such as Chiari malformations and syringomyelia. All the data for our study was obtained retrospectively from 100 patients (50 males, 50 females) who had a CT scan of the head and neck region in Adnan Menderes University Hospital, Department of Radiology. To examine the foramen magnum in each and every occipital bone, we measured the foramen magnum's anteroposterior diameter, transverse diameter, the area of the foramen magnum and its circumference. We found that men have a higher average value than women in our study. According to Student's t-test results; in all measured parameters, there is significant difference between the genders (p discriminant function test is performed for all four measurements, the discrimination rate is 64% for all women, 70% for all men and 67% for both genders. As a result of our study, the metric data we obtained will be useful in cases where the skeletons' sex could not be determined by any other methods. We believe that, our study may be useful for other studies in determining of sex from foramen magnum. Our measurements could give some information of the normal ranges of the foramen magnum in normal population, so that this can contribute to the diagnosis process of some diseases by imaging. (Folia Morphol 2018; 77, 1: 99-104).

  7. MYB transcription factor gene involved in sex determination in Asparagus officinalis.

    Science.gov (United States)

    Murase, Kohji; Shigenobu, Shuji; Fujii, Sota; Ueda, Kazuki; Murata, Takanori; Sakamoto, Ai; Wada, Yuko; Yamaguchi, Katsushi; Osakabe, Yuriko; Osakabe, Keishi; Kanno, Akira; Ozaki, Yukio; Takayama, Seiji

    2017-01-01

    Dioecy is a plant mating system in which individuals of a species are either male or female. Although many flowering plants evolved independently from hermaphroditism to dioecy, the molecular mechanism underlying this transition remains largely unknown. Sex determination in the dioecious plant Asparagus officinalis is controlled by X and Y chromosomes; the male and female karyotypes are XY and XX, respectively. Transcriptome analysis of A. officinalis buds showed that a MYB-like gene, Male Specific Expression 1 (MSE1), is specifically expressed in males. MSE1 exhibits tight linkage with the Y chromosome, specific expression in early anther development and loss of function on the X chromosome. Knockout of the MSE1 orthologue in Arabidopsis induces male sterility. Thus, MSE1 acts in sex determination in A. officinalis. © 2016 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  8. XX/XY system of sex determination in the geophilomorph centipede Strigamia maritima

    Czech Academy of Sciences Publication Activity Database

    Green, J. E.; Dalíková, Martina; Sahara, K.; Marec, František; Akam, M.

    2016-01-01

    Roč. 11, č. 2 (2016), č. článku e0150292. E-ISSN 1932-6203 R&D Projects: GA AV ČR IAA600960925; GA ČR(CZ) GA14-22765S Institutional support: RVO:60077344 Keywords : sex determination * Strigamia maritima * XX/XY system Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.806, year: 2016 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0150292

  9. A complex interaction of imprinted and maternal-effect genes modifies sex determination in Odd Sex (Ods) mice.

    Science.gov (United States)

    Poirier, Christophe; Qin, Yangjun; Adams, Carolyn P; Anaya, Yanett; Singer, Jonathan B; Hill, Annie E; Lander, Eric S; Nadeau, Joseph H; Bishop, Colin E

    2004-11-01

    The transgenic insertional mouse mutation Odd Sex (Ods) represents a model for the long-range regulation of Sox9. The mutation causes complete female-to-male sex reversal by inducing a male-specific expression pattern of Sox9 in XX Ods/+ embryonic gonads. We previously described an A/J strain-specific suppressor of Ods termed Odsm1(A). Here we show that phenotypic sex depends on a complex interaction between the suppressor and the transgene. Suppression can be achieved only if the transgene is transmitted paternally. In addition, the suppressor itself exhibits a maternal effect, suggesting that it may act on chromatin in the early embryo.

  10. Incubation temperature and gonadal sex affect growth and physiology in the leopard gecko (Eublepharis macularius), a lizard with temperature-dependent sex determination.

    Science.gov (United States)

    Tousignant, A; Crews, D

    1995-05-01

    Temperature-dependent sex determination (TSD), in which the temperature at which an egg incubates determines the sex of the individual, occurs in egg-laying reptiles of three separate orders. Previous studies have shown that the embryonic environment can have effects lasting beyond the period of sex determination. We investigated the relative roles of incubation temperature, exogenous estradiol, and gonadal sex (testis vs. ovary) in the differentiation of adult morphological and physiological traits of the leopard gecko, Eublepharis macularius. The results indicate that incubation temperature, steroid hormones, and gonads interact in the development of morphological and physiological characters with incubation temperature resulting in the greatest differences in adult phenotype. Incubation temperature did not affect reproductive success directly, but may influence offspring survival in natural situations through effects on adult female body size. Postnatal hormones seem to be more influential in the formation of adult phenotypes than prenatal hormones. These results demonstrate that TSD species can be used to investigate the effects of the physical environment on development in individuals without a predetermined genetic sex and thus provide further insight into the roles of gonadal sex and the embryonic environment in sexual differentiation.

  11. Embryonic origin of mate choice in a lizard with temperature-dependent sex determination.

    Science.gov (United States)

    Putz, Oliver; Crews, David

    2006-01-01

    Individual differences in the adult sexual behavior of vertebrates are rooted in the fetal environment. In the leopard gecko (Eublepharis macularius), a species with temperature-dependent sex determination (TSD), hatchling sex ratios differ between incubation temperatures, as does sexuality in same-sex animals. This variation can primarily be ascribed to the temperature having direct organizing actions on the brain. Here we demonstrate that embryonic temperature can affect adult mate choice in the leopard gecko. Given the simultaneous choice between two females from different incubation temperatures (30.0 and 34.0 degrees C), males from one incubation temperature (30.0 degrees C) preferred the female from 34.0 degrees C, while males from another incubation temperature (32.5 degrees C) preferred the female from 30.0 degrees C. We suggest that this difference in mate choice is due to an environmental influence on brain development leading to differential perception of opposite-sex individuals. This previously unrecognized modulator of adult mate choice lends further support to the view that mate choice is best understood in the context of an individual's entire life-history. Thus, sexual selection results from a combination of the female's as well as the male's life history. Female attractiveness and male choice therefore are complementary. Copyright 2005 Wiley Periodicals, Inc.

  12. Comparison of cranial sex determination by discriminant analysis and logistic regression.

    Science.gov (United States)

    Amores-Ampuero, Anabel; Alemán, Inmaculada

    2016-04-05

    Various methods have been proposed for estimating dimorphism. The objective of this study was to compare sex determination results from cranial measurements using discriminant analysis or logistic regression. The study sample comprised 130 individuals (70 males) of known sex, age, and cause of death from San José cemetery in Granada (Spain). Measurements of 19 neurocranial dimensions and 11 splanchnocranial dimensions were subjected to discriminant analysis and logistic regression, and the percentages of correct classification were compared between the sex functions obtained with each method. The discriminant capacity of the selected variables was evaluated with a cross-validation procedure. The percentage accuracy with discriminant analysis was 78.2% for the neurocranium (82.4% in females and 74.6% in males) and 73.7% for the splanchnocranium (79.6% in females and 68.8% in males). These percentages were higher with logistic regression analysis: 85.7% for the neurocranium (in both sexes) and 94.1% for the splanchnocranium (100% in females and 91.7% in males).

  13. Metric Sex Determination of the Human Coxal Bone on a Virtual Sample using Decision Trees.

    Science.gov (United States)

    Savall, Frédéric; Faruch-Bilfeld, Marie; Dedouit, Fabrice; Sans, Nicolas; Rousseau, Hervé; Rougé, Daniel; Telmon, Norbert

    2015-11-01

    Decision trees provide an alternative to multivariate discriminant analysis, which is still the most commonly used in anthropometric studies. Our study analyzed the metric characterization of a recent virtual sample of 113 coxal bones using decision trees for sex determination. From 17 osteometric type I landmarks, a dataset was built with five classic distances traditionally reported in the literature and six new distances selected using the two-step ratio method. A ten-fold cross-validation was performed, and a decision tree was established on two subsamples (training and test sets). The decision tree established on the training set included three nodes and its application to the test set correctly classified 92% of individuals. This percentage was similar to the data of the literature. The usefulness of decision trees has been demonstrated in numerous fields. They have been already used in sex determination, body mass prediction, and ancestry estimation. This study shows another use of decision trees enabling simple and accurate sex determination. © 2015 American Academy of Forensic Sciences.

  14. Deciphering the link between doubly uniparental inheritance of mtDNA and sex determination in bivalves: Clues from comparative transcriptomics

    Science.gov (United States)

    Capt, Charlotte; Renaut, Sébastien; Ghiselli, Fabrizio; Milani, Liliana; Johnson, Nathan A.; Sietman, Bernard E.; Stewart, Donald; Breton, Sophie

    2018-01-01

    Bivalves exhibit an astonishing diversity of sexual systems and sex-determining mechanisms. They can be gonochoric, hermaphroditic or androgenetic, with both genetic and environmental factors known to determine or influence sex. One unique sex-determining system involving the mitochondrial genome has also been hypothesized to exist in bivalves with doubly uniparental inheritance (DUI) of mtDNA. However, the link between DUI and sex determination remains obscure. In this study, we performed a comparative gonad transcriptomics analysis for two DUI-possessing freshwater mussel species to better understand the mechanisms underlying sex determination and DUI in these bivalves. We used a BLAST reciprocal analysis to identify orthologs between Venustaconcha ellipsiformis and Utterbackia peninsularis and compared our results with previously published sex-specific bivalve transcriptomes to identify conserved sex-determining genes. We also compared our data with other DUI species to identify candidate genes possibly involved in the regulation of DUI. A total of ∼12,000 orthologous relationships were found, with 2,583 genes differentially expressed in both species. Among these genes, key sex-determining factors previously reported in vertebrates and in bivalves (e.g., Sry, Dmrt1, Foxl2) were identified, suggesting that some steps of the sex-determination pathway may be deeply conserved in metazoans. Our results also support the hypothesis that a modified ubiquitination mechanism could be responsible for the retention of the paternal mtDNA in male bivalves, and revealed that DNA methylation could also be involved in the regulation of DUI. Globally, our results suggest that sets of genes associated with sex determination and DUI are similar in distantly-related DUI species.

  15. Automatic Sex Determination of Skulls Based on a Statistical Shape Model

    Directory of Open Access Journals (Sweden)

    Li Luo

    2013-01-01

    Full Text Available Sex determination from skeletons is an important research subject in forensic medicine. Previous skeletal sex assessments are through subjective visual analysis by anthropologists or metric analysis of sexually dimorphic features. In this work, we present an automatic sex determination method for 3D digital skulls, in which a statistical shape model for skulls is constructed, which projects the high-dimensional skull data into a low-dimensional shape space, and Fisher discriminant analysis is used to classify skulls in the shape space. This method combines the advantages of metrical and morphological methods. It is easy to use without professional qualification and tedious manual measurement. With a group of Chinese skulls including 127 males and 81 females, we choose 92 males and 58 females to establish the discriminant model and validate the model with the other skulls. The correct rate is 95.7% and 91.4% for females and males, respectively. Leave-one-out test also shows that the method has a high accuracy.

  16. MPK-1 ERK controls membrane organization in C. elegans oogenesis via a sex-determination module.

    Science.gov (United States)

    Arur, Swathi; Ohmachi, Mitsue; Berkseth, Matt; Nayak, Sudhir; Hansen, David; Zarkower, David; Schedl, Tim

    2011-05-17

    Tissues that generate specialized cell types in a production line must coordinate developmental mechanisms with physiological demand, although how this occurs is largely unknown. In the Caenorhabditis elegans hermaphrodite, the developmental sex-determination cascade specifies gamete sex in the distal germline, while physiological sperm signaling activates MPK-1/ERK in the proximal germline to control plasma membrane biogenesis and organization during oogenesis. We discovered repeated utilization of a self-contained negative regulatory module, consisting of NOS-3 translational repressor, FEM-CUL-2 (E3 ubiquitin ligase), and TRA-1 (Gli transcriptional repressor), which acts both in sex determination and in physiological demand control of oogenesis, coordinating these processes. In the distal germline, where MPK-1 is not activated, TRA-1 represses the male fate as NOS-3 functions in translational repression leading to inactivation of the FEM-CUL-2 ubiquitin ligase. In the proximal germline, sperm-dependent physiological MPK-1 activation results in phosphorylation-based inactivation of NOS-3, FEM-CUL-2-mediated degradation of TRA-1 and the promotion of membrane organization during oogenesis. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Phylogeny determines flower size-dependent sex allocation at flowering in a hermaphroditic family.

    Science.gov (United States)

    Teixido, A L; Guzmán, B; Staggemeier, V G; Valladares, F

    2017-11-01

    In animal-pollinated hermaphroditic plants, optimal floral allocation determines relative investment into sexes, which is ultimately dependent on flower size. Larger flowers disproportionally increase maleness whereas smaller and less rewarding flowers favour female function. Although floral traits are considered strongly conserved, phylogenetic relationships in the interspecific patterns of resource allocation to floral sex remain overlooked. We investigated these patterns in Cistaceae, a hermaphroditic family. We reconstructed phylogenetic relationships among Cistaceae species and quantified phylogenetic signal for flower size, dry mass and nutrient allocation to floral structures in 23 Mediterranean species using Blomberg's K-statistic. Lastly, phylogenetically-controlled correlational and regression analyses were applied to examine flower size-based allometry in resource allocation to floral structures. Sepals received the highest dry mass allocation, followed by petals, whereas sexual structures increased nutrient allocation. Flower size and resource allocation to floral structures, except for carpels, showed a strong phylogenetic signal. Larger-flowered species allometrically allocated more resources to maleness, by increasing allocation to corollas and stamens. Our results suggest a major role of phylogeny in determining interspecific changes in flower size and subsequent floral sex allocation. This implies that flower size balances the male-female function over the evolutionary history of Cistaceae. While allometric resource investment in maleness is inherited across species diversification, allocation to the female function seems a labile trait that varies among closely related species that have diversified into different ecological niches. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  18. Determinants of condom breakage among female sex workers in Karnataka, India

    Directory of Open Access Journals (Sweden)

    Bradley Janet

    2011-12-01

    Full Text Available Abstract Background Condoms are effective in preventing the transmission of HIV and other sexually transmitted infections, when properly used. However, recent data from surveys of female sex workers (FSWs in Karnataka in south India, suggest that condom breakage rates may be quite high. It is important therefore to quantify condom breakage rates, and examine what factors might precipitate condom breakage, so that programmers can identify those at risk, and develop appropriate interventions. Methods We explored determinants of reported condom breakage in the previous month among 1,928 female sex workers in four districts of Karnataka using data from cross-sectional surveys undertaken from July 2008 to February 2009. Using stepwise multivariate logistic regression, we examined the possible determinants of condom breakage, controlling for several independent variables including the district and client load. Results Overall, 11.4% of FSWs reported at least one condom break in the previous month. FSWs were much more likely to report breakage if under 20 years of age (AOR 3.43, p = 0.005; if divorced/ separated/widowed (AOR 1.52, p = 0.012; if they were regular alcohol users (AOR 1.63, p = 0.005; if they mostly entertained clients in lodges/rented rooms (AOR 2.99, p = 0.029 or brothels (AOR 4.77, p = 0.003, compared to street based sex workers; if they had ever had anal sex (AOR 2.03, p = 0.006; if the sex worker herself (as opposed to the client applied the condom at last use (AOR 1.90, p Conclusions The reported incidence of condom breakage was high in this study, and this is a major concern for HIV/STI prevention programs, for which condom use is a key prevention tool. Younger and more marginalized female sex workers were most vulnerable to condom breakage. Special effort is therefore required to seek out such women and to provide information and skills on correct condom use. More research is also needed on what specific situational parameters

  19. Determinants of condom breakage among female sex workers in Karnataka, India.

    Science.gov (United States)

    Bradley, Janet; Rajaram, S; Alary, Michel; Isac, Shajy; Washington, Reynold; Moses, Stephen; Ramesh, B M

    2011-12-29

    Condoms are effective in preventing the transmission of HIV and other sexually transmitted infections, when properly used. However, recent data from surveys of female sex workers (FSWs) in Karnataka in south India, suggest that condom breakage rates may be quite high. It is important therefore to quantify condom breakage rates, and examine what factors might precipitate condom breakage, so that programmers can identify those at risk, and develop appropriate interventions. We explored determinants of reported condom breakage in the previous month among 1,928 female sex workers in four districts of Karnataka using data from cross-sectional surveys undertaken from July 2008 to February 2009. Using stepwise multivariate logistic regression, we examined the possible determinants of condom breakage, controlling for several independent variables including the district and client load. Overall, 11.4% of FSWs reported at least one condom break in the previous month. FSWs were much more likely to report breakage if under 20 years of age (AOR 3.43, p = 0.005); if divorced/ separated/widowed (AOR 1.52, p = 0.012); if they were regular alcohol users (AOR 1.63, p = 0.005); if they mostly entertained clients in lodges/rented rooms (AOR 2.99, p = 0.029) or brothels (AOR 4.77, p = 0.003), compared to street based sex workers; if they had ever had anal sex (AOR 2.03, p = 0.006); if the sex worker herself (as opposed to the client) applied the condom at last use (AOR 1.90, p < 0.001); if they were inconsistent condom users (AOR 2.77, p < 0.001); and if they had never seen a condom demonstration (AOR 2.37, p < 0.001). The reported incidence of condom breakage was high in this study, and this is a major concern for HIV/STI prevention programs, for which condom use is a key prevention tool. Younger and more marginalized female sex workers were most vulnerable to condom breakage. Special effort is therefore required to seek out such women and to provide information and skills on correct

  20. Evidence for the evolutionary nascence of a novel sex determination pathway in honeybees

    DEFF Research Database (Denmark)

    Hasselmann, Martin; Gempe, Tanja; Schiøtt, Morten

    2008-01-01

    and hemizygotes (haploid individuals) are males. Although at least 15 different csd alleles are known among natural bee populations, the mechanisms linking allelic interactions to switching of the sexual development programme are still obscure. Here we report a new component of the sex-determining pathway...... in honeybees, encoded 12 kilobases upstream of csd. The gene feminizer (fem) is the ancestrally conserved progenitor gene from which csd arose and encodes an SR-type protein, harbouring an Arg/Ser-rich domain. Fem shares the same arrangement of Arg/Ser- and proline-rich-domain with the Drosophila principal sex......, whereas the female-specific splice variant encodes the functional protein. We show that RNA interference (RNAi)-induced knockdowns of the female-specific fem splice variant result in male bees, indicating that the fem product is required for entire female development. Furthermore, RNAi-induced knockdowns...

  1. Sex determination by tooth size in a sample of Greek population.

    Science.gov (United States)

    Mitsea, A G; Moraitis, K; Leon, G; Nicopoulou-Karayianni, K; Spiliopoulou, C

    2014-08-01

    Sex assessment from tooth measurements can be of major importance for forensic and bioarchaeological investigations, especially when only teeth or jaws are available. The purpose of this study is to assess the reliability and applicability of establishing sex identity in a sample of Greek population using the discriminant function proposed by Rösing et al. (1995). The study comprised of 172 dental casts derived from two private orthodontic clinics in Athens. The individuals were randomly selected and all had clear medical history. The mesiodistal crown diameters of all the teeth were measured apart from those of the 3rd molars. The values quoted for the sample to which the discriminant function was first applied were similar to those obtained for the Greek sample. The results of the preliminary statistical analysis did not support the use of the specific discriminant function for a reliable determination of sex by means of the mesiodistal diameter of the teeth. However, there was considerable variation between different populations and this might explain the reason for lack of discriminating power of the specific function in the Greek population. In order to investigate whether a better discriminant function could be obtained using the Greek data, separate discriminant function analysis was performed on the same teeth and a different equation emerged without, however, any real improvement in the classification process, with an overall correct classification of 72%. The results showed that there were a considerably higher percentage of females correctly classified than males. The results lead to the conclusion that the use of the mesiodistal diameter of teeth is not as a reliable method as one would have expected for determining sex of human remains from a forensic context. Therefore, this method could be used only in combination with other identification approaches. Copyright © 2014. Published by Elsevier GmbH.

  2. GLOBAL EPIDEMIOLOGY OF HIV AMONG FEMALE SEX WORKERS: INFLUENCE OF STRUCTURAL DETERMINANTS

    Science.gov (United States)

    Shannon, K; Strathdee, SA; Goldenberg, SM; Duff, P; Mwangi, P; Rusakova, M; Reza-Paul, S; Lau, J; Deering, K; Pickles, M; Boily, M-C

    2014-01-01

    SUMMARY Female sex workers (FSWs) bear a disproportionately large burden of HIV infection worldwide. Despite decades of research and programme activity, the epidemiology of HIV and the role that structural determinants have in mitigating or potentiating HIV epidemics and access to care for FSWs is poorly understood. We reviewed available published data for HIV prevalence and incidence, condom use, and structural determinants among this group. Only 87 (43%) of 204 unique studies reviewed explicitly examined structural determinants of HIV. Most studies were from Asia, with few from areas with a heavy burden of HIV such as sub-Saharan Africa, Russia, and eastern Europe. To further explore the potential effect of structural determinants on the course of epidemics, we used a deterministic transmission model to simulate potential HIV infections averted through structural changes in regions with concentrated and generalised epidemics, and high HIV prevalence among FSWs. This modelling suggested that elimination of sexual violence alone could avert 17% of HIV infections in Kenya (95% uncertainty interval [UI] 1–31) and 20% in Canada (95% UI 3–39) through its immediate and sustained effect on non-condom use) among FSWs and their clients in the next decade. In Kenya, scaling up of access to antiretroviral therapy among FSWs and their clients to meet WHO eligibility of a CD4 cell count of less than 500 cells per μL could avert 34% (95% UI 25–42) of infections and even modest coverage of sex worker-led outreach could avert 20% (95% UI 8–36) of infections in the next decade. Decriminalisation of sex work would have the greatest effect on the course of HIV epidemics across all settings, averting 33–46% of HIV infections in the next decade. Multipronged structural and community-led interventions are crucial to increase access to prevention and treatment and to promote human rights for FSWs worldwide. PMID:25059947

  3. Sex determination in beetles: Production of all male progeny by Parental RNAi knockdown of transformer

    Science.gov (United States)

    Shukla, Jayendra Nath; Palli, Subba Reddy

    2012-01-01

    Sex in insects is determined by a cascade of regulators ultimately controlling sex-specific splicing of a transcription factor, Doublesex (Dsx). We recently identified homolog of dsx in the red flour beetle, Tribolium castaneum (Tcdsx). Here, we report on the identification and characterization of a regulator of Tcdsx splicing in T. castaneum. Two male-specific and one female-specific isoforms of T. castaneum transformer (Tctra) were identified. RNA interference-aided knockdown of Tctra in pupa or adults caused a change in sex from females to males by diverting the splicing of Tcdsx pre-mRNA to male-specific isoform. All the pupa and adults developed from Tctra dsRNA injected final instar larvae showed male-specific sexually dimorphic structures. Tctra parental RNAi caused an elimination of females from the progeny resulting in production of all male progeny. Transformer parental RNAi could be used to produce all male population for use in pest control though sterile male release methods. PMID:22924109

  4. Fibroblast growth factor receptor 2 regulates proliferation and Sertoli differentiation during male sex determination

    Science.gov (United States)

    Kim, Yuna; Bingham, Nathan; Sekido, Ryohei; Parker, Keith L.; Lovell-Badge, Robin; Capel, Blanche

    2007-01-01

    Targeted mutagenesis of Fgf9 in mice causes male-to-female sex reversal. Among the four FGF receptors, FGFR2 showed two highly specific patterns based on antibody staining, suggesting that it might be the receptor-mediating FGF9 signaling in the gonad. FGFR2 was detected at the plasma membrane in proliferating coelomic epithelial cells and in the nucleus in Sertoli progenitor cells. This expression pattern suggested that Fgfr2 might play more than one role in testis development. To test the hypothesis that Fgfr2 is required for male sex determination, we crossed mice carrying a floxed allele of Fgfr2 with two different Cre lines to induce a temporal or cell-specific deletion of this receptor. Results show that deletion of Fgfr2 in embryonic gonads phenocopies deletion of Fgf9 and leads to male-to-female sex reversal. Using these two Cre lines, we provide the first genetic evidence that Fgfr2 plays distinct roles in proliferation and Sertoli cell differentiation during testis development. PMID:17940049

  5. Sexual dimorphism in mammalian autosomal gene regulation is determined not only by Sry but by sex chromosome complement as well.

    Science.gov (United States)

    Wijchers, Patrick J; Yandim, Cihangir; Panousopoulou, Eleni; Ahmad, Mushfika; Harker, Nicky; Saveliev, Alexander; Burgoyne, Paul S; Festenstein, Richard

    2010-09-14

    Differences between males and females are normally attributed to developmental and hormonal differences between the sexes. Here, we demonstrate differences between males and females in gene silencing using a heterochromatin-sensitive reporter gene. Using "sex-reversal" mouse models with varying sex chromosome complements, we found that this differential gene silencing was determined by X chromosome complement, rather than sex. Genome-wide transcription profiling showed that the expression of hundreds of autosomal genes was also sensitive to sex chromosome complement. These genome-wide analyses also uncovered a role for Sry in modulating autosomal gene expression in a sex chromosome complement-specific manner. The identification of this additional layer in the establishment of sexual dimorphisms has implications for understanding sexual dimorphisms in physiology and disease. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. The role of Fanconi anemia/BRCA genes in zebrafish sex determination.

    Science.gov (United States)

    Rodríguez-Marí, Adriana; Postlethwait, John H

    2011-01-01

    Fanconi anemia (FA) is a human disease of bone marrow failure, leukemia, squamous cell carcinoma, and developmental anomalies, including hypogonadism and infertility. Bone marrow transplants improve hematopoietic phenotypes but do not prevent other cancers. FA arises from mutation in any of the 15 FANC genes that cooperate to repair double stranded DNA breaks by homologous recombination. Zebrafish has a single ortholog of each human FANC gene and unexpectedly, mutations in at least two of them (fancl and fancd1(brca2)) lead to female-to-male sex reversal. Investigations show that, as in human, zebrafish fanc genes are required for genome stability and for suppressing apoptosis in tissue culture cells, in embryos treated with DNA damaging agents, and in meiotic germ cells. The sex reversal phenotype requires the action of Tp53 (p53), an activator of apoptosis. These results suggest that in normal sex determination, zebrafish oocytes passing through meiosis signal the gonadal soma to maintain expression of aromatase, an enzyme that converts androgen to estrogen, thereby feminizing the gonad and the individual. According to this model, normal male and female zebrafish differ in genetic factors that control the strength of the late meiotic oocyte-derived signal, probably by regulating the number of meiotic oocytes, which environmental factors can also alter. Transcripts from fancd1(brca2) localize at the animal pole of the zebrafish oocyte cytoplasm and are required for normal oocyte nuclear architecture, for normal embryonic development, and for preventing ovarian tumors. Embryonic DNA repair and sex reversal phenotypes provide assays for the screening of small molecule libraries for therapeutic substances for FA. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. The roles of Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes in sex determination and differentiation mechanisms: Ubiquity and diversity across the animal kingdom.

    Science.gov (United States)

    Picard, Marion Anne-Lise; Cosseau, Céline; Mouahid, Gabriel; Duval, David; Grunau, Christoph; Toulza, Ève; Allienne, Jean-François; Boissier, Jérôme

    2015-07-01

    The Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes have been intensively studied because they represent major transcription factors in the pathways governing sex determination and differentiation. These genes have been identified in animal groups ranging from cnidarians to mammals, and some of the genes functionally studied. Here, we propose to analyze (i) the presence/absence of various Dmrt gene groups in the different taxa across the animal kingdom; (ii) the relative expression levels of the Dmrt genes in each sex; (iii) the specific spatial (by organ) and temporal (by developmental stage) variations in gene expression. This review considers non-mammalian animals at all levels of study (i.e. no particular importance is given to animal models), and using all types of sexual strategy (hermaphroditic or gonochoric) and means of sex determination (i.e. genetic or environmental). To conclude this global comparison, we offer an analysis of the DM domains conserved among the different DMRT proteins, and propose a general sex-specific pattern for each member of the Dmrt gene family. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  8. Genetic studies on sex determination and colouration in Nile tilapia (Oreochromis niloticus L.)

    International Nuclear Information System (INIS)

    Karayuecel, I.

    1999-05-01

    The present study was undertaken to investigate colour and sex determination mechanisms through the application of androgenesis, gynogenesis and controlled breeding programme with the objective of producing all red males in O. niloticus. The highest yield of androgenetic haploid to pigmentation stage was 24.6±3.5% (relative to controls) with optimal UV irradiation dose of 450JM -2 for 5 minutes. The highest survival rate of diploid androgens was 0.07±0.07% (relative to controls) to yolk sac stage using a heat shock of 42.5 deg. C for 3 minutes 30 seconds applied at 25 minutes after fertilisation. All paternal inheritance of diploid androgenetic tilapia was verified using DNA fingerprinting. The mean recombination frequency of the red skin colour gene in meiotic gynogens was 0.12±0.04. All maternal inheritance of meiotic gynogens was verified using the isozyme locus ADA*. Analyses of sex ratios of meiotic gynogens suggested that male progenies were produced by an epistatic sex determining locus (SDL-2 with two alleles SR and sr) causing female to male sex reversal in the homozygous phase (srsr) but with limited penetrance. A close linkage was found between a sex determining locus (SDL-2) and the red gene. No significant difference was found between colour genotypes (namely homozygous red, heterozygous red and wild type) in terms of total fecundity, ISI (inter spawning interval), egg size and survival rate. Overall mean ISI was 26.3±1.0 days. Mean total fecundity was 1096 eggs. Fecundity varied over successive spawns but this variation did not appear to be related to spawning periodicity. Hormonal and thermal feminization were compared on all YY male progeny of O. niloticus. While similar female percentages of 32.0±5.2 and 33.8±1.5% were produced, significantly higher intersex percentages of 18.5±2.5 and 1.6±0.8 were observed in heat and DES treated groups, respectively. Heat treatment groups showed the lowest survival rate of 62.6±9.8% compared to the

  9. Genetic studies on sex determination and colouration in Nile tilapia (Oreochromis niloticus L.)

    Energy Technology Data Exchange (ETDEWEB)

    Karayuecel, I

    1999-05-01

    The present study was undertaken to investigate colour and sex determination mechanisms through the application of androgenesis, gynogenesis and controlled breeding programme with the objective of producing all red males in O. niloticus. The highest yield of androgenetic haploid to pigmentation stage was 24.6{+-}3.5% (relative to controls) with optimal UV irradiation dose of 450JM{sup -2} for 5 minutes. The highest survival rate of diploid androgens was 0.07{+-}0.07% (relative to controls) to yolk sac stage using a heat shock of 42.5 deg. C for 3 minutes 30 seconds applied at 25 minutes after fertilisation. All paternal inheritance of diploid androgenetic tilapia was verified using DNA fingerprinting. The mean recombination frequency of the red skin colour gene in meiotic gynogens was 0.12{+-}0.04. All maternal inheritance of meiotic gynogens was verified using the isozyme locus ADA*. Analyses of sex ratios of meiotic gynogens suggested that male progenies were produced by an epistatic sex determining locus (SDL-2 with two alleles SR and sr) causing female to male sex reversal in the homozygous phase (srsr) but with limited penetrance. A close linkage was found between a sex determining locus (SDL-2) and the red gene. No significant difference was found between colour genotypes (namely homozygous red, heterozygous red and wild type) in terms of total fecundity, ISI (inter spawning interval), egg size and survival rate. Overall mean ISI was 26.3{+-}1.0 days. Mean total fecundity was 1096 eggs. Fecundity varied over successive spawns but this variation did not appear to be related to spawning periodicity. Hormonal and thermal feminization were compared on all YY male progeny of O. niloticus. While similar female percentages of 32.0{+-}5.2 and 33.8{+-}1.5% were produced, significantly higher intersex percentages of 18.5{+-}2.5 and 1.6{+-}0.8 were observed in heat and DES treated groups, respectively. Heat treatment groups showed the lowest survival rate of 62

  10. Determine sex ratios of green turtles along the U.S. West Coast through examinations of hormones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A testosterone (T) enzyme-linked immunosorbent assay (ELISA) was validated for use with green turtle plasma in order to determine the sex of juvenile turtles. We...

  11. Sex-specific genetic determinants for arterial stiffness in Dahl salt-sensitive hypertensive rats.

    Science.gov (United States)

    Decano, Julius L; Pasion, Khristine A; Black, Nicole; Giordano, Nicholas J; Herrera, Victoria L; Ruiz-Opazo, Nelson

    2016-01-11

    Arterial stiffness is an independent predictor of cardiovascular outcomes in hypertensive patients including myocardial infarction, fatal stroke, cerebral micro-bleeds which predicts cerebral hemorrhage in hypertensive patients, as well as progression to hypertension in non-hypertensive subjects. The association between arterial stiffness and various cardiovascular outcomes (coronary heart disease, stroke) remains after adjusting for age, sex, blood pressure, body mass index and other known predictors of cardiovascular disease, suggesting that arterial stiffness, measured via carotid-femoral pulse wave velocity, has a better predictive value than each of these factors. Recent evidence shows that arterial stiffening precedes the onset of high blood pressure; however their molecular genetic relationship (s) and sex-specific determinants remain uncertain. We investigated whether distinct or shared genetic determinants might underlie susceptibility to arterial stiffening in male and female Dahl salt-sensitive rats. Thus, we performed a genome-wide scan for quantitative trait loci (QTLs) affecting arterial stiffness in six-week old F2 (Dahl S x R)-intercross male and female rats characterized for abdominal aortic pulse wave velocity and aortic strain by high-resolution ultrasonography. We detected five highly significant QTLs affecting aortic stiffness: two interacting QTLs (AS-m1 on chromosome 4 and AS-m2 on chromosome16, LOD 8.8) in males and two distinct interacting QTLs (AS-f1 on chromosome 9 and AS-f2 on chromosome11, LOD 8.9) in females affecting pulse wave velocity. One QTL (AS-1 on chromosome 3, LOD 4.3) was found to influence aortic strain in a sex-independent manner. None of these arterial stiffness QTLs co-localized with previously reported blood pressure QTLs detected in equivalent genetic intercrosses. These data reveal sex-specific genetic determinants for aortic pulse wave velocity and suggest distinct polygenic susceptibility for arterial stiffness and

  12. Bombyx mori histone methyltransferase BmAsh2 is essential for silkworm piRNA-mediated sex determination.

    Science.gov (United States)

    Li, Zhiqian; You, Lang; Yan, Dong; James, Anthony A; Huang, Yongping; Tan, Anjiang

    2018-02-01

    Sex determination is a hierarchically-regulated process with high diversity in different organisms including insects. The W chromosome-derived Fem piRNA has been identified as the primary sex determination factor in the lepidopteran insect, Bombyx mori, revealing a distinctive piRNA-mediated sex determination pathway. However, the comprehensive mechanism of silkworm sex determination is still poorly understood. We show here that the silkworm PIWI protein BmSiwi, but not BmAgo3, is essential for silkworm sex determination. CRISPR/Cas9-mediated depletion of BmSiwi results in developmental arrest in oogenesis and partial female sexual reversal, while BmAgo3 depletion only affects oogenesis. We identify three histone methyltransferases (HMTs) that are significantly down-regulated in BmSiwi mutant moths. Disruption one of these, BmAsh2, causes dysregulation of piRNAs and transposable elements (TEs), supporting a role for it in the piRNA signaling pathway. More importantly, we find that BmAsh2 mutagenesis results in oogenesis arrest and partial female-to-male sexual reversal as well as dysregulation of the sex determination genes, Bmdsx and BmMasc. Mutagenesis of other two HMTs, BmSETD2 and BmEggless, does not affect piRNA-mediated sex determination. Histological analysis and immunoprecipitation results support a functional interaction between the BmAsh2 and BmSiwi proteins. Our data provide the first evidence that the HMT, BmAsh2, plays key roles in silkworm piRNA-mediated sex determination.

  13. Bombyx mori histone methyltransferase BmAsh2 is essential for silkworm piRNA-mediated sex determination.

    Directory of Open Access Journals (Sweden)

    Zhiqian Li

    2018-02-01

    Full Text Available Sex determination is a hierarchically-regulated process with high diversity in different organisms including insects. The W chromosome-derived Fem piRNA has been identified as the primary sex determination factor in the lepidopteran insect, Bombyx mori, revealing a distinctive piRNA-mediated sex determination pathway. However, the comprehensive mechanism of silkworm sex determination is still poorly understood. We show here that the silkworm PIWI protein BmSiwi, but not BmAgo3, is essential for silkworm sex determination. CRISPR/Cas9-mediated depletion of BmSiwi results in developmental arrest in oogenesis and partial female sexual reversal, while BmAgo3 depletion only affects oogenesis. We identify three histone methyltransferases (HMTs that are significantly down-regulated in BmSiwi mutant moths. Disruption one of these, BmAsh2, causes dysregulation of piRNAs and transposable elements (TEs, supporting a role for it in the piRNA signaling pathway. More importantly, we find that BmAsh2 mutagenesis results in oogenesis arrest and partial female-to-male sexual reversal as well as dysregulation of the sex determination genes, Bmdsx and BmMasc. Mutagenesis of other two HMTs, BmSETD2 and BmEggless, does not affect piRNA-mediated sex determination. Histological analysis and immunoprecipitation results support a functional interaction between the BmAsh2 and BmSiwi proteins. Our data provide the first evidence that the HMT, BmAsh2, plays key roles in silkworm piRNA-mediated sex determination.

  14. Mandibular ramus: A predictor for sex determination - A digital radiographic study

    Directory of Open Access Journals (Sweden)

    Kotya Naik Maloth

    2017-01-01

    Full Text Available Aim: To evaluate mandibular ramus linear measurements on digital panoramic radiographs and to assess the usefulness of mandibular ramus in sex determination. Material and Methods: A retrospective study was conducted on 100 patients (50 males and 50 females using digital panoramic radiographs of Khammam population with age ranging from 20 to 50 years. Standard digital panoramic radiographs were taken without any errors by Sirona, ORTHOPHOS XG 5 machine. The following five mandibular linear measurements were performed in cm such as upper ramus breadth, lower ramus breadth, condylar ramus height, projective ramus height, and coronoid ramus height. The obtained data were analyzed with the software SPSS 13.0 for statistical analysis using discriminate methods. Results: In the present study, all the linear measurements of mandibular ramus on digital panoramic radiographs showed a statistically significant difference between the genders. Conclusion: We conclude that the use of mandibular ramus is recommended as an aid for sex determination in forensic science due to their unique feature of sexual dimorphism.

  15. Sex Determination Using Inion-Opistocranium-Asterion (IOA Triangle in Nigerians’ Skulls

    Directory of Open Access Journals (Sweden)

    C. N. Orish

    2014-01-01

    Full Text Available Background. Determination of sex is an important concern to the forensic anthropologists as it is critical for individual identification. This study has investigated the existence of sexual dimorphism in the dimensions and the area of the IOA triangle. Methods. A total of 100 adult dry skulls, (78 males; 22 females from departments of anatomy in Nigerian universities were used for this study. Automatic digital calliper was used for the measurement. Coefficient of variation, correlation, linear regression, percentiles, and sexual dimorphism ratio were computed from the IOA triangle measurements. The IOA triangle area was compared between sexes. Results. The male parameters were significantly (P<0.05 higher than female parameters. The left opistocranium-asterion length was 71.09±0.56 and 61.68±3.35 mm and the right opistocranium-asterion length was 69.73±0.49 and 60.92±2.10 mm for male and female, respectively. A total area of IOA triangle of 1938.88 mm2 and 1305.68 mm2 for male and female, respectively, was calculated. The left IOA indices were 46.42% and 37.40% in males and females, respectively, while the right IOA indices for males and females were 47.19% and 38.87%, respectively. Conclusion. The anthropometry of inion-opistocranium-asterion IOA triangle can be a guide in gender determination of unknown individuals.

  16. Label-free detection of sex determining region Y (SRY) via capacitive biosensor

    KAUST Repository

    Sivashankar, Shilpa

    2016-10-20

    In this work, we present for the first time, the use of a simple fractal capacitive biosensor for the quantification and detection of sex-determining region Y (SRY) genes. This section of genetic code, which is found on the Y chromosome, finds importance for study as it causes fetuses to develop characteristics of male sex-like gonads when a mutation occurs. It is also an important genetic code in men, and disorders involving the SRY gene can cause infertility and sexual malfunction that lead to a variety of gene mutational disorders. We have therefore designed silicon-based, label-free fractal capacitive biosensors to quantify various proteins and genes. We take advantage of a good dielectric material, Parylene C for enhancing the performance of the sensors. We have integrated these sensors with a simple microchannel for easy handling of fluids on the detection area. The read-out value of an Agilent LCR meter used to measure capacitance of the sensor at a frequency of 1 MHz determined gene specificity and gene quantification. These data revealed that the capacitance measurement of the capacitive biosensor for the SRY gene depended on both the target and the concentration of DNA. The experimental outcomes in the present study can be used to detect DNA and its variations in crucial fields that have a great impact on our daily lives, such as clinical and veterinary diagnostics, industrial and environmental testing and forensic sciences.

  17. Mapping and validation of the major sex-determining region in Nile tilapia (Oreochromis niloticus L. Using RAD sequencing.

    Directory of Open Access Journals (Sweden)

    Christos Palaiokostas

    Full Text Available Sex in Oreochromis niloticus (Nile tilapia is principally determined by an XX/XY locus but other genetic and environmental factors also influence sex ratio. Restriction Associated DNA (RAD sequencing was used in two families derived from crossing XY males with females from an isogenic clonal line, in order to identify Single Nucleotide Polymorphisms (SNPs and map the sex-determining region(s. We constructed a linkage map with 3,802 SNPs, which corresponded to 3,280 informative markers, and identified a major sex-determining region on linkage group 1, explaining nearly 96% of the phenotypic variance. This sex-determining region was mapped in a 2 cM interval, corresponding to approximately 1.2 Mb in the O. niloticus draft genome. In order to validate this, a diverse family (4 families; 96 individuals in total and population (40 broodstock individuals test panel were genotyped for five of the SNPs showing the highest association with phenotypic sex. From the expanded data set, SNPs Oni23063 and Oni28137 showed the highest association, which persisted both in the case of family and population data. Across the entire dataset all females were found to be homozygous for these two SNPs. Males were heterozygous, with the exception of five individuals in the population and two in the family dataset. These fish possessed the homozygous genotype expected of females. Progeny sex ratios (over 95% females from two of the males with the "female" genotype indicated that they were neomales (XX males. Sex reversal induced by elevated temperature during sexual differentiation also resulted in phenotypic males with the "female" genotype. This study narrows down the region containing the main sex-determining locus, and provides genetic markers tightly linked to this locus, with an association that persisted across the population. These markers will be of use in refining the production of genetically male O. niloticus for aquaculture.

  18. An Overview of Age, Sex and Race Determination from Teeth and Skull

    Directory of Open Access Journals (Sweden)

    Manas Gupta

    2015-01-01

    Full Text Available Background : Forensic dentistry represents the overlap between the dental and legal professions. Throughout this century, odontological examinations have been a critical determinant in the search for identity of individual remains. Dental maturity has played an important role in estimating the chronological age of individuals. Age estimation is a sub-discipline of the forensic sciences and should be an important part of every identification process, especially when information relating to the deceased is unavailable. Forensic dentist helps in identification of deceased victims by age, sex and race determination from teeth and skull. Since the scope of forensic odontology is very broad and challenging, dental surgeons trained in forensic odontology can make unique contributions in the administration of justice, which is the key note of democracy.

  19. Sex determination mode does not affect body or genital development of the central bearded dragon (Pogona vitticeps

    Directory of Open Access Journals (Sweden)

    Sarah L. Whiteley

    2017-12-01

    Full Text Available Abstract Background The development of male- or female-specific phenotypes in squamates is typically controlled by either temperature-dependent sex determination (TSD or chromosome-based genetic sex determination (GSD. However, while sex determination is a major switch in individual phenotypic development, it is unknownhow evolutionary transitions between GSD and TSD might impact on the evolution of squamate phenotypes, particularly the fast-evolving and diverse genitalia. Here, we take the unique opportunity of studying the impact of both sex determination mechanisms on the embryological development of the central bearded dragon (Pogona vitticeps. This is possible because of the transitional sex determination system of this species, in which genetically male individuals reverse sex at high incubation temperatures. This can trigger the evolutionary transition of GSD to TSD in a single generation, making P. vitticeps an ideal model organism for comparing the effects of both sex determination processes in the same species. Results We conducted four incubation experiments on 265 P. vitticeps eggs, covering two temperature regimes (“normal” at 28 °C and “sex reversing” at 36 °C and the two maternal sexual genotypes (concordant ZW females or sex-reversed ZZ females. From this, we provide the first detailed staging system for the species, with a focus on genital and limb development. This was augmented by a new sex chromosome identification methodology for P. vitticeps that is non-destructive to the embryo. We found a strong correlation between embryo age and embryo stage. Aside from faster growth in 36 °C treatments, body and external genital development was entirely unperturbed by temperature, sex reversal or maternal sexual genotype. Unexpectedly, all females developed hemipenes (the genital phenotype of adult male P. vitticeps, which regress close to hatching. Conclusions The tight correlation between embryo age and embryo stage

  20. Sex determination in Turdus amaurochalinus (Passeriformes: Muscicapidae: morphometrical analysis supported by CHD gene

    Directory of Open Access Journals (Sweden)

    Katyucha Von Kossel de Andrade Silva

    2011-06-01

    Full Text Available Sex determination is important for conservation and population studies, particularly for reproduction programs of threatened species and behavioural ecology. Turdus amaurochalinus, Creamy-bellied Thrush, only exhibits sexual dimorphism during the breeding season, when males are considered to show intense yellow bills, and females and immature males show dark brown bills. The objectives of this study were: 1 to determine the sex of individuals using genetic techniques, and 2 to test the hypothesis that sex dimorphism can be detected by morphometry. This study was carried out at Parque Nacional da Restinga de Jurubatiba, a preserved area located on the North coast of Rio de Janeiro State. The birds were captured using ornithological nets, singly marked with metal rings, weighed, measured and had blood samples collected before being released. The sex of 42 T. amaurochalinus individuals was determined using the CHD gene marker. A total of 20 males and 22 females were identified from June to August, with peak capture frequency in June. Turdus amaurochalinus females and males differed significantly in morphometrical measures. The most important traits to distinguish males from females were wing length (Student t-test=4.34, df=40, p=0.0001 and weight (Student t-test=2.08,df=40, p=0.044: females were heavier and had significantly shorter wing length than males. Females and males were correctly classified in 86% and 75% of cases, respectively, using Discriminant Analysis. The molecular analysis was the most secure method for sex determination in the studied species. Rev. Biol. Trop. 59 (2: 789- 794. Epub 2011 June 01.La determinación del sexo es importante para la conservación y los estudios poblacionales. Turdus amaurochalinus no presenta aparente dimorfismo sexual. El objetivo de este estudio fue determinar el sexo a través de una técnica genética, mediante el uso del marcador del gen CHD y se puso a prueba la hipótesis de que el dimorfismo

  1. The lesser known challenge of climate change: thermal variance and sex-reversal in vertebrates with temperature-dependent sex determination.

    Directory of Open Access Journals (Sweden)

    Jennifer L Neuwald

    Full Text Available Climate change is expected to disrupt biological systems. Particularly susceptible are species with temperature-dependent sex determination (TSD, as in many reptiles. While the potentially devastating effect of rising mean temperatures on sex ratios in TSD species is appreciated, the consequences of increased thermal variance predicted to accompany climate change remain obscure. Surprisingly, no study has tested if the effect of thermal variance around high-temperatures (which are particularly relevant given climate change predictions has the same or opposite effects as around lower temperatures. Here we show that sex ratios of the painted turtle (Chrysemys picta were reversed as fluctuations increased around low and high unisexual mean-temperatures. Unexpectedly, the developmental and sexual responses around female-producing temperatures were decoupled in a more complex manner than around male-producing values. Our novel observations are not fully explained by existing ecological models of development and sex determination, and provide strong evidence that thermal fluctuations are critical for shaping the biological outcomes of climate change.

  2. Sex Determination and Polyploid Gigantism in the Dwarf Surfclam (Mulinia Lateralis Say)

    Science.gov (United States)

    Guo, X.; Allen-Jr., S. K.

    1994-01-01

    Mulinia lateralis, the dwarf surfclam, is a suitable model for bivalve genetics because it is hardy and has a short generation time. In this study, gynogenetic and triploid. M. lateralis were successfully induced. For gynogenesis, eggs were fertilized with sperm irradiated with ultraviolet light and subsequently treated with cytochalasin B to block the release of the second polar body (PB2). Triploidy was induced by blocking PB2 in normally fertilized eggs. The survival of gynogenetic diploids was very low, only 0.7% to 8 days post-fertilization (PF), compared with 15.2% in the triploid groups and 27.5% in the normal diploid control. Larvae in all groups metamorphosed at 8-10 days PF, and there was no significant post-larval mortality. At sexual maturation (2-3 months PF), all gynogenetic diploids were female, and there was no significant difference (P > 0.05) in sex ratio between diploids and triploids. These results suggested that the dwarf surfclam may have an XX-female, XY-male sex determination with Y-domination. Compared with diploids, triploids had a relative fecundity of 59% for females and 80% for males. Eggs produced by triploid females were 53% larger (P 0.33) different from normal diploid females, suggesting that inbreeding depression was minimal in meiosis II gynogens. Triploid clams were significantly larger (P gigantism due to the increased cell volume and a lack of cell-number compensation. PMID:7896101

  3. The fate of W chromosomes in hybrids between wild silkmoths, Samia cynthia ssp.: no role in sex determination and reproduction.

    Science.gov (United States)

    Yoshido, A; Marec, F; Sahara, K

    2016-05-01

    Moths and butterflies (Lepidoptera) have sex chromosome systems with female heterogamety (WZ/ZZ or derived variants). The maternally inherited W chromosome is known to determine female sex in the silkworm, Bombyx mori. However, little is known about the role of W chromosome in other lepidopteran species. Here we describe two forms of the W chromosome, W and neo-W, that are transmitted to both sexes in offspring of hybrids from reciprocal crosses between subspecies of wild silkmoths, Samia cynthia. We performed crosses between S. c. pryeri (2n=28, WZ/ZZ) and S. c. walkeri (2n=26, neo-Wneo-Z/neo-Zneo-Z) and examined fitness and sex chromosome constitution in their hybrids. The F1 hybrids of both reciprocal crosses had reduced fertility. Fluorescence in situ hybridization revealed not only the expected sex chromosome constitutions in the backcross and F2 hybrids of both sexes but also females without the W (or neo-W) chromosome and males carrying the W (or neo-W) chromosome. Furthermore, crosses between the F2 hybrids revealed no association between the presence or absence of W (or neo-W) chromosome and variations in the hatchability of their eggs. Our results clearly suggest that the W (or neo-W) chromosome of S. cynthia ssp. plays no role in sex determination and reproduction, and thus does not contribute to the formation of reproductive barriers between different subspecies.

  4. Sex Determination in Bees. IV. Genetic Control of Juvenile Hormone Production in MELIPONA QUADRIFASCIATA (Apidae)

    Science.gov (United States)

    Kerr, Warwick Estevam; Akahira, Yukio; Camargo, Conceição A.

    1975-01-01

    Cell number and volume of corpora allata was determined for 8 phases of development, the first prepupal stage to adults 30 days old, in the social Apidae Melipona quadrifasciata. In the second prepupal stage a strong correlation was found between cell number and body weight ( r=0.651**), and cell number and corpora allata volume in prepupal stage (r=0.535*), which indicates that juvenile hormone has a definite role in caste determination in Melipona. The distribution of the volume of corpus allatum suggest a 3:1 segregation between bees with high volume of corpora allata against low and medium volume. This implies that genes xa and xb code for an enzyme that directly participates in juvenile hormone production. It was also concluded that the number of cells in the second prepupal stage is more important than the weight of the prepupa for caste determination. A scheme summarizing the genic control of sex and caste determination in Melipona bees in the prepupal phase is given. PMID:1213273

  5. Temperature-dependent sex determination in the leopard gecko, Eublepharis macularius.

    Science.gov (United States)

    Viets, B E; Tousignant, A; Ewert, M A; Nelson, C E; Crews, D

    1993-05-01

    The leopard gecko, Eublepharis macularius, has temperature-dependent sex determination (TSD). Previous reports have shown that females are produced predominantly at cool incubation temperatures and males are produced predominantly at warm incubation temperatures (Pattern Ib). We report here that incubation at even higher temperatures (34 and 35 degrees C) produces mostly females (Pattern II). The lethal maximum constant incubation temperature for this species appears to be just above 35 degrees C. Although a previous study indicated that females from a warm incubation temperature (32 degrees C) failed to lay eggs, we found that 12 of 14 mature females incubated at 32.5 degrees C, and 5 of 6 mature females incubated at 34 degrees C produced fertile eggs and viable hatchlings.

  6. Sex determination of human mandible using metrical parameters by computed tomography: A prospective radiographic short study

    Directory of Open Access Journals (Sweden)

    Basavaraj N Kallalli

    2016-01-01

    Full Text Available Introduction: Sex determination of unidentified human remains is very important in forensic medicine, medicolegal cases, and forensic anthropology. The mandible is the largest and hardest facial bone that commonly resists postmortem damage and forms an important source of personal identification. Additional studies have demonstrated the applicability of facial reconstruction using three-dimensional computed tomography scan (3D-CT for the purpose of individual identification. Aim: To determine the sex of human mandible using metrical parameters by CT. Materials and Methods: The study included thirty subjects (15 males and 15 females, with age group ranging between 10 and 60 years obtained from the outpatient department of Oral Medicine and Radiology, Narsinhbhai Patel Dental College and Hospital. CT scan was performed on all the subjects, and the data obtained were reconstructed for 3D viewing. After obtaining 3D-CT scan, a total of seven mandibular measurements, i.e., gonial angle (G-angle, ramus length (Ramus-L, minimum ramus breadth and gonion-gnathion length (G-G-L, bigonial breadth, bicondylar breadth (BIC-Br, and coronoid length (CO-L were measured; collected data were analyzed using SPSS statistical analysis program by Student's t-test. Results: The result of the study showed that out of seven parameters, G-angle, Ramus-L, G-G-L, BIC-Br, and CO-L showed a significant statistical difference (P < 0.05, with overall accuracy of 86% for males and 82% for females. Conclusion: Personal identification using mandible by conventional methods has already been proved but with variable efficacies. Advanced imaging modalities can aid in personal identification with much higher accuracy than conventional methods.

  7. Spatial pattern of Baccharis platypoda shrub as determined by sex and life stages

    Science.gov (United States)

    Fonseca, Darliana da Costa; de Oliveira, Marcio Leles Romarco; Pereira, Israel Marinho; Gonzaga, Anne Priscila Dias; de Moura, Cristiane Coelho; Machado, Evandro Luiz Mendonça

    2017-11-01

    Spatial patterns of dioecious species can be determined by their nutritional requirements and intraspecific competition, apart from being a response to environmental heterogeneity. The aim of the study was to evaluate the spatial pattern of populations of a dioecious shrub reporting to sex and reproductive stage patterns of individuals. Sampling was carried out in three areas located in the meridional portion of Serra do Espinhaço, where in individuals of the studied species were mapped. The spatial pattern was determined through O-ring analysis and Ripley's K-function and the distribution of individuals' frequencies was verified through x2 test. Populations in two areas showed an aggregate spatial pattern tending towards random or uniform according to the observed scale. Male and female adults presented an aggregate pattern at smaller scales, while random and uniform patterns were verified above 20 m for individuals of both sexes of the areas A2 and A3. Young individuals presented an aggregate pattern in all areas and spatial independence in relation to adult individuals, especially female plants. The interactions between individuals of both genders presented spatial independence with respect to spatial distribution. Baccharis platypoda showed characteristics in accordance with the spatial distribution of savannic and dioecious species, whereas the population was aggregated tending towards random at greater spatial scales. Young individuals showed an aggregated pattern at different scales compared to adults, without positive association between them. Female and male adult individuals presented similar characteristics, confirming that adult individuals at greater scales are randomly distributed despite their distinct preferences for environments with moisture variation.

  8. MPK-1 ERK Controls Membrane Organization in C. elegans Oogenesis via a Sex-Determination Module

    OpenAIRE

    Arur, Swathi; Ohmachi, Mitsue; Berkseth, Matt; Nayak, Sudhir; Hansen, David; Zarkower, David; Schedl, Tim

    2011-01-01

    Tissues that generate specialized cell-types in a production line must coordinate developmental mechanisms with physiological demand, although how this occurs is largely unknown. In the C. elegans hermaphrodite, the developmental sex-determination cascade specifies gamete sex in the distal germline, while physiological sperm signaling activates MPK-1/ERK in the proximal germline to control plasma membrane biogenesis/organization during oogenesis. We discovered repeated utilization of a self-c...

  9. The fate of W chromosomes in hybrids between wild silkmoths, Samia cynthia ssp.: no role in sex determination and reproduction

    Czech Academy of Sciences Publication Activity Database

    Yoshido, Atsuo; Marec, František; Sahara, K.

    2016-01-01

    Roč. 116, č. 5 (2016), s. 424-433 ISSN 0018-067X R&D Projects: GA ČR(CZ) GA14-22765S Grant - others:The European Union Seventh Framework Programme (FP7/2007-2013)(CZ) 316304 Program:FP7 Institutional support: RVO:60077344 Keywords : hybrids * sex chromosomes * sex determination Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.961, year: 2016

  10. The ecology and evolution of temperature-dependent reaction norms for sex determination in reptiles: a mechanistic conceptual model.

    Science.gov (United States)

    Pezaro, Nadav; Doody, J Sean; Thompson, Michael B

    2017-08-01

    Sex-determining mechanisms are broadly categorised as being based on either genetic or environmental factors. Vertebrate sex determination exhibits remarkable diversity but displays distinct phylogenetic patterns. While all eutherian mammals possess XY male heterogamety and female heterogamety (ZW) is ubiquitous in birds, poikilothermic vertebrates (fish, amphibians and reptiles) exhibit multiple genetic sex-determination (GSD) systems as well as environmental sex determination (ESD). Temperature is the factor controlling ESD in reptiles and temperature-dependent sex determination (TSD) in reptiles has become a focal point in the study of this phenomenon. Current patterns of climate change may cause detrimental skews in the population sex ratios of reptiles exhibiting TSD. Understanding the patterns of variation, both within and among populations and linking such patterns with the selection processes they are associated with, is the central challenge of research aimed at predicting the capacity of populations to adapt to novel conditions. Here we present a conceptual model that innovates by defining an individual reaction norm for sex determination as a range of incubation temperatures. By deconstructing individual reaction norms for TSD and revealing their underlying interacting elements, we offer a conceptual solution that explains how variation among individual reaction norms can be inferred from the pattern of population reaction norms. The model also links environmental variation with the different patterns of TSD and describes the processes from which they may arise. Specific climate scenarios are singled out as eco-evolutionary traps that may lead to demographic extinction or a transition to either male or female heterogametic GSD. We describe how the conceptual principles can be applied to interpret TSD data and to explain the adaptive capacity of TSD to climate change as well as its limits and the potential applications for conservation and management

  11. Plasticity of gene-regulatory networks controlling sex determination: of masters, slaves, usual suspects, newcomers, and usurpators.

    Science.gov (United States)

    Herpin, Amaury; Schartl, Manfred

    2015-10-01

    Sexual dimorphism is one of the most pervasive and diverse features of animal morphology, physiology, and behavior. Despite the generality of the phenomenon itself, the mechanisms controlling how sex is determined differ considerably among various organismic groups, have evolved repeatedly and independently, and the underlying molecular pathways can change quickly during evolution. Even within closely related groups of organisms for which the development of gonads on the morphological, histological, and cell biological level is undistinguishable, the molecular control and the regulation of the factors involved in sex determination and gonad differentiation can be substantially different. The biological meaning of the high molecular plasticity of an otherwise common developmental program is unknown. While comparative studies suggest that the downstream effectors of sex-determining pathways tend to be more stable than the triggering mechanisms at the top, it is still unclear how conserved the downstream networks are and how all components work together. After many years of stasis, when the molecular basis of sex determination was amenable only in the few classical model organisms (fly, worm, mouse), recently, sex-determining genes from several animal species have been identified and new studies have elucidated some novel regulatory interactions and biological functions of the downstream network, particularly in vertebrates. These data have considerably changed our classical perception of a simple linear developmental cascade that makes the decision for the embryo to develop as male or female, and how it evolves. © 2015 The Authors.

  12. Expression of putative sex-determining genes during the thermosensitive period of gonad development in the snapping turtle, Chelydra serpentina.

    Science.gov (United States)

    Rhen, T; Metzger, K; Schroeder, A; Woodward, R

    2007-01-01

    Modes of sex determination are quite variable in vertebrates. The developmental decision to form a testis or an ovary can be influenced by one gene, several genes, environmental variables, or a combination of these factors. Nevertheless, certain morphogenetic aspects of sex determination appear to be conserved in amniotes. Here we clone fragments of nine candidate sex-determining genes from the snapping turtle Chelydra serpentina, a species with temperature-dependent sex determination (TSD). We then analyze expression of these genes during the thermosensitive period of gonad development. In particular, we compare gene expression profiles in gonads from embryos incubated at a male-producing temperature to those from embryos at a female-producing temperature. Expression of Dmrt1 and Sox9 mRNA increased gradually at the male-producing temperature, but was suppressed at the female-producing temperature. This finding suggests that Dmrt1 and Sox9 play a role in testis development. In contrast, expression of aromatase, androgen receptor (Ar), and Foxl2 mRNA was constant at the male-producing temperature, but increased several-fold in embryos at the female-producing temperature. Aromatase, Ar, and Foxl2 may therefore play a role in ovary development. In addition, there was a small temperature effect on ER alpha expression with lower mRNA levels found in embryos at the female-producing temperature. Finally, Dax1, Fgf9, and SF-1 were not differentially expressed during the sex-determining period, suggesting these genes are not involved in sex determination in the snapping turtle. Comparison of gene expression profiles among amniotes indicates that Dmrt1 and Sox9 are part of a core testis-determining pathway and that Ar, aromatase, ER alpha, and Foxl2 are part of a core ovary-determining pathway. 2007 S. Karger AG, Basel

  13. A single sex pheromone receptor determines chemical response specificity of sexual behavior in the silkmoth Bombyx mori.

    Science.gov (United States)

    Sakurai, Takeshi; Mitsuno, Hidefumi; Haupt, Stephan Shuichi; Uchino, Keiro; Yokohari, Fumio; Nishioka, Takaaki; Kobayashi, Isao; Sezutsu, Hideki; Tamura, Toshiki; Kanzaki, Ryohei

    2011-06-01

    In insects and other animals, intraspecific communication between individuals of the opposite sex is mediated in part by chemical signals called sex pheromones. In most moth species, male moths rely heavily on species-specific sex pheromones emitted by female moths to identify and orient towards an appropriate mating partner among a large number of sympatric insect species. The silkmoth, Bombyx mori, utilizes the simplest possible pheromone system, in which a single pheromone component, (E, Z)-10,12-hexadecadienol (bombykol), is sufficient to elicit full sexual behavior. We have previously shown that the sex pheromone receptor BmOR1 mediates specific detection of bombykol in the antennae of male silkmoths. However, it is unclear whether the sex pheromone receptor is the minimally sufficient determination factor that triggers initiation of orientation behavior towards a potential mate. Using transgenic silkmoths expressing the sex pheromone receptor PxOR1 of the diamondback moth Plutella xylostella in BmOR1-expressing neurons, we show that the selectivity of the sex pheromone receptor determines the chemical response specificity of sexual behavior in the silkmoth. Bombykol receptor neurons expressing PxOR1 responded to its specific ligand, (Z)-11-hexadecenal (Z11-16:Ald), in a dose-dependent manner. Male moths expressing PxOR1 exhibited typical pheromone orientation behavior and copulation attempts in response to Z11-16:Ald and to females of P. xylostella. Transformation of the bombykol receptor neurons had no effect on their projections in the antennal lobe. These results indicate that activation of bombykol receptor neurons alone is sufficient to trigger full sexual behavior. Thus, a single gene defines behavioral selectivity in sex pheromone communication in the silkmoth. Our findings show that a single molecular determinant can not only function as a modulator of behavior but also as an all-or-nothing initiator of a complex species-specific behavioral sequence.

  14. A single sex pheromone receptor determines chemical response specificity of sexual behavior in the silkmoth Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Takeshi Sakurai

    2011-06-01

    Full Text Available In insects and other animals, intraspecific communication between individuals of the opposite sex is mediated in part by chemical signals called sex pheromones. In most moth species, male moths rely heavily on species-specific sex pheromones emitted by female moths to identify and orient towards an appropriate mating partner among a large number of sympatric insect species. The silkmoth, Bombyx mori, utilizes the simplest possible pheromone system, in which a single pheromone component, (E, Z-10,12-hexadecadienol (bombykol, is sufficient to elicit full sexual behavior. We have previously shown that the sex pheromone receptor BmOR1 mediates specific detection of bombykol in the antennae of male silkmoths. However, it is unclear whether the sex pheromone receptor is the minimally sufficient determination factor that triggers initiation of orientation behavior towards a potential mate. Using transgenic silkmoths expressing the sex pheromone receptor PxOR1 of the diamondback moth Plutella xylostella in BmOR1-expressing neurons, we show that the selectivity of the sex pheromone receptor determines the chemical response specificity of sexual behavior in the silkmoth. Bombykol receptor neurons expressing PxOR1 responded to its specific ligand, (Z-11-hexadecenal (Z11-16:Ald, in a dose-dependent manner. Male moths expressing PxOR1 exhibited typical pheromone orientation behavior and copulation attempts in response to Z11-16:Ald and to females of P. xylostella. Transformation of the bombykol receptor neurons had no effect on their projections in the antennal lobe. These results indicate that activation of bombykol receptor neurons alone is sufficient to trigger full sexual behavior. Thus, a single gene defines behavioral selectivity in sex pheromone communication in the silkmoth. Our findings show that a single molecular determinant can not only function as a modulator of behavior but also as an all-or-nothing initiator of a complex species

  15. Population and colony-level determinants of tertiary sex ratio in the declining barn swallow.

    Directory of Open Access Journals (Sweden)

    Nicola Saino

    Full Text Available Sex ratio of adults (tertiary sex ratio, TSR is a major feature of animal populations with consequences for their behaviour, genetic structure and viability. Spatial and temporal variation in TSR occurs within species but the mechanisms behind it are poorly understood. In this long-term study of a declining population of a socially monogamous, colonial, migratory bird, the barn swallow (Hirundo rustica, we first analyzed population-level variation in TSR ( =  proportion of males of yearlings at sexual maturation in relation to ecological conditions as gauged by annual survival rate of adults. TSR was male-biased both among yearlings and older individuals, but male bias of yearlings was more pronounced after years with larger decline in adult survival. Thus, male offspring were less susceptible to the adverse ecological conditions that cause increased mortality. Dispersal and settling site decisions can have major consequences on fitness via the effects of local TSR on mating and sperm competition. Breeding barn swallows are highly philopatric while natal dispersal is high and, together with mortality, is the main determinant of colony TSR. We thus also investigated the mechanisms of breeding colony choice by yearlings and found that TSR of new-settlers in a given colony and year was negatively predicted by TSR of returning, early arriving older individuals in that year, but not by overall TSR at the colony in the previous year. This suggests that in our male-biased population new-settler males respond to local TSR upon arrival to choose the sites with larger breeding opportunities. Hence, variation in ecological conditions as reflected by adult survival can shift the TSR of individuals recruiting into a local population, with potentially various demographic consequences. However, breeding site choice based on TSR tends to homogenize TSR at a population level likely by facilitating settling of dispersing males in colonies with less male

  16. Dynamic karyotype evolution and unique sex determination systems in Leptidea wood white butterflies.

    Science.gov (United States)

    Šíchová, Jindra; Voleníková, Anna; Dincă, Vlad; Nguyen, Petr; Vila, Roger; Sahara, Ken; Marec, František

    2015-05-19

    Chromosomal rearrangements have the potential to limit the rate and pattern of gene flow within and between species and thus play a direct role in promoting and maintaining speciation. Wood white butterflies of the genus Leptidea are excellent models to study the role of chromosome rearrangements in speciation because they show karyotype variability not only among but also within species. In this work, we investigated genome architecture of three cryptic Leptidea species (L. juvernica, L. sinapis and L. reali) by standard and molecular cytogenetic techniques in order to reveal causes of the karyotype variability. Chromosome numbers ranged from 2n = 85 to 91 in L. juvernica and 2n = 69 to 73 in L. sinapis (both from Czech populations) to 2n = 51 to 55 in L. reali (Spanish population). We observed significant differences in chromosome numbers and localization of cytogenetic markers (rDNA and H3 histone genes) within the offspring of individual females. Using FISH with the (TTAGG) n telomeric probe we also documented the presence of multiple chromosome fusions and/or fissions and other complex rearrangements. Thus, the intraspecific karyotype variability is likely due to irregular chromosome segregation of multivalent meiotic configurations. The analysis of female meiotic chromosomes by GISH and CGH revealed multiple sex chromosomes: W1W2W3Z1Z2Z3Z4 in L. juvernica, W1W2W3Z1Z2Z3 in L. sinapis and W1W2W3W4Z1Z2Z3Z4 in L. reali. Our results suggest a dynamic karyotype evolution and point to the role of chromosomal rearrangements in the speciation of Leptidea butterflies. Moreover, our study revealed a curious sex determination system with 3-4 W and 3-4 Z chromosomes, which is unique in the Lepidoptera and which could also have played a role in the speciation process of the three Leptidea species.

  17. Developmental expression of "germline"- and "sex determination"-related genes in the ctenophore Mnemiopsis leidyi.

    Science.gov (United States)

    Reitzel, Adam M; Pang, Kevin; Martindale, Mark Q

    2016-01-01

    An essential developmental pathway in sexually reproducing animals is the specification of germ cells and the differentiation of mature gametes, sperm and oocytes. The "germline" genes vasa, nanos and piwi are commonly identified in primordial germ cells, suggesting a molecular signature for the germline throughout animals. However, these genes are also expressed in a diverse set of somatic stem cells throughout the animal kingdom leaving open significant questions for whether they are required for germline specification. Similarly, members of the Dmrt gene family are essential components regulating sex determination and differentiation in bilaterian animals, but the functions of these transcription factors, including potential roles in sex determination, in early diverging animals remain unknown. The phylogenetic position of ctenophores and the genome sequence of the lobate Mnemiopsis leidyi motivated us to determine the compliment of these gene families in this species and determine expression patterns during development. Our phylogenetic analyses of the vasa, piwi and nanos gene families show that Mnemiopsis has multiple genes in each family with multiple lineage-specific paralogs. Expression domains of Mnemiopsis nanos, vasa and piwi, during embryogenesis from fertilization to the cydippid stage, were diverse, with little overlapping expression and no or little expression in what we think are the germ cells or gametogenic regions. piwi paralogs in Mnemiopsis had distinct expression domains in the ectoderm during development. We observed overlapping expression domains in the apical organ and tentacle apparatus of the cydippid for a subset of "germline genes," which are areas of high cell proliferation, suggesting that these genes are involved with "stem cell" specification and maintenance. Similarly, the five Dmrt genes show diverse non-overlapping expression domains, with no clear evidence for expression in future gametogenic regions of the adult. We also

  18. Sexy transgenes: the impact of gene transfer and gene inactivation technologies on the understanding of mammalian sex determination.

    Science.gov (United States)

    Vaiman, Daniel

    2003-06-01

    Amongst the various developmental pathways ending in a sound mammal, sex determination presents the peculiarity of a choice between two equally viable options: female or male. Therefore, destroying a 'male-determining gene' or a 'female-determining gene' should generally not be lethal. Genetic sex determination is divided into two consecutive steps: construction of the bipotential gonad, and then sex determination per se. The genes involved in the first step are in fact involved in the development of various body compartments, and their mutation is generally far from innocuous. From transgenic and inactivation studies carried out on the laboratory mouse, a complete picture of the two steps is beginning to emerge, where the gonad itself and the necessary ducts are shown to evolve in a very coordinate way, with well-defined sex-specificities. Compared with testis determination, the ovarian side of the picture is still relatively empty, but this situation can change rapidly as candidate ovarian genes for inactivation studies are beginning to be identified.

  19. Molecular Sex Determination of Captive Komodo Dragons (Varanus komodoensis at Gembira Loka Zoo, Surabaya Zoo, and Ragunan Zoo, Indonesia

    Directory of Open Access Journals (Sweden)

    SRI SULANDARI

    2014-06-01

    Full Text Available Captive breeding of endangered species is often difficult, and may be hampered by many factors. Sexual monomorphism, in which males and females are not easily distinguishable, is one such factor and is a common problem in captive breeding of many avian and reptile species. Species-specific nuclear DNA markers, recently developed to identify portions of sex chromosomes, were employed in this study for sex determination of Komodo dragons (Varanus Komodoensis. Each animal was uniquely tagged using a passive integrated micro-transponder (TROVAN 100A type transponders of 13 mm in length and 2 mm in diameter. The sex of a total of 81 individual Komodo dragons (44 samples from Ragunan zoo, 26 samples from Surabaya zoo, and 11 samples from Gembira Loka zoo were determined using primers Ksex 1for and Ksex 3rev. A series of preliminary PCR amplifications were conducted using DNA from individuals of known sex. During these preliminary tests, researchers varied the annealing temperatures, number of cycles, and concentrations of reagents, in order to identify the best protocol for sex determination using our sample set. We thus developed our own PCR protocol for this study, which resulted in the amplification of band A in females and band C in males. Results from band B, however, turned out to be non-determinative in our study because, for females, band B was not always visible, and for males sometimes a similar, but lighter band was also amplified, making interpretation difficult. In this study, sex determination was based mainly on the difference in size between the female-specific 812 bp fragment and the homologous, longer fragment amplified for males.

  20. The role of the transformer gene in sex determination and reproduction in the tephritid fruit fly, Bactrocera dorsalis (Hendel).

    Science.gov (United States)

    Peng, Wei; Zheng, Wenping; Handler, Alfred M; Zhang, Hongyu

    2015-12-01

    Transformer (tra) is a switch gene in the somatic sex-determination hierarchy that regulates sexual dimorphism based on RNA splicing in many insects. In tephritids, a Y-linked male determining gene (M) controls sex in the sex-determination pathway. Here, homologues of Drosophila tra and transformer-2 (tra-2) genes were isolated and characterized in Bactrocera dorsalis (Hendel), one of the most destructive agricultural insect pests in many Asian countries. Two male-specific and one female-specific isoforms of B. dorsalis transformer (Bdtra) were identified. The presence of multiple TRA/TRA-2 binding sites in Bdtra suggests that the TRA/TRA-2 proteins are splicing regulators promoting and maintaining, epigenetically, female sex determination by a tra positive feedback loop in XX individuals during development. The expression patterns of female-specific Bdtra transcripts during early embryogenesis shows that a peak appears at 15 h after egg laying. Using dsRNA to knock-down Bdtra expression in the embryo and adult stages, we showed that sexual formation is determined early in the embryo stage and that parental RNAi does not lead to the production of all male progeny as in Tribolium castaneum. RNAi results from adult abdominal dsRNA injections show that Bdtra has a positive influence on female yolk protein gene (Bdyp1) expression and fecundity.

  1. Genetic and physical maps around the sex-determining M-locus of the dioecious plant asparagus.

    Science.gov (United States)

    Telgmann-Rauber, Alexa; Jamsari, Ari; Kinney, Michael S; Pires, J Chris; Jung, Christian

    2007-09-01

    Asparagus officinalis L. is a dioecious plant. A region called the M-locus located on a pair of homomorphic sex chromosomes controls the sexual dimorphism in asparagus. The aim of this work was to clone the region determining sex in asparagus from its position in the genome. The structure of the region encompassing M should be investigated and compared to the sex-determining regions in other dioecious model species. To establish an improved basis for physical mapping, a high-resolution genetic map was enriched with AFLP markers closely linked to the target locus by carrying out a bulked segregant analysis. By screening a BAC library with AFLP- and STS-markers followed by chromosome walking, a physical map with eight contigs could be established. However, the gaps between the contigs could not be closed due to a plethora of repetitive elements. Surprisingly, two of the contigs on one side of the M-locus did not overlap although they have been established with two markers, which mapped in a distance as low as 0.25 cM flanking the sex locus. Thus, the clustering of the markers indicates a reduced recombination frequency within the M-region. On the opposite side of the M-locus, a contig was mapped in a distance of 0.38 cM. Four closely linked BAC clones were partially sequenced and 64 putative ORFs were identified. Interestingly, only 25% of the ORFs showed sequence similarity to known proteins and ESTs. In addition, an accumulation of repetitive sequences and a low gene density was revealed in the sex-determining region of asparagus. Molecular cytogenetic and sequence analysis of BACs flanking the M-locus indicate that the BACs contain highly repetitive sequences that localize to centromeric and pericentromeric locations on all asparagus chromosomes, which hindered the localization of the M-locus to the single pair of sex chromosomes. We speculate that dioecious Silene, papaya and Asparagus species may represent three stages in the evolution of XX, XY sex

  2. Sex determination based on amelogenin DNA by modified electrode with gold nanoparticle.

    Science.gov (United States)

    Mazloum-Ardakani, Mohammad; Rajabzadeh, Nooshin; Benvidi, Ali; Heidari, Mohammad Mehdi

    2013-12-15

    We have developed a simple and renewable electrochemical biosensor based on carbon paste electrode (CPE) for the detection of DNA synthesis and hybridization. CPE was modified with gold nanoparticles (AuNPs), which are helpful for immobilization of thiolated bioreceptors. AuNPs were characterized by scanning electron microscopy (SEM). Self-assembled monolayers (SAMs) of thiolated single-stranded DNA (SH-ssDNA) of the amelogenin gene was formed on CPE. The immobilization of the probe and its hybridization with the target DNA was optimized using different experimental conditions. The modified electrode was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrochemical response of ssDNA hybridization and DNA synthesis was measured using differential pulse voltammetry (DPV) with methylene blue (MB) as an electroactive indicator. The new biosensor can distinguish between complementary and non-complementary strands of amelogenin ssDNA. Genomic DNA was extracted from blood and was detected based on changes in the MB reduction signal. These results demonstrated that the new biosensor could be used for sex determination. The proposed biosensor in this study could be used for detection and discrimination of polymerase chain reaction (PCR) products of amelogenin DNA. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Expression profile of the sex determination gene doublesex in a gynandromorph of bumblebee, Bombus ignitus

    Science.gov (United States)

    Ugajin, Atsushi; Matsuo, Koshiro; Kubo, Ryohei; Sasaki, Tetsuhiko; Ono, Masato

    2016-04-01

    Gynandromorphy that has both male and female features is known in many insect orders, including Hymenoptera. In most cases, however, only external morphology and behavioral aspects have been studied. We found a gynandromorph of bumblebee, Bombus ignitus, that showed almost bilateral distribution of external sexual traits, with male characters observed on the left side and female characters on the right side. This individual never exhibited sexual behavior toward new queens. The dissection of the head part showed that it had bilaterally dimorphic labial glands, only the left of which was well developed and synthesized male-specific pheromone components. In contrast, the gynandromorph possessed an ovipositor and a pair of ovaries in the abdominal part, suggesting that it had a uniformly female reproductive system. Furthermore, we characterized several internal organs of the gynandromorph by a molecular biological approach. The expression analyses of a sex determination gene, doublesex, in the brain, the fat bodies, the hindgut, and the ovaries of the gynandromorph revealed a male-type expression pattern exclusively in the left brain hemisphere and consistent female-type expression in other tissues. These findings clearly indicate the sexual discordance between external traits and internal organs in the gynandromorph. The results of genetic analyses using microsatellite markers suggested that this individual consisted of both genetically male- and female-type tissues.

  4. Non-invasive prenatal diagnosis for fetal sex determination: benefits and disadvantages from the service users' perspective.

    Science.gov (United States)

    Lewis, Celine; Hill, Melissa; Skirton, Heather; Chitty, Lyn S

    2012-11-01

    Prenatal fetal sex determination is clinically indicated for women who are at risk of having a child with a serious genetic disorder affecting a particular sex. Ultrasound has been the traditional method used, but early fetal sex determination using non-invasive prenatal diagnosis (NIPD) can now be performed using cell-free fetal DNA in maternal plasma. The study aim was to assess the views and experiences of service users who had used NIPD for fetal sex determination. In this paper, we report on the perceived benefits and disadvantages. A qualitative approach using semi-structured interviews was used. A total of 44 participants (38 women and 6 partners of participating women) were recruited. Participants' views and experiences of NIPD were overwhelmingly positive. Concerning benefits over traditional methods, three themes emerged: (1) technical aspects of technology; (2) timing; and (3) enhanced decision-making. Practical advantages of NIPD included avoiding miscarriage, and there were a number of psychological advantages associated with timing such as perceived control, early re-engagement, normalization of pregnancy and peace of mind. Participants also valued NIPD as it enabled a stepwise approach to decision-making. A number of disadvantages were discussed including concerns about social sexing and increased bonding at a time in pregnancy when miscarriage risk is high. However, participants felt these were fairly minor in comparison with the advantages of NIPD. Until definitive genetic diagnosis using NIPD is available, NIPD for fetal sex determination is perceived as a good interim measure with a number of notable advantages over traditional methods.

  5. Non-invasive prenatal diagnosis for fetal sex determination: benefits and disadvantages from the service users' perspective

    Science.gov (United States)

    Lewis, Celine; Hill, Melissa; Skirton, Heather; Chitty, Lyn S

    2012-01-01

    Prenatal fetal sex determination is clinically indicated for women who are at risk of having a child with a serious genetic disorder affecting a particular sex. Ultrasound has been the traditional method used, but early fetal sex determination using non-invasive prenatal diagnosis (NIPD) can now be performed using cell-free fetal DNA in maternal plasma. The study aim was to assess the views and experiences of service users who had used NIPD for fetal sex determination. In this paper, we report on the perceived benefits and disadvantages. A qualitative approach using semi-structured interviews was used. A total of 44 participants (38 women and 6 partners of participating women) were recruited. Participants' views and experiences of NIPD were overwhelmingly positive. Concerning benefits over traditional methods, three themes emerged: (1) technical aspects of technology; (2) timing; and (3) enhanced decision-making. Practical advantages of NIPD included avoiding miscarriage, and there were a number of psychological advantages associated with timing such as perceived control, early re-engagement, normalization of pregnancy and peace of mind. Participants also valued NIPD as it enabled a stepwise approach to decision-making. A number of disadvantages were discussed including concerns about social sexing and increased bonding at a time in pregnancy when miscarriage risk is high. However, participants felt these were fairly minor in comparison with the advantages of NIPD. Until definitive genetic diagnosis using NIPD is available, NIPD for fetal sex determination is perceived as a good interim measure with a number of notable advantages over traditional methods. PMID:22453293

  6. The Effects of the Determinants of Women's Movement Into and Out of Male-dominated Occupations on Occupational Sex Segregation.

    Science.gov (United States)

    Sheridan, Jennifer T.

    Although occupational sex segregation has decreased over the last 25 years, it is still a major social concern primarily because of the role it plays in perpetuating the gender wage gap. This paper uses data from the Wisconsin Longitudinal Study, a study that followed a random sample of 10,317 high school graduates, to assess the determinants of…

  7. [The frequency of sex chromatine occurring in cell nuclei of internal organs determined by the smear method (author's transl)].

    Science.gov (United States)

    Michailow, R

    1975-09-05

    The frequency of sex chromatine occurring in cell nuclei of twelve organs from 25 male and female corpses was determined using the smear method. It was found to be about 60% in the case of female, and about 6% in the case of male corpses.

  8. HIV INFECTION AMONG FEMALE SEX WORKERS IN CONCENTRATED AND HIGH PREVALENCE EPIDEMICS: WHY A STRUCTURAL DETERMINANTS FRAMEWORK IS NEEDED

    Science.gov (United States)

    Shannon, Kate; Goldenberg, Shira M.; Deering, Kathleen N.; Strathdee, Steffanie A.

    2014-01-01

    Purpose of review This article reviews the current state of the epidemiological literature on female sex work and HIV from the past 18 months. We offer a conceptual framework for structural HIV determinants and sex work that unpacks intersecting structural, interpersonal, and individual biological and behavioural factors. Recent findings Our review suggests that despite the heavy HIV burden among female sex workers (FSWs) globally, data on the structural determinants shaping HIV transmission dynamics have only begun to emerge. Emerging research suggests that factors operating at macrostructural (e.g., migration, stigma, criminalized laws), community organization (e.g., empowerment) and work environment levels (e.g., violence, policing, access to condoms HIV testing, HAART) act dynamically with interpersonal (e.g., dyad factors, sexual networks) and individual biological and behavioural factors to confer risks or protections for HIV transmission in female sex work. Summary Future research should be guided by a Structural HIV Determinants Framework to better elucidate the complex and iterative effects of structural determinants with interpersonal and individual biological and behavioural factors on HIV transmission pathways among FSWs, and meet critical gaps in optimal access to HIV prevention, treatment, and care for FSWs globally. PMID:24464089

  9. Expression profiles of amhy and major sex-related genes during gonadal sex differentiation and their relation with genotypic and temperature-dependent sex determination in pejerrey Odontesthes bonariensis.

    Science.gov (United States)

    Zhang, Yan; Hattori, Ricardo S; Sarida, Munti; García, Estefany L; Strüssmann, Carlos Augusto; Yamamoto, Yoji

    2018-03-15

    To shed light on the mechanisms of and interactions of GSD and TSD in pejerrey, we investigated how the transcriptional profiles of amhy and amha are affected by feminizing (17 °C) and masculinizing (29 °C) temperatures during the critical period of sex determination/differentiation and their relation with the expression profiles of AMH receptor type II (amhrII), gonadal aromatase (cyp19a1a), and 11 beta-hydroxysteroid dehydrogenase 2 (hsd11b2). Careful consideration of the results of this study and all information currently available for this species, including similar analyzes for an intermediate, mixed-sex promoting temperature (25 °C), suggests a model for genotypic/temperature-dependent sex determination and gonadal sex differentiation that involves a) cyp19a1a-dependent, developmentally-programmed ovarian development as the default state that becomes self-sustaining in the absence of a potent and timely masculinizing stimulus, b) early, developmentally-programmed amhy expression and high temperature as masculinization signals that antagonize the putative female pathway by suppressing cyp19a1a expression, c) increasing stress response, cortisol, and the synthesis of the masculinizing androgen 11-keto-testosterone via hsd11b2 with increasing temperature that is important for masculinization in both genotypes but particularly so in XX individuals, and d) an endocrine network with positive/negative feedback mechanisms that ensure fidelity of the male/female pathway once started. The proposed model, albeit tentative and non-all inclusive, accounts for the continuum of responses, from all-females at low temperatures to all-males at high temperatures and for the balanced-, genotype-linked sex ratios obtained at intermediate temperatures, and therefore supports the coexistence of TSD and GSD in pejerrey across the range of viable temperatures for this species. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Policing practices as a structural determinant for HIV among sex workers: a systematic review of empirical findings.

    Science.gov (United States)

    Footer, Katherine Ha; Silberzahn, Bradley E; Tormohlen, Kayla N; Sherman, Susan G

    2016-01-01

    Sex workers are disproportionately infected with HIV worldwide. Significant focus has been placed on understanding the structural determinants of HIV and designing related interventions. Although there is growing international evidence that policing is an important structural HIV determinant among sex workers, the evidence has not been systematically reviewed. We conducted a systematic review of quantitative studies to examine the effects of policing on HIV and STI infection and HIV-related outcomes (condom use; syringe use; number of clients; HIV/STI testing and access) among cis and trans women sex workers. Databases included PubMed, Embase, Scopus, Sociological Abstracts, Popline, Global Health (OVID), Web of Science, IBSS, IndMed and WHOLIS. We searched for studies that included police practices as an exposure for HIV or STI infection or HIV-related outcomes. Of the 137 peer-reviewed articles identified for full text review, 14 were included, representing sex workers' experiences with police across five settings. Arrest was the most commonly explored measure with between 6 and 45% of sex workers reporting having ever been arrested. Sexual coercion was observed between 3 and 37% of the time and police extortion between 12 and 28% across studies. Half the studies used a single measure to capture police behaviours. Studies predominantly focused on "extra-legal policing practices," with insufficient attention to the role of "legal enforcement activities". All studies found an association between police behaviours and HIV or STI infection, or a related risk behaviour. The review points to a small body of evidence that confirms policing practices as an important structural HIV determinant for sex workers, but studies lack generalizability with respect to identifying those police behaviours most relevant to women's HIV risk environment.

  11. DEHP exposure in utero disturbs sex determination and is potentially linked with precocious puberty in female mice

    International Nuclear Information System (INIS)

    Wang, Yongan; Yang, Qing; Liu, Wei; Yu, Mingxi; Zhang, Zhou; Cui, Xiaoyu

    2016-01-01

    Human's ubiquitous exposure to di (2-ethylhexyl) phthalate (DEHP) is thought to be associated with female reproductive toxicity. Previous studies found that DEHP inhibited follicle growth and decreased estradiol levels in adult female mice. However, limited information is available on the link between in utero DEHP exposure and ovarian development in female mouse offspring. The present study evaluates the disturbances in regulatory genes involved in female sex determination and the ovarian outcomes in fetal and postnatal female mice treated with in utero DEHP exposure. Pregnant mice were exposed to DEHP by gavage, with the dosage regime beginning at human relevant exposure levels. After in utero DEHP exposure, increased follicular atresia was observed in the female pups at postnatal days (PND) 21. Foxl2 expression was significantly upregulated, and Fst was significantly downregulated by DEHP above 2 mg/kg/d at PND 1 and 21. This suggests that lesion of granulosa cell differentiation and disturbance of follicle development in postnatal female mice. The expression of Cyp11a1 and Star were significantly downregulated by in utero DEHP exposure, indicating effects on estradiol biosynthesis. The female sex determination pathway was disturbed in fetus by DEHP at 2 mg/kg/d and above during the critical time window of sex determination causing significant upregulation of Foxl2, Wnt4, β-catenin and Fst. Furthermore, the increased expression of Wnt4 was supported by whole-mount in situ hybridization (WISH). These results suggest a possible association between in utero DEHP exposure and precocious puberty in the postnatal life of mice offspring, where disturbance of the sex determination regulating pathway acted as an important mechanism. - Highlights: • Maternal exposure to di (2-ethylhexyl) phthalate disturbs fetus sex determination. • DEHP upregulated Foxl2 expression potentially disturbs postnatal granulosa cell differentiation. • DEHP accelerated medulla

  12. DEHP exposure in utero disturbs sex determination and is potentially linked with precocious puberty in female mice

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yongan [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, Liaoning 116024 (China); Yang, Qing [School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning 116024 (China); Liu, Wei, E-mail: liu_wei@dlut.edu.cn [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, Liaoning 116024 (China); Yu, Mingxi; Zhang, Zhou; Cui, Xiaoyu [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, Liaoning 116024 (China)

    2016-09-15

    Human's ubiquitous exposure to di (2-ethylhexyl) phthalate (DEHP) is thought to be associated with female reproductive toxicity. Previous studies found that DEHP inhibited follicle growth and decreased estradiol levels in adult female mice. However, limited information is available on the link between in utero DEHP exposure and ovarian development in female mouse offspring. The present study evaluates the disturbances in regulatory genes involved in female sex determination and the ovarian outcomes in fetal and postnatal female mice treated with in utero DEHP exposure. Pregnant mice were exposed to DEHP by gavage, with the dosage regime beginning at human relevant exposure levels. After in utero DEHP exposure, increased follicular atresia was observed in the female pups at postnatal days (PND) 21. Foxl2 expression was significantly upregulated, and Fst was significantly downregulated by DEHP above 2 mg/kg/d at PND 1 and 21. This suggests that lesion of granulosa cell differentiation and disturbance of follicle development in postnatal female mice. The expression of Cyp11a1 and Star were significantly downregulated by in utero DEHP exposure, indicating effects on estradiol biosynthesis. The female sex determination pathway was disturbed in fetus by DEHP at 2 mg/kg/d and above during the critical time window of sex determination causing significant upregulation of Foxl2, Wnt4, β-catenin and Fst. Furthermore, the increased expression of Wnt4 was supported by whole-mount in situ hybridization (WISH). These results suggest a possible association between in utero DEHP exposure and precocious puberty in the postnatal life of mice offspring, where disturbance of the sex determination regulating pathway acted as an important mechanism. - Highlights: • Maternal exposure to di (2-ethylhexyl) phthalate disturbs fetus sex determination. • DEHP upregulated Foxl2 expression potentially disturbs postnatal granulosa cell differentiation. • DEHP accelerated medulla

  13. Fetal sex determination in the first trimester of pregnancy using a Y chromosome-specific DNA probe

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Y.; Huang, S.; Chen, M.; Huang, Y.; Zhang, M.; Dong, J.; Ku, A.; Xu, S.

    1987-05-01

    Prenatal determination of fetal sex is important for the prevention of X-linked disorders such as hemophilia, Lesch-Nyhan syndrome and Duchenne muscular dystrophy. The complex procedures of prenatal diagnosis for X-linked disorders are unnecessary if the fetus is female, because usually no clinical symptoms ever appear in female. pY 3.4 probe used in this work for sex determination is a 3.4 kilobase human repeat sequence. The probe is specific for the Y chromosome of males and can be used for sex determination. The other prove pBLUR used in this paper as control is a widely dispersed, highly repeated human Alu family DNA sequence, represented equally in male and female DNA. On the basis of the relative densities of the autoradiographic spots produced by hybridization of fetal DNA with pY3.4 and pBLUR, the sex of fetus can be clearly identified. Further the authors can determine the radioactive intensity (cpm) of the hybridized DNA spots and the ratio of hybridization with Y3.4 to pBLUR (Y3.4/pBLUR x 10). Results show that the hybridization ratio of DNA from chorionic villi of male (1.03 +/- 0.24) is significantly higher than that of female (0.16 +/- 0.09). Therefore, sex determination of the fetus can be made, based on the ratio of pY3.4/pBLUR x 10. If necessary they can also use Southern hybridization with pY 3.4 probe of DNA isolated from chorionic villi to confirm the result of dot hybridization.

  14. The reliability of morphometric discriminant functions in determining the sex of Chilean flamingos Phoenicopterus chilensis

    OpenAIRE

    Diego MONTALTI et al

    2012-01-01

    Monomorphic birds cannot be sexed visually and discriminant functions on the basis of external morphological variations are frequently used. Our objective was to evaluate the reliability of sex classification functions created from structural measurements of Chilean flamingos Phoenicopterus chilensis museum skins for the gender assignment of live birds. Five measurements were used to develop four discriminant functions: culmen, bill height and width, tarsus length and middle toe claw. The fun...

  15. The Wright stuff: reimagining path analysis reveals novel components of the sex determination hierarchy in Drosophila melanogaster.

    Science.gov (United States)

    Fear, Justin M; Arbeitman, Michelle N; Salomon, Matthew P; Dalton, Justin E; Tower, John; Nuzhdin, Sergey V; McIntyre, Lauren M

    2015-09-04

    The Drosophila sex determination hierarchy is a classic example of a transcriptional regulatory hierarchy, with sex-specific isoforms regulating morphology and behavior. We use a structural equation modeling approach, leveraging natural genetic variation from two studies on Drosophila female head tissues--DSPR collection (596 F1-hybrids from crosses between DSPR sub-populations) and CEGS population (75 F1-hybrids from crosses between DGRP/Winters lines to a reference strain w1118)--to expand understanding of the sex hierarchy gene regulatory network (GRN). This approach is completely generalizable to any natural population, including humans. We expanded the sex hierarchy GRN adding novel links among genes, including a link from fruitless (fru) to Sex-lethal (Sxl) identified in both populations. This link is further supported by the presence of fru binding sites in the Sxl locus. 754 candidate genes were added to the pathway, including the splicing factors male-specific lethal 2 and Rm62 as downstream targets of Sxl which are well-supported links in males. Independent studies of doublesex and transformer mutants support many additions, including evidence for a link between the sex hierarchy and metabolism, via Insulin-like receptor. The genes added in the CEGS population were enriched for genes with sex-biased splicing and components of the spliceosome. A common goal of molecular biologists is to expand understanding about regulatory interactions among genes. Using natural alleles we can not only identify novel relationships, but using supervised approaches can order genes into a regulatory hierarchy. Combining these results with independent large effect mutation studies, allows clear candidates for detailed molecular follow-up to emerge.

  16. Gender preference and awareness regarding sex determination among antenatal mothers attending a medical college of eastern India.

    Science.gov (United States)

    Yasmin, Shamima; Mukherjee, Anindya; Manna, Nirmalya; Baur, Baijayanti; Datta, Mousumi; Sau, Manabendra; Roy, Manidipa; Dasgupta, Samir

    2013-06-01

    There are many women "missing" due to an unfavourable sex ratio in India, which has strong patriarchal norms and a preference for sons. Female gender discrimination has been reported in health care, nutrition, education, and resource allocation due to man-made norms, religious beliefs, and recently by ultrasonography resulting in lowered sex ratio. The present study attempts to find out the level of awareness regarding sex determination and to explore preference of gender and factors associated among antenatal mothers attending a medical college in eastern India. Interviews were done by predesigned pretested proforma over 6 months. The data were analysed by SPSS 16.0 software for proportions with chi-squared tests and binary logistic regression analysis. Most women who were multigravida did not know about contraceptives; 1.8% of mothers knew the sex of the fetus in present pregnancy while another 34.7% expressed willingness; 13.6% knew of a place which could tell sex of the fetus beforehand; 55.6% expressed their preference of sex of the baby for present pregnancy while 50.6% of their husbands had gender preference. Gender preference was significantly high in subjects with: lower socioeconomic status (p=0.011); lower level of education of mother (p=0.047) and husband (p=0.0001); multigravida (p=0.002); presence of living children (p=0.0001); and husband having preference of sex of baby (p=0.0001). Parental education, socioeconomic background, and number of living issues were the main predictors for gender preference. Awareness regarding gender preference and related law and parental counselling to avoid gender preference with adoption of small family norm is recommended.

  17. Establishment and evaluation of sex determination method from 12 th thoracic vertebrae based on three-dimensional reconstructed models

    International Nuclear Information System (INIS)

    Guo Ming; Hou Weibin; Jing Yue; Li Youqiong; Zhou Jianying

    2011-01-01

    Objective: To establish the method of using the 12 th vertebrae for sex determination of adult Chinese and evaluate its effect. Methods: The 12 th thoracic vertebrae were developed by the clinic abdomen CT images. A total of 25 linear measurements on 7 aspects of the vertebrae were measured and 4 ratios were calculated. The items were selected which had the significant difference to establish the sex determination equation and its effect was evaluated. Results: Of the total 29 traits, 27 were sexually dimorphic (P<0.05), the accuracy was 56.3% - 89.2%, 8 traits had the accuracies mean or over 80.0%. The trait iVL had the highest accuracy of 89.2%. A function with four variables predicting sex with 90.8% accuracy was derived by using stepwise method of discriminant function analysis: Y=2.98 x iBDsm + 1.97 x PH + 3.37 x BHp + 3.27 x sVL/BHa - 32.80 (mean centroids= -7.69). Conclusion: The method of using the selected traits for sex determination of adult Chinese is practicable and it has a relatively high accuracy. (authors)

  18. Inheritance of nesting behaviour across natural environmental variation in a turtle with temperature-dependent sex determination.

    Science.gov (United States)

    McGaugh, Suzanne E; Schwanz, Lisa E; Bowden, Rachel M; Gonzalez, Julie E; Janzen, Fredric J

    2010-04-22

    Nesting behaviour is critical for reproductive success in oviparous organisms with no parental care. In organisms where sex is determined by incubation temperature, nesting behaviour may be a prime target of selection in response to unbalanced sex ratios. To produce an evolutionary change in response to sex-ratio selection, components of nesting behaviour must be heritable. We estimated the field heritability of two key components of nesting behaviour in a population of painted turtles (Chrysemys picta) with temperature-dependent sex determination by applying the 'animal model' to a pedigree reconstructed from genotype data. We obtained estimates of low to non-detectable heritability using repeated records across all environments. We then determined environment-specific heritability by grouping records with similar temperatures for the winter preceding the nesting season, a variable known to be highly associated with our two traits of interest, nest vegetation cover and Julian date of nesting. The heritability estimates of nest vegetation cover and Julian date of nesting were qualitatively highest and significant, or nearly so, after hot winters. Additive genetic variance for these traits was not detectable after cold winters. Our analysis suggests that the potential for evolutionary change of nesting behaviour may be dependent on the thermal conditions of the preceding winter, a season that is predicted to be especially subject to climate change.

  19. Charactering the ZFAND3 gene mapped in the sex-determining locus in hybrid tilapia (Oreochromis spp.)

    Science.gov (United States)

    Ma, Keyi; Liao, Minghui; Liu, Feng; Ye, Baoqing; Sun, Fei; Yue, Gen Hua

    2016-01-01

    Zinc finger AN1-type domain 3 (ZFAND3) is essential for spermatogenesis in mice. However, its function in teleosts remains unclear. In this study, we characterized the ZFAND3 gene (termed as OsZFAND3) in an important food fish, tilapia. The OsZFAND3 cDNA sequence is 1,050 bp in length, containing an ORF of 615 bp, which encodes a putative peptide of 204 amino acid residues. Quantitative real-time PCR revealed that the OsZFAND3 transcripts were exclusively expressed in the testis and ovary. In situ hybridization showed that the high expression of OsZFAND3 transcripts was predominantly localized in the spermatocyte and spermatid. These results suggest that OsZFAND3 is involved in male germ cell maturation. Three single nucleotide polymorphisms (SNPs) were detected in the introns of OsZFAND3. The OsZFAND3 gene was mapped in the sex-determining locus on linkage group 1 (LG1). The three SNPs in the OsZFAND3 gene were strictly associated with sex phenotype, suggesting that the OsZFAND3 gene is tightly linked to the sex-determining locus. Our study provides new insights into the functions of the OsZFAND3 gene in tilapia and a foundation for further detailed analysis of the OsZFAND3 gene in sex determination and differentiation. PMID:27137111

  20. Application of real-time PCR of sex-independent insertion-deletion polymorphisms to determine fetal sex using cell-free fetal DNA from maternal plasma.

    Science.gov (United States)

    Ho, Sherry Sze Yee; Barrett, Angela; Thadani, Henna; Asibal, Cecille Laureano; Koay, Evelyn Siew-Chuan; Choolani, Mahesh

    2015-07-01

    Prenatal diagnosis of sex-linked disorders requires invasive procedures, carrying a risk of miscarriage of up to 1%. Cell-free fetal DNA (cffDNA) present in cell-free DNA (cfDNA) from maternal plasma offers a non-invasive source of fetal genetic material for analysis. Detection of Y-chromosome sequences in cfDNA indicates presence of a male fetus; in the absence of a Y-chromosome signal a female fetus is inferred. We aimed to validate the clinical utility of insertion-deletion polymorphisms (INDELs) to confirm presence of a female fetus using cffDNA. Quantitative real-time PCR (qPCR) for the Y-chromosome-specific sequence, SRY, was performed on cfDNA from 82 samples at 6-39 gestational weeks. In samples without detectable SRY, qPCRs for eight INDELs were performed on maternal genomic DNA and cfDNA. Detection of paternally inherited fetal alleles in cfDNA negative for SRY confirmed a female fetus. Fetal sex was correctly determined in 77/82 (93.9%) cfDNA samples. SRY was detected in all 39 samples from male-bearing pregnancies, and none of the 43 female-bearing pregnancies (sensitivity and specificity of SRY qPCR is therefore 100%; 95% CI 91%-100%). Paternally inherited fetal alleles were detected in 38/43 samples with no SRY signal, confirming the presence of a female fetus (INDEL assay sensitivity is therefore 88.4%; 95% CI 74.1%-95.6%). Since paternally inherited fetal INDELs were not used in women bearing male fetuses, the specificity of INDELs cannot be calculated. Five cfDNA samples were negative for both SRY and INDELS. We have validated a non-invasive prenatal test to confirm fetal sex as early as 6 gestational weeks using cffDNA from maternal plasma.

  1. Gonad Transcriptome Analysis of the Pacific Oyster Crassostrea gigas Identifies Potential Genes Regulating the Sex Determination and Differentiation Process.

    Science.gov (United States)

    Yue, Chenyang; Li, Qi; Yu, Hong

    2018-04-01

    The Pacific oyster Crassostrea gigas is a commercially important bivalve in aquaculture worldwide. C. gigas has a fascinating sexual reproduction system consisting of dioecism, sex change, and occasional hermaphroditism, while knowledge of the molecular mechanisms of sex determination and differentiation is still limited. In this study, the transcriptomes of male and female gonads at different gametogenesis stages were characterized by RNA-seq. Hierarchical clustering based on genes differentially expressed revealed that 1269 genes were expressed specifically in female gonads and 817 genes were expressed increasingly over the course of spermatogenesis. Besides, we identified two and one gene modules related to female and male gonad development, respectively, using weighted gene correlation network analysis (WGCNA). Interestingly, GO and KEGG enrichment analysis showed that neurotransmitter-related terms were significantly enriched in genes related to ovary development, suggesting that the neurotransmitters were likely to regulate female sex differentiation. In addition, two hub genes related to testis development, lncRNA LOC105321313 and Cg-Sh3kbp1, and one hub gene related to ovary development, Cg-Malrd1-like, were firstly investigated. This study points out the role of neurotransmitter and non-coding RNA regulation during gonad development and produces lists of novel relevant candidate genes for further studies. All of these provided valuable information to understand the molecular mechanisms of C. gigas sex determination and differentiation.

  2. Molecular cytogenetic characterization of the dioecious Cannabis sativa with an XY chromosome sex determination system.

    Directory of Open Access Journals (Sweden)

    Mikhail G Divashuk

    Full Text Available Hemp (Cannabis sativa L. was karyotyped using by DAPI/C-banding staining to provide chromosome measurements, and by fluorescence in situ hybridization with probes for 45 rDNA (pTa71, 5S rDNA (pCT4.2, a subtelomeric repeat (CS-1 and the Arabidopsis telomere probes. The karyotype has 18 autosomes plus a sex chromosome pair (XX in female and XY in male plants. The autosomes are difficult to distinguish morphologically, but three pairs could be distinguished using the probes. The Y chromosome is larger than the autosomes, and carries a fully heterochromatic DAPI positive arm and CS-1 repeats only on the less intensely DAPI-stained, euchromatic arm. The X is the largest chromosome of all, and carries CS-1 subtelomeric repeats on both arms. The meiotic configuration of the sex bivalent locates a pseudoautosomal region of the Y chromosome at the end of the euchromatic CS-1-carrying arm. Our molecular cytogenetic study of the C. sativa sex chromosomes is a starting point for helping to make C. sativa a promising model to study sex chromosome evolution.

  3. XX/XY System of Sex Determination in the Geophilomorph Centipede Strigamia maritima.

    Directory of Open Access Journals (Sweden)

    Jack E Green

    Full Text Available We show that the geophilomorph centipede Strigamia maritima possesses an XX/XY system of sex chromosomes, with males being the heterogametic sex. This is, to our knowledge, the first report of sex chromosomes in any geophilomorph centipede. Using the recently assembled Strigamia genome sequence, we identified a set of scaffolds differentially represented in male and female DNA sequence. Using quantitative real-time PCR, we confirmed that three candidate X chromosome-derived scaffolds are present at approximately twice the copy number in females as in males. Furthermore, we confirmed that six candidate Y chromosome-derived scaffolds contain male-specific sequences. Finally, using this molecular information, we designed an X chromosome-specific DNA probe and performed fluorescent in situ hybridization against mitotic and meiotic chromosome spreads to identify the Strigamia XY sex-chromosome pair cytologically. We found that the X and Y chromosomes are recognizably different in size during the early pachytene stage of meiosis, and exhibit incomplete and delayed pairing.

  4. Traffic Violations: Determining the Meaning of Violence in Sexual Trafficking Versus Sex Work

    Science.gov (United States)

    Saunders, Penelope

    2005-01-01

    This contribution will consider the current linkages among migration, sex work, trafficking in persons, and violence. Efforts to end trafficking in persons are perhaps the most important contribution to antiviolence program design in the global arena over the past decade. Significant funding and technical assistance are flowing to organizations to…

  5. Molecular cytogenetic characterization of the dioecious Cannabis sativa with an XY chromosome sex determination system.

    Science.gov (United States)

    Divashuk, Mikhail G; Alexandrov, Oleg S; Razumova, Olga V; Kirov, Ilya V; Karlov, Gennady I

    2014-01-01

    Hemp (Cannabis sativa L.) was karyotyped using by DAPI/C-banding staining to provide chromosome measurements, and by fluorescence in situ hybridization with probes for 45 rDNA (pTa71), 5S rDNA (pCT4.2), a subtelomeric repeat (CS-1) and the Arabidopsis telomere probes. The karyotype has 18 autosomes plus a sex chromosome pair (XX in female and XY in male plants). The autosomes are difficult to distinguish morphologically, but three pairs could be distinguished using the probes. The Y chromosome is larger than the autosomes, and carries a fully heterochromatic DAPI positive arm and CS-1 repeats only on the less intensely DAPI-stained, euchromatic arm. The X is the largest chromosome of all, and carries CS-1 subtelomeric repeats on both arms. The meiotic configuration of the sex bivalent locates a pseudoautosomal region of the Y chromosome at the end of the euchromatic CS-1-carrying arm. Our molecular cytogenetic study of the C. sativa sex chromosomes is a starting point for helping to make C. sativa a promising model to study sex chromosome evolution.

  6. Sex differences in antihypertensive drug use : determinants of the choice of medication for hypertension

    NARCIS (Netherlands)

    Klungel, O.H.; de Boer, A; Paes, A.H.P.; Seidell, J C; Bakker, A

    1998-01-01

    OBJECTIVE: To describe and explain sex differences in antihypertensive drug use. DESIGN AND METHODS: From 1987 to 1995, two cross-sectional population-based surveys of cardiovascular disease risk factors in The Netherlands were carried out among 56026 men and women aged 20-59 years. Polytomous

  7. Determinants of consistent condom use among female sex workers in Savannakhet, Lao PDR.

    Science.gov (United States)

    Andrews, Carin Hillerdal; Faxelid, Elisabeth; Sychaerun, Vanphanom; Phrasisombath, Ketkesone

    2015-08-19

    Female sex workers (FSWs) are a high-risk population for HIV. Correct and consistent use of condoms is the most effective measure for reducing transmission of HIV. Lao PDR is a low HIV-prevalence country, but FSWs have a relatively high HIV prevalence. To be able to make recommendations for condom promotion interventions in Lao PDR it is important to know more about the context specific situation. This study looked at reasons for and associated factors of consistent condom use among FSWs. A cross-sectional survey among 258 FSWs in Kaysone Phomvihan district in Savannakhet province was performed. Almost all FSWs had enough condoms (94%), condoms always available (100%) and could always afford condoms (92%). Consistent condom use was 97% with non-regular partners and 60% with regular partners. Almost all respondents (95%) had received information about condoms from the drop-in centre. Stated reasons for consistent condom use were prevention of HIV (94%), STIs (88%) and pregnancy (87%). Most reasons for inconsistent condom use were related to partners not wanting to use condoms because of reduced sexual pleasure. Some FSWs reported that they were physically abused and forced not to use condoms. Shorter time in sex work, higher education and FSW not having regular partners were significantly associated with consistent condom use. Consistent condom use was very high with non-regular partners, but less frequent with regular partners. The main reason for inconsistent condom use was that the partner did not want to use a condom. Associated factors for consistent condom use were not having regular partners, higher education and shorter time in sex work. Condom promotion programs should include both FSWs and their partners and female condoms should be included in condom intervention efforts. Future studies should investigate the validity of self-reported sexual practices, partners' reasons for inconsistent condom use, risk of violence in sex work and why shorter time in sex

  8. Mayfly and fish species identification and sex determination in bleak (Alburnus alburnus) by MALDI-TOF mass spectrometry.

    Science.gov (United States)

    Maasz, G; Takács, P; Boda, P; Varbiro, G; Pirger, Z

    2017-12-01

    Besides food quality control of fish or cephalopods, the novel mass spectrometry (MS) approaches could be effective and beneficial methods for the investigation of biodiversity in ecological research. Our aims were to verify the applicability of MALDI-TOF MS in the rapid identification of closely related species, and to further develop it for sex determination in phenotypically similar fish focusing on the low mass range. For MALDI-TOF MS spectra analysis, ClinProTools software was applied, but our observed classification was also confirmed by Self Organizing Map. For verifying the wide applicability of the method, brains from invertebrate and vertebrate species were used in order to detect the species related markers from two mayflies and eight fish as well as sex-related markers within bleak. Seven Ephemera larvae and sixty-one fish species related markers were observed and nineteen sex-related markers were identified in bleak. Similar patterns were observed between the individuals within one species. In contrast, there were markedly diverse patterns between the different species and sexes visualized by SOMs. Two different Ephemera species and male or female fish were identified with 100% accuracy. The various fish species were classified into 8 species with a high level of accuracy (96.2%). Based on MS data, dendrogram was generated from different fish species by using ClinProTools software. This MS-based dendrogram shows relatively high correspondence with the phylogenetic relationships of both the studied species and orders. In summary, MALDI-TOF MS provides a cheap, reliable, sensitive and fast identification tool for researchers in the case of closely related species using mass spectra acquired in a low mass range to define specific molecular profiles. Moreover, we presented evidence for the first time for determination of sex within one fish species by using this method. We conclude that it is a powerful tool that can revolutionize ecological and

  9. Sex determination using discriminant function analysis in Indigenous (Kurubas children and adolescents of Coorg, Karnataka, India: A lateral cephalometric study

    Directory of Open Access Journals (Sweden)

    Darshan Devang Divakar

    2016-11-01

    Full Text Available Aim: To test the validity of sex discrimination using lateral cephalometric radiograph and discriminant function analysis in Indigenous (Kuruba children and adolescents of Coorg, Karnataka, India. Methods and materials: Six hundred and sixteen lateral cephalograms of 380 male and 236 females of age ranging from 6.5 to 18 years of Indigenous population of Coorg, Karnataka, India called Kurubas having a normal occlusion were included in the study. Lateral cephalograms were obtained in a standard position with teeth in centric occlusion and lips relaxed. Each radiograph was traced and cephalometric landmarks were measured using digital calliper. Calculations of 24 cephalometric measurements were performed. Results: Males exhibited significantly greater mean angular and linear cephalometric measurements as compared to females (p < 0.05 (Table 5. Also, significant differences (p < 0.05 were observed in all the variables according to age (Table 6. Out of 24 variables, only ULTc predicts the gender. The reliability of the derived discriminant function was assessed among study subjects; 100% of males and females were recognized correctly. Conclusion: The final outcome of this study validates the existence of sexual dimorphism in the skeleton as early as 6.5 years of age. There is a need for further research to determine other landmarks that can help in sex determination and norms for Indigenous (Kuruba population and also other Indigenous population of Coorg, Karnataka, India. Keywords: Discriminant function analysis, Forensic investigation, Indigenous, Lateral cephalograms, Sex determination

  10. Sex Determination from Fragmented and Degenerated DNA by Amplified Product-Length Polymorphism Bidirectional SNP Analysis of Amelogenin and SRY Genes

    Science.gov (United States)

    Masuyama, Kotoka; Shojo, Hideki; Nakanishi, Hiroaki; Inokuchi, Shota; Adachi, Noboru

    2017-01-01

    Sex determination is important in archeology and anthropology for the study of past societies, cultures, and human activities. Sex determination is also one of the most important components of individual identification in criminal investigations. We developed a new method of sex determination by detecting a single-nucleotide polymorphism in the amelogenin gene using amplified product-length polymorphisms in combination with sex-determining region Y analysis. We particularly focused on the most common types of postmortem DNA damage in ancient and forensic samples: fragmentation and nucleotide modification resulting from deamination. Amplicon size was designed to be less than 60 bp to make the method more useful for analyzing degraded DNA samples. All DNA samples collected from eight Japanese individuals (four male, four female) were evaluated correctly using our method. The detection limit for accurate sex determination was determined to be 20 pg of DNA. We compared our new method with commercial short tandem repeat analysis kits using DNA samples artificially fragmented by ultraviolet irradiation. Our novel method was the most robust for highly fragmented DNA samples. To deal with allelic dropout resulting from deamination, we adopted “bidirectional analysis,” which analyzed samples from both sense and antisense strands. This new method was applied to 14 Jomon individuals (3500-year-old bone samples) whose sex had been identified morphologically. We could correctly identify the sex of 11 out of 14 individuals. These results show that our method is reliable for the sex determination of highly degenerated samples. PMID:28052096

  11. Sex Determination from Fragmented and Degenerated DNA by Amplified Product-Length Polymorphism Bidirectional SNP Analysis of Amelogenin and SRY Genes.

    Directory of Open Access Journals (Sweden)

    Kotoka Masuyama

    Full Text Available Sex determination is important in archeology and anthropology for the study of past societies, cultures, and human activities. Sex determination is also one of the most important components of individual identification in criminal investigations. We developed a new method of sex determination by detecting a single-nucleotide polymorphism in the amelogenin gene using amplified product-length polymorphisms in combination with sex-determining region Y analysis. We particularly focused on the most common types of postmortem DNA damage in ancient and forensic samples: fragmentation and nucleotide modification resulting from deamination. Amplicon size was designed to be less than 60 bp to make the method more useful for analyzing degraded DNA samples. All DNA samples collected from eight Japanese individuals (four male, four female were evaluated correctly using our method. The detection limit for accurate sex determination was determined to be 20 pg of DNA. We compared our new method with commercial short tandem repeat analysis kits using DNA samples artificially fragmented by ultraviolet irradiation. Our novel method was the most robust for highly fragmented DNA samples. To deal with allelic dropout resulting from deamination, we adopted "bidirectional analysis," which analyzed samples from both sense and antisense strands. This new method was applied to 14 Jomon individuals (3500-year-old bone samples whose sex had been identified morphologically. We could correctly identify the sex of 11 out of 14 individuals. These results show that our method is reliable for the sex determination of highly degenerated samples.

  12. Analysis of the sex-determining region of the Y chromosome (SRY) in sex reversed patients: point-mutation in SRY causing sex-reversion in a 46,XY female

    DEFF Research Database (Denmark)

    Müller, Jørn; Schwartz, M; Skakkebaek, N E

    1992-01-01

    The first and essential step in normal sexual differentiation takes place during the 5th-6th week of gestation. The testis determining factor (TDF) directs the undifferentiated gonad into a testis, which secretes hormones responsible for normal male development. A new candidate for TDF has recently...... been reported, and it has been called the sex determining region of the Y (SRY). The hypothesis has been supported by the finding of XX individuals with SRY, and two females with 46,XY karyotype and a mutation in SRY. However, XX males without SRY has been reported, and the role of SRY still has...... to be determined. We have tested three human females with 46,XY karyotype and gonadal dysgenesis and two 46,XX males for the presence of SRY using the polymerase chain reaction and subsequent DNA sequencing. Both 46,XX males contained SRY, whereas one of the 46,XY females had suffered a point mutation in SRY...

  13. Individual heterogeneity determines sex differences in mortality in a monogamous bird with reversed sexual dimorphism

    DEFF Research Database (Denmark)

    Colchero, Fernando; Aliaga, Alix Eva; Jones, Owen

    2017-01-01

    in shaping demographic trajectories in wild populations. The link between these two processes has seldom been explored. 2. We used Bayesian survival trajectory analysis to study age-specific mortality trajectories in the Eurasian sparrowhawk (Accipiter nisus), a monogamous raptor with reversed sexual size...... driven by the differences in individual heterogeneity between the two sexes. Females were more heterogeneous than males in their level of frailty. Thus, a larger number of females with low frailty are able to survive to older ages than males, with life expectancy for the least frail adult females....... Although we found that variables that relate to the cost of reproduction and sexual dimorphism are at least partially involved in determing these sex differences, it is through their effect on the level of frailty that they affect age patterns of mortality. Therefore, our results raise the possibility...

  14. Age Effect in the Morphological Traits Performance for Sex Determination in Human Skulls and Mandibles

    OpenAIRE

    Suazo Galdames, Iván; Zavando, Daniela

    2012-01-01

    In this study we tested the hypothesis that diagnostic performance of the morphological indicators for sexual dimorphism are reduced as they are applied in skull and mandibles of older subjects. We used 275 adult human skulls, 250 of these with mandible, all subjects with sex and age registry. Sixteen classic morphological indicators of sexual dimorphism were evaluated, this information was compared with the registry and results noted in terms of precision. The best general performance of mor...

  15. Sexual risk behaviour and its determinants among men who have sex with men in Catalonia, Spain.

    Science.gov (United States)

    Folch, C; Munoz, R; Zaragoza, K; Casabona, J

    2009-11-26

    To evaluate the prevalence of sexual risk behaviours among men who have sex with men (MSM) in Catalonia and to identify sociodemographic, psychosocial, and behavioural factors associated with unprotected anal intercourse (UAI) with casual partners a convenience sample of 850 MSM was recruited in 2006. An anonymous questionnaire was used to explore risk behaviours during the previous 12 months. Logistic regression models were used to examine the variables associated with UAI. Mean age was 41 years and 20.4% were immigrants. Among those with casual partners (91.7% of all respondents), 31.4% had UAI. The multivariate analysis revealed that the likelihood of UAI was higher in men who were HIV-positive (OR: 1.77), used more than four drugs before sex (OR: 4.90 for +6), were not from Spain (OR: 2.10 for Latin American; OR: 1.86 for other immigrants), had more than 20 sexual partners (OR: 1.56), met casual sex partners on the Internet (OR:1.45) and presented a high level of internalised homophobia (OR: 2.40). HIV/STI prevention programmes for MSM in Catalonia should incorporate activities that strengthen self-esteem, take into account the impact of internalised homophobia, and adapt to the sociocultural reality of immigrants. Furthermore, these programmes should also address substance abuse and alert HIV-positive men about the risk of HIV re-infection and transmission of other STI.

  16. Using RNA-seq to determine patterns of sex-bias in gene expression in the brain of the sex-role reversed Gulf Pipefish (Syngnathus scovelli).

    Science.gov (United States)

    Beal, Andria P; Martin, F Douglas; Hale, Matthew C

    2018-02-01

    Sex-bias in gene expression is a widespread mechanism for controlling the development of phenotypes that differ between males and females. Most studies on sex-bias in gene expression have focused on species that exhibit traditional sex-roles (male-male competition and female parental care). By contrast the Syngnathid fishes (sea horses, pipefish, and sea dragons) are a group of organisms where many species exhibit male brooding and sex-role reversal (female-female competition for mates and paternal parental care), and little is known about how patterns of sex-bias in gene expression vary in species with sex-role reversal. Here we utilize RNA-seq technology to investigate patterns of sex-bias in gene expression in the brain tissue of the Gulf Pipefish (Syngnathus scovelli) a species that exhibits sex-role reversal. Gene expression analysis identified 73 sex-biased genes, 26 genes upregulated in females and 47 genes upregulated in males. Gene ontology analysis found 52 terms enriched for the sex-biased genes in a wide range of pathways suggesting that multiple functions and processes differ between the sexes. We focused on two areas of interest: sex steroids/hormones and circadian rhythms, both of which exhibited sex-bias in gene expression, and are known to influence sexual development in other species. Lastly, the work presented herein contributes to a growing body of genome data available for the Syngnathids, increasing our knowledge on patterns of gene expression in these unusual fishes. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. The mating type locus (MAT and sexual reproduction of Cryptococcus heveanensis: insights into the evolution of sex and sex-determining chromosomal regions in fungi.

    Directory of Open Access Journals (Sweden)

    Banu Metin

    2010-05-01

    transitions in sexuality concomitant with emergence of a pathogenic clade. These studies provide insight into convergent processes that independently punctuated evolution of sex-determining loci and sex chromosomes in fungi, plants, and animals.

  18. Fine time course expression analysis identifies cascades of activation and repression and maps a putative regulator of mammalian sex determination.

    Directory of Open Access Journals (Sweden)

    Steven C Munger

    Full Text Available In vertebrates, primary sex determination refers to the decision within a bipotential organ precursor to differentiate as a testis or ovary. Bifurcation of organ fate begins between embryonic day (E 11.0-E12.0 in mice and likely involves a dynamic transcription network that is poorly understood. To elucidate the first steps of sexual fate specification, we profiled the XX and XY gonad transcriptomes at fine granularity during this period and resolved cascades of gene activation and repression. C57BL/6J (B6 XY gonads showed a consistent ~5-hour delay in the activation of most male pathway genes and repression of female pathway genes relative to 129S1/SvImJ, which likely explains the sensitivity of the B6 strain to male-to-female sex reversal. Using this fine time course data, we predicted novel regulatory genes underlying expression QTLs (eQTLs mapped in a previous study. To test predictions, we developed an in vitro gonad primary cell assay and optimized a lentivirus-based shRNA delivery method to silence candidate genes and quantify effects on putative targets. We provide strong evidence that Lmo4 (Lim-domain only 4 is a novel regulator of sex determination upstream of SF1 (Nr5a1, Sox9, Fgf9, and Col9a3. This approach can be readily applied to identify regulatory interactions in other systems.

  19. A new physical mapping approach refines the sex-determining gene positions on the Silene latifolia Y-chromosome

    Science.gov (United States)

    Kazama, Yusuke; Ishii, Kotaro; Aonuma, Wataru; Ikeda, Tokihiro; Kawamoto, Hiroki; Koizumi, Ayako; Filatov, Dmitry A.; Chibalina, Margarita; Bergero, Roberta; Charlesworth, Deborah; Abe, Tomoko; Kawano, Shigeyuki

    2016-01-01

    Sex chromosomes are particularly interesting regions of the genome for both molecular genetics and evolutionary studies; yet, for most species, we lack basic information, such as the gene order along the chromosome. Because they lack recombination, Y-linked genes cannot be mapped genetically, leaving physical mapping as the only option for establishing the extent of synteny and homology with the X chromosome. Here, we developed a novel and general method for deletion mapping of non-recombining regions by solving “the travelling salesman problem”, and evaluate its accuracy using simulated datasets. Unlike the existing radiation hybrid approach, this method allows us to combine deletion mutants from different experiments and sources. We applied our method to a set of newly generated deletion mutants in the dioecious plant Silene latifolia and refined the locations of the sex-determining loci on its Y chromosome map.

  20. Sexing sirenians: validation of visual and molecular sex determination in both wild dugongs (Dugong dugon) and Florida manatees (Trichechus manatus latirostris). Aquatic Mammals 35(2):187-192.

    Science.gov (United States)

    Bonde, Robert K.; Lanyon, J.; Sneath, H.; Ovenden, J.; Broderick, D.

    2009-01-01

    Sexing wild marine mammals that show little to no sexual dimorphism is challenging. For sirenians that are difficult to catch or approach closely, molecular sexing from tissue biopsies offers an alternative method to visual discrimination. This paper reports the results of a field study to validate the use of two sexing methods: (1) visual discrimination of sex vs (2) molecular sexing based on a multiplex PCR assay which amplifies the male-specific SRY gene and differentiates ZFX and ZFY gametologues. Skin samples from 628 dugongs (Dugong dugon) and 100 Florida manatees (Trichechus manatus latirostris) were analysed and assigned as male or female based on molecular sex. These individuals were also assigned a sex based on either direct observation of the genitalia and/or the association of the individual with a calf. Individuals of both species showed 93 to 96% congruence between visual and molecular sexing. For the remaining 4 to 7%, the discrepancies could be explained by human error. To mitigate this error rate, we recommend using both of these robust techniques, with routine inclusion of sex primers into microsatellite panels employed for identity, along with trained field observers and stringent sample handling.

  1. Sexing sirenians: Validation of visual and molecular sex determination in both wild dugongs (Dugong dugon) and Florida manatees (Trichechus manatus latirostris)

    Science.gov (United States)

    Lanyon, J.M.; Sneath, H.L.; Ovenden, J.R.; Broderick, D.; Bonde, R.K.

    2009-01-01

    Sexing wild marine mammals that show little to no sexual dimorphism is challenging. For sirenians that are difficult to catch or approach closely, molecular sexing from tissue biopsies offers an alternative method to visual discrimination. This paper reports the results of a field study to validate the use of two sexing methods: (1) visual discrimination of sex vs (2) molecular sexing based on a multiplex PCR assay which amplifies the male-specific SRY gene and differentiates ZFX and ZFY gametologues. Skin samples from 628 dugongs (Dugong dugon) and 100 Florida manatees (Trichechus manatus latirostris) were analysed and assigned as male or female based on molecular sex. These individuals were also assigned a sex based on either direct observation of the genitalia and/or the association of the individual with a calf. Individuals of both species showed 93 to 96% congruence between visual and molecular sexing. For the remaining 4 to 7%, the discrepancies could be explained by human error. To mitigate this error rate, we recommend using both of these robust techniques, with routine inclusion of sex primers into microsatellite panels employed for identity, along with trained field observers and stringent sample handling.

  2. Determinants of consistent condom use among female sex workers in Savannakhet, Lao PDR

    OpenAIRE

    Andrews, Carin Hillerdal; Faxelid, Elisabeth; Sychaerun, Vanphanom; Phrasisombath, Ketkesone

    2015-01-01

    Background Female sex workers (FSWs) are a high-risk population for HIV. Correct and consistent use of condoms is the most effective measure for reducing transmission of HIV. Lao PDR is a low HIV-prevalence country, but FSWs have a relatively high HIV prevalence. To be able to make recommendations for condom promotion interventions in Lao PDR it is important to know more about the context specific situation. This study looked at reasons for and associated factors of consistent condom use amon...

  3. Clinical significance of determination serum sex hormones levels in patients with secondary amenorrhea

    International Nuclear Information System (INIS)

    Jiang Hua

    2007-01-01

    Objective: To explore the clinical significance of changes of serum sex hormones levels in patients with secondary amenorrhea. Methods: Serum levels of E 2 , FSH, LH, PRL and P were detected with RIA in 33 patients with secondary amenorrhea and 30 controls. Results: In the patients, the serum E 2 levels were significantly lower and FSH, LH, PRL and P levels were significantly higher than those in controls (P 2 , FSH, LH, PRL and P levels is of help for assessment of severity of secondary amenorrhea as well as outcome prediction. (authors)

  4. Multiband modulation spectroscopy for determination of sex and species of mosquitoes in flight

    DEFF Research Database (Denmark)

    Gebru, Alem; Jansson, Samuel; Ignell, Rickard

    2018-01-01

    We present a dual-wavelength polarimetric measurement method to distinguish species and sexes of disease transmitting mosquitoes in flight. By measuring co- and de-polarized backscattered light at 808 and 1550 nm, the degree of linear polarization, wingbeat frequency, reflectance, spectral ratio...... and glossiness of mosquitoes can be retrieved. Body and wing contributions to these signals can be separated. Whereas the optical cross-section is sensitive to the aspect of observation, thus the heading direction of the insect in flight, we demonstrate that polarimetric- and spectral- band ratios are largely...

  5. Evolution of the complementary sex-determination gene of honey bees: balancing selection and trans-species polymorphisms.

    Science.gov (United States)

    Cho, Soochin; Huang, Zachary Y; Green, Daniel R; Smith, Deborah R; Zhang, Jianzhi

    2006-11-01

    The mechanism of sex determination varies substantively among evolutionary lineages. One important mode of genetic sex determination is haplodiploidy, which is used by approximately 20% of all animal species, including >200,000 species of the entire insect order Hymenoptera. In the honey bee Apis mellifera, a hymenopteran model organism, females are heterozygous at the csd (complementary sex determination) locus, whereas males are hemizygous (from unfertilized eggs). Fertilized homozygotes develop into sterile males that are eaten before maturity. Because homozygotes have zero fitness and because common alleles are more likely than rare ones to form homozygotes, csd should be subject to strong overdominant selection and negative frequency-dependent selection. Under these selective forces, together known as balancing selection, csd is expected to exhibit a high degree of intraspecific polymorphism, with long-lived alleles that may be even older than the species. Here we sequence the csd genes as well as randomly selected neutral genomic regions from individuals of three closely related species, A. mellifera, Apis cerana, and Apis dorsata. The polymorphic level is approximately seven times higher in csd than in the neutral regions. Gene genealogies reveal trans-species polymorphisms at csd but not at any neutral regions. Consistent with the prediction of rare-allele advantage, nonsynonymous mutations are found to be positively selected in csd only in early stages after their appearances. Surprisingly, three different hypervariable repetitive regions in csd are present in the three species, suggesting variable mechanisms underlying allelic specificities. Our results provide a definitive demonstration of balancing selection acting at the honey bee csd gene, offer insights into the molecular determinants of csd allelic specificities, and help avoid homozygosity in bee breeding.

  6. [Different sedimentation rates of X- and Y- sperm and the question of arbitrary sex determination].

    Science.gov (United States)

    Bhattacharya, B C

    1962-01-01

    Separation of X and Y sperm using their sedimentation rates is repor ted. A colloidal medium (egg yolk and glycocoll solution) of a particular viscosity and density was developed for this purpose. Rabbit and bull sperm yeilded a 2-peaked curve when separated into sedimentatio n fractions, while rooster sperm gave a single-peak curve. Sedimentation rate of live and dead sperm were similar. 176 female rabbits were fertilized with various sedimentation fractions. 23.3% became pregnant, resulting in 122 young. The sex of the young was clearly related to the sedimentation rate of the sperm: the 2 uppermost fractions yielded 77.4% (P 0.01) male offspring, while the 2 lowest fractions gave 28.2% males (p 0.01) and the middle yielded 54.7% male young.

  7. Clinical use of anti-Müllerian hormone (AMH) determinations in patients with disorders of sex development

    DEFF Research Database (Denmark)

    Hagen, Casper P; Aksglaede, Lise; Sørensen, Kaspar

    2011-01-01

    Determination of postnatal AMH levels in circulation has been used for decades when evaluating a child with ambiguous genitalia. We describe the age- and gender-specific changes of postnatal AMH serum levels to enable an appropriate clinical use of AMH assessment in pediatric endocrinology...... the sexes until puberty. Ambiguous genitalia due to impaired androgen secretion or action may be a result of various conditions with low, normal or high AMH. Furthermore, low AMH is a marker of premature ovarian failure in Turner Syndrome girls. Measurement of AMH is an important tool in assessing gonadal...

  8. The ecology of sex explains patterns of helping in arthropod societies.

    Science.gov (United States)

    Davies, Nicholas G; Ross, Laura; Gardner, Andy

    2016-08-01

    Across arthropod societies, sib-rearing (e.g. nursing or nest defence) may be provided by females, by males or by both sexes. According to Hamilton's 'haplodiploidy hypothesis', this diversity reflects the relatedness consequences of diploid vs. haplodiploid inheritance. However, an alternative 'preadaptation hypothesis' instead emphasises an interplay of ecology and the co-option of ancestral, sexually dimorphic traits for sib-rearing. The preadaptation hypothesis has recently received empirical support, but remains to be formalised. Here, we mathematically model the coevolution of sex-specific helping and sex allocation, contrasting these hypotheses. We find that ploidy per se has little effect. Rather, the ecology of sex shapes patterns of helping: sex-specific preadaptation strongly influences who helps; a freely adjustable sex ratio magnifies sex biases and promotes helping; and sib-mating, promiscuity, and reproductive autonomy also modulate the sex and abundance of helpers. An empirical survey reveals that patterns of sex-specific helping in arthropod taxa are consistent with the preadaptation hypothesis. © 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  9. Sex determination using anthropometric measurements from multi-slice computed tomography of the 12th thoracic and the first lumbar vertebrae among adult Egyptians

    Directory of Open Access Journals (Sweden)

    Fatma M.M. Badr El Dine

    2015-09-01

    Conclusion: Finally, it was concluded that the 12th thoracic vertebra is more accurate for sex determination than the first lumbar vertebra in the Egyptian population, which means that bone dimensions are population specific.

  10. Determinants of unmet needs for healthcare and sexual health counselling among Ugandan university students with same-sex sexuality experience.

    Science.gov (United States)

    Larsson, Markus; Ross, Michael W; Tumwine, Gilbert; Agardh, Anette

    2016-01-01

    Research from sub-Saharan Africa has shown that persons with same-sex sexuality experience are at elevated risk for ill health due to sexual risk taking, stigma, and discrimination. However, studies of healthcare seeking among young people in this region with same-sex sexuality experience are limited. To identify determinants of unmet healthcare and sexual health counselling needs, respectively, among Ugandan university students with experience of same-sex sexuality. In 2010, 1,954 Ugandan university students completed a questionnaire assessing socio-demographic factors, mental health, alcohol usage, sexual behaviours, and healthcare seeking. The study population consisted of those 570 who reported ever being in love with, sexually attracted to, sexually fantasised about, or sexually engaged with someone of the same sex. Findings showed that 56% and 30% reported unmet healthcare and sexual health counselling needs, respectively. Unmet healthcare needs were associated with poor mental health and exposure to sexual coercion (OR 3.9, 95% confidence intervals [CI]: 2.7-5.7; OR 2.0, 95% CI: 1.3-3.0, respectively). Unmet sexual health counselling needs were significantly associated with poor mental health (OR 3.2, 95% CI: 2.1-4.8), exposure to sexual coercion (OR 2.6, 95% CI: 1.7-3.9), frequent heavy episodic drinking (OR 3.3, 95% CI: 1.9-5.8), and number of sexual partners (OR 1.9, 95% CI: 1.04-3.3). The associations between poor mental health, sexual coercion, and unmet healthcare needs (AOR 4.2, 95% CI: 2.1-8.5; AOR 2.8, 95% CI: 1.3-5.8) and unmet needs for sexual health counselling (AOR 3.3, 95% CI: 1.6-7.1; AOR 2.7, 95% CI: 1.4-5.4) persisted after adjustment for socio-demographic factors, number of sexual partners, and frequent heavy episodic drinking. These findings indicate that exposure to sexual coercion and poor mental health may influence healthcare seeking behaviours of same-sex sexuality experienced students. Targeted interventions that integrate mental

  11. Determinants of unmet needs for healthcare and sexual health counselling among Ugandan university students with same-sex sexuality experience

    Directory of Open Access Journals (Sweden)

    Markus Larsson

    2016-03-01

    Full Text Available Background: Research from sub-Saharan Africa has shown that persons with same-sex sexuality experience are at elevated risk for ill health due to sexual risk taking, stigma, and discrimination. However, studies of healthcare seeking among young people in this region with same-sex sexuality experience are limited. Objective: To identify determinants of unmet healthcare and sexual health counselling needs, respectively, among Ugandan university students with experience of same-sex sexuality. Design: In 2010, 1,954 Ugandan university students completed a questionnaire assessing socio-demographic factors, mental health, alcohol usage, sexual behaviours, and healthcare seeking. The study population consisted of those 570 who reported ever being in love with, sexually attracted to, sexually fantasised about, or sexually engaged with someone of the same sex. Results: Findings showed that 56% and 30% reported unmet healthcare and sexual health counselling needs, respectively. Unmet healthcare needs were associated with poor mental health and exposure to sexual coercion (OR 3.9, 95% confidence intervals [CI]: 2.7–5.7; OR 2.0, 95% CI: 1.3–3.0, respectively. Unmet sexual health counselling needs were significantly associated with poor mental health (OR 3.2, 95% CI: 2.1–4.8, exposure to sexual coercion (OR 2.6, 95% CI: 1.7–3.9, frequent heavy episodic drinking (OR 3.3, 95% CI: 1.9–5.8, and number of sexual partners (OR 1.9, 95% CI: 1.04–3.3. The associations between poor mental health, sexual coercion, and unmet healthcare needs (AOR 4.2, 95% CI: 2.1–8.5; AOR 2.8, 95% CI: 1.3–5.8 and unmet needs for sexual health counselling (AOR 3.3, 95% CI: 1.6–7.1; AOR 2.7, 95% CI: 1.4–5.4 persisted after adjustment for socio-demographic factors, number of sexual partners, and frequent heavy episodic drinking. Conclusions: These findings indicate that exposure to sexual coercion and poor mental health may influence healthcare seeking behaviours of

  12. Mutations in the testis-specific enhancer of SOX9 in the SRY independent sex-determining mechanism in the genus Tokudaia.

    Directory of Open Access Journals (Sweden)

    Ryutaro Kimura

    Full Text Available SRY (sex-determining region Y is widely conserved in eutherian mammals as a sex-determining gene located on the Y chromosome. SRY proteins bind to the testis-specific enhancer of SOX9 (TES with SF1 to upregulate SOX9 expression in undifferentiated gonads of XY embryos of humans and mice. The core region within TES, named TESCO, is an important enhancer for mammalian sex determination. We show that TESCO of the genus Tokudaia lost enhancer activity caused by mutations in its SRY and SF1 binding sites. Two species of Tokudaia do not have the Y chromosome or SRY, and one species has multiple SRYs located on the neo-Y chromosome consisting of the Y fused with an autosome. The sequence of Tokudaia TESCO exhibited more than 83% identity with mouse TESCO, however, nucleotide substitution(s were found in two out of three SRY binding sites and in five out of six SF1 binding sites. TESCO of all species showed low enhancer activity in cells co-transfected with SRY and SF1, and SOX9 and SF1 in reporter gene assays. Mutated TESCO, in which nucleotide substitutions found in SRY and SF1 binding sites were replaced with mouse sequence, recovered the activity. Furthermore, SRYs of the SRY-positive species could not activate the mutated TESCO or mouse TESCO, suggesting that SRYs lost function as a sex-determining gene any more. Our results indicate that the SRY dependent sex-determining mechanism was lost in a common ancestor of the genus Tokudaia caused by nucleotide substitutions in SRY and SF1 binding sites after emergence of a new sex-determining gene. We present the first evidence for an intermediate stage of the switchover from SRY to a new sex-determining gene in the evolution of mammalian sex-determining mechanism.

  13. Mutations in the testis-specific enhancer of SOX9 in the SRY independent sex-determining mechanism in the genus Tokudaia.

    Science.gov (United States)

    Kimura, Ryutaro; Murata, Chie; Kuroki, Yoko; Kuroiwa, Asato

    2014-01-01

    SRY (sex-determining region Y) is widely conserved in eutherian mammals as a sex-determining gene located on the Y chromosome. SRY proteins bind to the testis-specific enhancer of SOX9 (TES) with SF1 to upregulate SOX9 expression in undifferentiated gonads of XY embryos of humans and mice. The core region within TES, named TESCO, is an important enhancer for mammalian sex determination. We show that TESCO of the genus Tokudaia lost enhancer activity caused by mutations in its SRY and SF1 binding sites. Two species of Tokudaia do not have the Y chromosome or SRY, and one species has multiple SRYs located on the neo-Y chromosome consisting of the Y fused with an autosome. The sequence of Tokudaia TESCO exhibited more than 83% identity with mouse TESCO, however, nucleotide substitution(s) were found in two out of three SRY binding sites and in five out of six SF1 binding sites. TESCO of all species showed low enhancer activity in cells co-transfected with SRY and SF1, and SOX9 and SF1 in reporter gene assays. Mutated TESCO, in which nucleotide substitutions found in SRY and SF1 binding sites were replaced with mouse sequence, recovered the activity. Furthermore, SRYs of the SRY-positive species could not activate the mutated TESCO or mouse TESCO, suggesting that SRYs lost function as a sex-determining gene any more. Our results indicate that the SRY dependent sex-determining mechanism was lost in a common ancestor of the genus Tokudaia caused by nucleotide substitutions in SRY and SF1 binding sites after emergence of a new sex-determining gene. We present the first evidence for an intermediate stage of the switchover from SRY to a new sex-determining gene in the evolution of mammalian sex-determining mechanism.

  14. Sex determination using discriminant function analysis in Indigenous (Kurubas) children and adolescents of Coorg, Karnataka, India: A lateral cephalometric study.

    Science.gov (United States)

    Devang Divakar, Darshan; John, Jacob; Al Kheraif, Abdulaziz Abdullah; Mavinapalla, Seema; Ramakrishnaiah, Ravikumar; Vellappally, Sajith; Hashem, Mohamed Ibrahim; Dalati, M H N; Durgesh, B H; Safadi, Rima A; Anil, Sukumaran

    2016-11-01

    Aim: To test the validity of sex discrimination using lateral cephalometric radiograph and discriminant function analysis in Indigenous (Kuruba) children and adolescents of Coorg, Karnataka, India. Methods and materials: Six hundred and sixteen lateral cephalograms of 380 male and 236 females of age ranging from 6.5 to 18 years of Indigenous population of Coorg, Karnataka, India called Kurubas having a normal occlusion were included in the study. Lateral cephalograms were obtained in a standard position with teeth in centric occlusion and lips relaxed. Each radiograph was traced and cephalometric landmarks were measured using digital calliper. Calculations of 24 cephalometric measurements were performed. Results: Males exhibited significantly greater mean angular and linear cephalometric measurements as compared to females ( p  gender. The reliability of the derived discriminant function was assessed among study subjects; 100% of males and females were recognized correctly. Conclusion: The final outcome of this study validates the existence of sexual dimorphism in the skeleton as early as 6.5 years of age. There is a need for further research to determine other landmarks that can help in sex determination and norms for Indigenous (Kuruba) population and also other Indigenous population of Coorg, Karnataka, India.

  15. Human Sex Determination at the Edge of Ambiguity: INHERITED XY SEX REVERSAL DUE TO ENHANCED UBIQUITINATION AND PROTEASOMAL DEGRADATION OF A MASTER TRANSCRIPTION FACTOR.

    Science.gov (United States)

    Racca, Joseph D; Chen, Yen-Shan; Yang, Yanwu; Phillips, Nelson B; Weiss, Michael A

    2016-10-14

    A general problem is posed by analysis of transcriptional thresholds governing cell fate decisions in metazoan development. A model is provided by testis determination in therian mammals. Its key step, Sertoli cell differentiation in the embryonic gonadal ridge, is initiated by SRY, a Y-encoded architectural transcription factor. Mutations in human SRY cause gonadal dysgenesis leading to XY female development (Swyer syndrome). Here, we have characterized an inherited mutation compatible with either male or female somatic phenotypes as observed in an XY father and XY daughter, respectively. The mutation (a crevice-forming substitution at a conserved back surface of the SRY high mobility group box) markedly destabilizes the domain but preserves specific DNA affinity and induced DNA bend angle. On transient transfection of diverse human and rodent cell lines, the variant SRY exhibited accelerated proteasomal degradation (relative to wild type) associated with increased ubiquitination; in vitro susceptibility to ubiquitin-independent ("default") cleavage by the 20S core proteasome was unchanged. The variant's gene regulatory activity (as assessed in a cellular model of the rat embryonic XY gonadal ridge) was reduced by 2-fold relative to wild-type SRY at similar levels of mRNA expression. Chemical proteasome inhibition restored native-like SRY expression and transcriptional activity in association with restored occupancy of a sex-specific enhancer element in principal downstream gene Sox9, demonstrating that the variant SRY exhibits essentially native activity on a per molecule basis. Our findings define a novel mechanism of impaired organogenesis, accelerated ubiquitin-directed proteasomal degradation of a master transcription factor leading to a developmental decision poised at the edge of ambiguity. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. The value of CT scanning of Horus in determining the method of mummification and the sex of the mummy

    International Nuclear Information System (INIS)

    Davey, Janet; Stewart, Margaret E.B.; Drummer, Olaf H.

    2013-01-01

    Radiology was used to determine the sex of a child mummy who had conflicting records based on two different translations of a name written in a section of papyrus inserted into the mummy wrappings and also to determine the type of mummification used to preserve the body. Ancient texts of Herodotus and Diodorus Siculus were consulted for references to mummification, and Nicholson Museum records provided details of the mummy which was examined at Central Sydney Imaging using Toshiba Aquilion 64 CT machine (Toshiba Medical Systems Corporation, Tochigi, Japan). The original CT scan data were loaded into a Vitrea 2 (Vital Images, Minnetonka, MN, USA) workstation at the Victorian Institute of Forensic Medicine, Melbourne, Australia, for further study. The scans showed that the child had been elaborately mummified according to ancient descriptions albeit with one variation. The provenance of the child was unknown but stylistically appeared to be from the Greco-Roman Period of ancient Egypt. Interpretation of the CT images determined that the child was male, had died of unknown cause and had been excerebrated and eviscerated post-mortem when the heart was removed. Unexplained inclusions were identified within the abdomen and thorax. Broken and displaced ribs showed evidence of a previous endoscopic investigation. This study provided evidence that CT scanning was an excellent non-invasive modality to evaluate ancient mummies in its ability to demonstrate fine anatomical detail and identify post-mortem changes. The study underlined the role of using current medical practice to determine sex rather than relying on ancient texts and uncorroborated opinion.

  17. Maintaining continuity through a scientific revolution: a rereading of E. B. Wilson and T. H. Morgan on sex determination and Mendelism.

    Science.gov (United States)

    Kingsland, Sharon E

    2007-09-01

    A rereading of the American scientific literature on sex determination from 1902 to 1926 leads to a different understanding of the construction of the Mendelian-chromosome theory after 1910. There was significant intellectual continuity, which has not been properly appreciated, underlying this scientific "revolution." After reexamining the relationship between the ideas of key scientists, in particular Edmund B. Wilson and Thomas Hunt Morgan, I argue that, contrary to the historical literature, Wilson and Morgan did not adopt opposing views on Mendelism and sex determination. Rather, each preferred a non-Mendelian explanation of the determination of sex. Around 1910, both integrated the Mendelian and non-Mendelian theories to create a synthetic theory. One problem was the need to avoid an overly deterministic view of sex while also accepting the validity of Mendelism. Morgan's discovery of mutations on the X chromosome takes on different significance when set in the context of the debate about sex determination, and Calvin Bridges's work on sex determination is better seen as a development of Morgan's ideas, rather than a departure from them. Conclusions point to the role of synthesis within fields as a way to advance scientific theories and reflect on the relationship between synthesis and explanatory "pluralism" in biology.

  18. determination of sex in south african blacks by discriminant function analysis of mandibular linear dimensions : A preliminary investigation using the zulu local population.

    Science.gov (United States)

    Franklin, Daniel; O'Higgins, Paul; Oxnard, Charles E; Dadour, Ian

    2006-12-01

    The determination of sex is a critical component in forensic anthropological investigation. The literature attests to numerous metrical standards, each utilizing diffetent skeletal elements, for sex determination in South A frican Blacks. Metrical standards are popular because they provide a high degree of expected accuracy and are less error-prone than subjective nonmetric visual techniques. We note, however, that there appears to be no established metric mandible discriminant function standards for sex determination in this population.We report here on a preliminary investigation designed to evaluate whether the mandible is a practical element for sex determination in South African Blacks. The sample analyzed comprises 40 nonpathological Zulu individuals drawn from the R.A. Dart Collection. Ten linear measurements, obtained from mathematically trans-formed three-dimensional landmark data, are analyzed using basic univariate statistics and discriminant function analyses. Seven of the 10 measurements examined are found to be sexually dimorphic; the dimensions of the ramus are most dimorphic. The sex classification accuracy of the discriminant functions ranged from 72.5 to 87.5% for the univariate method, 92.5% for the stepwise method, and 57.5 to 95% for the direct method. We conclude that the mandible is an extremely useful element for sex determination in this population.

  19. Polytene chromosomes of monogenic and amphogenic Chrysomya species (Calliphoridae, Diptera): analysis of banding patterns and in situ hybridization with Drosophila sex determining gene sequences.

    Science.gov (United States)

    Puchalla, S

    1994-03-01

    Standard maps for the five banded polytene chromosomes found in trichogen cell nuclei of the monogenic blowfly Chrysomya rufifacies and the amphogenic Chrysomya pinguis are presented. The chromosomes are highly homologous in the two species; differences in banding patterns are predominantly caused by one pericentric and ten paracentric inversions. In chromosome 5 of the amphogenic Chrysomya phaonis, also analysed in this paper, an additional paracentric inversion was observed. The distribution of species specific inversions indicates that the monogenic C. rufifacies is phylogenetically older than the amphogenic species. The maternal sex realizer locus F'/f on polytene chromosome 5 of C. rufifacies is not associated with a structural heterozygosity. Chromosome pair 6 of C. rufifacies and the sex chromosome pair of C. pinguis are under-replicated in polytene nuclei; they consist of irregular chromatin granules, frequently associated with nucleolus material. Evolution of heteromorphic sex chromosomes in Chrysomya is probably correlated with heterochromatin accumulation. A search for sex determining genes in Chrysomya was initiated using sex determining sequences from Drosophila melanogaster for in situ hybridization. The polytene band 41A1 on chromosome 5 of monogenic and amphogenic Chrysomya species contains sequences homologous to the maternal sex determining gene daughterless (da). Homology to the zygotic gene Sex-lethal (Sxl) of Drosophila is detected in band 39A1 on chromosome 5 of C. rufifacies. The findings reported here are the first evidence for a possible homology between the da gene of Drosophila and the maternal sex realizer F' of C. rufifacies. An hypothesis for the evolution of the maternal effect sex determination of C. rufifacies is proposed.

  20. Sex impact on the quality of fatty liver and its genetic determinism in mule ducks.

    Science.gov (United States)

    Marie-Etancelin, C; Retailleau, B; Alinier, A; Vitezica, Z G

    2015-09-01

    Recent changes to French regulations now allow farmers to produce "foie gras" from both male and female mule ducks. The aim of this study was to assess the quality of female fatty liver and to compare, from a phenotypic and genetic point of view, liver quality in males and females. A total of 914 mule ducks (591 males and 323 females), hatched in a single pedigree batch, were reared until 86 d of age and then force-fed for 12 d, before being slaughtered. Carcasses and livers were weighed and liver quality was assessed by grading the extent of liver veining and measuring the liver melting rate, either after sterilization of 60 g of liver or pasteurization of 180 g of liver. Sexual dimorphism was observed in favor of males, with a difference of approximately 10% in carcass and liver weights and up to 54% for the liver melting rate. Moreover, one-third of female livers showed moderate to high veining, whereas this was not the case for male livers. The fatty livers of female mule ducks are, therefore, of poorer quality and could not be transformed into a product with the appellation "100% fatty liver." According to sex and parental line, heritability values ranged from 0.12 ± 0.05 to 0.18 ± 0.07 for fatty liver weight and from 0.09 ± 0.05 to 0.18 ± 0.05 for the 2 melting rate traits. The genetic correlations between the fatty liver weight and both melting rates were high (greater than +0.80) in the Muscovy population, whereas in the Pekin population, the liver weight and melting rates were less strongly correlated (estimates ranging from +0.36 ± 0.30 to +0.45 ± 0.28). Selection for lower liver melting rates without reducing the liver weight would, therefore, be easier to achieve in the Pekin population. Finally, as the 2 melting rate measurements are highly correlated (0.91 and over 0.95 for phenotypic and genetic correlations, respectively), we suggest using the easiest method, that is, sterilization of 60 g of liver.

  1. Sex, Scandals, and Celebrities”? Exploring the Determinants of Popularity in Online News.

    Directory of Open Access Journals (Sweden)

    Angèle Christin

    2015-11-01

    Full Text Available What kinds of articles are read most often on news websites? In web newsrooms, journalists now have access to software programs that allow them to track the preferences of their readers in real time. Based on this data, web journalists often claim that “sex, scandals, and celebrities” are the best recipe for attracting readers and “clicks.” Conversely, journalists assert that articles on world news, politics, and culture fare poorly online. Journalists also strongly distinguish between groups of readers, depending on whether they “click,” “like,” “tweet,” or write comments. This paper compares qualitative material and quantitative data to explore whether journalists’ representations of their “quantified audience” diverge from the actual behavior of their readers. Drawing on an original data set composed of 13,159 articles published between 2007 and 2012 on a French news site, I find that articles about sex, scandals, and celebrities indeed attract more readers than articles about world news or culture. Yet articles about politics, long articles, and user-generated contributions are also highly popular. In addition, the preferences of readers vary depending on whether one measures this by the number of “clicks,” “likes,” “tweets,” or comments on the articles. Though regression models do not reveal significant differences, a more qualitative approach indicates that the most popular articles on Facebook and Twitter are humorous pieces and user-generated contributions, whereas controversial political topics attract more comments. I propose several explanations in order to make sense of this gap between the journalists’ representations and the behavior of online readers. These involve the editorial line and audience of the French website under consideration, the changing political context and media coverage of politics in France, and the specific temporal structure of internet traffic for longer articles. Quels

  2. The evolutionary process of mammalian sex determination genes focusing on marsupial SRYs.

    Science.gov (United States)

    Katsura, Yukako; Kondo, Hiroko X; Ryan, Janelle; Harley, Vincent; Satta, Yoko

    2018-01-16

    Maleness in mammals is genetically determined by the Y chromosome. On the Y chromosome SRY is known as the mammalian male-determining gene. Both placental mammals (Eutheria) and marsupial mammals (Metatheria) have SRY genes. However, only eutherian SRY genes have been empirically examined by functional analyses, and the involvement of marsupial SRY in male gonad development remains speculative. In order to demonstrate that the marsupial SRY gene is similar to the eutherian SRY gene in function, we first examined the sequence differences between marsupial and eutherian SRY genes. Then, using a parsimony method, we identify 7 marsupial-specific ancestral substitutions, 13 eutherian-specific ancestral substitutions, and 4 substitutions that occurred at the stem lineage of therian SRY genes. A literature search and molecular dynamics computational simulations support that the lineage-specific ancestral substitutions might be involved with the functional differentiation between marsupial and eutherian SRY genes. To address the function of the marsupial SRY gene in male determination, we performed luciferase assays on the testis enhancer of Sox9 core (TESCO) using the marsupial SRY. The functional assay shows that marsupial SRY gene can weakly up-regulate the luciferase expression via TESCO. Despite the sequence differences between the marsupial and eutherian SRY genes, our functional assay indicates that the marsupial SRY gene regulates SOX9 as a transcription factor in a similar way to the eutherian SRY gene. Our results suggest that SRY genes obtained the function of male determination in the common ancestor of Theria (placental mammals and marsupials). This suggests that the marsupial SRY gene has a function in male determination, but additional experiments are needed to be conclusive.

  3. Maternal malnutrition and offspring sex determine juvenile obesity and metabolic disorders in a swine model of leptin resistance.

    Directory of Open Access Journals (Sweden)

    Alicia Barbero

    Full Text Available The present study aimed to determine, in a swine model of leptin resistance, the effects of type and timing of maternal malnutrition on growth patterns, adiposity and metabolic features of the progeny when exposed to an obesogenic diet during their juvenile development and possible concomitant effects of the offspring sex. Thus, four groups were considered. A CONTROL group involved pigs born from sows fed with a diet fulfilling their daily maintenance requirements for pregnancy. The treated groups involved the progeny of females fed with the same diet but fulfilling either 160% or 50% of pregnancy requirements during the entire gestation (OVERFED and UNDERFED, respectively or 100% of requirements until Day 35 of pregnancy and 50% of such amount from Day 36 onwards (LATE-UNDERFED. OVERFED and UNDERFED offspring were more prone to higher corpulence and fat deposition from early postnatal stages, during breast-feeding; adiposity increased significantly when exposed to obesogenic diets, especially in females. The effects of sex were even more remarkable in LATE-UNDERFED offspring, which had similar corpulence to CONTROL piglets; however, females showed a clear predisposition to obesity. Furthermore, the three groups of pigs with maternal malnutrition showed evidences of metabolic syndrome and, in the case of individuals born from OVERFED sows, even of insulin resistance and the prodrome of type-2 diabetes. These findings support the main role of early nutritional programming in the current rise of obesity and associated diseases in ethnics with leptin resistance.

  4. "If a woman has even one daughter, I refuse to perform the abortion": Sex determination and safe abortion in India.

    Science.gov (United States)

    Potdar, Pritam; Barua, Alka; Dalvie, Suchitra; Pawar, Anand

    2015-05-01

    In India, safe abortion services are sought mainly in the private sector for reasons of privacy, confidentiality, and the absence of delays and coercion to use contraception. In recent years, the declining sex ratio has received much attention, and implementation of the Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act (2003) has become stringent. However, rather than targeting sex determination, many inspection visits target abortion services. This has led to many private medical practitioners facing negative media publicity, defamation and criminal charges. As a result, they have started turning women away not only in the second trimester but also in the first. Samyak, a Pune-based, non-governmental organization, came across a number of cases of refusal of abortion services during its work and decided to explore the experiences of private medical practitioners with the regulatory mechanisms and what happened to the women. The study showed that as a fallout from the manner of implementation of the PCPNDT Act, safe abortion services were either difficult for women to access or outright denied to them. There is an urgent need to recognize this impact of the current regulatory environment, which is forcing women towards illegal and unsafe abortions. Copyright © 2015. Published by Elsevier Ltd.

  5. The Sertoli Cell Only Syndrome and Glaucoma in a Sex - Determining Region Y (SRY) Positive XX Infertile Male.

    Science.gov (United States)

    Jain, Manish; V, Veeramohan; Chaudhary, Isha; Halder, Ashutosh

    2013-07-01

    The XX male syndrome is a rare genetic disorder. The phenotype is variable; it ranges from a severe impairment of the external genitalia to a normal male phenotype with infertility. It generally results from an unequal crossing over between the short arms of the sex chromosomes (X and Y). We are reporting a case of a 38-year-old man who presented with infertility and the features of hypogonadism and glaucoma. The examinations revealed normal external male genitalia, soft small testes, gynaecomastia and glaucoma. The semen analysis showed azoospermia. The serum gonadotropins were high, with low Anti Mullerian Hormone (AMH) and Inhibin B levels. The chromosomal analysis demonstrated a 46, XX karyotype. Fluorescent In-Situ Hybridization (FISH) and Polymerase Chain Reaction (PCR) revealed the presence of a Sex-determining Region Y (SRY). Testicular Fine Needle Aspiration Cytology (FNAC) revealed the Sertoli Cell Only Syndrome (SCOS). The presence of only Sertoli Cells in the testes, with glaucoma in the XX male syndrome, to our knowledge, has not been reported in the literature.

  6. Evolutionary Significance of Wolbachia-to-Animal Horizontal Gene Transfer: Female Sex Determination and the f Element in the Isopod Armadillidium vulgare.

    Science.gov (United States)

    Cordaux, Richard; Gilbert, Clément

    2017-07-21

    An increasing number of horizontal gene transfer (HGT) events from bacteria to animals have been reported in the past years, many of which involve Wolbachia bacterial endosymbionts and their invertebrate hosts. Most transferred Wolbachia genes are neutrally-evolving fossils embedded in host genomes. A remarkable case of Wolbachia HGT for which a clear evolutionary significance has been demonstrated is the " f element", a nuclear Wolbachia insert involved in female sex determination in the terrestrial isopod Armadillidium vulgare . The f element represents an instance of bacteria-to-animal HGT that has occurred so recently that it was possible to infer the donor (feminizing Wolbachia closely related to the w VulC Wolbachia strain of A. vulgare ) and the mechanism of integration (a nearly complete genome inserted by micro-homology-mediated recombination). In this review, we summarize our current knowledge of the f element and discuss arising perspectives regarding female sex determination, unstable inheritance, population dynamics and the molecular evolution of the f element. Overall, the f element unifies three major areas in evolutionary biology: symbiosis, HGT and sex determination. Its characterization highlights the tremendous impact sex ratio distorters can have on the evolution of sex determination mechanisms and sex chromosomes in animals and plants.

  7. Evolutionary Significance of Wolbachia-to-Animal Horizontal Gene Transfer: Female Sex Determination and the f Element in the Isopod Armadillidium vulgare

    Directory of Open Access Journals (Sweden)

    Richard Cordaux

    2017-07-01

    Full Text Available An increasing number of horizontal gene transfer (HGT events from bacteria to animals have been reported in the past years, many of which involve Wolbachia bacterial endosymbionts and their invertebrate hosts. Most transferred Wolbachia genes are neutrally-evolving fossils embedded in host genomes. A remarkable case of Wolbachia HGT for which a clear evolutionary significance has been demonstrated is the “f element”, a nuclear Wolbachia insert involved in female sex determination in the terrestrial isopod Armadillidium vulgare. The f element represents an instance of bacteria-to-animal HGT that has occurred so recently that it was possible to infer the donor (feminizing Wolbachia closely related to the wVulC Wolbachia strain of A. vulgare and the mechanism of integration (a nearly complete genome inserted by micro-homology-mediated recombination. In this review, we summarize our current knowledge of the f element and discuss arising perspectives regarding female sex determination, unstable inheritance, population dynamics and the molecular evolution of the f element. Overall, the f element unifies three major areas in evolutionary biology: symbiosis, HGT and sex determination. Its characterization highlights the tremendous impact sex ratio distorters can have on the evolution of sex determination mechanisms and sex chromosomes in animals and plants.

  8. Sox5 is involved in germ-cell regulation and sex determination in medaka following co-option of nested transposable elements.

    Science.gov (United States)

    Schartl, Manfred; Schories, Susanne; Wakamatsu, Yuko; Nagao, Yusuke; Hashimoto, Hisashi; Bertin, Chloé; Mourot, Brigitte; Schmidt, Cornelia; Wilhelm, Dagmar; Centanin, Lazaro; Guiguen, Yann; Herpin, Amaury

    2018-01-29

    Sex determination relies on a hierarchically structured network of genes, and is one of the most plastic processes in evolution. The evolution of sex-determining genes within a network, by neo- or sub-functionalization, also requires the regulatory landscape to be rewired to accommodate these novel gene functions. We previously showed that in medaka fish, the regulatory landscape of the master male-determining gene dmrt1bY underwent a profound rearrangement, concomitantly with acquiring a dominant position within the sex-determining network. This rewiring was brought about by the exaptation of a transposable element (TE) called Izanagi, which is co-opted to act as a silencer to turn off the dmrt1bY gene after it performed its function in sex determination. We now show that a second TE, Rex1, has been incorporated into Izanagi. The insertion of Rex1 brought in a preformed regulatory element for the transcription factor Sox5, which here functions in establishing the temporal and cell-type-specific expression pattern of dmrt1bY. Mutant analysis demonstrates the importance of Sox5 in the gonadal development of medaka, and possibly in mice, in a dmrt1bY-independent manner. Moreover, Sox5 medaka mutants have complete female-to-male sex reversal. Our work reveals an unexpected complexity in TE-mediated transcriptional rewiring, with the exaptation of a second TE into a network already rewired by a TE. We also show a dual role for Sox5 during sex determination: first, as an evolutionarily conserved regulator of germ-cell number in medaka, and second, by de novo regulation of dmrt1 transcriptional activity during primary sex determination due to exaptation of the Rex1 transposable element.

  9. Differentiation of sex chromosomes and karyotypic evolution in the eye-lid geckos (Squamata: Gekkota: Eublepharidae), a group with different modes of sex determination

    Czech Academy of Sciences Publication Activity Database

    Pokorná, M.; Rábová, Marie; Ráb, Petr; Kratochvíl, L.

    2010-01-01

    Roč. 18, č. 6 (2010), s. 748-748 ISSN 0967-3849. [19th International Colloquium on animal cytogenetics and gene mapping. 06.06.-09.06.2010, Krakow] Institutional research plan: CEZ:AV0Z50450515 Keywords : sex chromosomes * karyotypic evolution * eye-lid geckos Subject RIV: EB - Genetics ; Molecular Biology

  10. Evolution of sex determination systems with heterogametic males and females in Silene

    Czech Academy of Sciences Publication Activity Database

    Šlancarová, Veronika; Ždánská, Jana; Janoušek, Bohuslav; Talianová, Martina; Zschach, C.; Žlůvová, Jitka; Široký, Jiří; Kováčová, Viera; Blavet, Hana; Danihelka, J.; Oxelman, B.; Widmer, A.; Vyskot, Boris

    2013-01-01

    Roč. 67, č. 12 (2013), s. 3669-3677 ISSN 0014-3820 R&D Projects: GA ČR(CZ) GA13-06264S; GA ČR(CZ) GAP501/10/0102; GA ČR(CZ) GBP501/12/G090; GA ČR(CZ) GAP501/12/2220 Institutional support: RVO:68081707 Keywords : ANCESTRAL CHARACTER STATES * MAXIMUM-LIKELIHOOD * DETERMINATION PATHWAY Subject RIV: BO - Biophysics Impact factor: 4.659, year: 2013

  11. Safe sex

    Science.gov (United States)

    ... sex; Sexually transmitted - safe sex; GC - safe sex; Gonorrhea - safe sex; Herpes - safe sex; HIV - safe sex; ... contact. STIs include: Chlamydia Genital herpes Genital warts Gonorrhea Hepatitis HIV HPV Syphilis STIs are also called ...

  12. Gamete types, sex determination and stable equilibria of all-hybrid populations of diploid and triploid edible frogs (Pelophylax esculentus

    Directory of Open Access Journals (Sweden)

    Christiansen Ditte G

    2009-06-01

    Full Text Available Abstract Background Triploid individuals often play a key role in speciation by hybridization. An understanding of the gamete types (ploidy and genomic content and stability of hybrid populations with triploid individuals is therefore of importance for exploring the role of hybridization in evolution. The all-hybrid populations of the edible frog, Pelophylax esculentus, are unique in their composition and genetic dynamics: Diploid (genotype LR and triploid (LLR and LRR hybrids depend on each other's different gamete contributions for successful reproduction and maintenance of the populations, as the parental genotypes P. lessonae (LL and P. ridibundus (RR are absent among adults. This study provides data and interpretations on gamete types and sex determination that are essential for understanding the function, evolutionary potential and threats of this intriguing system. Results Dissection of metamorphs from a crossing experiment confirmed that sex determination is an XX-XY system with the Y confined to the L genome. From microsatellite analysis of parents and offspring from the crossings, gamete frequencies could be deduced: Triploids of both sexes mostly made haploid gametes with the genome they had in double dose, however LLR females also made approximately 10% LL gametes by automixis. LR frogs showed much variation in their gamete production. In LRR-rich populations, their LR sperm production was sufficiently high (22% to explain the observed proportion of LRR males, the formation of which has not previously been understood. A model was constructed to calculate equilibrium genotype proportions for different population types on the basis of the gamete proportions found. These equilibria agreed well with empirical literature data. Conclusion If population differentiation with respect to genotype proportions is really driven by gamete patterns, as strongly suggested by the present study, all-hybrid populations constitute not one, but several

  13. Genetic method of combating the cabbage root fly. Part II. Localization of factor determining male sex in the cabbage root fly Delia brassicae bouche

    International Nuclear Information System (INIS)

    Samoilov, Yu.B.

    1986-01-01

    Cytogenetic analysis was conducted of 15 lines of the cabbage root fly with hereditary semisterility in the form of late embryonic lethals (LEL). In 14 lines (93%), the presence of translocations was noted. A high yield of translocations linked with the male sex was obtained, which was caused by the fact that determination of male sex in this species is apparently associated with the largest chromosome 6, and not with chromosome 1, as was believed previously

  14. The Interplay Between Fat Mass and Fat Distribution as Determinants of the Metabolic Syndrome Is Sex-Dependent.

    Science.gov (United States)

    Lind, Lars; Ärnlöv, Johan; Lampa, Erik

    2017-09-01

    Fat mass and fat distribution are major determinants of the metabolic syndrome (MetS), but the interplay between them has not been thoroughly investigated. In addition, fat mass and fat distribution are generally different in men than in women. We aimed to determine whether the interplay between fat mass and fat distribution regarding MetS and its components is sex-dependent using data from the large-scale population-based sample EpiHealth. Occurrence of MetS and its components was determined together with fat mass by bioimpedance in 19,094 participants in the EpiHealth sample [mean age 61 years (SD 8.5), 56% females]. MetS was defined by the NCEP/ATPIII-criteria. MetS prevalence was 23.0%. Fat mass (percent of body weight) was more strongly related to MetS (and the number of MetS components) in men than in women (P distribution on the fat mass versus MetS-relationship is stronger in women.

  15. Sex determines the influence of smoking and gene polymorphism on glutathione peroxidase activity in erythrocytes

    DEFF Research Database (Denmark)

    Malling, Tine Halsen; Sigsgaard, Torben; Andersen, Helle Raun

    2009-01-01

    OBJECTIVE: Glutathione peroxidase 1 (GPX1) is one of the major oxidative enzymes. Our aim was to characterize factors influencing its activity and to determine whether or not the activity is associated with asthma. MATERIAL AND METHODS: Serum selenium concentration was measured, GPX1 polymorphisms...... %) had doctor-diagnosed asthma. RESULTS: The average serum selenium concentration was too low for optimal enzyme activity (mean (SE), 83.4 (0.76) ng/mL). GPX1 activity in men was lower than in women, 52.6 (0.66) and 56.4 (0.59) U/g protein, respectively (p... associated with serum selenium concentration (p = 0.005) and negatively associated with both active smoking (p = 0.009) and exposure to environmental tobacco smoke (p = 0.02). In women, activity was associated with genotypes with 59.2 (1.4), 56.0 (1.4) and 54.2 (1.4) U/g protein in the homozygote wild...

  16. Differentiation of sex chromosomes and karyotypic evolution in the eye-lid geckos (Squamata: Gekkota: Eublepharidae), a group with different modes of sex determination

    Czech Academy of Sciences Publication Activity Database

    Pokorná, M.; Rábová, Marie; Ráb, Petr; Ferguson-Smith, M. A.; Rens, W.; Kratochvíl, L.

    2010-01-01

    Roč. 18, č. 6 (2010), s. 809-820 ISSN 0967-3849 R&D Projects: GA ČR GAP506/10/0718; GA MŠk LC06073 Grant - others:GA ČR(CZ) GP206/06/P282 Program:GP Institutional research plan: CEZ:AV0Z50450515 Keywords : reptile cytogenetics * FISH * neo- sex hromosomes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.130, year: 2010

  17. Determinants of hazardous drinking among black South African men who have sex with men.

    Science.gov (United States)

    Knox, Justin; Reddy, Vasu; Lane, Tim; Lovasi, Gina; Hasin, Deborah; Sandfort, Theo

    2017-11-01

    There is a known heavy burden of hazardous drinking and its associated health risks among black South African MSM; however, no study to date has identified risk factors for hazardous drinking among this nor any other African MSM population. A cross-sectional survey was conducted among 480 black South African MSM recruited using respondent-driven sampling. All analyses were adjusted using an RDS II estimator. Multivariable logistic regression was used to assess the relationship between demographic characteristics, psychosocial factors, behavioral attributes and hazardous drinking. More than half of the men (62%, 95%CI=56%-68%) screened positive as hazardous drinkers. In multivariable analyses, living in a township (versus the city of Pretoria) (aOR=1.9, 95%CI=1.2-3.1, pchild (aOR=2.6, 95%CI=1.1-6.4, p=.03), having anxiety (aOR=5.4, 95%CI=1.2-24.3, p=.03), and social network drinking behavior (aOR=5.4, 95%CI=1.2-24.3, p=.03) were positively associated with hazardous drinking. Being sexually attracted only to men (aOR=0.3, 95%CI=0.1-0.8, p=.01) was negatively associated with hazardous drinking. Hazardous drinking is highly prevalent among black South African MSM. Multiple indicators of social vulnerability were identified as independent determinants of hazardous drinking. These findings are of heightened concern because these health problems often work synergistically to increase risk of HIV infection and should be taken into consideration by efforts aimed at reducing hazardous drinking among this critical population. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Determinants of human adipose tissue gene expression: impact of diet, sex, metabolic status, and cis genetic regulation.

    Directory of Open Access Journals (Sweden)

    Nathalie Viguerie

    2012-09-01

    Full Text Available Weight control diets favorably affect parameters of the metabolic syndrome and delay the onset of diabetic complications. The adaptations occurring in adipose tissue (AT are likely to have a profound impact on the whole body response as AT is a key target of dietary intervention. Identification of environmental and individual factors controlling AT adaptation is therefore essential. Here, expression of 271 transcripts, selected for regulation according to obesity and weight changes, was determined in 515 individuals before, after 8-week low-calorie diet-induced weight loss, and after 26-week ad libitum weight maintenance diets. For 175 genes, opposite regulation was observed during calorie restriction and weight maintenance phases, independently of variations in body weight. Metabolism and immunity genes showed inverse profiles. During the dietary intervention, network-based analyses revealed strong interconnection between expression of genes involved in de novo lipogenesis and components of the metabolic syndrome. Sex had a marked influence on AT expression of 88 transcripts, which persisted during the entire dietary intervention and after control for fat mass. In women, the influence of body mass index on expression of a subset of genes persisted during the dietary intervention. Twenty-two genes revealed a metabolic syndrome signature common to men and women. Genetic control of AT gene expression by cis signals was observed for 46 genes. Dietary intervention, sex, and cis genetic variants independently controlled AT gene expression. These analyses help understanding the relative importance of environmental and individual factors that control the expression of human AT genes and therefore may foster strategies aimed at improving AT function in metabolic diseases.

  19. Steroid signaling system responds differently to temperature and hormone manipulation in the red-eared slider turtle (Trachemys scripta elegans), a reptile with temperature-dependent sex determination.

    Science.gov (United States)

    Ramsey, M; Crews, D

    2007-01-01

    Many reptiles, including the red-eared slider turtle (Trachemys scripta elegans), exhibit temperature-dependent sex determination (TSD). Temperature determines gonadal sex during the middle of embryogenesis, or the temperature-sensitive period (TSP), when gonadal sex is labile to both temperature and hormones--particularly estrogen. The biological actions of steroid hormones are mediated by their receptors as defined here as the classic transcriptional regulation of target genes. To elucidate estrogen action during sex determination, we examined estrogen receptor alpha (Esr1, hereafter referred to as ERalpha), estrogen receptor beta (Esr2, hereafter referred to as ERbeta), and androgen receptor (Ar, hereafter referred to as AR) expression in slider turtle gonads before, during and after the TSP, as well as following sex reversal via temperature or steroid hormone manipulation. ERalpha and AR levels spike at the female-producing temperature while ovarian sex is determined, but none of the receptors exhibited sexually dimorphic localization within the gonad prior to morphological differentiation. All three receptors respond differentially to sex-reversing treatments. When shifted to female-producing temperatures, embryos maintain ERalpha and AR expression while ERbeta is reduced. When shifted to male-producing temperatures, medullary expression of all three receptors is reduced. Feminization via estradiol (E(2)) treatment at a male-producing temperature profoundly changed the expression patterns for all three receptors. ERalpha and ERbeta redirected to the cortex in E(2)-created ovaries, while AR medullary expression was transiently reduced. Although warmer incubation temperature and estrogen result in the same endpoint (ovarian development), our results indicate different steroid signaling patterns between temperature- and estrogen-induced feminization. 2007 S. Karger AG, Basel

  20. A Single Sex Pheromone Receptor Determines Chemical Response Specificity of Sexual Behavior in the Silkmoth Bombyx mori

    OpenAIRE

    Sakurai, Takeshi; Mitsuno, Hidefumi; Haupt, Stephan Shuichi; Uchino, Keiro; Yokohari, Fumio; Nishioka, Takaaki; Kobayashi, Isao; Sezutsu, Hideki; Tamura, Toshiki; Kanzaki, Ryohei

    2011-01-01

    In insects and other animals, intraspecific communication between individuals of the opposite sex is mediated in part by chemical signals called sex pheromones. In most moth species, male moths rely heavily on species-specific sex pheromones emitted by female moths to identify and orient towards an appropriate mating partner among a large number of sympatric insect species. The silkmoth, Bombyx mori, utilizes the simplest possible pheromone system, in which a single pheromone component, (E, Z...

  1. Accuracy and reliability in sex determination from skulls: a comparison of Fordisc® 3.0 and the discriminant function analysis.

    Science.gov (United States)

    Guyomarc'h, Pierre; Bruzek, Jaroslav

    2011-05-20

    Identification in forensic anthropology and the definition of a biological profile in bioarchaeology are essential to each of those fields and use the same methodologies. Sex, age, stature and ancestry can be conclusive or dispensable, depending on the field. The Fordisc(®) 3.0 computer program was developed to aid in the identification of the sex, stature and ancestry of skeletal remains by exploiting the Forensic Data Bank (FDB) and computing discriminant function analyses (DFAs). Although widely used, this tool has been recently criticised, principally when used to determine ancestry. Two sub-samples of individuals of known sex were drawn from French (n=50) and Thai (n=91) osteological collections and used to assess the reliability of sex determination using Fordisc(®) 3.0 with 12 cranial measurements. Comparisons were made using the whole FDB as well as using select groups, taking into account the posterior and typicality probabilities. The results of Fordisc(®) 3.0 vary between 52.2% and 77.8% depending on the options and groups selected. Tests of published discriminant functions and the computation of specific DFA were performed in order to discuss the applicability of this software and, overall, to question the pertinence of the use of DFA and linear distances in sex determination, in light of the huge cranial morphological variability. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  2. A reliable genetic technique for sex determination of giant panda (Ailuropoda melanoleuca) from non-invasively collected hair samples

    NARCIS (Netherlands)

    Durnin, Matthew E.; Palsboll, Per J.; Ryder, Oliver A.; McCullough, Dale R.

    Extractions from non-invasive hair samples usually yield low amounts of highly degraded DNA. Previously developed mammal molecular sexing methods were not designed with such sub-optimal conditions in mind. We developed a simple and reliable PCR-based sexing method aimed at degraded, low yield DNA

  3. Effect of exogenous estradiol applied at different embryonic stages on sex determination, growth, and mortality in the leopard gecko (Eublepharis macularius).

    Science.gov (United States)

    Tousignant, A; Crews, D

    1994-01-01

    Temperature-dependent sex determination (TSD) occurs in three orders of reptiles. Several studies have examined the ability of estradiol to produce female hatchlings incubated at a male-producing temperature. The results of these experiments support the idea that estradiol could be used as a powerful tool in the conservation of endangered species with TSD by manipulating hatchling sex ratios. However, these experiments have concentrated on the mechanism of determination. This experiment was designed to test the efficacy of various dosages of estradiol applied at two different stages to alter the hatchling sex ratio as well as determining the potential use of such manipulation for conservation efforts by monitoring egg mortality and hatchling growth. The leopard gecko (Eublepharis macularius) exhibits TSD and reaches reproductive maturity in less than one year, making it an excellent model for evaluating the long-term effects of estradiol. The results demonstrate that estradiol has a dose-dependent effect on the hatchling sex ratio while only high dosages applied at the later stage of development showed increased mortality. Estrogen-determined females grew at the same rate as temperature-determined females and have produced viable hatchlings. Estradiol treatment of eggs from endangered species may provide a method of insuring female offspring when the TSD pattern is unknown or equipment for controlled incubation is unavailable.

  4. Chimeric Sex-Determining Chromosomal Regions and Dysregulation of Cell-Type Identity in a Sterile Zygosaccharomyces Allodiploid Yeast.

    Directory of Open Access Journals (Sweden)

    Melissa Bizzarri

    Full Text Available Allodiploidization is a fundamental yet evolutionarily poorly characterized event, which impacts genome evolution and heredity, controlling organismal development and polyploid cell-types. In this study, we investigated the sex determination system in the allodiploid and sterile ATCC 42981 yeast, a member of the Zygosaccharomyces rouxii species complex, and used it to study how a chimeric mating-type gene repertoire contributes to hybrid reproductive isolation. We found that ATCC 42981 has 7 MAT-like (MTL loci, 3 of which encode α-idiomorph and 4 encode a-idiomorph. Two phylogenetically divergent MAT expression loci were identified on different chromosomes, accounting for a hybrid a/α genotype. Furthermore, extra a-idimorph-encoding loci (termed MTLa copies 1 to 3 were recognized, which shared the same MATa1 ORFs but diverged for MATa2 genes. Each MAT expression locus was linked to a HML silent cassette, while the corresponding HMR loci were located on another chromosome. Two putative parental sex chromosome pairs contributed to this unusual genomic architecture: one came from an as-yet-undescribed taxon, which has the NCYC 3042 strain as a unique representative, while the other did not match any MAT-HML and HMR organizations previously described in Z. rouxii species. This chimeric rearrangement produces two copies of the HO gene, which encode for putatively functional endonucleases essential for mating-type switching. Although both a and α coding sequences, which are required to obtain a functional cell-type a1-α2 regulator, were present in the allodiploid ATCC 42981 genome, the transcriptional circuit, which regulates entry into meiosis in response to meiosis-inducing salt stress, appeared to be turned off. Furthermore, haploid and α-specific genes, such as MATα1 and HO, were observed to be actively transcribed and up-regulated under hypersaline stress. Overall, these evidences demonstrate that ATCC 42981 is unable to repress haploid

  5. Preliminary Study to Test the Feasibility of Sex Identification of Human (Homo sapiens) Bones Based on Differences in Elemental Profiles Determined by Handheld X-ray Fluorescence.

    Science.gov (United States)

    Nganvongpanit, Korakot; Buddhachat, Kittisak; Brown, Janine L; Klinhom, Sarisa; Pitakarnnop, Tanita; Mahakkanukrauh, Pasuk

    2016-09-01

    Sex assignment of human remains is a crucial step in forensic anthropological studies. The aim of this study was to examine elemental differences between male and female bones using X-ray fluorescence (XRF) and determine if elemental profiling could be used for sex discrimination. Cranium, humerus, and os coxae of 60 skeletons (30 male, 30 female) from the Chiang Mai University Skeletal Collection were scanned by XRF and differences in elemental profiles between male and female bones determined using discriminant analysis. In the cranium, three elements (S, Ca, Pb) were significantly higher in males and five elements (Si, Mn, Fe, Zn, Ag) plus light elements (atomic number lower than 12) were higher in females. In humerus and os coxae, nine elements were significantly higher in male and one element was higher in female samples. The accuracy rate for sex estimation was 60, 63, and 61 % for cranium, humerus, and os coxae, respectively, and 67 % when data for all three bones were combined. We conclude that there are sex differences in bone elemental profiles; however, the accuracy of XRF analyses for discriminating between male and female samples was low compared to standard morphometric and molecular methods. XRF could be used on small samples that cannot be sexed by traditional morphological methods, but more work is needed to increase the power of this technique for gender assignment.

  6. Distinct sperm nucleus behaviors between genotypic and temperature-dependent sex determination males are associated with replication and expression-related pathways in a gynogenetic fish.

    Science.gov (United States)

    Zhu, Yao-Jun; Li, Xi-Yin; Zhang, Jun; Li, Zhi; Ding, Miao; Zhang, Xiao-Juan; Zhou, Li; Gui, Jian-Fang

    2018-06-05

    Coexistence and transition of diverse sex determination strategies have been revealed in some ectothermic species, but the variation between males caused by different sex determination strategies and the underlying mechanism remain unclear. Here, we used the gynogenetic gibel carp (Carassius gibelio) with both genotypic sex determination (GSD) and temperature-dependent sex determination (TSD) strategies to illustrate this issue. We found out that males of GSD and TSD in gibel carp had similar morphology, testicular histology, sperm structure and sperm vitality. However, when maternal individuals were mated with males of GSD, sperm nucleus swelling and fusing with the female pronucleus were observed in the fertilized eggs. On the contrary, when maternal individuals were mated with males of TSD, sperm nucleus remained in the condensed status throughout the whole process. Subsequently, semen proteomics analysis unveiled that DNA replication and gene expression-related pathways were inhibited in the sperm from males of TSD compared to males of GSD, and most differentially expressed proteins associated with DNA replication, transcription and translation were down-regulated. Moreover, via BrdU incorporation and immunofluorescence detection, male nucleus replication was revealed to be present in the fertilized eggs by the sperm from males of GSD, but absent in the fertilized eggs by the sperm from males of TSD. These findings indicate that DNA replication and gene expression-related pathways are associated with the distinct sperm nucleus development behaviors in fertilized eggs in response to the sperm from males of GSD and TSD. And this study is the first attempt to screen the differences between males determined via GSD and TSD in gynogenetic species, which might give a hint for understanding evolutionary adaption of diverse sex determination mechanisms in unisexual vertebrates.

  7. A Tandem Duplicate of Anti-Müllerian Hormone with a Missense SNP on the Y Chromosome Is Essential for Male Sex Determination in Nile Tilapia, Oreochromis niloticus

    Science.gov (United States)

    Li, Minghui; Sun, Yunlv; Zhao, Jiue; Shi, Hongjuan; Zeng, Sheng; Ye, Kai; Jiang, Dongneng; Zhou, Linyan; Sun, Lina; Tao, Wenjing; Nagahama, Yoshitaka; Kocher, Thomas D.; Wang, Deshou

    2015-01-01

    Variation in the TGF-β signaling pathway is emerging as an important mechanism by which gonadal sex determination is controlled in teleosts. Here we show that amhy, a Y-specific duplicate of the anti-Müllerian hormone (amh) gene, induces male sex determination in Nile tilapia. amhy is a tandem duplicate located immediately downstream of amhΔ-y on the Y chromosome. The coding sequence of amhy was identical to the X-linked amh (amh) except a missense SNP (C/T) which changes an amino acid (Ser/Leu92) in the N-terminal region. amhy lacks 5608 bp of promoter sequence that is found in the X-linked amh homolog. The amhΔ-y contains several insertions and deletions in the promoter region, and even a 5 bp insertion in exonVI that results in a premature stop codon and thus a truncated protein product lacking the TGF-β binding domain. Both amhy and amhΔ-y expression is restricted to XY gonads from 5 days after hatching (dah) onwards. CRISPR/Cas9 knockout of amhy in XY fish resulted in male to female sex reversal, while mutation of amhΔ-y alone could not. In contrast, overexpression of Amhy in XX fish, using a fosmid transgene that carries the amhy/amhΔ-y haplotype or a vector containing amhy ORF under the control of CMV promoter, resulted in female to male sex reversal, while overexpression of AmhΔ-y alone in XX fish could not. Knockout of the anti-Müllerian hormone receptor type II (amhrII) in XY fish also resulted in 100% complete male to female sex reversal. Taken together, these results strongly suggest that the duplicated amhy with a missense SNP is the candidate sex determining gene and amhy/amhrII signal is essential for male sex determination in Nile tilapia. These findings highlight the conserved roles of TGF-β signaling pathway in fish sex determination. PMID:26588702

  8. Agreement of molecular biology and morphology methods in sex determination of human bones from Žatec cemetery (11th-13th Century AD)

    Czech Academy of Sciences Publication Activity Database

    Bromová, Markéta; Černý, Viktor; Hájek, Martin; Brůžek, J.

    2003-01-01

    Roč. 55, č. 4 (2003), s. 687-695 ISSN 0323-1267 R&D Projects: GA AV ČR IAB9002001 Institutional research plan: CEZ:AV0Z8002910 Keywords : archaeogenetics * sex determination Subject RIV: AC - Archeology, Anthropology, Ethnology

  9. Structure–function analysis of mouse Sry reveals dual essential roles of the C-terminal polyglutamine tract in sex determination

    Science.gov (United States)

    Zhao, Liang; Ng, Ee Ting; Davidson, Tara-Lynne; Longmuss, Enya; Urschitz, Johann; Elston, Marlee; Moisyadi, Stefan; Bowles, Josephine; Koopman, Peter

    2014-01-01

    The mammalian sex-determining factor SRY comprises a conserved high-mobility group (HMG) box DNA-binding domain and poorly conserved regions outside the HMG box. Mouse Sry is unusual in that it includes a C-terminal polyglutamine (polyQ) tract that is absent in nonrodent SRY proteins, and yet, paradoxically, is essential for male sex determination. To dissect the molecular functions of this domain, we generated a series of Sry mutants, and studied their biochemical properties in cell lines and transgenic mouse embryos. Sry protein lacking the polyQ domain was unstable, due to proteasomal degradation. Replacing this domain with irrelevant sequences stabilized the protein but failed to restore Sry’s ability to up-regulate its key target gene SRY-box 9 (Sox9) and its sex-determining function in vivo. These functions were restored only when a VP16 transactivation domain was substituted. We conclude that the polyQ domain has important roles in protein stabilization and transcriptional activation, both of which are essential for male sex determination in mice. Our data disprove the hypothesis that the conserved HMG box domain is the only functional domain of Sry, and highlight an evolutionary paradox whereby mouse Sry has evolved a novel bifunctional module to activate Sox9 directly, whereas SRY proteins in other taxa, including humans, seem to lack this ability, presumably making them dependent on partner proteins(s) to provide this function. PMID:25074915

  10. Structure-function analysis of mouse Sry reveals dual essential roles of the C-terminal polyglutamine tract in sex determination.

    Science.gov (United States)

    Zhao, Liang; Ng, Ee Ting; Davidson, Tara-Lynne; Longmuss, Enya; Urschitz, Johann; Elston, Marlee; Moisyadi, Stefan; Bowles, Josephine; Koopman, Peter

    2014-08-12

    The mammalian sex-determining factor SRY comprises a conserved high-mobility group (HMG) box DNA-binding domain and poorly conserved regions outside the HMG box. Mouse Sry is unusual in that it includes a C-terminal polyglutamine (polyQ) tract that is absent in nonrodent SRY proteins, and yet, paradoxically, is essential for male sex determination. To dissect the molecular functions of this domain, we generated a series of Sry mutants, and studied their biochemical properties in cell lines and transgenic mouse embryos. Sry protein lacking the polyQ domain was unstable, due to proteasomal degradation. Replacing this domain with irrelevant sequences stabilized the protein but failed to restore Sry's ability to up-regulate its key target gene SRY-box 9 (Sox9) and its sex-determining function in vivo. These functions were restored only when a VP16 transactivation domain was substituted. We conclude that the polyQ domain has important roles in protein stabilization and transcriptional activation, both of which are essential for male sex determination in mice. Our data disprove the hypothesis that the conserved HMG box domain is the only functional domain of Sry, and highlight an evolutionary paradox whereby mouse Sry has evolved a novel bifunctional module to activate Sox9 directly, whereas SRY proteins in other taxa, including humans, seem to lack this ability, presumably making them dependent on partner proteins(s) to provide this function.

  11. Steroid Signaling and Temperature-Dependent Sex Determination – Reviewing the Evidence for Early Action of Estrogen during Ovarian Determination in the Red-Eared Slider Turtle (Trachemys scripta elegans)

    Science.gov (United States)

    Ramsey, Mary; Crews, David

    2009-01-01

    The developmental processes underlying gonadal differentiation are conserved across vertebrates, but the triggers initiating these trajectories are extremely variable. The red-eared slider turtle (Trachemys scripta elegans) exhibits temperature-dependent sex determination (TSD), a system where incubation temperature during a temperature-sensitive period of development determines offspring sex. However, gonadal sex is sensitive to both temperature and hormones during this period – particularly estrogen. We present a model for temperature-based differences in aromatase expression as a critical step in ovarian determination. Localized estrogen production facilitates ovarian development while inhibiting male-specific gene expression. At male-producing temperatures aromatase is not upregulated, thereby allowing testis development. PMID:18992835

  12. Sox9 gene regulation and the loss of the XY/XX sex-determining mechanism in the mole vole Ellobius lutescens.

    Science.gov (United States)

    Bagheri-Fam, Stefan; Sreenivasan, Rajini; Bernard, Pascal; Knower, Kevin C; Sekido, Ryohei; Lovell-Badge, Robin; Just, Walter; Harley, Vincent R

    2012-01-01

    In most mammals, the Y chromosomal Sry gene initiates testis formation within the bipotential gonad, resulting in male development. SRY is a transcription factor and together with SF1 it directly up-regulates the expression of the pivotal sex-determining gene Sox9 via a 1.3-kb cis-regulatory element (TESCO) which contains an evolutionarily conserved region (ECR) of 180 bp. Remarkably, several rodent species appear to determine sex in the absence of Sry and a Y chromosome, including the mole voles Ellobius lutescens and Ellobius tancrei, whereas Ellobius fuscocapillus of the same genus retained Sry. The sex-determining mechanisms in the Sry-negative species remain elusive. We have cloned and sequenced 1.1 kb of E. lutescens TESCO which shares 75% sequence identity with mouse TESCO indicating that testicular Sox9 expression in E. lutescens might still be regulated via TESCO. We have also cloned and sequenced the ECRs of E. tancrei and E. fuscocapillus. While the three Ellobius ECRs are highly similar (94-97% sequence identity), they all display a 14-bp deletion (Δ14) removing a highly conserved SOX/TCF site. Introducing Δ14 into mouse TESCO increased both basal activity and SF1-mediated activation of TESCO in HEK293T cells. We propose a model whereby Δ14 may have triggered up-regulation of Sox9 in XX gonads leading to destabilization of the XY/XX sex-determining mechanism in Ellobius. E. lutescens/E. tancrei and E. fuscocapillus could have independently stabilized their sex determination mechanisms by Sry-independent and Sry-dependent approaches, respectively.

  13. Conserved regulatory modules in the Sox9 testis-specific enhancer predict roles for SOX, TCF/LEF, Forkhead, DMRT, and GATA proteins in vertebrate sex determination.

    Science.gov (United States)

    Bagheri-Fam, Stefan; Sinclair, Andrew H; Koopman, Peter; Harley, Vincent R

    2010-03-01

    While the primary sex determining switch varies between vertebrate species, a key downstream event in testicular development, namely the male-specific up-regulation of Sox9, is conserved. To date, only two sex determining switch genes have been identified, Sry in mammals and the Dmrt1-related gene Dmy (Dmrt1bY) in the medaka fish Oryzias latipes. In mice, Sox9 expression is evidently up-regulated by SRY and maintained by SOX9 both of which directly activate the core 1.3 kb testis-specific enhancer of Sox9 (TESCO). How Sox9 expression is up-regulated and maintained in species without Sry (i.e. non-mammalian species) is not understood. In this study, we have undertaken an in-depth comparative genomics approach and show that TESCO contains an evolutionarily conserved region (ECR) of 180 bp which is present in marsupials, monotremes, birds, reptiles and amphibians. The ECR contains highly conserved modules that predict regulatory roles for SOX, TCF/LEF, Forkhead, DMRT, and GATA proteins in vertebrate sex determination/differentiation. Our data suggest that tetrapods share common aspects of Sox9 regulation in the testis, despite having different sex determining switch mechanisms. They also suggest that Sox9 autoregulation is an ancient mechanism shared by all tetrapods, raising the possibility that in mammals, SRY evolved by mimicking this regulation. The validation of ECR regulatory sequences conserved from human to frogs will provide new insights into vertebrate sex determination. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. QTL for white spot syndrome virus resistance and the sex-determining locus in the Indian black tiger shrimp (Penaeus monodon).

    Science.gov (United States)

    Robinson, Nicholas A; Gopikrishna, Gopalapillay; Baranski, Matthew; Katneni, Vinaya Kumar; Shekhar, Mudagandur S; Shanmugakarthik, Jayakani; Jothivel, Sarangapani; Gopal, Chavali; Ravichandran, Pitchaiyappan; Gitterle, Thomas; Ponniah, Alphis G

    2014-08-28

    Shrimp culture is a fast growing aquaculture sector, but in recent years there has been a shift away from tiger shrimp Penaeus monodon to other species. This is largely due to the susceptibility of P. monodon to white spot syndrome virus disease (Whispovirus sp.) which has impacted production around the world. As female penaeid shrimp grow more rapidly than males, mono-sex production would be advantageous, however little is known about genes controlling or markers associated with sex determination in shrimp. In this study, a mapped set of 3959 transcribed single nucleotide polymorphisms were used to scan the P. monodon genome for loci associated with resistance to white-spot syndrome virus and sex in seven full-sibling tiger shrimp families challenged with white spot syndrome virus. Linkage groups 2, 3, 5, 6, 17, 18, 19, 22, 27 and 43 were found to contain quantitative trait loci significantly associated with hours of survival after white spot syndrome virus infection (P shrimp.

  15. Loss of Mitogen-Activated Protein Kinase Kinase Kinase 4 (MAP3K4) Reveals a Requirement for MAPK Signalling in Mouse Sex Determination

    Science.gov (United States)

    Bogani, Debora; Siggers, Pam; Brixey, Rachel; Warr, Nick; Beddow, Sarah; Edwards, Jessica; Williams, Debbie; Wilhelm, Dagmar; Koopman, Peter; Flavell, Richard A.; Chi, Hongbo; Ostrer, Harry; Wells, Sara; Cheeseman, Michael; Greenfield, Andy

    2009-01-01

    Sex determination in mammals is controlled by the presence or absence of the Y-linked gene SRY. In the developing male (XY) gonad, sex-determining region of the Y (SRY) protein acts to up-regulate expression of the related gene, SOX9, a transcriptional regulator that in turn initiates a downstream pathway of testis development, whilst also suppressing ovary development. Despite the requirement for a number of transcription factors and secreted signalling molecules in sex determination, intracellular signalling components functioning in this process have not been defined. Here we report a role for the phylogenetically ancient mitogen-activated protein kinase (MAPK) signalling pathway in mouse sex determination. Using a forward genetic screen, we identified the recessive boygirl (byg) mutation. On the C57BL/6J background, embryos homozygous for byg exhibit consistent XY gonadal sex reversal. The byg mutation is an A to T transversion causing a premature stop codon in the gene encoding MAP3K4 (also known as MEKK4), a mitogen-activated protein kinase kinase kinase. Analysis of XY byg/byg gonads at 11.5 d post coitum reveals a growth deficit and a failure to support mesonephric cell migration, both early cellular processes normally associated with testis development. Expression analysis of mutant XY gonads at the same stage also reveals a dramatic reduction in Sox9 and, crucially, Sry at the transcript and protein levels. Moreover, we describe experiments showing the presence of activated MKK4, a direct target of MAP3K4, and activated p38 in the coelomic region of the XY gonad at 11.5 d post coitum, establishing a link between MAPK signalling in proliferating gonadal somatic cells and regulation of Sry expression. Finally, we provide evidence that haploinsufficiency for Map3k4 accounts for T-associated sex reversal (Tas). These data demonstrate that MAP3K4-dependent signalling events are required for normal expression of Sry during testis development, and create a novel

  16. Loss of mitogen-activated protein kinase kinase kinase 4 (MAP3K4 reveals a requirement for MAPK signalling in mouse sex determination.

    Directory of Open Access Journals (Sweden)

    Debora Bogani

    2009-09-01

    Full Text Available Sex determination in mammals is controlled by the presence or absence of the Y-linked gene SRY. In the developing male (XY gonad, sex-determining region of the Y (SRY protein acts to up-regulate expression of the related gene, SOX9, a transcriptional regulator that in turn initiates a downstream pathway of testis development, whilst also suppressing ovary development. Despite the requirement for a number of transcription factors and secreted signalling molecules in sex determination, intracellular signalling components functioning in this process have not been defined. Here we report a role for the phylogenetically ancient mitogen-activated protein kinase (MAPK signalling pathway in mouse sex determination. Using a forward genetic screen, we identified the recessive boygirl (byg mutation. On the C57BL/6J background, embryos homozygous for byg exhibit consistent XY gonadal sex reversal. The byg mutation is an A to T transversion causing a premature stop codon in the gene encoding MAP3K4 (also known as MEKK4, a mitogen-activated protein kinase kinase kinase. Analysis of XY byg/byg gonads at 11.5 d post coitum reveals a growth deficit and a failure to support mesonephric cell migration, both early cellular processes normally associated with testis development. Expression analysis of mutant XY gonads at the same stage also reveals a dramatic reduction in Sox9 and, crucially, Sry at the transcript and protein levels. Moreover, we describe experiments showing the presence of activated MKK4, a direct target of MAP3K4, and activated p38 in the coelomic region of the XY gonad at 11.5 d post coitum, establishing a link between MAPK signalling in proliferating gonadal somatic cells and regulation of Sry expression. Finally, we provide evidence that haploinsufficiency for Map3k4 accounts for T-associated sex reversal (Tas. These data demonstrate that MAP3K4-dependent signalling events are required for normal expression of Sry during testis development, and

  17. SKR-1, a homolog of Skp1 and a member of the SCFSEL-10 complex, regulates sex-determination and LIN-12/Notch signaling in C. elegans

    Science.gov (United States)

    Killian, Darrell J.; Harvey, Elizabeth; Johnson, Peter; Otori, Muneyoshi; Mitani, Shohei; Xue, Ding

    2008-01-01

    Sex-determination in C. elegans requires regulation of gene transcription and protein activity and stability. sel-10 encodes a WD40-repeat-containing F-box protein that likely mediates the ubiquitin-mediated degradation of important sex-determination factors. Loss of sel-10 results in a mild masculinization of hermaphrodites, whereas dominant alleles of sel-10, such as sel-10(n1074), cause a more severe masculinization, including a reversal of the life versus death decision in sex-specific neurons. To investigate about how sel-10 regulates sex-determination, we conducted a sel-10(n1074) suppressor screen and isolated a weak loss-of-function allele of skr-1, one of 21 Skp1-related genes in C. elegans. Skp1, Cullin, and F-box proteins, such as SEL-10, are components of the SCF E3 ubiquitin ligase complex. We present genetic evidence that the sel-10(n1074) masculinization phenotype is dependent upon skr-1 and cul-1 activity. Furthermore, we show that the SKR-1(M140I) weak loss-of-function mutation interferes with SKR-1/SEL-10 binding. Unexpectedly, we found that the G567E substitution in SEL-10 caused by the n1074 allele impairs the binding of SEL-10 to SKR-1 and the dimerization of SEL-10, which may be important for SEL-10 function. Our results suggest that SKR-1, CUL-1 and SEL-10 constitute an SCF E3 ligase complex that plays an important role in modulating sex-determination and LIN-12/Notch signaling in C. elegans. PMID:18718460

  18. A microsatellite-based linkage map of salt tolerant tilapia (Oreochromis mossambicus x Oreochromis spp.) and mapping of sex-determining loci

    Science.gov (United States)

    2013-01-01

    Background Tilapia is the common name for a group of cichlid fishes and is one of the most important aquacultured freshwater food fish. Mozambique tilapia and its hybrids, including red tilapia are main representatives of salt tolerant tilapias. A linkage map is an essential framework for mapping QTL for important traits, positional cloning of genes and understanding of genome evolution. Results We constructed a consensus linkage map of Mozambique tilapia and red tilapia using 95 individuals from two F1 families and 401 microsatellites including 282 EST-derived markers. In addition, we conducted comparative mapping and searched for sex-determining loci on the whole genome. These 401 microsatellites were assigned to 22 linkage groups. The map spanned 1067.6 cM with an average inter-marker distance of 3.3 cM. Comparative mapping between tilapia and stickleback, medaka, pufferfish and zebrafish revealed clear homologous relationships between chromosomes from different species. We found evidence for the fusion of two sets of two independent chromosomes forming two new chromosome pairs, leading to a reduction of 24 chromosome pairs in their ancestor to 22 pairs in tilapias. The XY sex determination locus in Mozambique tilapia was mapped on LG1, and verified in five families containing 549 individuals. The major XY sex determination locus in red tilapia was located on LG22, and verified in two families containing 275 individuals. Conclusions A first-generation linkage map of salt tolerant tilapia was constructed using 401 microsatellites. Two separate fusions of two sets of two independent chromosomes may lead to a reduction of 24 chromosome pairs in their ancestor to 22 pairs in tilapias. The XY sex-determining loci from Mozambique tilapia and red tilapia were mapped on LG1 and LG22, respectively. This map provides a useful resource for QTL mapping for important traits and comparative genome studies. The DNA markers linked to the sex-determining loci could be used in

  19. A microsatellite-based linkage map of salt tolerant tilapia (Oreochromis mossambicus x Oreochromis spp. and mapping of sex-determining loci

    Directory of Open Access Journals (Sweden)

    Liu Feng

    2013-01-01

    Full Text Available Abstract Background Tilapia is the common name for a group of cichlid fishes and is one of the most important aquacultured freshwater food fish. Mozambique tilapia and its hybrids, including red tilapia are main representatives of salt tolerant tilapias. A linkage map is an essential framework for mapping QTL for important traits, positional cloning of genes and understanding of genome evolution. Results We constructed a consensus linkage map of Mozambique tilapia and red tilapia using 95 individuals from two F1 families and 401 microsatellites including 282 EST-derived markers. In addition, we conducted comparative mapping and searched for sex-determining loci on the whole genome. These 401 microsatellites were assigned to 22 linkage groups. The map spanned 1067.6 cM with an average inter-marker distance of 3.3 cM. Comparative mapping between tilapia and stickleback, medaka, pufferfish and zebrafish revealed clear homologous relationships between chromosomes from different species. We found evidence for the fusion of two sets of two independent chromosomes forming two new chromosome pairs, leading to a reduction of 24 chromosome pairs in their ancestor to 22 pairs in tilapias. The XY sex determination locus in Mozambique tilapia was mapped on LG1, and verified in five families containing 549 individuals. The major XY sex determination locus in red tilapia was located on LG22, and verified in two families containing 275 individuals. Conclusions A first-generation linkage map of salt tolerant tilapia was constructed using 401 microsatellites. Two separate fusions of two sets of two independent chromosomes may lead to a reduction of 24 chromosome pairs in their ancestor to 22 pairs in tilapias. The XY sex-determining loci from Mozambique tilapia and red tilapia were mapped on LG1 and LG22, respectively. This map provides a useful resource for QTL mapping for important traits and comparative genome studies. The DNA markers linked to the sex-determining

  20. Maternal factors associated with fetal growth and birthweight are independent determinants of placental weight and exhibit differential effects by fetal sex.

    Directory of Open Access Journals (Sweden)

    Marie Cecilie Paasche Roland

    Full Text Available INTRODUCTION: Maternal nutritional and metabolic factors influence the developmental environment of the fetus. Virtually any nutritional factor in the maternal blood has to pass the placental membranes to reach the fetal blood. Placental weight is a commonly used measure to summarize placental growth and function. Placental weight is an independent determinant of fetal growth and birthweight and modifies the associations between maternal metabolic factors and fetal growth. We hypothesized that maternal factors known to be related to fetal growth, newborn size and body composition are determinants of placental weight and that effects of maternal metabolic factors on placental weight differ between the genders. METHODS: The STORK study is a prospective longitudinal study including 1031 healthy pregnant women of Scandinavian heritage with singleton pregnancies. Maternal determinants (parity, body mass index, gestational weight gain and fasting plasma glucose of placental weight were explored by linear regression models, stratified by fetal sex. RESULTS: Parity, maternal BMI, gestational weight gain and fasting glucose had positive effects on placental weight. There was a sex specific effect in these associations. Fasting glucose was significantly associated with placental weight in females but not in males. CONCLUSION: Maternal factors known to influence fetal growth, birthweight and neonatal body composition are determinants of placental weight. The effect of maternal factors on placental weight is influenced by sex as illustrated in the relation between maternal glucose and placental weight.

  1. Sex-related differences in the determinants and process of science and mathematics choice in pre-university education

    NARCIS (Netherlands)

    van Langen, A.; Rekers-Mombarg, L; Dekkers, H

    2006-01-01

    The more science and mathematics subjects that pupils in pre-university education include in their final examination package, the more future academic routes are available to them. Equality of educational opportunity is thus threatened when groups of pupils, distinguished by sex and family

  2. Origin-related, environmental, sex, and age determinants of immunocompetence, susceptibility to ectoparasites, and disease symptoms in the barn owl

    NARCIS (Netherlands)

    Roulin, Alexandre; Christe, Philippe; Dijkstra, Cor; Ducrest, Anne-Lyse; Jungi, Thomas W.

    Knowledge of the role of origin-related, environmental, sex, and age factors on host defence mechanisms is important to understand variation in parasite intensity. Because alternative components of parasite defence may be differently sensitive to various factors, they may not necessarily covary.

  3. Genes involved in sex pheromone biosynthesis of Ephestia cautella, an important food storage pest, are determined by transcriptome sequencing

    KAUST Repository

    Antony, Binu; Soffan, Alan; Jakše, Jernej; Alfaifi, Sulieman; Sutanto, Koko D.; Aldosari, Saleh A.; Aldawood, Abdulrahman S.; Pain, Arnab

    2015-01-01

    Our study provides important background information on the enzymes involved in pheromone biosynthesis. This information will be useful for the in vitro production of E. cautella sex pheromones and may provide potential targets for disrupting the pheromone-based communication system of E. cautella to prevent infestations.

  4. Development of a reliable method for determining sex for a primitive rodent, the Point Arena mountain beaver (Aplodontia rufa nigra)

    Science.gov (United States)

    Kristine L. Pilgrim; William J. Zielinski; Fredrick V. Schlexer; Michael K. Schwartz

    2012-01-01

    The mountain beaver (Aplodontia rufa) is a primitive species of rodent, often considered a living fossil. The Point Arena mountain beaver (Aplodontia rufa nigra) is an endangered subspecies that occurs in a very restricted range in northern California. Efforts to recover this taxon have been limited by the lack of knowledge on their demography, particularly sex and age...

  5. Sex trafficking and health care in Metro Manila: identifying social determinants to inform an effective health system response.

    Science.gov (United States)

    Williams, Timothy P; Alpert, Elaine J; Ahn, Roy; Cafferty, Elizabeth; Konstantopoulos, Wendy Macias; Wolferstan, Nadya; Castor, Judith Palmer; McGahan, Anita M; Burke, Thomas F

    2010-12-15

    This social science case study examines the sex trafficking of women and girls in Metro Manila through a public health lens. Through key informant interviews with 51 health care and anti-trafficking stakeholders in Metro Manila, this study reports on observations about sex trafficking in Metro Manila that provide insight into understanding of risk factors for sex trafficking at multiple levels of the social environment: individual (for example, childhood abuse), socio-cultural (for example, gender inequality and a "culture of migration"), and macro (for example, profound poverty caused, inter alia, by environmental degradation disrupting traditional forms of labor). It describes how local health systems currently assist sex-trafficking victims, and provides a series of recommendations, ranging from prevention to policy, for how health care might play a larger role in promoting the health and human rights of this vulnerable population. Copyright © 2010 Williams, Alpert, Ahn, Cafferty, Konstantopoulos, Wolferstan, Castor, McGahan, and Burke. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.

  6. Sex determines effect of physical activity on diet preference: Association of striatal opioids and gut microbiota composition.

    Science.gov (United States)

    Lee, Jenna R; Muckerman, Julie E; Wright, Anna M; Davis, Daniel J; Childs, Tom E; Gillespie, Catherine E; Vieira-Potter, Victoria J; Booth, Frank W; Ericsson, Aaron C; Will, Matthew J

    2017-09-15

    Previous studies suggest an interaction between the level of physical activity and diet preference. However, this relationship has not been well characterized for sex differences that may exist. The present study examined the influence of sex on diet preference in male and female Wistar rats that were housed under either sedentary (no wheel access) (SED) or voluntary wheel running access (RUN) conditions. Following a 1 week acclimation period to these conditions, standard chow was replaced with concurrent ad libitum access to a choice of 3 pelleted diets (high-fat, high-sucrose, and high-corn starch) in the home cage. SED and RUN conditions remained throughout the next 4 week diet preference assessment period. Body weight, running distance, and intake of each diet were measured daily. At the conclusion of the 4 week diet preference test, animals were sacrificed and brains were collected for mRNA analysis. Fecal samples were also collected before and after the 4 week diet preference phase to characterize microbiota composition. Results indicate sex dependent interactions between physical activity and both behavioral and physiological measures. Females in both RUN and SED conditions preferred the high-fat diet, consuming significantly more high-fat diet than either of the other two diets. While male SED rats also preferred the high-fat diet, male RUN rats consumed significantly less high-fat diet than the other groups, instead preferring all three diets equally. There was also a sex dependent influence of physical activity on both reward related opioid mRNA expression in the ventral striatum and the characterization of gut microbiota. The significant sex differences in response to physical activity observed through both behavioral and physiological measures suggest potential motivational or metabolic difference between males and females. The findings highlight the necessity for further exploration between male and female response to physical activity and feeding

  7. Viability of human dental pulp in determination of sex of an individual by identifying srygene through DNA analysis: A single blind pilot study

    Directory of Open Access Journals (Sweden)

    Prachi Ravikant Naik

    2012-01-01

    Full Text Available Recognition of importance of human teeth in personal identification has been recognized from time immemorial. In any natural calamity or man-made catastrophe identification of an individual is of paramount importance. Here tooth plays an important role as it is the last one to get affected in a disaster due to its durable nature and good survival rate. This information comes under the aegis of forensic odontology and is of paramount importance from legal and social viewpoints. This analysis uses highly informative genetic markers and can be carried out easily in a typical forensic lab oratory. The SRY gene marker (sex determining region Y is a sex-determining gene on the Y chromosome in the therians (placental mammals and marsupials and this gene marker is considered as a signature gene to differentiate the male from female sex chromosome. The detection of SRY gene in the DNA from a forensic sample can be confirmatory to type the gender as male. This study was taken up to identify the viability of human tooth pulp by identification of SRY gene in gender determination.

  8. Auger electron spectroscopy for the determination of sex and age related Ca/P ratio at different bone sites

    International Nuclear Information System (INIS)

    Balatsoukas, Ioannis; Kourkoumelis, Nikolaos; Tzaphlidou, Margaret

    2010-01-01

    The Ca/P ratio of normal cortical and trabecular rat bone was measured by Auger electron spectroscopy (AES). Semiquantitative analysis was carried out using ratio techniques to draw conclusions on how age, sex and bone site affect the relative composition of calcium and phosphorus. Results show that Ca/P ratio is not sex dependent; quite the opposite, bone sites exhibit variations in elemental stoichiometry where femoral sections demonstrate higher Ca/P ratio than rear and front tibias. Age-related changes are more distinct for cortical bone in comparison with the trabecular bone. The latter's Ca/P ratio remains unaffected from all the parameters under study. This study confirms that AES is able to successfully quantify bone mineral main elements when certain critical points, related to the experimental conditions, are addressed effectively.

  9. Sex Therapy

    Science.gov (United States)

    Sex therapy Overview Sex therapy is a type of psychotherapy — a general term for treating mental health problems by talking with a mental health professional. Through sex therapy, you can address concerns about sexual function, ...

  10. ACC oxidase and miRNA 159a, and their involvement in fresh fruit bunch yield (FFB) via sex ratio determination in oil palm.

    Science.gov (United States)

    Somyong, Suthasinee; Poopear, Supannee; Sunner, Supreet Kaur; Wanlayaporn, Kitti; Jomchai, Nukoon; Yoocha, Thippawan; Ukoskit, Kittipat; Tangphatsornruang, Sithichoke; Tragoonrung, Somvong

    2016-06-01

    Oil palm (Elaeis guineesis Jacq.) is the most productive oil-bearing crop, yielding more oil per area than any other oil-bearing crops. However, there are still efforts to improve oil palm yield, in order to serve consumer and manufacturer demand. Oil palm produces female and male inflorescences in an alternating cycle. So, high sex ratio (SR), the ratio of female inflorescences to the total inflorescences, is a favorable trait in term of increasing yields in oil palm. This study aims to understand the genetic control for SR related traits, such as fresh fruit bunch yield (FFB), by characterizing genes at FFB quantitative trait loci (QTLs) on linkage 10 (chromosome 6) and linkage 15 (chromosome 10). Published oil palm sequences at the FFB QTLs were used to develop gene-based and simple sequence repeat (SSR) markers. We used the multiple QTL analysis model (MQM) to characterize the relationship of new markers with the SR traits in the oil palm population. The RNA expression of the most linked QTL genes was also evaluated in various tissues of oil palm. We identified EgACCO1 (encoding aminocyclopropane carboxylate (ACC) oxidase) at chromosome 10 and EgmiR159a (microRNA 159a) at chromosome 6 to be the most linked QTL genes or determinants for FFB yield and/or female inflorescence number with a phenotype variance explained (PVE) from 10.4 to 15 % and suggest that these play the important roles in sex determination and differentiation in oil palm. The strongest expression of EgACCO1 and the predicted precursor of EgmiR159a was found in ovaries and, to a lesser extent, fruit development. In addition, highly normalized expression of EgmiR159a was found in female flowers. In summary, the QTL analysis and the RNA expression reveal that EgACCO1 and EgmiR159a are the potential genetic factors involved in female flower determination and hence would affect yield in oil palm. However, to clarify how these genetic factors regulate female flower determination, more investigation

  11. Similar but not the same: insights into the evolutionary history of paralogous sex-determining genes of the dwarf honey bee Apis florea.

    Science.gov (United States)

    Biewer, M; Lechner, S; Hasselmann, M

    2016-01-01

    Studying the fate of duplicated genes provides informative insight into the evolutionary plasticity of biological pathways to which they belong. In the paralogous sex-determining genes complementary sex determiner (csd) and feminizer (fem) of honey bee species (genus Apis), only heterozygous csd initiates female development. Here, the full-length coding sequences of the genes csd and fem of the phylogenetically basal dwarf honey bee Apis florea are characterized. Compared with other Apis species, remarkable evolutionary changes in the formation and localization of a protein-interacting (coiled-coil) motif and in the amino acids coding for the csd characteristic hypervariable region (HVR) are observed. Furthermore, functionally different csd alleles were isolated as genomic fragments from a random population sample. In the predicted potential specifying domain (PSD), a high ratio of πN/πS=1.6 indicated positive selection, whereas signs of balancing selection, commonly found in other Apis species, are missing. Low nucleotide diversity on synonymous and genome-wide, non-coding sites as well as site frequency analyses indicated a strong impact of genetic drift in A. florea, likely linked to its biology. Along the evolutionary trajectory of ~30 million years of csd evolution, episodic diversifying selection seems to have acted differently among distinct Apis branches. Consistently low amino-acid differences within the PSD among pairs of functional heterozygous csd alleles indicate that the HVR is the most important region for determining allele specificity. We propose that in the early history of the lineage-specific fem duplication giving rise to csd in Apis, A. florea csd stands as a remarkable example for the plasticity of initial sex-determining signals.

  12. Sex chromosomes and sex determination in Lepidoptera

    Czech Academy of Sciences Publication Activity Database

    Traut, W.; Sahara, K.; Marec, František

    1[2007], č. 6 (2008), s. 332-346 ISSN 1661-5425 R&D Projects: GA ČR GA206/06/1860 Institutional research plan: CEZ:AV0Z50070508 Keywords : balanced lethal * butterfly * evolution Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.000, year: 2008

  13. Mapping the expression of the sex determining factor Doublesex1 in Daphnia magna using a knock-in reporter.

    Science.gov (United States)

    Nong, Quang Dang; Mohamad Ishak, Nur Syafiqah; Matsuura, Tomoaki; Kato, Yasuhiko; Watanabe, Hajime

    2017-11-02

    Sexually dimorphic traits are common and widespread among animals. The expression of the Doublesex-/Mab-3-domain (DM-domain) gene family has been widely studied in model organisms and has been proven to be essential for the development and maintenance of sex-specific traits. However, little is known about the detailed expression patterns in non-model organisms. In the present study, we demonstrated the spatiotemporal expression of the DM-domain gene, doublesex1 (dsx1), in the crustacean Daphnia magna, which parthenogenetically produces males in response to environmental cues. We developed a dsx1 reporter strain to track dsx1 activity in vivo by inserting the mCherry gene into the dsx1 locus using the TALEN-mediated knock-in approach. After confirming dsx1 expression in male-specific traits in juveniles and adults, we performed time-lapse imaging of embryogenesis. Shortly after gastrulation stage, a presumptive primary organiser, named cumulus, first showed male-specific dsx1 expression. This cell mass moved to the posterior growth zone that distributes dsx1-expressing progenitor cells across the body during axial elongation, before embryos start male-specific dsx1 expression in sexually dimorphic structures. The present study demonstrated the sex-specific dsx1 expression in cell populations involved in basal body formation.

  14. X- and Y-chromosome specific variants of the amelogenin gene allow sex determination in sheep (Ovis aries and European red deer (Cervus elaphus

    Directory of Open Access Journals (Sweden)

    Brenig B

    2005-03-01

    Full Text Available Abstract Background Simple and precise methods for sex determination in animals are a pre-requisite for a number of applications in animal production and forensics. However, some of the existing methods depend only on the detection of Y-chromosome specific sequences. Therefore, the abscence of a signal does not necessarily mean that the sample is of female origin, because experimental errors can also lead to negative results. Thus, the detection of Y- and X-chromosome specific sequences is advantageous. Results A novel method for sex identification in mammals (sheep, Ovis aries and European red deer, Cervus elaphus is described, using a polymerase chain reaction (PCR and sequencing of a part of the amelogenin gene. A partial sequence of the amelogenin gene of sheep and red deer was obtained, which exists on both X and Y chromosomes with a deletion region on the Y chromosome. With a specific pair of primers a DNA fragment of different length between the male and female mammal was amplified. Conclusion PCR amplification using the amelogenin gene primers is useful in sex identification of samples from sheep and red deer and can be applied to DNA analysis of micro samples with small amounts of DNA such as hair roots as well as bones or embryo biopsies.

  15. Analysis of the sex-determining region of the Y chromosome (SRY) in sex reversed patients: point-mutation in SRY causing sex-reversion in a 46,XY female

    DEFF Research Database (Denmark)

    Müller, Jørn; Schwartz, M; Skakkebaek, N E

    1992-01-01

    The first and essential step in normal sexual differentiation takes place during the 5th-6th week of gestation. The testis determining factor (TDF) directs the undifferentiated gonad into a testis, which secretes hormones responsible for normal male development. A new candidate for TDF has recently...

  16. A Single Transcriptome of a Green Toad (Bufo viridis Yields Candidate Genes for Sex Determination and -Differentiation and Non-Anonymous Population Genetic Markers.

    Directory of Open Access Journals (Sweden)

    Jörn F Gerchen

    Full Text Available Large genome size, including immense repetitive and non-coding fractions, still present challenges for capacity, bioinformatics and thus affordability of whole genome sequencing in most amphibians. Here, we test the performance of a single transcriptome to understand whether it can provide a cost-efficient resource for species with large unknown genomes. Using RNA from six different tissues from a single Palearctic green toad (Bufo viridis specimen and Hiseq2000, we obtained 22,5 Mio reads and publish >100,000 unigene sequences. To evaluate efficacy and quality, we first use this data to identify green toad specific candidate genes, known from other vertebrates for their role in sex determination and differentiation. Of a list of 37 genes, the transcriptome yielded 32 (87%, many of which providing the first such data for this non-model anuran species. However, for many of these genes, only fragments could be retrieved. In order to allow also applications to population genetics, we further used the transcriptome for the targeted development of 21 non-anonymous microsatellites and tested them in genetic families and backcrosses. Eleven markers were specifically developed to be located on the B. viridis sex chromosomes; for eight markers we can indeed demonstrate sex-specific transmission in genetic families. Depending on phylogenetic distance, several markers, which are sex-linked in green toads, show high cross-amplification success across the anuran phylogeny, involving nine systematic anuran families. Our data support the view that single transcriptome sequencing (based on multiple tissues provides a reliable genomic resource and cost-efficient method for non-model amphibian species with large genome size and, despite limitations, should be considered as long as genome sequencing remains unaffordable for most species.

  17. Characterization and expression profile of the ovarian cytochrome P-450 aromatase (cyp19A1) gene during thermolabile sex determination in Pejerrey, Odontesthes bonariensis

    Science.gov (United States)

    Karube, M.; Fernandino, J.I.; Strobl-Mazzulla, P.; Strussmann, C.A.; Yoshizaki, G.; Somoza, G.M.; Patino, R.

    2007-01-01

    Cytochrome P450 aromatase (cyp19) is an enzyme that catalyzes the conversion of androgens to estrogens and may play a role in temperature- dependent sex determination (TSD) of reptiles, amphibians, and fishes. In this study, the ovarian P450 aromatase form (cyp19A1) of pejerrey Odontesthes bonariensis, a teleost with marked TSD, was cloned and its expression profile evaluated during gonadal differentiation at feminizing (17??C, 100% females), mixed-sex producing (24 and 25??C, 73.3 and 26.7% females, respectively), and masculinizing (29??C, 0% females) temperatures. The deduced cyp19A1 amino acid sequence shared high identity (>77.8%) with that from other teleosts but had low identity (<61.8%) with brain forms (cyp19A2), including that of pejerrey itself. The tissue distribution analysis of cyp19A1 mRNA in adult fish revealed high expression in the ovary. Semi-quantitative reverse transcription polymerase chain reaction analysis of the bodies of larvae revealed that cyp19A1 expression increased before the appearance of the first histological signs of ovarian differentiation at the feminizing temperature but remained low at the masculinizing temperature. The expression levels at mixed-sex producing temperatures were bimodal rather than intermediate, showing low and high modal values similar to those at the feminizing and masculinizing temperatures, respectively. The population percentages of high and low expression levels at intermediate temperatures were proportional to the percentage of females and males, respectively, and high levels were first observed at about the time of sex differentiation of females. These results suggest that cyp19A1 is involved in the process of ovarian formation and possibly also in the TSD of pejerrey. ?? 2007 Wiley-Liss, Inc.

  18. Opportunities to improve competitiveness in male sexual strain has genetic sex determination Ceratitis capitata Wiedemann (Diptera: Tephritidae)

    International Nuclear Information System (INIS)

    Tlemcani, Meriem

    2010-01-01

    The success of TIS program depends essentially on the capacity of the sterile males to compete with fertile males to couple with wild females. This program becomes more and more efficient if one good mastery its various factors, mainly the performances of males of the origin of ceratite in genetic sexing within the production unit of sterile flies of the National Center of the Sciences and Nuclear Technologies. Researches turned to the improvement of the competitiveness of the sterile males by the addition of bacteria in the nourishing circles of breeding. By basing itself on the symbiotic relations between the present bacteria in the bowel of the ceratite, we adopted, in this present work, a method of breeding which could improve the quality of the males of genetic sexing GSS. This method consists in introducing certain beneficial bacteria in the ceratite (Enterobacteriaceae and Pseudomonas aerogenes) into the middle of breeding according to various combinations. The effect of these bacteria was analyzed by making various tests of quality control (weight, emergence, capacity in the flight, the longevity) and of reproduction (competitiveness, lasted mating, latent period). It turns out that the addition of Enterobacteriaceae in the middle of breeding outstandingly improved the percentage of emergence of the males of the GSS. Besides, these bacteria contributed to the improvement of the competitiveness of these males with regard to those of the other circles. Besides, the addition of Pseudomonas aerogenes in the middle of breeding gave the best latent period to the males GSS. We also noticed that the association of Enterobacteriaceae with Pseudomonas aerogenes has a positive effect on the capacity in the flight of the males of the GSS and their duration of mating.

  19. Epigenetic modifications and their relation to caste and sex determination and adult division of labor in the stingless bee Melipona scutellaris.

    Science.gov (United States)

    Cardoso-Júnior, Carlos A M; Fujimura, Patrícia Tieme; Santos-Júnior, Célio Dias; Borges, Naiara Araújo; Ueira-Vieira, Carlos; Hartfelder, Klaus; Goulart, Luiz Ricardo; Bonetti, Ana Maria

    2017-01-01

    Stingless bees of the genus Melipona, have long been considered an enigmatic case among social insects for their mode of caste determination, where in addition to larval food type and quantity, the genotype also has a saying, as proposed over 50 years ago by Warwick E. Kerr. Several attempts have since tried to test his Mendelian two-loci/two-alleles segregation hypothesis, but only recently a single gene crucial for sex determination in bees was evidenced to be sex-specifically spliced and also caste-specifically expressed in a Melipona species. Since alternative splicing is frequently associated with epigenetic marks, and the epigenetic status plays a major role in setting the caste phenotype in the honey bee, we investigated here epigenetic chromatin modification in the stingless bee Melipona scutellaris. We used an ELISA-based methodology to quantify global methylation status and western blot assays to reveal histone modifications. The results evidenced DNA methylation/demethylation events in larvae and pupae, and significant differences in histone methylation and phosphorylation between newly emerged adult queens and workers. The epigenetic dynamics seen in this stingless bee species represent a new facet in the caste determination process in Melipona bees and suggest a possible mechanism that is likely to link a genotype component to the larval diet and adult social behavior of these bees.

  20. Epigenetic modifications and their relation to caste and sex determination and adult division of labor in the stingless bee Melipona scutellaris

    Directory of Open Access Journals (Sweden)

    Carlos A.M. Cardoso-Júnior

    2017-03-01

    Full Text Available Abstract Stingless bees of the genus Melipona, have long been considered an enigmatic case among social insects for their mode of caste determination, where in addition to larval food type and quantity, the genotype also has a saying, as proposed over 50 years ago by Warwick E. Kerr. Several attempts have since tried to test his Mendelian two-loci/two-alleles segregation hypothesis, but only recently a single gene crucial for sex determination in bees was evidenced to be sex-specifically spliced and also caste-specifically expressed in a Melipona species. Since alternative splicing is frequently associated with epigenetic marks, and the epigenetic status plays a major role in setting the caste phenotype in the honey bee, we investigated here epigenetic chromatin modification in the stingless bee Melipona scutellaris. We used an ELISA-based methodology to quantify global methylation status and western blot assays to reveal histone modifications. The results evidenced DNA methylation/demethylation events in larvae and pupae, and significant differences in histone methylation and phosphorylation between newly emerged adult queens and workers. The epigenetic dynamics seen in this stingless bee species represent a new facet in the caste determination process in Melipona bees and suggest a possible mechanism that is likely to link a genotype component to the larval diet and adult social behavior of these bees.

  1. Hybrid incompatibilities in the parasitic wasp genus Nasonia: negative effects of hemizygosity and the identification of transmission ratio distortion loci.

    Science.gov (United States)

    Koevoets, T; Niehuis, O; van de Zande, L; Beukeboom, L W

    2012-03-01

    The occurrence of hybrid incompatibilities forms an important stage during the evolution of reproductive isolation. In early stages of speciation, males and females often respond differently to hybridization. Haldane's rule states that the heterogametic sex suffers more from hybridization than the homogametic sex. Although haplodiploid reproduction (haploid males, diploid females) does not involve sex chromosomes, sex-specific incompatibilities are predicted to be prevalent in haplodiploid species. Here, we evaluate the effect of sex/ploidy level on hybrid incompatibilities and locate genomic regions that cause increased mortality rates in hybrid males of the haplodiploid wasps Nasonia vitripennis and Nasonia longicornis. Our data show that diploid F(1) hybrid females suffer less from hybridization than haploid F(2) hybrid males. The latter not only suffer from an increased mortality rate, but also from behavioural and spermatogenic sterility. Genetic mapping in recombinant F(2) male hybrids revealed that the observed hybrid mortality is most likely due to a disruption of cytonuclear interactions. As these sex-specific hybrid incompatibilities follow predictions based on Haldane's rule, our data accentuate the need to broaden the view of Haldane's rule to include species with haplodiploid sex determination, consistent with Haldane's original definition.

  2. Sex Reversal in Birds.

    Science.gov (United States)

    Major, Andrew T; Smith, Craig A

    2016-01-01

    Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while females are ZW. Gene(s) on the sex chromosomes must initiate gonadal sex differentiation during embryonic life, inducing paired testes in ZZ individuals and unilateral ovaries in ZW individuals. The traditional view of avian sexual differentiation aligns with that expounded for other vertebrates; upon sexual differentiation, the gonads secrete sex steroid hormones that masculinise or feminise the rest of the body. However, recent studies on naturally occurring or experimentally induced avian sex reversal suggest a significant role for direct genetic factors, in addition to sex hormones, in regulating sexual differentiation of the soma in birds. This review will provide an overview of sex determination in birds and both naturally and experimentally induced sex reversal, with emphasis on the key role of oestrogen. We then consider how recent studies on sex reversal and gynandromorphic birds (half male:half female) are shaping our understanding of sexual differentiation in avians and in vertebrates more broadly. Current evidence shows that sexual differentiation in birds is a mix of direct genetic and hormonal mechanisms. Perturbation of either of these components may lead to sex reversal. © 2016 S. Karger AG, Basel.

  3. Sex reversal in vertebrates

    OpenAIRE

    2016-01-01

    This special topic issue of Sexual Development gives an overview of sex reversal in vertebrates, from fishes naturally changing their sex, to rodents escaping the mammalian SRY-determining system. It offers eight up-to-date reviews on specific subjects in sex reversal, considering fishes, amphibians, reptiles, birds, marsupials, and placental mammals, including humans. The broad scope of represented animals makes this ideal for students and researchers, especially those interested in the...

  4. Digit Sucking, Age, Sex, and Socioeconomic Status as Determinants of Oral Hygiene Status and Gingival Health of Children in Suburban Nigeria.

    Science.gov (United States)

    Agbaje, Hakeem O; Kolawole, Kikelomo A; Folayan, Morenike O; Onyejaka, Nneka K; Oziegbe, Elizabeth O; Oyedele, Titus A; Chukwumah, Nneka M; Oshomoji, Olusegun V

    2016-09-01

    This study determines prevalence of digit sucking and gingivitis, and association among age, sex, socioeconomic status, presence of digit-sucking habits, oral hygiene status (OHS), and gingivitis among a group of Nigerian children. Data of 992 children aged 1 to 12 years recruited through a household survey conducted in Osun State, Nigeria were analyzed. Information on age, sex, socioeconomic status, and history of digit-sucking habits were collected. Children were assessed for OHS and severity of gingivitis using the simplified oral hygiene index and the gingival index, respectively. Predictors of presence of gingivitis and poor oral hygiene were determined using multivariate logistic regression. One (0.2%) and 454 (93.0%) children aged 1 to 5 years had poor oral hygiene and mild gingivitis, respectively. Twenty-two (4.4%) and 361 (72.9%) children aged 6 to 12 years had poor oral hygiene and mild gingivitis, respectively. The odds of having poor oral hygiene (adjusted odds ratio [AOR]: 0.26; 95% confidence interval [CI]: 0.20 to 0.35; P oral hygiene and gingivitis. Increasing age and low socioeconomic status were factors that significantly increased chances of having poor oral hygiene and gingivitis.

  5. Female sex, poverty and globalization as determinants of obesity among rural South African type 2 diabetics: a cross-sectional study.

    Science.gov (United States)

    Adeniyi, Oladele Vincent; Longo-Mbenza, Benjamin; Ter Goon, Daniel

    2015-03-27

    Countries in Sub-Saharan Africa have recently been experiencing increases in the prevalence of obesity, type 2 diabetes mellitus (T2DM) and other non-communicable diseases in both urban and rural areas. Despite their growing influence on population health in the region, there is a paucity of epidemiological studies on the twin epidemic of obesity and T2DM, particularly in the rural communities in South Africa. We investigated the prevalence and the determinants of overall obesity among patients with T2DM in rural and semi-urban areas surrounding the town of Mthatha, South Africa. This hospital-based cross-sectional study was conducted among patients with T2DM attending the outpatient department at Mthatha General Hospital, Eastern Cape Province, South Africa. Data were obtained from 327 participants using standardized questionnaires that included items on sex, age, level of education, type of residence, employment status, smoking status, physical activity, diet and alcohol intake. After taking measurements of height and weight, participants were defined as obese if their body mass index exceeded 30 kg/m(2). Univariate and multivariate logistic regression analyses were performed to identify the determinants of obesity in our sample population. We found that 60.2% of our sample population were defined as obese. In our univariate analyses, female sex (p rural residence (p poverty reduction and public education are urgently needed to address the growing obesity epidemic in rural areas of South Africa.

  6. Turtle sex determination assay: Mass balance and responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3,3',4,4',5-pentachlorobiphenyl

    Science.gov (United States)

    Gale, Robert W.; Bergeron, Judith M.; Willingham, Emily J.; Crews, David

    2002-01-01

    Polyhalogenated hydrocarbons have been implicated in the anomalous sexual differentiation of mammals and reptiles. Here, a temperature-sensitive turtle sex determination assay using the red-eared slider (Trachemys scripta elegans) was used to determine the estrogenic or antiestrogenic activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3,3′,4,4′,5-pentachlorobiphenyl (PCB-126). Neither TCDD nor PCB-126 showed a statistically significant difference in the resulting sex ratios (Fisher's exact test, p < 0.45). As a consequence of the dosing technique (eggshell spotting), the shell retained 90 and 96% of the dose for PCB-126 and TCDD, respectively, similar to retention of estradiol-17β. However, the dosing allowed transfer of sufficient chemical to achieve tissue concentrations that were greater than most concentrations reported for environmentally incurred residues. Similar relative mass distributions of PCB-126 and TCDD were observed in albumin (14–20%), yolk (55–70%), and embryo (16–25%). Relative concentration distributions in the embryo approached those in the yolk, 37 to 40% and 40 to 52%, respectively, while relative concentrations in the albumin remained at 11 to 20%. Lipid-normalized TCDD and PCB-126 concentrations were 30- to 40-fold greater in the embryo than in the yolk. It is hypothesized that nonpassive partitioning processes may have occurred in the embryo.

  7. Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development.

    Science.gov (United States)

    Radhakrishnan, Srihari; Literman, Robert; Neuwald, Jennifer; Severin, Andrew; Valenzuela, Nicole

    2017-01-01

    Vertebrate sexual fate is decided primarily by the individual's genotype (GSD), by the environmental temperature during development (TSD), or both. Turtles exhibit TSD and GSD, making them ideal to study the evolution of sex determination. Here we analyze temperature-specific gonadal transcriptomes (RNA-sequencing validated by qPCR) of painted turtles (Chrysemys picta TSD) before and during the thermosensitive period, and at equivalent stages in soft-shell turtles (Apalone spinifera-GSD), to test whether TSD's and GSD's transcriptional circuitry is identical but deployed differently between mechanisms. Our data show that most elements of the mammalian urogenital network are active during turtle gonadogenesis, but their transcription is generally more thermoresponsive in TSD than GSD, and concordant with their sex-specific function in mammals [e.g., upregulation of Amh, Ar, Esr1, Fog2, Gata4, Igf1r, Insr, and Lhx9 at male-producing temperature, and of β-catenin, Foxl2, Aromatase (Cyp19a1), Fst, Nf-kb, Crabp2 at female-producing temperature in Chrysemys]. Notably, antagonistic elements in gonadogenesis (e.g., β-catenin and Insr) were thermosensitive only in TSD early-embryos. Cirbp showed warm-temperature upregulation in both turtles disputing its purported key TSD role. Genes that may convert thermal inputs into sex-specific development (e.g., signaling and hormonal pathways, RNA-binding and heat-shock) were differentially regulated. Jak-Stat, Nf-κB, retinoic-acid, Wnt, and Mapk-signaling (not Akt and Ras-signaling) potentially mediate TSD thermosensitivity. Numerous species-specific ncRNAs (including Xist) were differentially-expressed, mostly upregulated at colder temperatures, as were unannotated loci that constitute novel TSD candidates. Cirbp showed warm-temperature upregulation in both turtles. Consistent transcription between turtles and alligator revealed putatively-critical reptilian TSD elements for male (Sf1, Amh, Amhr2) and female (Crabp2 and Hspb1

  8. Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development.

    Directory of Open Access Journals (Sweden)

    Srihari Radhakrishnan

    Full Text Available Vertebrate sexual fate is decided primarily by the individual's genotype (GSD, by the environmental temperature during development (TSD, or both. Turtles exhibit TSD and GSD, making them ideal to study the evolution of sex determination. Here we analyze temperature-specific gonadal transcriptomes (RNA-sequencing validated by qPCR of painted turtles (Chrysemys picta TSD before and during the thermosensitive period, and at equivalent stages in soft-shell turtles (Apalone spinifera-GSD, to test whether TSD's and GSD's transcriptional circuitry is identical but deployed differently between mechanisms. Our data show that most elements of the mammalian urogenital network are active during turtle gonadogenesis, but their transcription is generally more thermoresponsive in TSD than GSD, and concordant with their sex-specific function in mammals [e.g., upregulation of Amh, Ar, Esr1, Fog2, Gata4, Igf1r, Insr, and Lhx9 at male-producing temperature, and of β-catenin, Foxl2, Aromatase (Cyp19a1, Fst, Nf-kb, Crabp2 at female-producing temperature in Chrysemys]. Notably, antagonistic elements in gonadogenesis (e.g., β-catenin and Insr were thermosensitive only in TSD early-embryos. Cirbp showed warm-temperature upregulation in both turtles disputing its purported key TSD role. Genes that may convert thermal inputs into sex-specific development (e.g., signaling and hormonal pathways, RNA-binding and heat-shock were differentially regulated. Jak-Stat, Nf-κB, retinoic-acid, Wnt, and Mapk-signaling (not Akt and Ras-signaling potentially mediate TSD thermosensitivity. Numerous species-specific ncRNAs (including Xist were differentially-expressed, mostly upregulated at colder temperatures, as were unannotated loci that constitute novel TSD candidates. Cirbp showed warm-temperature upregulation in both turtles. Consistent transcription between turtles and alligator revealed putatively-critical reptilian TSD elements for male (Sf1, Amh, Amhr2 and female (Crabp2 and

  9. Determinants of HIV Phylogenetic Clustering in Chicago Among Young Black Men Who Have Sex With Men From the uConnect Cohort.

    Science.gov (United States)

    Morgan, Ethan; Nyaku, Amesika N; DʼAquila, Richard T; Schneider, John A

    2017-07-01

    Phylogenetic analysis determines similarities among HIV genetic sequences from persons infected with HIV, identifying clusters of transmission. We determined characteristics associated with both membership in an HIV transmission cluster and the number of clustered sequences among a cohort of young black men who have sex with men (YBMSM) in Chicago. Pairwise genetic distances of HIV-1 pol sequences were collected during 2013-2016. Potential transmission ties were identified among HIV-infected persons whose sequences were ≤1.5% genetically distant. Putative transmission pairs were defined as ≥1 tie to another sequence. We then determined demographic and risk attributes associated with both membership in an HIV transmission cluster and the number of ties to the sequences from other persons in the cluster. Of 86 available sequences, 31 (36.0%) were tied to ≥1 other sequence. Through multivariable analyses, we determined that those who reported symptoms of depression and those who had a higher number of confidants in their network had significantly decreased odds of membership in transmission clusters. We found that those who had unstable housing and who reported heavy marijuana use had significantly more ties to other individuals within transmission clusters, whereas those identifying as bisexual, those participating in group sex, and those with higher numbers of sexual partners had significantly fewer ties. This study demonstrates the potential for combining phylogenetic and individual and network attributes to target HIV control efforts to persons with potentially higher transmission risk, as well as suggesting some unappreciated specific predictors of transmission risk among YBMSM in Chicago for future study.

  10. Diploid male production in a leaf-cutting ant

    DEFF Research Database (Denmark)

    Armitage, S.; Boomsma, J.; Baer, Boris

    2010-01-01

    1. In haplodiploid social insects where males are haploid and females are diploid, inbreeding depression is expressed as the production of diploid males when homozygosity at the sex-determining locus results in the production of diploid individuals with a male phenotype. Diploid males are often a...

  11. Inheritance of gynandromorphism in the parasitic wasp Nasonia vitripennis

    NARCIS (Netherlands)

    Kamping, Albert; Katju, Vaishali; Beukeboom, Leo W.; Werren, Jobn H.; Werren, John H.; Kaufman, T.C.

    The parasitic wasp Nasonia vitripennis has haplo-diploid sex determination. Males develop from unfertilized eggs and are haploid, whereas females develop from fertilized eggs and are diploid. Females and males can be easily distinguished by their morphology. A strain that produces individuals with

  12. Genes involved in sex pheromone biosynthesis of Ephestia cautella, an important food storage pest, are determined by transcriptome sequencing

    KAUST Repository

    Antony, Binu

    2015-07-18

    . Phylogenetic trees were constructed for desaturases, FARs and FATs, and transcripts that clustered with the ∆14, ∆12 and ∆9 desaturases, PG-specific FARs and potential candidate FATs, respectively, were identified. Transcripts encoding putative pheromone degrading enzymes, and candidate pheromone carrier and receptor proteins expressed in the E. cautella PG, were also identified. Conclusions Our study provides important background information on the enzymes involved in pheromone biosynthesis. This information will be useful for the in vitro production of E. cautella sex pheromones and may provide potential targets for disrupting the pheromone-based communication system of E. cautella to prevent infestations.

  13. Nucleotide Variability at Its Limit? Insights into the Number and Evolutionary Dynamics of the Sex-Determining Specificities of the Honey Bee Apis mellifera

    Science.gov (United States)

    Lechner, Sarah; Ferretti, Luca; Schöning, Caspar; Kinuthia, Wanja; Willemsen, David; Hasselmann, Martin

    2014-01-01

    Deciphering the evolutionary processes driving nucleotide variation in multiallelic genes is limited by the number of genetic systems in which such genes occur. The complementary sex determiner (csd) gene in the honey bee Apis mellifera is an informative example for studying allelic diversity and the underlying evolutionary forces in a well-described model of balancing selection. Acting as the primary signal of sex determination, diploid individuals heterozygous for csd develop into females, whereas csd homozygotes are diploid males that have zero fitness. Examining 77 of the functional heterozygous csd allele pairs, we established a combinatorical criteria that provide insights into the minimum number of amino acid differences among those pairs. Given a data set of 244 csd sequences, we show that the total number of csd alleles found in A. mellifera ranges from 53 (locally) to 87 (worldwide), which is much higher than was previously reported (20). Using a coupon-collector model, we extrapolate the presence of in total 116–145 csd alleles worldwide. The hypervariable region (HVR) is of particular importance in determining csd allele specificity, and we provide for this region evidence of high evolutionary rate for length differences exceeding those of microsatellites. The proportion of amino acids driven by positive selection and the rate of nonsynonymous substitutions in the HVR-flanking regions reach values close to 1 but differ with respect to the HVR length. Using a model of csd coalescence, we identified the high originating rate of csd specificities as a major evolutionary force, leading to an origin of a novel csd allele every 400,000 years. The csd polymorphism frequencies in natural populations indicate an excess of new mutations, whereas signs of ancestral transspecies polymorphism can still be detected. This study provides a comprehensive view of the enormous diversity and the evolutionary forces shaping a multiallelic gene. PMID:24170493

  14. Nucleotide variability at its limit? Insights into the number and evolutionary dynamics of the sex-determining specificities of the honey bee Apis mellifera.

    Science.gov (United States)

    Lechner, Sarah; Ferretti, Luca; Schöning, Caspar; Kinuthia, Wanja; Willemsen, David; Hasselmann, Martin

    2014-02-01

    Deciphering the evolutionary processes driving nucleotide variation in multiallelic genes is limited by the number of genetic systems in which such genes occur. The complementary sex determiner (csd) gene in the honey bee Apis mellifera is an informative example for studying allelic diversity and the underlying evolutionary forces in a well-described model of balancing selection. Acting as the primary signal of sex determination, diploid individuals heterozygous for csd develop into females, whereas csd homozygotes are diploid males that have zero fitness. Examining 77 of the functional heterozygous csd allele pairs, we established a combinatorical criteria that provide insights into the minimum number of amino acid differences among those pairs. Given a data set of 244 csd sequences, we show that the total number of csd alleles found in A. mellifera ranges from 53 (locally) to 87 (worldwide), which is much higher than was previously reported (20). Using a coupon-collector model, we extrapolate the presence of in total 116-145 csd alleles worldwide. The hypervariable region (HVR) is of particular importance in determining csd allele specificity, and we provide for this region evidence of high evolutionary rate for length differences exceeding those of microsatellites. The proportion of amino acids driven by positive selection and the rate of nonsynonymous substitutions in the HVR-flanking regions reach values close to 1 but differ with respect to the HVR length. Using a model of csd coalescence, we identified the high originating rate of csd specificities as a major evolutionary force, leading to an origin of a novel csd allele every 400,000 years. The csd polymorphism frequencies in natural populations indicate an excess of new mutations, whereas signs of ancestral transspecies polymorphism can still be detected. This study provides a comprehensive view of the enormous diversity and the evolutionary forces shaping a multiallelic gene.

  15. Sex Headaches

    Science.gov (United States)

    Sex headaches Overview Sex headaches are brought on by sexual activity — especially an orgasm. You may notice a dull ache in your head ... severe headache just before or during orgasm. Most sex headaches are nothing to worry about. But some ...

  16. Evaluation of Sample Stability and Automated DNA Extraction for Fetal Sex Determination Using Cell-Free Fetal DNA in Maternal Plasma

    Directory of Open Access Journals (Sweden)

    Elena Ordoñez

    2013-01-01

    Full Text Available Objective. The detection of paternally inherited sequences in maternal plasma, such as the SRY gene for fetal sexing or RHD for fetal blood group genotyping, is becoming part of daily routine in diagnostic laboratories. Due to the low percentage of fetal DNA, it is crucial to ensure sample stability and the efficiency of DNA extraction. We evaluated blood stability at 4°C for at least 24 hours and automated DNA extraction, for fetal sex determination in maternal plasma. Methods. A total of 158 blood samples were collected, using EDTA-K tubes, from women in their 1st trimester of pregnancy. Samples were kept at 4°C for at least 24 hours before processing. An automated DNA extraction was evaluated, and its efficiency was compared with a standard manual procedure. The SRY marker was used to quantify cfDNA by real-time PCR. Results. Although lower cfDNA amounts were obtained by automated DNA extraction (mean 107,35 GE/mL versus 259,43 GE/mL, the SRY sequence was successfully detected in all 108 samples from pregnancies with male fetuses. Conclusion. We successfully evaluated the suitability of standard blood tubes for the collection of maternal blood and assessed samples to be suitable for analysis at least 24 hours later. This would allow shipping to a central reference laboratory almost from anywhere in Europe.

  17. Sex identification of Nigerian indigenous chicks using Auto-sexing ...

    African Journals Online (AJOL)

    Sexing has been a challenging task in Nigerian indigenous chickens due to the monomorphism of chicks which makes it impossible to distinguish the male from the female until eight weeks. . Therefore, this study was carried out to determine the sex of Nigerian indigenous chicks using the common auto-sexing methods.

  18. Two new loci and gene sets related to sex determination and cancer progression are associated with susceptibility to testicular germ cell tumor.

    Science.gov (United States)

    Kristiansen, Wenche; Karlsson, Robert; Rounge, Trine B; Whitington, Thomas; Andreassen, Bettina K; Magnusson, Patrik K; Fosså, Sophie D; Adami, Hans-Olov; Turnbull, Clare; Haugen, Trine B; Grotmol, Tom; Wiklund, Fredrik

    2015-07-15

    Genome-wide association (GWA) studies have reported 19 distinct susceptibility loci for testicular germ cell tumor (TGCT). A GWA study for TGCT was performed by genotyping 610 240 single-nucleotide polymorphisms (SNPs) in 1326 cases and 6687 controls from Sweden and Norway. No novel genome-wide significant associations were observed in this discovery stage. We put forward 27 SNPs from 15 novel regions and 12 SNPs previously reported, for replication in 710 case-parent triads and 289 cases and 290 controls. Predefined biological pathways and processes, in addition to a custom-built sex-determination gene set, were subject to enrichment analyses using Meta-Analysis Gene Set Enrichment of Variant Associations (M) and Improved Gene Set Enrichment Analysis for Genome-wide Association Study (I). In the combined meta-analysis, we observed genome-wide significant association for rs7501939 on chromosome 17q12 (OR = 0.78, 95% CI = 0.72-0.84, P = 1.1 × 10(-9)) and rs2195987 on chromosome 19p12 (OR = 0.76, 95% CI: 0.69-0.84, P = 3.2 × 10(-8)). The marker rs7501939 on chromosome 17q12 is located in an intron of the HNF1B gene, encoding a member of the homeodomain-containing superfamily of transcription factors. The sex-determination gene set (false discovery rate, FDRM cancer and apoptosis, was associated with TGCT (FDR utero are implicated in the development of TGCT. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Sex Education

    Directory of Open Access Journals (Sweden)

    R N Srivastava

    1994-06-01

    Full Text Available Sex, though not everything in life, is a profoundly important aspect of human existence. It has evolved to serve more than reproductive functions; relational and recreational functions having taken precedence over procrea­tional. Sex has come to play a much wider socio-psychological function. Human sexuality is complex and multidimensional. It is subject to influence by multitude of factors often grouped as biological (e.g. genes, hormones, psychological (e.g. fear, anxiety, mood and socio-cultural (e.g. sex roles, values- religious/moral/ethical, customs. It is the interaction and interrelationship of these factors from the time of conception, through intrauterine life, infancy, childhood and adolescence, till adulthood (even later in life that determine the sexual development expressed as sexual attitudes and behaviour of the people. Learning, both social and cognitive, plays a significantly important role in such development. Sexual dysfunctions in men and women, result from factors often categorised as physical or organic and psychological; more often a combination may be involved. Experience has shown that in majority of men and women in India having sexual problems, ignorance misconceptions and prevailing myths are invariably responsible in the causation of Ihese problems. Sexual problems in individual man (e.g. erectile failure and woman (e.g. vaginismus cause anxiety, feelings of frustration, lowered self esteem and symptoms of depression. The condition may also affect the spouse; he/she, as a reaction to the problem in the partner, may develop sexual and psychosocial problems including distressed marital relationship. This may also have influence on general couple relationship, effecting adversely the quality of family life. Modern therapeutic endevours have made it possible now to offer effective therapy to most people who seek help for their sexual problems, thus preventing the consequences on couple relationship. However, there is

  20. SEX EDUCATION

    Directory of Open Access Journals (Sweden)

    R N Srivastava

    1994-06-01

    Full Text Available Sex, though not everything in life, is a profoundly important aspect of human existence. It has evolved to serve more than reproductive functions; relational and recreational functions having taken precedence over procrea­tional. Sex has come to play a much wider socio-psychological function.Human sexuality is complex and multidimensional. It is subject to influence by multitude of factors often grouped as biological (e.g. genes, hormones, psychological (e.g. fear, anxiety, mood and socio-cultural (e.g. sex roles, values- religious/moral/ethical, customs. It is the interaction and interrelationship of these factors from the time of conception, through intrauterine life, infancy, childhood and adolescence, till adulthood (even later in life that determine the sexual development expressed as sexual attitudes and behaviour of the people. Learning, both social and cognitive, plays a significantly important role in such development.Sexual dysfunctions in men and women, result from factors often categorised as physical or organic and psychological; more often a combination may be involved. Experience has shown that in majority of men and women in India having sexual problems, ignorance misconceptions and prevailing myths are invariably responsible in the causation of Ihese problems. Sexual problems in individual man (e.g. erectile failure and woman (e.g. vaginismus cause anxiety, feelings of frustration, lowered self esteem and symptoms of depression. The condition may also affect the spouse; he/she, as a reaction to the problem in the partner, may develop sexual and psychosocial problems including distressed marital relationship. This may also have influence on general couple relationship, effecting adversely the quality of family life.Modern therapeutic endevours have made it possible now to offer effective therapy to most people who seek help for their sexual problems, thus preventing the consequences on couple relationship. However, there is also

  1. Muscle areas of lower limbs were determined by anthropometric and computed tomography in the adult of the masculine sex

    International Nuclear Information System (INIS)

    Fernandez Vieitez, Jorge Alberto; Alvarez Cuesta, Jose Alberto; Williams Wilson, Luis

    2000-01-01

    In a sample of 17 males (age 26 + - 5 years; weight 76.3 + - 7.1 kg and height 177.2 + - 3.9 cm) the differences, ratios and interchangeability among muscle areas (cm 2 ) of lower limbs (medial thigh and maximum leg) were determined by anthropometric (muscle area= [limb circumference (cm)- 0.31416 skinfold (mm)]2 /12.5664 and computed tomography. The anthropometric method overestimated muscle areas in both regions (thigh + 9.0 + - 12.8; p= 0.01 and leg: +8.5 + - 11.2; p=0.006). Relation between the two procedures was statistically significant (thigh r=0.9; p= 8.8 .10-7 and leg r=0.52; p=0.03). Both methods were interchangeable since neither the correlation coefficient (thigh r=0.42; leg r=0.38) nor the regression gradient (thigh b 0 .21 + - 0.12; leg b = -0.44 + - 0.28) between the differences (anthropometric ? TAC) and the averages (anthropometric + TAC/ 2) in both methods were statistically significant (p>0.05). It was concluded that the anthropometric method requires certain adjustments to be able to estimate more accurately the muscle areas of lower limbs

  2. Social, psychological, and environmental-structural factors determine consistent condom use among rural-to-urban migrant female sex workers in Shanghai China

    Directory of Open Access Journals (Sweden)

    Ye Xiuxia

    2012-08-01

    Full Text Available Abstract Background To determine potential social, psychological, and environmental-structural factors that may result in motivating female sex workers (FSWs, who are rural-to-urban migrants, and their paying partners in Shanghai, China to promote consistent condom use (CCU. Methods A cross-sectional study was conducted in five districts of Shanghai, including three suburbs and two downtown locales. We adopted a cluster randomized sampling method to obtain 20 geographic sites, which consisted of 1 or more communities/villages proximal to a location where FSWs were accessible. Five hundred four FSWs from 132 Xitou Fang (shampoo wash rooms, massage parlors, and hair salons who explicitly provided sexual services were enrolled in the study. Each participant completed a questionnaire survey and interview aimed to collect information on the perceptions and behaviors of individuals associated with a risk for human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS,self-efficacy at negotiating safe sex,and the physical, social, and policy environment of the establishments where they worked. Results The percentage of FSWs who reported consistent condom use with their paying partners was 63.3%. Controlling for socio-demographic characteristics in multivariate analyses, environmental-structural support (OR, 3.96; CI, 2.52–6.22 for condom use was the most significant positive predictor of CCU among FSWs and their regular paying partners. A high perception of susceptibility and risk of HIV/AIDS (OR, 1.96; CI, 1.25–3.01, a high perception of benefits on condom use to protect themselves (OR, 2.06; CI, 1.32–3.22, and high safe sex self-efficacy (OR, 2.52; CI, 1.64–3.85 also play important roles on CCU based on multivariate analyses. Conclusions Environmental-structural factor support for condom use, in addition to social, psychological, and individual cognitive factors are significant predictors of CCU among FSWs, which should be

  3. Sex ratios

    OpenAIRE

    West, Stuart A; Reece, S E; Sheldon, Ben C

    2002-01-01

    Sex ratio theory attempts to explain variation at all levels (species, population, individual, brood) in the proportion of offspring that are male (the sex ratio). In many cases this work has been extremely successful, providing qualitative and even quantitative explanations of sex ratio variation. However, this is not always the situation, and one of the greatest remaining problems is explaining broad taxonomic patterns. Specifically, why do different organisms show so ...

  4. Sex reversal of brook trout (Salvelinus fontinalis) by 17α-methyltestosterone exposure: A serial experimental approach to determine optimal timing and delivery regimes.

    Science.gov (United States)

    Fatima, Shafaq; Adams, Mark; Wilkinson, Ryan

    2016-12-01

    Commercial culture of Brook trout (Salvelinus fontinalis) in Tasmania was partly abandoned due to sexual maturation of male fish early on during the estuarine rearing phase. Maturation adversely affects body mass, flesh quality and immunocompetency effectively. Sex reversal techniques such as the in-feed addition of a synthetic androgen have proven difficult to adapt in brook trout. An appropriate timing, duration and delivery vehicle for administration of 17α-methyltestosterone (MT) to produce phenotypic males (neomales) from genotypically female brook trout required further investigation. In this study, groups of brook trout eggs (n=1000) maintained at 9.5±0.15-10±0.14°C, were immersed in MT (400μgL -1 ) for four hours on two alternate days (two immersions/group) staggered over a two week period surrounding the hatch of embryos (control groups excluded). The groups were then split and half received MT-supplemented feed for 60days and the other a standard diet. Following an 11 month on-growing period sex phenotypes were determined by gross & histological gonad morphology. The highest proportion of male phenotypes (75%) was found in fish immersed six and four days pre-hatch and subsequently fed a normal diet. Fish fed a MT supplemented diet and immersed in MT showed significantly higher proportions of sterile fish. These data indicate that a pre-hatch immersion-only regime (4-6days pre-hatch at 9.5°C) should be pursued as a target for optimization studies to further refine the effective concentration and duration of exposure to MT for the successful production of neo-male brook trout. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. 70-kDa Heat Shock Cognate Protein hsc70 Mediates Calmodulin-dependent Nuclear Import of the Sex-determining Factor SRY*

    Science.gov (United States)

    Kaur, Gurpreet; Lieu, Kim G.; Jans, David A.

    2013-01-01

    We recently showed that the developmentally important family of SOX (SRY (sex determining region on the Y chromosome)-related high mobility group (HMG) box) proteins require the calcium-binding protein calmodulin (CaM) for optimal nuclear accumulation, with clinical mutations in SRY that specifically impair nuclear accumulation via this pathway resulting in XY sex reversal. However, the mechanism by which CaM facilitates nuclear accumulation is unknown. Here, we show, for the first time, that the 70-kDa heat shock cognate protein hsc70 plays a key role in CaM-dependent nuclear import of SRY. Using a reconstituted nuclear import assay, we show that antibodies to hsc70 significantly reduce nuclear accumulation of wild type SRY and mutant derivatives thereof that retain CaM-dependent nuclear import, with an increased rate of nuclear accumulation upon addition of both CaM and hsc70, in contrast to an SRY mutant derivative with impaired CaM binding. siRNA knockdown of hsc70 in intact cells showed similar results, indicating clear dependence upon hsc70 for CaM-dependent nuclear import. Analysis using the technique of fluorescence recovery after photobleaching indicated that hsc70 is required for the maximal rate of SRY nuclear import in living cells but has no impact upon SRY nuclear retention/nuclear dynamics. Finally, we demonstrate direct binding of hsc70 to the SRY·CaM complex, with immunoprecipitation experiments from cell extracts showing association of hsc70 with wild type SRY, but not with a mutant derivative with impaired CaM binding, dependent on Ca2+. Our novel findings strongly implicate hsc70 in CaM-dependent nuclear import of SRY. PMID:23235156

  6. Frequency and determinants of consistent STI/HIV testing among men who have sex with men testing at STI outpatient clinics in the Netherlands: a longitudinal study.

    Science.gov (United States)

    Visser, Maartje; Heijne, Janneke C M; Hogewoning, Arjan A; van Aar, Fleur

    2017-09-01

    Men who have sex with men (MSM) are at highest risk for STIs and HIV infections in the Netherlands. However, official guidelines on STI testing among MSM are lacking. They are advised to test for STIs at least every six months, but their testing behaviour is not well known. This study aimed to get insight into the proportion and determinants of consistent 6-monthly STI testing among MSM testing at STI outpatient clinics in the Netherlands. This study included longitudinal surveillance data of STI consultations among MSM from all 26 STI outpatient clinics in the Netherlands between 1 June 2014 and 31 December 2015. Multinomial logistic regression analysis was used to identify determinants of consistent 6-monthly testing compared with single testing and inconsistent testing. Determinants of time between consultations among men with multiple consultations were analysed using a Cox Prentice-Williams-Peterson gap-time model. A total of 34 605 STI consultations of 18 634 MSM were included. 8966 (48.1%) men had more than one consultation, and 3516 (18.9%) men tested consistently 6-monthly. Indicators of high sexual risk behaviour, including having a history of STI, being HIV positive and having more than 10 sex partners, were positively associated with both being a consistent tester and returning to the STI clinic sooner. Men who were notified by a partner or who reported STI symptoms were also more likely to return to the STI clinic sooner, but were less likely to be consistent testers, identifying a group of event-driven testers. The proportion of consistent 6-monthly testers among MSM visiting Dutch STI outpatient clinics was low. Testing behaviour was associated with sexual risk behaviour, but exact motives to test consistently remain unclear. Evidence-based testing guidelines are needed to achieve optimal reductions in STI transmission in the future. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence

  7. Mapping lexical-semantic networks and determining hemispheric language dominance: Do task design, sex, age, and language performance make a difference?

    Science.gov (United States)

    Chang, Yu-Hsuan A; Javadi, Sogol S; Bahrami, Naeim; Uttarwar, Vedang S; Reyes, Anny; McDonald, Carrie R

    2018-04-01

    Blocked and event-related fMRI designs are both commonly used to localize language networks and determine hemispheric dominance in research and clinical settings. We compared activation profiles on a semantic monitoring task using one of the two designs in a total of 43 healthy individual to determine whether task design or subject-specific factors (i.e., age, sex, or language performance) influence activation patterns. We found high concordance between the two designs within core language regions, including the inferior frontal, posterior temporal, and basal temporal region. However, differences emerged within inferior parietal cortex. Subject-specific factors did not influence activation patterns, nor did they interact with task design. These results suggest that despite high concordance within perisylvian regions that are robust to subject-specific factors, methodological differences between blocked and event-related designs may contribute to parietal activations. These findings provide important information for researchers incorporating fMRI results into meta-analytic studies, as well as for clinicians using fMRI to guide pre-surgical planning. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Creating Sex

    DEFF Research Database (Denmark)

    Cahana, Jonathan

    2016-01-01

    Thomas Laqueur’s influential yet controversial study Making Sex has, in many ways, revolutionized our understanding of sexuality in antiquity. Yet, most of Laqueur’s critics and supporters stressed the one-sex body, while the crux of his argument is the primacy of gender. Moreover, a systematic...

  9. The platelet-derived growth factor signaling system in snapping turtle embryos, Chelydra serpentina: potential role in temperature-dependent sex determination and testis development.

    Science.gov (United States)

    Rhen, Turk; Jangula, Adam; Schroeder, Anthony; Woodward-Bosh, Rikki

    2009-05-01

    The platelet-derived growth factor (Pdgf) signaling system is known to play a significant role during embryonic and postnatal development of testes in mammals and birds. In contrast, genes that comprise the Pdgf system in reptiles have never been cloned or studied in any tissue, let alone developing gonads. To explore the potential role of PDGF ligands and their receptors during embryogenesis, we cloned cDNA fragments of Pdgf-A, Pdgf-B, and receptors PdgfR-alpha and PdgfR-beta in the snapping turtle, a reptile with temperature-dependent sex determination (TSD). We then compared gene expression profiles in gonads from embryos incubated at a male-producing temperature to those from embryos at a female-producing temperature, as well as between hatchling testes and ovaries. Expression of Pdgf-B mRNA in embryonic gonads was significantly higher at a male temperature than at a female temperature, but there was no difference between hatchling testes and ovaries. This developmental pattern was reversed for Pdgf-A and PdgfR-alpha mRNA: expression of these genes did not differ in embryos, but diverged in hatchling testes and ovaries. Levels of PdgfR-beta mRNA in embryonic gonads were not affected by temperature and did not differ between testes and ovaries. However, expression of both receptors increased at least an order of magnitude from the embryonic to the post-hatching period. Finally, we characterized expression of these genes in several other embryonic tissues. The brain, heart, and liver displayed unique expression patterns that distinguished these tissues from each other and from intestine, lung, and muscle. Incubation temperature had a significant effect on expression of PdgfR-alpha and PdgfR-beta in the heart but not other tissues. Together, these findings demonstrate that temperature has tissue specific effects on the Pdgf system and suggest that Pdgf signaling is involved in sex determination and the ensuing differentiation of testes in the snapping turtle.

  10. Doing gender in sex and sex research.

    Science.gov (United States)

    Vanwesenbeeck, Ine

    2009-12-01

    Gender is central to sexuality, and vice versa, but there are a number of difficulties with the treatment of gender in sex research. Apparently, it is hard to find a balance between two conflicting needs. First, obviously, it is necessary to make distinctions between women and men, for political as well as research-technical and theoretical reasons. A second requirement, at odds with the first one, is the necessity to understand gender and its relation to sexuality and the body as much more complex than simplistically referring to two sets of individuals. This is all the more necessary when one realizes the possible drawbacks of exaggerating the differences between the sexes (in particular when they are biologically explained), because of stereotyping, stigmatizing, and expectancy confirmatory processes. This essay identifies and discusses 10 difficulties in the treatment of gender in sex research, reflects on their origins, and reviews theory and evidence with the aim to (1) consider the relative strength of gender/sex as an explanatory variable compared to other factors and processes explaining differences between men and women on a number of sexual aspects, (2) inform an understanding of gender and its relation to sexuality as an ongoing, open-ended, multi-determined, situated, interactional process, with the body as a third player, and (3) argue in favor of a nuanced, well-balanced treatment of gender in sex research.

  11. HIV infection and testing among Latino men who have sex with men in the United States: the role of location of birth and other social determinants.

    Directory of Open Access Journals (Sweden)

    Alexandra M Oster

    Full Text Available BACKGROUND: In the United States, Latino men who have sex with men (MSM are disproportionately affected by HIV. Latino MSM are a diverse group who differ culturally based on their countries or regions of birth and their time in the United States. We assessed differences in HIV prevalence and testing among Latino MSM by location of birth, time since arrival, and other social determinants of health. METHODS: For the 2008 National HIV Behavioral Surveillance System, a cross-sectional survey conducted in large US cities, MSM were interviewed and tested for HIV infection. We used generalized estimating equations to test associations between various factors and 1 prevalent HIV infection and 2 being tested for HIV infection in the past 12 months. RESULTS: Among 1734 Latino MSM, HIV prevalence was 19%. In multivariable analysis, increasing age, low income, and gay identity were associated with HIV infection. Moreover, men who were U.S.-born or who arrived ≥5 years ago had significantly higher HIV prevalence than recent immigrants. Among men not reporting a previous positive HIV test, 63% had been tested for HIV infection in the past 12 months; recent testing was most strongly associated with having seen a health care provider and disclosing male-male attraction/sexual behavior to a health care provider. CONCLUSIONS: We identified several social determinants of health associated with HIV infection and testing among Latino MSM. Lower HIV prevalence among recent immigrants contrasts with higher prevalence among established immigrants and suggests a critical window of opportunity for HIV prevention, which should prioritize those with low income, who are at particular risk for HIV infection. Expanding health care utilization and encouraging communication with health care providers about sexual orientation may increase testing.

  12. Determination of bone mineral content (BMC) by dual photon absorptiometry: Age-, sex-, and menopause-related changes in Bavaria and effect of estrogen replacement in early postmenopausal women

    International Nuclear Information System (INIS)

    Buttermann, G.; Eiber, J.; Henning, J.; Utz, G.; Scheffel, H.; Pabst, H.W.

    1988-01-01

    Cortical (neck of femur) and trabecular bone mass (L2-4) have been determined repeatedly with DPA using GD 153 (NOVO Lab 22 a) in 545 female and 112 male pts with no evidence of bone diseases. Measured 'normal', (age- and sex-related average) BMC values differed significantly from those of US people determined by same equipment, i.e., were in average about 30% lower, but matched well with corresponding results from Belgium. BMC-area was found the most suitable parameter both for cross-sectional and longitudinal studies, since BMC-area is independent from height and weight. But there is still need to reduce the overlap and improve accuracy and reproducibility for making decisions after shorter intervals. Assessment of the individual mineral loss and fracture risk by comparing to average values, however, remains problematic due to the wide range of 'normal' BMC and in women additionally due to the variable onset of menopause. For estimations of the individual fracture risk of elderly pts BMC should not be normalized on age, because at the age of 65 half of the women had 'pathologic' values, i.e. were below the so called 'osteoporosis threshold'. Comparison of the individually measured postmenopausal BMC to average values of premenopausal women and to BMC values normalized to their menopausal age may be helpful approaches for overcoming these difficulties. Because of the lack of earlier individual data in most cases repeated BMC measurements are still required for assessment of demineralization speed. Preliminary results of estrogen replacement therapy with low doses of natural conjugated estrogen show good prevention of bone loss in healthy but not in ovarectomized women. (orig./MG)

  13. Determinants of differences in the activity budgets of Rhinopithecus bieti by age/sex class at Xiangguqing in the Baimaxueshan nature reserve, China

    Directory of Open Access Journals (Sweden)

    Li Yanhong

    2015-01-01

    Full Text Available Ecological factors are known to influence the activity budgets of Yunnan snub-nosed monkeys (Rhinopithecus bieti. However, little is known about how activity budgets vary between age/sex classes, because the species is difficult to observe in the wild. This study provides the first detailed activity budgets subdivided by age/sex classes based on observations of the largest habituated group at Xiangguqing in Baimaxueshan Nature Reserve. This study was conducted from June 2008 to May 2009. We found that adult females spent more time feeding (44.8% than adult males (39.5%, juveniles (39.1%, and infants (14.2%. Adult males allocated more time to miscellaneous activities (12.5% than did adult females (3.8%. Infants were being groomed 6.9% of the time, which was the highest proportion among all age/sex classes. Adults spent more time feeding, while immature individuals allocated more time to moving and other activities. There are several reasons activity budgets may vary by age/sex class: 1 differential reproductive investment between males and females; 2 developmental differences among the age categories; 3 social relationships between members of different age/sex classes, particularly dominance. In addition, group size and adult sex ratio may also impact activity budgets. These variations in activity budgets among the different age/sex classes may become a selective pressure that shapes the development and growth pattern in this species.

  14. Adrenal-kidney-gonad complex measurements may not predict gonad-specific changes in gene expression patterns during temperature-dependent sex determination in the red-eared slider turtle (Trachemys scripta elegans).

    Science.gov (United States)

    Ramsey, Mary; Crews, David

    2007-08-01

    Many turtles, including the red-eared slider turtle (Trachemys scripta elegans) have temperature-dependent sex determination in which gonadal sex is determined by temperature during the middle third of incubation. The gonad develops as part of a heterogenous tissue complex that comprises the developing adrenal, kidney, and gonad (AKG complex). Owing to the difficulty in excising the gonad from the adjacent tissues, the AKG complex is often used as tissue source in assays examining gene expression in the developing gonad. However, the gonad is a relatively small component of the AKG, and gene expression in the adrenal-kidney (AK) compartment may interfere with the detection of gonad-specific changes in gene expression, particularly during early key phases of gonadal development and sex determination. In this study, we examine transcript levels as measured by quantitative real-time polymerase chain reaction for five genes important in slider turtle sex determination and differentiation (AR, ERalpha, ERbeta, aromatase, and Sf1) in AKG, AK, and isolated gonad tissues. In all cases, gonad-specific gene expression patterns were attenuated in AKG versus gonad tissue. All five genes were expressed in the AK in addition to the gonad at all stages/temperatures. Inclusion of the AK compartment masked important changes in gonadal gene expression. In addition, AK and gonad expression patterns are not additive, and gonadal gene expression cannot be predicted from intact AKG measurements. (c) 2007 Wiley-Liss, Inc.

  15. Oral sex.

    Science.gov (United States)

    1996-04-05

    The Gay and Lesbian Medical Association urges HIV prevention specialists to regard male-to-male oral-genital sex as a low-risk activity and concentrate instead on the danger of unprotected anal intercourse. According to the association, the confusion and mixed messages surrounding oral sex are harming efforts to encourage gay men to make rational choices about truly risky behavior. The recommendations appear in the association's position paper issued March 19, 1996.

  16. Why Sex?

    DEFF Research Database (Denmark)

    Nielsen, Rasmus

    2006-01-01

    It is assumed that most organisms have sex because the resulting genetic recombination allows Darwinian selection to work better. It is now shown that in water fleas, recombination does lead to fewer deleterious mutations.......It is assumed that most organisms have sex because the resulting genetic recombination allows Darwinian selection to work better. It is now shown that in water fleas, recombination does lead to fewer deleterious mutations....

  17. Structural determinants of inconsistent condom use with clients among migrant sex workers: findings of longitudinal research in an urban canadian setting.

    Science.gov (United States)

    Sou, Julie; Shannon, Kate; Li, Jane; Nguyen, Paul; Strathdee, Steffanie A; Shoveller, Jean; Goldenberg, Shira M

    2015-06-01

    Migrant women in sex work experience unique risks and protective factors related to their sexual health. Given the dearth of knowledge in high-income countries, we explored factors associated with inconsistent condom use by clients among migrant female sex workers over time in Vancouver, BC. Questionnaire and HIV/sexually transmitted infection testing data from a longitudinal cohort, An Evaluation of Sex Workers Health Access, were collected from 2010 to 2013. Logistic regression using generalized estimating equations was used to model correlates of inconsistent condom use by clients among international migrant sex workers over a 3-year study period. Of 685 participants, analyses were restricted to 182 (27%) international migrants who primarily originated from China. In multivariate generalized estimating equations analyses, difficulty accessing condoms (adjusted odds ratio [AOR], 3.76; 95% confidence interval [CI], 1.13-12.47) independently correlated with increased odds of inconsistent condom use by clients. Servicing clients in indoor sex work establishments (e.g., massage parlors) (AOR, 0.34; 95% CI, 0.15-0.77), and high school attainment (AOR, 0.22; 95% CI, 0.09-0.50) had independent protective effects on the odds of inconsistent condom use by clients. Findings of this longitudinal study highlight the persistent challenges faced by migrant sex workers in terms of accessing and using condoms. Migrant sex workers who experienced difficulty in accessing condoms were more than 3 times as likely to report inconsistent condom use by clients. Laws, policies, and programs promoting access to safer, decriminalized indoor work environments remain urgently needed to promote health, safety, and human rights for migrant workers in the sex industry.

  18. Same Sex Marriage and the Perceived Assault on Opposite Sex Marriage

    OpenAIRE

    Dinno, Alexis; Whitney, Chelsea

    2013-01-01

    BACKGROUND: Marriage benefits both individuals and societies, and is a fundamental determinant of health. Until recently same sex couples have been excluded from legally recognized marriage in the United States. Recent debate around legalization of same sex marriage has highlighted for anti-same sex marriage advocates and policy makers a concern that allowing same sex couples to marry will lead to a decrease in opposite sex marriages. Our objective is to model state trends in opposite sex mar...

  19. The many costs of sex.

    Science.gov (United States)

    Lehtonen, Jussi; Jennions, Michael D; Kokko, Hanna

    2012-03-01

    Explaining the evolution of sex is challenging for biologists. A 'twofold cost' compared with asexual reproduction is often quoted. If a cost of this magnitude exists, the benefits of sex must be large for it to have evolved and be maintained. Focusing on benefits can be misleading, as this sidelines important questions about the cost of sex: what is the source of the twofold cost: males, genome dilution or both? Does the cost deviate from twofold? What other factors make sex costly? How should the costs of sex be empirically measured? The total cost of sex and how it varies in different contexts must be known to determine the benefits needed to account for the origin and maintenance of sex. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Sex Differences in HIV Infection.

    Science.gov (United States)

    Scully, Eileen P

    2018-04-01

    This review will outline the multilevel effects of biological sex on HIV acquisition, pathogenesis, treatment response, and prospects for cure. Potential mechanisms will be discussed along with future research directions. HIV acquisition risk is modified by sex hormones and the vaginal microbiome, with the latter acting through both inflammation and local metabolism of pre-exposure prophylaxis drugs. Female sex associates with enhanced risk for non-AIDS morbidities including cardiovascular and cerebrovascular disease, suggesting different inflammatory profiles in men and women. Data from research on HIV cure points to sex differences in viral reservoir dynamics and a direct role for sex hormones in latency maintenance. Biological sex remains an important variable in determining the risk of HIV infection and subsequent viral pathogenesis, and emerging data suggest sex differences relevant to curative interventions. Recruitment of women in HIV clinical research is a pathway to both optimize care for women and to identify novel therapeutics for use in both men and women.

  1. Effect of hormonal manipulation on sociosexual behavior in adult female leopard geckos (Eublepharis macularius), a species with temperature-dependent sex determination.

    Science.gov (United States)

    Flores, D L; Crews, D

    1995-12-01

    Aggressive and sexual behavior in the adult leopard gecko (Eublepharis macularius), a species with temperature-dependent sex determination (TSD), is influenced by the temperature experienced as an egg, as well as by prenatal and perinatal hormones. This study focused on the effects of hormonal manipulation of adult female leopard geckos from different incubation temperatures. Following ovariectomy, females from both all-female (26 degrees C) and male-biased (32.5 degrees C) incubation temperatures exhibited a significant decrease in high-posture (HP) aggression toward male and female stimulus animals. Testosterone treatment attenuated this decrease in HP aggression toward female but not toward male stimulus animals. Ovariectomy also resulted in a loss in attractiveness in both groups of females. Following treatment with testosterone, over 50% of the females were attacked by male stimulus animals, suggesting a change in the pheromonal cues normally secreted by females. Unmanipulated females never exhibit tail vibrations, a male-typical courtship behavior. However, following ovariectomy with testosterone treatment, half of the females from both incubation temperatures exhibited this behavior, indicating an activational effect of testosterone. An effect of incubation temperature on aggression was evident with females from the male-biased incubation temperature exhibiting a greater likelihood of aggression compared to females from the all-female incubation temperature. This effect continued to be detected after hormone manipulation. Ovariectomized females from the all-female incubation temperature were less aggressive even with testosterone treatment toward males, whereas females from the male-biased incubation temperature showed no significant decline in aggression following testosterone treatment, suggesting that individuals from different incubation temperatures may have different sensitivities to hormones.

  2. Lower Activation in Frontal Cortex and Posterior Cingulate Cortex Observed during Sex Determination Test in Early-Stage Dementia of the Alzheimer Type

    Directory of Open Access Journals (Sweden)

    Ravi Rajmohan

    2017-05-01

    Full Text Available Face-labeling refers to the ability to classify faces into social categories. This plays a critical role in human interaction as it serves to define concepts of socially acceptable interpersonal behavior. The purpose of the current study was to characterize, what, if any, impairments in face-labeling are detectable in participants with early-stage clinically diagnosed dementia of the Alzheimer type (CDDAT through the use of the sex determination test (SDT. In the current study, four (1 female, 3 males CDDAT and nine (4 females, 5 males age-matched neurotypicals (NT completed the SDT using chimeric faces while undergoing BOLD fMRI. It was expected that CDDAT participants would have poor verbal fluency, which would correspond to poor performance on the SDT. This could be explained by decreased activation and connectivity patterns within the fusiform face area (FFA and anterior cingulate cortex (ACC. DTI was also performed to test the association of pathological deterioration of connectivity in the uncinate fasciculus (UF and verbally-mediated performance. CDDAT showed lower verbal fluency test (VFT performance, but VFT was not significantly correlated to SDT and no significant difference was seen between CDDAT and NT for SDT performance as half of the CDDAT performed substantially worse than NT while the other half performed similarly. BOLD fMRI of SDT displayed differences in the left superior frontal gyrus and posterior cingulate cortex (PCC, but not the FFA or ACC. Furthermore, although DTI showed deterioration of the right inferior and superior longitudinal fasciculi, as well as the PCC, it did not demonstrate significant deterioration of UF tracts. Taken together, early-stage CDDAT may represent a common emerging point for the loss of face labeling ability.

  3. Lower Activation in Frontal Cortex and Posterior Cingulate Cortex Observed during Sex Determination Test in Early-Stage Dementia of the Alzheimer Type.

    Science.gov (United States)

    Rajmohan, Ravi; Anderson, Ronald C; Fang, Dan; Meyer, Austin G; Laengvejkal, Pavis; Julayanont, Parunyou; Hannabas, Greg; Linton, Kitten; Culberson, John; Khan, Hafiz; De Toledo, John; Reddy, P Hemachandra; O'Boyle, Michael W

    2017-01-01

    Face-labeling refers to the ability to classify faces into social categories. This plays a critical role in human interaction as it serves to define concepts of socially acceptable interpersonal behavior. The purpose of the current study was to characterize, what, if any, impairments in face-labeling are detectable in participants with early-stage clinically diagnosed dementia of the Alzheimer type (CDDAT) through the use of the sex determination test (SDT). In the current study, four (1 female, 3 males) CDDAT and nine (4 females, 5 males) age-matched neurotypicals (NT) completed the SDT using chimeric faces while undergoing BOLD fMRI. It was expected that CDDAT participants would have poor verbal fluency, which would correspond to poor performance on the SDT. This could be explained by decreased activation and connectivity patterns within the fusiform face area (FFA) and anterior cingulate cortex (ACC). DTI was also performed to test the association of pathological deterioration of connectivity in the uncinate fasciculus (UF) and verbally-mediated performance. CDDAT showed lower verbal fluency test (VFT) performance, but VFT was not significantly correlated to SDT and no significant difference was seen between CDDAT and NT for SDT performance as half of the CDDAT performed substantially worse than NT while the other half performed similarly. BOLD fMRI of SDT displayed differences in the left superior frontal gyrus and posterior cingulate cortex (PCC), but not the FFA or ACC. Furthermore, although DTI showed deterioration of the right inferior and superior longitudinal fasciculi, as well as the PCC, it did not demonstrate significant deterioration of UF tracts. Taken together, early-stage CDDAT may represent a common emerging point for the loss of face labeling ability.

  4. Gene conversion and DNA sequence polymorphism in the sex-determination gene fog-2 and its paralog ftr-1 in Caenorhabditis elegans.

    Science.gov (United States)

    Rane, Hallie S; Smith, Jessica M; Bergthorsson, Ulfar; Katju, Vaishali

    2010-07-01

    Gene conversion, a form of concerted evolution, bears enormous potential to shape the trajectory of sequence and functional divergence of gene paralogs subsequent to duplication events. fog-2, a sex-determination gene unique to Caenorhabditis elegans and implicated in the origin of hermaphroditism in this species, resulted from the duplication of ftr-1, an upstream gene of unknown function. Synonymous sequence divergence in regions of fog-2 and ftr-1 (excluding recent gene conversion tracts) suggests that the duplication occurred 46 million generations ago. Gene conversion between fog-2 and ftr-1 was previously discovered in experimental fog-2 knockout lines of C. elegans, whereby hermaphroditism was restored in mutant obligately outcrossing male-female populations. We analyzed DNA-sequence variation in fog-2 and ftr-1 within 40 isolates of C. elegans from diverse geographic locations in order to evaluate the contribution of gene conversion to genetic variation in the two gene paralogs. The analysis shows that gene conversion contributes significantly to DNA-sequence diversity in fog-2 and ftr-1 (22% and 34%, respectively) and may have the potential to alter sexual phenotypes in natural populations. A radical amino acid change in a conserved region of the F-box domain of fog-2 was found in natural isolates of C. elegans with significantly lower fecundity. We hypothesize that the lowered fecundity is due to reduced masculinization and less sperm production and that amino acid replacement substitutions and gene conversion in fog-2 may contribute significantly to variation in the degree of inbreeding and outcrossing in natural populations.

  5. Social determinants of sex differences in disability among older adults: a multi-country decomposition analysis using the World Health Survey

    Directory of Open Access Journals (Sweden)

    Hosseinpoor Ahmad

    2012-09-01

    Full Text Available Abstract Introduction Women represent a growing proportion of older people and experience increasing disability in their longer lives. Using a universally agreed definition of disability based on the International Classification of Functioning, Disability and Health, this paper examines how, apart from age, social and economic factors contribute to disability differences between older men and women. Methods World Health Survey data were analyzed from 57 countries drawn from all income groups defined by the World Bank. The final sample comprises 63638 respondents aged 50 and older (28568 males and 35070 females. Item Response Theory was applied to derive a measure of disability which ensured cross country comparability. Individuals with scores at or above a threshold score were those who experienced significant difficulty in their everyday lives, irrespective of the underlying etiology. The population was then divided into “disabled” vs. “not disabled”. We firstly computed disability prevalence for males and females by socio-demographic factors, secondly used multiple logistic regression to estimate the adjusted effects of each social determinant on disability for males and females, and thirdly used a variant of the Blinder-Oaxaca decomposition technique to partition the measured inequality in disability between males and females into the “explained” part that arises because of differences between males and females in terms of age and social and economic characteristics, and an “unexplained” part attributed to the differential effects of these characteristics. Results Prevalence of disability among women compared with men aged 50+ years was 40.1% vs. 23.8%. Lower levels of education and economic status are associated with disability in women and men. Approximately 45% of the sex inequality in disability can be attributed to differences in the distribution of socio-demographic factors. Approximately 55% of the inequality results

  6. Curious Sex Ratios and Cytoplasmic Genes

    Indian Academy of Sciences (India)

    instances of curious sex ratios exemplify an important principle: the fitness ..... markable transition - the whole means of sex determination has changed. No longer ... to the cytoplasmic symbiont is self-evident; the symbionts simply increase the.

  7. Sex selection: treating different cases differently.

    Science.gov (United States)

    Dickens, B M; Serour, G I; Cook, R J; Qiu, R-Z

    2005-08-01

    This paper contrasts ethical approaches to sex selection in countries where discrimination against women is pervasive, resulting in selection against girl children, and in countries where there is less general discrimination and couples do not prefer children of either sex. National sex ratio imbalances where discrimination against women is common have resulted in laws and policies, such as in India and China, to deter and prevent sex selection. Birth ratios of children can be affected by techniques of prenatal sex determination and abortion, preconception sex selection and discarding disfavored embryos, and prefertilization sperm sorting, when disfavored sperm remain unused. Incentives for son preference are reviewed, and laws and policies to prevent sex selection are explained. The elimination of social, economic and other discrimination against women is urged to redress sex selection against girl children. Where there is no general selection against girl children, sex selection can be allowed to assist families that want children of both sexes.

  8. Demographic and Behavioral Determinants of Self-Reported History of Sexually-Transmitted Diseases (STDs) among Young Migrant Men Who Have Sex with Men (MSM) in Beijing, China

    Science.gov (United States)

    Song, Yan; Li, Xiaoming; Zhang, Liying; Liu, Yingjie; Jiang, Shulin; Stanton, Bonita

    2012-01-01

    Background: Sexually-transmitted disease (STD) is a facilitating cofactor that contributes to human immunodeficiency virus (HIV) transmission. Previous studies indicated a high prevalence of STDs among men who have sex with men (MSM) in China. To date, limited data are available for correlates of STD infection among young migrant MSM in China. The…

  9. Yes-associated protein and WW-containing transcription regulator 1 regulate the expression of sex-determining genes in Sertoli cells, but their inactivation does not cause sex reversal.

    Science.gov (United States)

    Levasseur, Adrien; Paquet, Marilène; Boerboom, Derek; Boyer, Alexandre

    2017-07-01

    Yes-associated protein (YAP) and WW-containing transcription regulator 1 (WWTR1) are two functionally redundant transcriptional regulators that are downstream effectors of the Hippo signaling pathway, and that act as major regulators of cell growth and differentiation. To elucidate their role in Sertoli cells, primary Sertoli cell culture from Yapflox/flox; Wwtr1flox/flox animals were infected with a Cre recombinase-expressing adenovirus. Concomitant inactivation of Yap and Wwtr1 resulted in a decrease in the mRNA levels of the male sex differentiation genes Dhh, Dmrt1, Sox9, and Wt1, whereas those of genes involved in female differentiation (Wnt4, Rspo1, and Foxl2) were induced. SOX9, FOXL2, and WNT4 proteins were regulated in the same manner as their mRNAs in response to loss of YAP and WWTR1. To further characterize the role of YAP and WWTR1 in Sertoli cells, we generated a mouse model (Yapflox/flox; Wwtr1flox/flox; Amhcre/+) in which Yap and Wwtr1 were conditionally deleted in Sertoli cells. An increase in the number of apoptotic cells was observed in the seminiferous tubules of 4 dpp mutant mice, leading to a reduction in testis weights and a decrease in the number of Sertoli cells in adult animals. Gene expression analyses of testes from 4 dpp Yapflox/flox; Wwtr1flox/flox; Amhcre/+ mice showed that Sertoli cell differentiation is initially altered, as Dhh, Dmrt1, and Sox9 mRNA levels were downregulated, whereas Wnt4 mRNA levels were increased. However, expression of these genes was not changed in older animals. Together, these results suggest a novel role of the Hippo signaling pathway in the mechanisms of sex differentiation. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Teleology and Defining Sex.

    Science.gov (United States)

    Gamble, Nathan K; Pruski, Michal

    2018-07-01

    Disorders of sexual differentiation lead to what is often referred to as an intersex state. This state has medical, as well as some legal, recognition. Nevertheless, the question remains whether intersex persons occupy a state in between maleness and femaleness or whether they are truly men or women. To answer this question, another important conundrum needs to be first solved: what defines sex? The answer seems rather simple to most people, yet when morphology does not coincide with haplotypes, and genetics might not correlate with physiology the issue becomes more complex. This paper tackles both issues by establishing where the essence of sex is located and by superimposing that framework onto the issue of the intersex. This is achieved through giving due consideration to the biology of sexual development, as well as through the use of a teleological framework of the meaning of sex. Using a range of examples, the paper establishes that sex cannot be pinpointed to one biological variable but is rather determined by how the totality of one's biology is oriented towards biological reproduction. A brief consideration is also given to the way this situation could be comprehended from a Christian understanding of sex and suffering.

  11. Sex. Dev.

    OpenAIRE

    Jakubiczka, S.; Schröder, C.; Ullmann, R.; Volleth, M.; Ledig, S.; Gilberg, E.; Kroisel, P.; P. Wieacker, P.

    2010-01-01

    Campomelic dysplasia (MIM 114290) is a severe malformation syndrome frequently accompanied by male-to-female sex reversal. Causative are mutations within the SOX9 gene on 17q24.3 as well as chromosomal aberrations (translocations, inversions or deletions) in the vicinity of SOX9 . Here, we report on a patient with muscular hypotonia, craniofacial dysmorphism, cleft palate, brachydactyly, malformations of thoracic spine, and gonadal dysgenesis with female external genitalia and müllerian duct ...

  12. Stress and sex: does cortisol mediate sex change in fish?

    Science.gov (United States)

    Goikoetxea, Alexander; Todd, Erica V; Gemmell, Neil J

    2017-12-01

    Cortisol is the main glucocorticoid (GC) in fish and the hormone most directly associated with stress. Recent research suggests that this hormone may act as a key factor linking social environmental stimuli and the onset of sex change by initiating a shift in steroidogenesis from estrogens to androgens. For many teleost fish, sex change occurs as a usual part of the life cycle. Changing sex is known to enhance the lifetime reproductive success of these fish and the modifications involved (behavioral, gonadal and morphological) are well studied. However, the exact mechanism behind the transduction of the environmental signals into the molecular cascade that underlies this singular process remains largely unknown. We here synthesize current knowledge regarding the role of cortisol in teleost sex change with a focus on two well-described transformations: temperature-induced masculinization and socially regulated sex change. Three non-mutually exclusive pathways are considered when describing the potential role of cortisol in mediating teleost sex change: cross-talk between GC and androgen pathways, inhibition of aromatase expression and upregulation of amh (the gene encoding anti-Müllerian hormone). We anticipate that understanding the role of cortisol in the initial stages of sex change will further improve our understanding of sex determination and differentiation across vertebrates, and may lead to new tools to control fish sex ratios in aquaculture. © 2017 Society for Reproduction and Fertility.

  13. Sex determination by three-dimensional geometric morphometrics of the vault and midsagittal curve of the neurocranium in a modern Greek population sample.

    Science.gov (United States)

    Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K

    2016-06-01

    The aim of this study is to assess sexual dimorphism of adult crania in the vault and midsagittal curve of the vault using three-dimensional geometric morphometric methods. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived during the 20th century in Greece. The three-dimensional co-ordinates of 31 ecto-cranial landmarks and 30 semi-landmarks were digitized using a MicroScribe 3DX contact digitizer. Generalized Procrustes analysis (GPA) was used to obtain size and shape variables for statistical analysis. Shape, size and form analyses were carried out by logistic regression and three discriminant function analyses. Results indicate that there are shape differences between sexes. Females in the region of the parietal bones are narrower and the axis forming the frontal and occipital bones is more elongated; the frontal bone is more vertical. Sex-specific shape differences give better classification results in the vault (79%) compared with the midsagittal curve of the neurocranium (68.8%). Size alone yielded better results for cranial vault (82%), while for the midsagittal curve of the vault the result is poorer (68.1%). As anticipated, the classification accuracy improves when both size and shape are combined (89.2% for vault, and 79.4% for midsagittal curve of the vault). These latter findings imply that, in contrast to the midsagittal curve of the neurocranium, the shape of the cranial vault can be used as an indicator of sex in the modern Greek population. Copyright © 2016. Published by Elsevier GmbH.

  14. When Sex Is Painful

    Science.gov (United States)

    ... AQ FREQUENTLY ASKED QUESTIONS GYNECOLOGIC PROBLEMS FAQ020 When Sex Is Painful • How common is painful sex? • What causes pain during sex? • Where is pain during sex felt? • When should ...

  15. Sex during Pregnancy

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Sex During Pregnancy KidsHealth / For Parents / Sex During Pregnancy ... satisfying and safe sexual relationship during pregnancy. Is Sex During Pregnancy Safe? Sex is considered safe during ...

  16. Haplodiploid androgenetic breeding in oat: genotypic variation in anther size and microspore development stage Melhoramento por haplodiploidização androgenética: variação genotípica no tamanho das anteras e no estágio de desenvolvimento dos micrósporos em aveia

    Directory of Open Access Journals (Sweden)

    Taniela De Cesaro

    2009-02-01

    Full Text Available Oat (Avena spp. is poorly responsive to the haplodiploidization process, which leads to the production of homozygous lines in one step, increasing breeding efficiency. Androgenetic haploids in small grain cereal crops are obtained from microspores cultured at the mononucleate stage, which can be identified by the size of anthers. In order to identify the appropriate anther size for in vitro culture, microspore cytological analyses were made in Avena sativa cultivars UPF 7, UPF 18, UFRGS 14, Stout and Avena sterilis CAV 3361, cultivated in growth chamber under controlled light and temperature conditions. Variation was observed within and among genotypes for anther size at each microspore developmental stage and according to the position of spikelets in the panicle. Architecture variation in panicle shape and non-linear microsporogenesis maturation increased the challenge of identifying potentially androgenetic oat anthers. Cytological screening before culture is critical in identifying microspores at the right stage for oat androgenesis.A aveia (Avena spp. tem sido pouco responsiva à haplodiploidização, um processo que aumenta a eficiência da seleção no melhoramento por gerar, em uma etapa, linhas puras homozigóticas. A fase mononucleada do micrósporo é critica para o sucesso da androgênese in vitro nos cereais de inverno e, em geral, pode ser inferida pelo tamanho da antera. Foram medidas anteras e analisados citológicamente micrósporos das cultivares de Avena sativa UPF 7, UPF 18, UFRGS 14, Stout e da linhagem CAV 3361 de Avena sterilis, cultivadas em câmaras de crescimento sob temperaturas dia-noite variando de 16ºC a 9ºC e 12 horas de intensidade luminosa de 300 mol m-2 s-1. O tamanho das anteras em cada fase de desenvolvimento dos micrósporos variou significativamente entre genótipos e de acordo com a região de inserção das espiguetas na panícula. A variação na arquitetura da panícula e a maturação não linear das

  17. Analyzing Medical Students' Definitions of Sex

    Science.gov (United States)

    Talley, Heather; Cho, Janice; Strassberg, Donald S.; Rullo, Jordan E.

    2016-01-01

    An inaccurate definition of what constitutes sex can negatively impact the sexual health and wellbeing of patients. This study aimed to determine which behaviors medical students consider to be sex. Survey questions about various sexual behaviors were administered to medical students. All participants agreed that penile-vaginal penetration is sex.…

  18. Relative Importance of Sex, Pre-Starvation Body Mass and Structural Body Size in the Determination of Exceptional Starvation Resistance of Anchomenus dorsalis (Coleoptera: Carabidae.

    Directory of Open Access Journals (Sweden)

    Michal Knapp

    Full Text Available In nature, almost all animals have to cope with periods of food shortage during their lifetimes. Starvation risks are especially high for carnivorous predatory species, which often experience long intervals between stochastic prey capturing events. A laboratory experiment using the common predatory carabid beetle Anchomenus dorsalis revealed an exceptional level of starvation resistance in this species: males survived up to 137 days and females up to 218 days without food at 20°C. Individual starvation resistance was strongly positively affected by pre-starvation body mass but only slightly by beetle structural body size per se. Females outperformed males even when the effect of gender was corrected for the effects of structural body size and pre-starvation body mass. The better performance of females compared to males and of beetles with higher relative pre-starvation body mass could be linked to higher fat content and lean dry mass before starvation, followed by a greater decrease in both during starvation. There was also a difference between the sexes in the extent of body mass changes both during ad libitum feeding and following starvation; the body masses of females fluctuated more compared to males. This study stresses the need to distinguish between body mass and structural body size when investigating the ecological and evolutionary consequences of body size. Investigation of the net effects of body size and sex is necessary to disentangle the causes of differences in individual performances in studies of species with significant sexual size dimorphism.

  19. Determining

    Directory of Open Access Journals (Sweden)

    Bahram Andarzian

    2015-06-01

    Full Text Available Wheat production in the south of Khuzestan, Iran is constrained by heat stress for late sowing dates. For optimization of yield, sowing at the appropriate time to fit the cultivar maturity length and growing season is critical. Crop models could be used to determine optimum sowing window for a locality. The objectives of this study were to evaluate the Cropping System Model (CSM-CERES-Wheat for its ability to simulate growth, development, grain yield of wheat in the tropical regions of Iran, and to study the impact of different sowing dates on wheat performance. The genetic coefficients of cultivar Chamran were calibrated for the CSM-CERES-Wheat model and crop model performance was evaluated with experimental data. Wheat cultivar Chamran was sown on different dates, ranging from 5 November to 9 January during 5 years of field experiments that were conducted in the Khuzestan province, Iran, under full and deficit irrigation conditions. The model was run for 8 sowing dates starting on 25 October and repeated every 10 days until 5 January using long-term historical weather data from the Ahvaz, Behbehan, Dezful and Izeh locations. The seasonal analysis program of DSSAT was used to determine the optimum sowing window for different locations as well. Evaluation with the experimental data showed that performance of the model was reasonable as indicated by fairly accurate simulation of crop phenology, biomass accumulation and grain yield against measured data. The normalized RMSE were 3%, 2%, 11.8%, and 3.4% for anthesis date, maturity date, grain yield and biomass, respectively. Optimum sowing window was different among locations. It was opened and closed on 5 November and 5 December for Ahvaz; 5 November and 15 December for Behbehan and Dezful;and 1 November and 15 December for Izeh, respectively. CERES-Wheat model could be used as a tool to evaluate the effect of sowing date on wheat performance in Khuzestan conditions. Further model evaluations

  20. Quantitative sexing (Q-Sexing) and relative quantitative sexing (RQ ...

    African Journals Online (AJOL)

    samer

    Key words: Polymerase chain reaction (PCR), quantitative real time polymerase chain reaction (qPCR), quantitative sexing, Siberian tiger. INTRODUCTION. Animal molecular sexing .... 43:3-12. Ellegren H (1996). First gene on the avian W chromosome (CHD) provides a tag for universal sexing of non-ratite birds. Proc.

  1. Roles of Self-Stigma, Social Support, and Positive and Negative Affects as Determinants of Depressive Symptoms Among HIV Infected Men who have Sex with Men in China.

    Science.gov (United States)

    Li, Jinghua; Mo, Phoenix K H; Wu, Anise M S; Lau, Joseph T F

    2017-01-01

    Poor mental health was prevalent among HIV positive men who have sex with men (HIVMSM), and a tremendous burden extents on their families and society. The present study investigated the prevalence of depression and its relationship with social support, HIV self-stigma, positive affect and negative affect among 321 HIVMSM in Chengdu, China. The study was conducted during July 2013 through October 2013. Findings showed that 55.8 % of the participants had mild to severe depression. The results of structural equation modeling showed that social support and positive affect were negatively associated with depression, while HIV self-stigma and negative affect were positively associated with depression. Social support, positive affect, and negative affect mediated the association between HIV self-stigma and depression. The hypothesized model had a satisfactory fit. Interventions improving mental health among this population are warranted.

  2. Using conjoint analysis to determine the impact of product and user characteristics on acceptability of rectal microbicides for HIV prevention among Peruvian men who have sex with men.

    Science.gov (United States)

    Tang, Eric C; Galea, Jerome T; Kinsler, Janni J; Gonzales, Pedro; Sobieszczyk, Magdalena E; Sanchez, Jorge; Lama, Javier R

    2016-05-01

    Men who have sex with men (MSM) are in need of novel and acceptable HIV prevention interventions. In Peru, a Phase II clinical trial was recently completed evaluating rectally applied tenofovir gel among Peruvian MSM and transgender women. If deemed safe and acceptable, the product could move into efficacy testing, but acceptability data for similar products are needed now in order to prepare for future implementation. Peru is in need of expanded, national acceptability data among likely users. Using conjoint analysis of an online cross-sectional survey taken by 1008 Peruvian MSM and transgender women, we tested the acceptability of eight hypothetical rectal microbicide (RM) products comprising six, dual-value attributes. We also assessed the relationship of select product attributes with sample characteristics. Highest acceptability was found for a RM that was 90% effective, used before and after sex, without side effects, costing approximately $0.30, had no prescription requirement and had a single-use applicator. Product effectiveness and presence of side effects were the factors most likely to drive RM acceptance and use. Education, sexual orientation, sexual role and concern for HIV infection were also related to aspects of RM acceptability. RM acceptability was high, confirming the results of earlier, smaller studies and placing confidence in the acceptability of RMs. Analysis of the relationships with product attributes and sample characteristics underscore the need to consider the impact of factors such as sexual orientation, sexual role, level of education and concern for HIV acquisition on RM acceptability. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  3. Did Lizards Follow Unique Pathways in Sex Chromosome Evolution?

    Science.gov (United States)

    Gleeson, Dianne; Georges, Arthur

    2018-01-01

    Reptiles show remarkable diversity in modes of reproduction and sex determination, including high variation in the morphology of sex chromosomes, ranging from homomorphic to highly heteromorphic. Additionally, the co-existence of genotypic sex determination (GSD) and temperature-dependent sex determination (TSD) within and among sister clades makes this group an attractive model to study and understand the evolution of sex chromosomes. This is particularly so with Lizards (Order Squamata) which, among reptiles, show extraordinary morphological diversity. They also show no particular pattern of sex chromosome degeneration of the kind observed in mammals, birds and or even in snakes. We therefore speculate that sex determination sensu sex chromosome evolution is labile and rapid and largely follows independent trajectories within lizards. Here, we review the current knowledge on the evolution of sex chromosomes in lizards and discuss how sex chromosome evolution within that group differs from other amniote taxa, facilitating unique evolutionary pathways. PMID:29751579

  4. Did Lizards Follow Unique Pathways in Sex Chromosome Evolution?

    Directory of Open Access Journals (Sweden)

    Shayer Mahmood Ibney Alam

    2018-05-01

    Full Text Available Reptiles show remarkable diversity in modes of reproduction and sex determination, including high variation in the morphology of sex chromosomes, ranging from homomorphic to highly heteromorphic. Additionally, the co-existence of genotypic sex determination (GSD and temperature-dependent sex determination (TSD within and among sister clades makes this group an attractive model to study and understand the evolution of sex chromosomes. This is particularly so with Lizards (Order Squamata which, among reptiles, show extraordinary morphological diversity. They also show no particular pattern of sex chromosome degeneration of the kind observed in mammals, birds and or even in snakes. We therefore speculate that sex determination sensu sex chromosome evolution is labile and rapid and largely follows independent trajectories within lizards. Here, we review the current knowledge on the evolution of sex chromosomes in lizards and discuss how sex chromosome evolution within that group differs from other amniote taxa, facilitating unique evolutionary pathways.

  5. Sex and life expectancy.

    Science.gov (United States)

    Seifarth, Joshua E; McGowan, Cheri L; Milne, Kevin J

    2012-12-01

    A sexual dimorphism in human life expectancy has existed in almost every country for as long as records have been kept. Although human life expectancy has increased each year, females still live longer, on average, than males. Undoubtedly, the reasons for the sex gap in life expectancy are multifaceted, and it has been discussed from both sociological and biological perspectives. However, even if biological factors make up only a small percentage of the determinants of the sex difference in this phenomenon, parity in average life expectancy should not be anticipated. The aim of this review is to highlight biological mechanisms that may underlie the sexual dimorphism in life expectancy. Using PubMed, ISI Web of Knowledge, and Google Scholar, as well as cited and citing reference histories of articles through August 2012, English-language articles were identified, read, and synthesized into categories that could account for biological sex differences in human life expectancy. The examination of biological mechanisms accounting for the female-based advantage in human life expectancy has been an active area of inquiry; however, it is still difficult to prove the relative importance of any 1 factor. Nonetheless, biological differences between the sexes do exist and include differences in genetic and physiological factors such as progressive skewing of X chromosome inactivation, telomere attrition, mitochondrial inheritance, hormonal and cellular responses to stress, immune function, and metabolic substrate handling among others. These factors may account for at least a part of the female advantage in human life expectancy. Despite noted gaps in sex equality, higher body fat percentages and lower physical activity levels globally at all ages, a sex-based gap in life expectancy exists in nearly every country for which data exist. There are several biological mechanisms that may contribute to explaining why females live longer than men on average, but the complexity of the

  6. SEX DIFFERENCES, GENDER AND ADDICTION

    OpenAIRE

    Becker, Jill B.; McClellan, Michele L.; Reed, Beth Glover

    2017-01-01

    This review discusses alcohol/other drug addiction as both a sociocultural and biological phenomenon. Sex differences and gender are not solely determined by biology, nor are they entirely sociocultural. The interactions among biological, environmental, sociocultural and developmental influences result in phenotypes that may be more masculine or more feminine. These gender-related sex differences in the brain can influence the responses to drugs of abuse, progressive changes in the brain afte...

  7. On the origin of sex chromosomes from meiotic drive

    Science.gov (United States)

    Úbeda, Francisco; Patten, Manus M.; Wild, Geoff

    2015-01-01

    Most animals and many plants make use of specialized chromosomes (sex chromosomes) to determine an individual's sex. Best known are the XY and ZW sex-determination systems. Despite having evolved numerous times, sex chromosomes present something of an evolutionary puzzle. At their origin, alleles that dictate development as one sex or the other (primitive sex chromosomes) face a selective penalty, as they will be found more often in the more abundant sex. How is it possible that primitive sex chromosomes overcome this disadvantage? Any theory for the origin of sex chromosomes must identify the benefit that outweighs this cost and enables a sex-determining mutation to establish in the population. Here we show that a new sex-determining allele succeeds when linked to a sex-specific meiotic driver. The new sex-determining allele benefits from confining the driving allele to the sex in which it gains the benefit of drive. Our model requires few special assumptions and is sufficiently general to apply to the evolution of sex chromosomes in outbreeding cosexual or dioecious species. We highlight predictions of the model that can discriminate between this and previous theories of sex-chromosome origins. PMID:25392470

  8. Same sex marriage and the perceived assault on opposite sex marriage.

    Science.gov (United States)

    Dinno, Alexis; Whitney, Chelsea

    2013-01-01

    Marriage benefits both individuals and societies, and is a fundamental determinant of health. Until recently same sex couples have been excluded from legally recognized marriage in the United States. Recent debate around legalization of same sex marriage has highlighted for anti-same sex marriage advocates and policy makers a concern that allowing same sex couples to marry will lead to a decrease in opposite sex marriages. Our objective is to model state trends in opposite sex marriage rates by implementation of same sex marriages and other same sex unions. Marriage data were obtained for all fifty states plus the District of Columbia from 1989 through 2009. As these marriage rates are non-stationary, a generalized error correction model was used to estimate long run and short run effects of same sex marriages and strong and weak same sex unions on rates of opposite sex marriage. We found that there were no significant long-run or short run effects of same sex marriages or of strong or weak same sex unions on rates of opposite sex marriage. A deleterious effect on rates of opposite sex marriage has been argued to be a motivating factor for both the withholding and the elimination of existing rights of same sex couples to marry by policy makers-including presiding justices of current litigation over the rights of same sex couples to legally marry. Such claims do not appear credible in the face of the existing evidence, and we conclude that rates of opposite sex marriages are not affected by legalization of same sex civil unions or same sex marriages.

  9. Same Sex Marriage and the Perceived Assault on Opposite Sex Marriage

    Science.gov (United States)

    Dinno, Alexis; Whitney, Chelsea

    2013-01-01

    Background Marriage benefits both individuals and societies, and is a fundamental determinant of health. Until recently same sex couples have been excluded from legally recognized marriage in the United States. Recent debate around legalization of same sex marriage has highlighted for anti-same sex marriage advocates and policy makers a concern that allowing same sex couples to marry will lead to a decrease in opposite sex marriages. Our objective is to model state trends in opposite sex marriage rates by implementation of same sex marriages and other same sex unions. Methods and Findings Marriage data were obtained for all fifty states plus the District of Columbia from 1989 through 2009. As these marriage rates are non-stationary, a generalized error correction model was used to estimate long run and short run effects of same sex marriages and strong and weak same sex unions on rates of opposite sex marriage. We found that there were no significant long-run or short run effects of same sex marriages or of strong or weak same sex unions on rates of opposite sex marriage. Conclusion A deleterious effect on rates of opposite sex marriage has been argued to be a motivating factor for both the withholding and the elimination of existing rights of same sex couples to marry by policy makers–including presiding justices of current litigation over the rights of same sex couples to legally marry. Such claims do not appear credible in the face of the existing evidence, and we conclude that rates of opposite sex marriages are not affected by legalization of same sex civil unions or same sex marriages. PMID:23776536

  10. Hybridization in East African swarm-raiding army ants

    DEFF Research Database (Denmark)

    Kronauer, Daniel Jc; Peters, Marcell K; Schöning, Caspar

    2011-01-01

    Hybridization can have complex effects on evolutionary dynamics in ants because of the combination of haplodiploid sex-determination and eusociality. While hybrid non-reproductive workers have been found in a range of species, examples of gene-flow via hybrid queens and males are rare. We studied...... hybridization in East African army ants (Dorylus subgenus Anomma) using morphology, mitochondrial DNA sequences, and nuclear microsatellites....

  11. Do sex-specific densities affect local survival of free-ranging great tits?

    NARCIS (Netherlands)

    Michler, Stephanie P. M.; Nicolaus, Marion; Ubels, Richard; van der Velde, Marco; Both, Christiaan; Tinbergen, Joost M.; Komdeur, Jan

    2011-01-01

    Competition within sexes is expected when resources are sex specific, whereas competition between sexes can occur when similar resources are exploited. Local population density and sex ratio will determine the amount of sex-specific interactions and thus the potential degree of sex-specific

  12. Sex-linked dominant

    Science.gov (United States)

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... can be either an autosomal chromosome or a sex chromosome. It also depends on whether the trait ...

  13. Multiple sex partner

    African Journals Online (AJOL)

    User

    intercourse, about 60% reported having a single sexual partner and 40% reported having multiple ... masturbation, start having sex at a younger age, have sex with married people and/or .... sex were considered unacceptable by 89 vs.

  14. Turnover of sex chromosomes induced by sexual conflict

    NARCIS (Netherlands)

    van Doorn, G. S.; Kirkpatrick, Mark

    2007-01-01

    Sex-determination genes are among the most fluid features of the genome in many groups of animals(1,2). In some taxa the master sex-determining gene moves frequently between chromosomes, whereas in other taxa different genes have been recruited to determine the sex of the zygotes. There is a well

  15. Interactive Effects of Culture and Sex Hormones on Sex Role Orientation

    Directory of Open Access Journals (Sweden)

    Belinda ePletzer

    2015-07-01

    Full Text Available Sex role orientation, i.e. a person’s masculinity or femininity, influences cognitive and emotional performance, like biological sex. While it is now widely accepted that sex differences are modulated by the hormonal status of female participants (menstrual cycle, hormonal contraceptive use, the question, whether hormonal status and sex hormones also modulate participants sex role orientation has hardly been addressed previously. The present study assessed sex role orientation and hormonal status as well as sex hormone levels in three samples of participants from two different cultures (Northern American, Middle European. Menstrual cycle phase did not affect participant’s masculinity or femininity, but had a significant impact on reference group. While women in their follicular phase (low levels of female sex hormones determined their masculinity and femininity in reference to men, women in their luteal phase (high levels of female sex hormones determined their masculinity and femininity in reference to women. Hormonal contraceptive users rated themselves as significantly more feminine and less masculine than naturally cycling women. Furthermore, the impact of biological sex on the factorial structure of sex role orientation as well as the relationship of estrogen to masculinity/femininity was modulated by culture. We conclude that culture and sex hormones interactively affect sex role orientation and hormonal status of participants should be controlled for when assessing masculinity and/or femininity.

  16. Criminal Profiles of Violent Juvenile Sex and Violent Juvenile Non-Sex Offenders: An Explorative Longitudinal Study

    Science.gov (United States)

    van Wijk, Anton Ph.; Mali, Bas R. F.; Bullens, Ruud A. R.; Vermeiren, Robert R.

    2007-01-01

    Few studies have longitudinally investigated the criminal profiles of violent juvenile sex and violent juvenile non-sex offenders. To make up for this lack, this study used police records of juveniles to determine the nature of the criminal profiles of violent sex offenders (n = 226) and violent non-sex offenders (n = 4,130). All offenders…

  17. Sex differences, gender and addiction.

    Science.gov (United States)

    Becker, Jill B; McClellan, Michele L; Reed, Beth Glover

    2017-01-02

    This review discusses alcohol and other forms of drug addiction as both a sociocultural and biological phenomenon. Sex differences and gender are not solely determined by biology, nor are they entirely sociocultural. The interactions among biological, environmental, sociocultural, and developmental influences result in phenotypes that may be more masculine or more feminine. These gender-related sex differences in the brain can influence the responses to drugs of abuse, progressive changes in the brain after exposure to drugs of abuse and whether addiction results from drug-taking experiences. In addition, the basic laboratory evidence for sex differences is discussed within the context of four types of sex/gender differences. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Understanding Sex for Sale

    DEFF Research Database (Denmark)

    This book Understanding Sex for Sale: Meanings and Moralities of Sexual Commerce is dedicated to the exploration of the ways in which sex prostitution, sex work or sex for sale are taken for granted by particularly looking at how the relation between sex and money is interpreted and enacted....... This interdisciplinary book aims to understand how prostitution, sex work or sex for sale are defined, delineated, contested and understood in different places and times. The book offers contributions from a number of scholars who, based on their on their own research, discuss on going theoretical issues and analytical...... challenges Some chapters focuses on how prostitution, sex work or sex for sale have been regulated by the authorities and what understandings this regulation builds on. Other chapters investigate the experiences of the sex workers and sex buyers asking how these actors adjust to or resist the categorisation...

  19. Expression profiles for six zebrafish genes during gonadal sex differentiation

    DEFF Research Database (Denmark)

    Jørgensen, Anne; Morthorst, Jane Ebsen; Andersen, Ole

    2008-01-01

    BACKGROUND: The mechanism of sex determination in zebrafish is largely unknown and neither sex chromosomes nor a sex-determining gene have been identified. This indicates that sex determination in zebrafish is mediated by genetic signals from autosomal genes. The aim of this study was to determine...... the precise timing of expression of six genes previously suggested to be associated with sex differentiation in zebrafish. The current study investigates the expression of all six genes in the same individual fish with extensive sampling dates during sex determination and -differentiation. RESULTS......: In the present study, we have used quantitative real-time PCR to investigate the expression of ar, sox9a, dmrt1, fig alpha, cyp19a1a and cyp19a1b during the expected sex determination and gonadal sex differentiation period. The expression of the genes expected to be high in males (ar, sox9a and dmrt1a) and high...

  20. Significance of determination of female sex hormones (E2, LH, FSH), insulin-like growth factor I (IGF-I) and leptin in girls with precocious puberty

    International Nuclear Information System (INIS)

    Huang Jianrong

    2004-01-01

    Objective: To investigate the diagnostic value of determination of serum levels of estradiol (E 2 ), luteinizing hormone (LH) and follicle stimulating hormone (FSH), insulin-like growth factor (IGF-I) and leptin in girls with idiopathic central precocious puberty (ICPP). Methods: Serum E 2 , LH, FSH, IGF-I (with chemiluminescence immunoassay) and leptin (with RIA) levels were determined in 35 girls with early development of breast as the sign of precocious puberty, of which, 15 was considered to be of the ICPP group and 20 of simple premature thelarche group (SPT). Criteria of diagnosis for ICPP were: peak LH value>12IU/L and LH/FSH>1 after GnRH stimulating test. Results: Serum E 2 , LH, FSH, IGF-I leptin levels in girls with ICPP were significantly higher than those in the girls with SPT (P 0.2 as the cut-off value for diagnosis of ICPP there would still be a positive rate of 86.6% suggesting that the diagnostic criteria might be set lower. Serum IGF-I levels were positively correlated to those of E 2 (r=0.47, P 2 and IGF-I. Conclusion: Determinations of serum E 2 , LH, FHS, IGF-I and leptin levels were helpful for the early diagnosis of ICPP. (author)

  1. Fungal Sex: The Mucoromycota.

    Science.gov (United States)

    Lee, Soo Chan; Idnurm, Alexander

    2017-03-01

    Although at the level of resolution of genes and molecules most information about mating in fungi is from a single lineage, the Dikarya, many fundamental discoveries about mating in fungi have been made in the earlier branches of the fungi. These are nonmonophyletic groups that were once classified into the chytrids and zygomycetes. Few species in these lineages offer the potential of genetic tractability, thereby hampering the ability to identify the genes that underlie those fundamental insights. Research performed during the past decade has now established the genes required for mating type determination and pheromone synthesis in some species in the phylum Mucoromycota, especially in the order Mucorales. These findings provide striking parallels with the evolution of mating systems in the Dikarya fungi. Other discoveries in the Mucorales provide the first examples of sex-cell type identity being driven directly by a gene that confers mating type, a trait considered more of relevance to animal sex determination but difficult to investigate in animals. Despite these discoveries, there remains much to be gleaned about mating systems from these fungi.

  2. Molecular study for the sex identification in Japanese quails ...

    African Journals Online (AJOL)

    In many birds' species such as Japanese quail, sex determination in young and many adult birds is very difficult. Nowadays, sex identification of animals throughout their lives is possible by molecular genetic techniques such as polymerase chain reaction (PCR). The aim of this study was to determine the sex of Japanese ...

  3. Great tit hatchling sex ratios

    NARCIS (Netherlands)

    Lessells, C.M.; Mateman, A.C.; Visser, J.

    1996-01-01

    The sex of Great Tit Parus major nestlings was determined using PCR RAPDs. Because this technique requires minute amounts of DNA, chicks could be sampled soon (0-2d) after hatching, before any nestling mortality occurred. The proportion of males among 752 chicks hatching in 102 broods (98.9% of

  4. Performance and carcass yield of sexed broiler chickens reared on ...

    African Journals Online (AJOL)

    Performance and carcass yield of sexed broiler chickens reared on two housing types. ... Bulletin of Animal Health and Production in Africa ... This study thereby determined the performance, carcass yield and meat composition of 300 sexed ...

  5. Effects of Sex Steroids in the Human Brain.

    Science.gov (United States)

    Nguyen, Tuong-Vi; Ducharme, Simon; Karama, Sherif

    2017-11-01

    Sex steroids are thought to play a critical developmental role in shaping both cortical and subcortical structures in the human brain. Periods of profound changes in sex steroids invariably coincide with the onset of sex differences in mental health vulnerability, highlighting the importance of sex steroids in determining sexual differentiation of the brain. Yet, most of the evidence for the central effects of sex steroids relies on non-human studies, as several challenges have limited our understanding of these effects in humans: the lack of systematic assessment of the human sex steroid metabolome, the different developmental trajectories of specific sex steroids, the impact of genetic variation and epigenetic changes, and the plethora of interactions between sex steroids, sex chromosomes, neurotransmitters, and other hormonal systems. Here we review how multimodal strategies may be employed to bridge the gap between the basic and clinical understanding of sex steroid-related changes in the human brain.

  6. Sex differences in heritability of neck Pain

    DEFF Research Database (Denmark)

    Fejer, René; Hartvigsen, Jan; Kyvik, Kirsten Ohm

    2006-01-01

    Experimental studies have suggested biological factors as a possible explanation for gender disparities in perception of pain. Recently, heritability of liability to neck pain (NP) has been found to be statistically significantly larger in women compared to men. However, no studies have been...... conducted to determine whether the sex differences in heritability of NP are due to sex-specific genetic factors. Data on lifetime prevalence of NP from a population-based cross-sectional survey of 33,794 Danish twins were collected and age-stratified univariate biometrical modeling using sex......-limitation models was performed based on 10,605 dizygotic (DZ) twins of opposite sex to estimate the qualitative sex differences. In a full sex-limitation model the genetic component in females were higher than in males, but the genetic and the shared environmental correlations were equal to what is normally...

  7. Evolutionary stability of sex chromosomes in snakes.

    Science.gov (United States)

    Rovatsos, Michail; Vukić, Jasna; Lymberakis, Petros; Kratochvíl, Lukáš

    2015-12-22

    Amniote vertebrates possess various mechanisms of sex determination, but their variability is not equally distributed. The large evolutionary stability of sex chromosomes in viviparous mammals and birds was believed to be connected with their endothermy. However, some ectotherm lineages seem to be comparably conserved in sex determination, but previously there was a lack of molecular evidence to confirm this. Here, we document a stability of sex chromosomes in advanced snakes based on the testing of Z-specificity of genes using quantitative PCR (qPCR) across 37 snake species (our qPCR technique is suitable for molecular sexing in potentially all advanced snakes). We discovered that at least part of sex chromosomes is homologous across all families of caenophidian snakes (Acrochordidae, Xenodermatidae, Pareatidae, Viperidae, Homalopsidae, Colubridae, Elapidae and Lamprophiidae). The emergence of differentiated sex chromosomes can be dated back to about 60 Ma and preceded the extensive diversification of advanced snakes, the group with more than 3000 species. The Z-specific genes of caenophidian snakes are (pseudo)autosomal in the members of the snake families Pythonidae, Xenopeltidae, Boidae, Erycidae and Sanziniidae, as well as in outgroups with differentiated sex chromosomes such as monitor lizards, iguanas and chameleons. Along with iguanas, advanced snakes are therefore another example of ectothermic amniotes with a long-term stability of sex chromosomes comparable with endotherms. © 2015 The Author(s).

  8. Sex Education: Another View

    Science.gov (United States)

    Hamilton, Jennifer

    1977-01-01

    The mother of a 14-year-old mentally retarded boy comments on the viewpoints of Dr. Sol Gordon (a sex education columnist) regarding masturbation, questions on sex, marriage, and the parents' role. (SBH)

  9. Sex hormone binding globulin phenotypes

    DEFF Research Database (Denmark)

    Cornelisse, M M; Bennett, Patrick; Christiansen, M

    1994-01-01

    Human sex hormone binding globulin (SHBG) is encoded by a normal and a variant allele. The resulting SHBG phenotypes (the homozygous normal SHBG, the heterozygous SHBG and the homozygous variant SHBG phenotype) can be distinguished by their electrophoretic patterns. We developed a novel detection....... This method of detection was used to determine the distribution of SHBG phenotypes in healthy controls of both sexes and in five different pathological conditions characterized by changes in the SHBG level or endocrine disturbances (malignant and benign ovarian neoplasms, hirsutism, liver cirrhosis...... on the experimental values. Differences in SHBG phenotypes do not appear to have any clinical significance and no sex difference was found in the SHBG phenotype distribution....

  10. Sex differences in cough reflex.

    Science.gov (United States)

    Plevkova, J; Buday, T; Kavalcikova-Bogdanova, N; Ioan, I; Demoulin-Alexikova, S

    2017-11-01

    Majority of patients visiting cough clinics are postmenopausal women, who are affected by intractable cough for years. Why the cough reflex becomes exaggerated in women is not known. Basic research excludes females from the studies contributing to the sex bias which may be responsible for lack of understanding of "hypersensitive" cough in women. Biological and behavioural differences between women and men are the factors affecting cough physiology. Gender also shapes the patterns of behaviour and determines the character of environmental exposures which differs between sexes. The article offers an insight into the physiology of the cough, differences in the maturation of it and biological, social and behavioural factors contributing to the sex differences in cough. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Sex in situ

    DEFF Research Database (Denmark)

    Krøgholt, Ida

    2017-01-01

    Sex er en del af vores sociale praksis og centralt for det, vi hver især er. Men bortset fra pornoindustrien, har vi ikke mange muligheder for at få adgang til billeder af sex. Teater Nordkrafts forestilling Sex in situ vil gøre seksuelle billeder til noget, der kan deles, udveksles og tales om, og...

  12. Coeducation and Sex Roles.

    Science.gov (United States)

    Harris, Mary B.

    1986-01-01

    A study of the sex role stereotypes held by 538 first-term Australian university students from single-sex and coeducational high schools is presented. Results suggest that coeducational schooling may have some advantages for fostering interactions with the opposite sex. (MSE)

  13. sex and Cannibalism

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 12. The Secret Sex Lives of Rotifers Sex - sex and Cannibalism. T Ramakrishna Rao. General Article Volume 5 Issue 12 December 2000 pp 41-47. Fulltext. Click here to view fulltext PDF. Permanent link:

  14. A Sex Work Research Symposium: Examining Positionality in Documenting Sex Work and Sex Workers’ Rights

    OpenAIRE

    Megan Lowthers; Magdalena Sabat; Elya M. Durisin; Kamala Kempadoo

    2017-01-01

    Historically, academic literature on sex work has documented the changing debates, policies, and cultural discourse surrounding the sex industry, and their impact on the rights of sex workers worldwide. As sex work scholars look to the future of sex workers’ rights, however, we are also in a critical moment of self-reflection on how sex work scholarship engages with sex worker communities, produces knowledge surrounding sex work, and represents the lived experiences of sex workers’ rights, or...

  15. Neuroprotection of Sex Steroids

    Science.gov (United States)

    Liu, Mingyue; Kelley, Melissa H.; Herson, Paco S.; Hurn, Patricia D.

    2011-01-01

    Sex steroids are essential for reproduction and development in animals and humans, and sex steroids also play an important role in neuroprotection following brain injury. New data indicate that sex-specific responses to brain injury occur at the cellular and molecular levels. This review summarizes the current understanding of neuroprotection by sex steroids, particularly estrogen, androgen, and progesterone, based on both in vitro and in vivo studies. Better understanding of the role of sex steroids under physiological and pathological conditions will help us to develop novel effective therapeutic strategies for brain injury. PMID:20595940

  16. Understanding sex determination in the mouse: genetics ...

    Indian Academy of Sciences (India)

    challenge now is to understand how controlled epigenomic changes effect the now familiar sexually dimorphic transcriptomic profiles of the ... Cattanach, personal communication, April 2015. .... The human homologue, DMRT1, is found on.

  17. Sex determining signal in Drosophila melanogaster

    Indian Academy of Sciences (India)

    Administrator

    Addition of almost any segment of the X chromosome pro- duced a shift towards ... It is now well established that the X/A signal acts to set the functional state ... tionally related because a defect in one of them can be partly. COMMENTARY ON ...

  18. Sex chromosome repeats tip the balance towards speciation.

    Science.gov (United States)

    O'Neill, Michael J; O'Neill, Rachel J

    2018-04-06

    Because sex chromosomes, by definition, carry genes that determine sex, mutations that alter their structural and functional stability can have immediate consequences for the individual by reducing fertility, but also for a species by altering the sex ratio. Moreover, the sex-specific segregation patterns of heteromorphic sex chromosomes make them havens for selfish genetic elements that not only create sub-optimal sex ratios, but can also foster sexual antagonism. Compensatory mutations to mitigate antagonism or return sex ratios to a Fisherian optimum can create hybrid incompatibility and establish reproductive barriers leading to species divergence. The destabilizing influence of these selfish elements is often manifest within populations as copy number variants (CNVs) in satellite repeats and transposable elements (TE) or as CNVs involving sex determining genes, or genes essential to fertility and sex chromosome dosage compensation. This review catalogs several examples of well-studied sex chromosome CNVs in Drosophilids and mammals that underlie instances of meiotic drive, hybrid incompatibility and disruptions to sex differentiation and sex chromosome dosage compensation. While it is difficult to pinpoint a direct cause/effect relationship between these sex chromosome CNVs and speciation, it is easy to see how their effects in creating imbalances between the sexes, and the compensatory mutations to restore balance, can lead to lineage splitting and species formation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  19. Sexing young snowy owls

    Science.gov (United States)

    Seidensticker, M.T.; Holt, D.W.; Detienne, J.; Talbot, S.; Gray, K.

    2011-01-01

    We predicted sex of 140 Snowy Owl (Bubo scandiacus) nestlings out of 34 nests at our Barrow, Alaska, study area to develop a technique for sexing these owls in the field. We primarily sexed young, flightless owls (3844 d old) by quantifying plumage markings on the remiges and tail, predicting sex, and collecting blood samples to test our field predictions using molecular sexing techniques. We categorized and quantified three different plumage markings: two types of bars (defined as markings that touch the rachis) and spots (defined as markings that do not touch the rachis). We predicted sex in the field assuming that males had more spots than bars and females more bars than spots on the remiges and rectrices. Molecular data indicated that we correctly sexed 100% of the nestlings. We modeled the data using random forests and classification trees. Both models indicated that the number and type of markings on the secondary feathers were the most important in classifying nestling sex. The statistical models verified our initial qualitative prediction that males have more spots than bars and females more bars than spots on flight feathers P6P10 for both wings and tail feathers T1 and T2. This study provides researchers with an easily replicable and highly accurate method for sexing young Snowy Owls in the field, which should aid further studies of sex-ratios and sex-related variation in behavior and growth of this circumpolar owl species. ?? 2011 The Raptor Research Foundation, Inc.

  20. Osho - Insights on sex.

    Science.gov (United States)

    Nagaraj, Anil Kumar Mysore

    2013-01-01

    Sex is a mysterious phenomenon, which has puzzled even great sages. Human beings have researched and mastered the biology of sex. But that is not all. Sex needs to be understood from the spiritual perspective too. The vision of Osho is an enlightening experience in this regard. Out of the thousands of lectures, five lectures on sex made Osho most notorious. Born into a Jain family of Madhya Pradesh, Rajneesh, who later wanted himself to be called Osho, is a great master. He has spoken volumes on a wide range of topics ranging from sex to super-consciousness. His contributions in the area of sex are based on the principles of "Tantra" which has its origin from Buddhism. This article focuses on his life and insights on sex, which if understood properly, can be a stepping stone for enlightenment.

  1. Helping Behavior: Effects of Sex and Sex-Typing.

    Science.gov (United States)

    Basow, Susan A.; Crawley, Donna M.

    1982-01-01

    Male and female experimenters requested adult shoppers (N=178) to fill out a questionnaire. Refusal data showed shoppers helping other-sex more than same-sex experimenters. Other results showed a significant three-way interaction among helper and helpee sex and sex-typing and situation sex-typing and that helper sex-typing did not have significant…

  2. Unusually dynamic sex roles in a fish.

    Science.gov (United States)

    Forsgren, Elisabet; Amundsen, Trond; Borg, Asa A; Bjelvenmark, Jens

    2004-06-03

    Sex roles are typically thought of as being fixed for a given species. In most animals males compete for females, whereas the females are more reluctant to mate. Therefore sexual selection usually acts most strongly on males. This is explained by males having a higher potential reproductive rate than females, leading to more males being sexually active (a male-biased operational sex ratio). However, what determines sex roles and the strength of sexual selection is a controversial and much debated question. In this large-scale field study, we show a striking temporal plasticity in the mating competition of a fish (two-spotted goby, Gobiusculus flavescens). Over the short breeding season fierce male-male competition and intensive courtship behaviour in males were replaced by female-female competition and actively courting females. Hence, sex role reversal occurred rapidly. This is the first time that a shift in sex roles has been shown in a vertebrate. The shift might be explained by a large decline in male abundance, strongly skewing the sex ratio towards females. Notably, the sex role reversal did not occur at an equal operational sex ratio, contrary to established sex role theory.

  3. Female Sex Offenders: Public Awareness and Attributions.

    Science.gov (United States)

    Cain, Calli M; Anderson, Amy L

    2016-12-01

    Traditional gender roles, sex scripts, and the way female sex offenders are portrayed in the media may lead to misconceptions about who can commit sexual offenses. Sexual crimes by women may go unnoticed or unreported if there is a general lack of awareness that females commit these crimes. Data from the 2012 Nebraska Annual Social Indicators Survey were used to determine whether the public perceives women as capable sex offenders and the perceived causes of female sex offending. The traditional focus on male sex offenders by researchers, media, and politicians, in addition to gender stereotypes, introduces the possibility of group differences (e.g., between men and women) in perceptions of female sex offenders. Consequently, two secondary analyses were conducted that tested for group differences in both the public's perception of whether females can commit sex offenses and the explanations selected for why females sexually offend. The findings suggest that the public does perceive women as capable sex offenders, although there were group differences in the causal attributions for female sex offending.

  4. Depression, anxiety symptoms and substance use amongst sex ...

    African Journals Online (AJOL)

    Background: Sex work is a high-risk occupation for mental health problems as sex workers are vulnerable to high rates of violence, sexual coercion, stigma and HIV. Aim: To determine the prevalence of depressive and anxiety symptoms and substance use in sex workers.Method: A crosssectional questionnaire survey of all ...

  5. Sex allocation in the sexually monomorphic fairy martin

    NARCIS (Netherlands)

    Magrath, MJL; Green, DJ; Komdeur, J

    Offspring sex ratios were examined at the population and family level in the sexually monomorphic, socially monogamous fairy martin Petrochelidon ariel at five colony sites over a 4-year period (1993 1996). The sex of 465 nestlings from 169 broods % as determined using sex-specific PCR at the CHD

  6. Conservation and sex-specific splicing of the doublesex gene

    Indian Academy of Sciences (India)

    Genetic control of sex determination in insects has been best characterized in Drosophila melanogaster, where the master gene Sxl codes for RNA that is sex specifically spliced to produce a functional protein only in females. SXL regulates the sex-specific splicing of transformer (tra) RNA which, in turn, regulates the ...

  7. Sex in an Evolutionary Perspective: Just Another Reaction Norm

    OpenAIRE

    Ah-King, Malin; Nylin, S?ren

    2010-01-01

    It is common to refer to all sorts of clear-cut differences between the sexes as something that is biologically almost inevitable. Although this does not reflect the status of evolutionary theory on sex determination and sexual dimorphism, it is probably a common view among evolutionary biologists as well, because of the impact of sexual selection theory. To get away from thinking about biological sex and traits associated with a particular sex as something static, it should be recognized tha...

  8. Abnormal sex chromosome constitution and longitudinal growth: serum levels of insulin-like growth factor (IGF)-I, IGF binding protein-3, luteinizing hormone, and testosterone in 109 males with 47,XXY, 47,XYY, or sex-determining region of the Y chromosome (SRY)-positive 46,XX karyotypes

    DEFF Research Database (Denmark)

    Aksglaede, L.; Skakkebaek, N.E.; Juul, A.

    2008-01-01

    CONTEXT: Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles. AIM: The aim of the study was to evaluate the role of abnormal chromosome constitution...... and elevated LH levels after puberty, whereas the sex hormone secretion of the 47,XYY boys remained normal. CONCLUSION: We found accelerated growth in early childhood in boys with 47,XXY and 47,XYY karyotypes, whereas 46,XX-males were shorter than controls. These abnormal growth patterns were not reflected...

  9. Why Do Sex Chromosomes Stop Recombining?

    Science.gov (United States)

    Ponnikas, Suvi; Sigeman, Hanna; Abbott, Jessica K; Hansson, Bengt

    2018-04-28

    It is commonly assumed that sex chromosomes evolve recombination suppression because selection favours linkage between sex-determining and sexually antagonistic genes. However, although the role of sexual antagonism during sex chromosome evolution has attained strong support from theory, experimental and observational evidence is rare or equivocal. Here, we highlight alternative, often neglected, hypotheses for recombination suppression on sex chromosomes, which invoke meiotic drive, heterozygote advantage, and genetic drift, respectively. We contrast the hypotheses, the situations when they are likely to be of importance, and outline why it is surprisingly difficult to test them. Lastly, we discuss future research directions (including modelling, population genomics, comparative approaches, and experiments) to disentangle the different hypotheses of sex chromosome evolution. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. The evolution of sex chromosomes in organisms with separate haploid sexes.

    Science.gov (United States)

    Immler, Simone; Otto, Sarah Perin

    2015-03-01

    The evolution of dimorphic sex chromosomes is driven largely by the evolution of reduced recombination and the subsequent accumulation of deleterious mutations. Although these processes are increasingly well understood in diploid organisms, the evolution of dimorphic sex chromosomes in haploid organisms (U/V) has been virtually unstudied theoretically. We analyze a model to investigate the evolution of linkage between fitness loci and the sex-determining region in U/V species. In a second step, we test how prone nonrecombining regions are to degeneration due to accumulation of deleterious mutations. Our modeling predicts that the decay of recombination on the sex chromosomes and the addition of strata via fusions will be just as much a part of the evolution of haploid sex chromosomes as in diploid sex chromosome systems. Reduced recombination is broadly favored, as long as there is some fitness difference between haploid males and females. The degeneration of the sex-determining region due to the accumulation of deleterious mutations is expected to be slower in haploid organisms because of the absence of masking. Nevertheless, balancing selection often drives greater differentiation between the U/V sex chromosomes than in X/Y and Z/W systems. We summarize empirical evidence for haploid sex chromosome evolution and discuss our predictions in light of these findings. © 2015 The Author(s).

  11. Neurogenin 3 Mediates Sex Chromosome Effects on the Generation of Sex Differences in Hypothalamic Neuronal Development

    Directory of Open Access Journals (Sweden)

    Maria Julia Scerbo

    2014-07-01

    Full Text Available The organizational action of testosterone during critical periods of development is the cause of numerous sex differences in the brain. However, sex differences in neuritogenesis have been detected in primary neuronal hypothalamic cultures prepared before the peak of testosterone production by fetal testis. In the present study we assessed the hypothesis of that cell-autonomous action of sex chromosomes can differentially regulate the expression of the neuritogenic gene neurogenin 3 (Ngn3 in male and female hypothalamic neurons, generating sex differences in neuronal development. Neuronal cultures were prepared from male and female E14 mouse hypothalami, before the fetal peak of testosterone. Female neurons showed enhanced neuritogenesis and higher expression of Ngn3 than male neurons. The silencing of Ngn3 abolished sex differences in neuritogenesis, decreasing the differentiation of female neurons. The sex difference in Ngn3 expression was determined by sex chromosomes, as demonstrated using the four core genotypes mouse model, in which a spontaneous deletion of the testis-determining gene Sry from the Y chromosome was combined with the insertion of the Sry gene onto an autosome. In addition, the expression of Ngn3, which is also known to mediate the neuritogenic actions of estradiol, was increased in the cultures treated with the hormone, but only in those from male embryos. Furthermore, the hormone reversed the sex differences in neuritogenesis promoting the differentiation of male neurons. These findings indicate that Ngn3 mediates both cell-autonomous actions of sex chromosomes and hormonal effects on neuritogenesis.

  12. Multiple sex-associated regions and a putative sex chromosome in zebrafish revealed by RAD mapping and population genomics.

    Directory of Open Access Journals (Sweden)

    Jennifer L Anderson

    Full Text Available Within vertebrates, major sex determining genes can differ among taxa and even within species. In zebrafish (Danio rerio, neither heteromorphic sex chromosomes nor single sex determination genes of large effect, like Sry in mammals, have yet been identified. Furthermore, environmental factors can influence zebrafish sex determination. Although progress has been made in understanding zebrafish gonad differentiation (e.g. the influence of germ cells on gonad fate, the primary genetic basis of zebrafish sex determination remains poorly understood. To identify genetic loci associated with sex, we analyzed F(2 offspring of reciprocal crosses between Oregon *AB and Nadia (NA wild-type zebrafish stocks. Genome-wide linkage analysis, using more than 5,000 sequence-based polymorphic restriction site associated (RAD-tag markers and population genomic analysis of more than 30,000 single nucleotide polymorphisms in our *ABxNA crosses revealed a sex-associated locus on the end of the long arm of chr-4 for both cross families, and an additional locus in the middle of chr-3 in one cross family. Additional sequencing showed that two SNPs in dmrt1 previously suggested to be functional candidates for sex determination in a cross of ABxIndia wild-type zebrafish, are not associated with sex in our AB fish. Our data show that sex determination in zebrafish is polygenic and that different genes may in