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Sample records for variance components heritability

  1. Heritability, variance components and genetic advance of some ...

    African Journals Online (AJOL)

    Eighty-eight (88) finger millet (Eleusine coracana (L.) Gaertn.) germplasm collections were tested using augmented randomized complete block design at Adet Agricultural Research Station in 2008 cropping season. The objective of this study was to find out heritability, variance components, variability and genetic advance ...

  2. Variance component and heritability estimates of early growth traits ...

    African Journals Online (AJOL)

    Restricted Maximum Likelihood (REML) procedures fitting three different models. Estimates were severely biased ... estimates for direct additive variance and heritability (h\\) when fitted simultaneously in an animal model. The genetic ..... demanding than the sire model with respect to CPU time used. For BW, 200 iterations ...

  3. Genetic variance components and heritability of multiallelic heterozygosity under inbreeding

    Science.gov (United States)

    Nietlisbach, P; Keller, L F; Postma, E

    2016-01-01

    The maintenance of genetic diversity in fitness-related traits remains a central topic in evolutionary biology, for example, in the context of sexual selection for genetic benefits. Among the solutions that have been proposed is directional sexual selection for heterozygosity. The importance of such selection is highly debated. However, a critical evaluation requires knowledge of the heritability of heterozygosity, a quantity that is rarely estimated in this context, and often assumed to be zero. This is at least partly the result of the lack of a general framework that allows for its quantitative prediction in small and inbred populations, which are the focus of most empirical studies. Moreover, while current predictors are applicable only to biallelic loci, fitness-relevant loci are often multiallelic, as are the neutral markers typically used to estimate genome-wide heterozygosity. To this end, we first review previous, but little-known, work showing that under most circumstances, heterozygosity at biallelic loci and in the absence of inbreeding is heritable. We then derive the heritability of heterozygosity and the underlying variances for multiple alleles and any inbreeding level. We also show that heterozygosity at multiallelic loci can be highly heritable when allele frequencies are unequal, and that this heritability is reduced by inbreeding. Our quantitative genetic framework can provide new insights into the evolutionary dynamics of heterozygosity in inbred and outbred populations. PMID:26174022

  4. Variance component and heritability estimates for growth traits in the ...

    African Journals Online (AJOL)

    CANTET, R.J.C., KRESS, D.D., ANDERSON, D,C., DOORNBOS,. D.8., BURFENING, P.J. & BLACKWELL, R.L., 1988. Direct and maternal variances and covariances and maternal phenotypic effects on pre-weaning growth of beef cattle. J. Anint. Sci. 66,648. DEESE, R.E. & KOGER, M., 1967. Maternal effects on pre-weaning.

  5. Variance component and heritability estimates for first and second ...

    African Journals Online (AJOL)

    46 S Afr] Anim Sci 1998 28(1). Variance component and heritability estimates for first and second lactation milk traits in the South African Ayrshire breed. G.J. Hallowell*. Agricultural Research Council, Animal Improvement Institute, Private Bag X2, Irene,. 0062 Republic of South Africa. J. van der Westhuizen and J8. van Wyk.

  6. Heritability of somatotype components: a multivariate analysis.

    Science.gov (United States)

    Peeters, M W; Thomis, M A; Loos, R J F; Derom, C A; Fagard, R; Claessens, A L; Vlietinck, R F; Beunen, G P

    2007-08-01

    To study the genetic and environmental determination of variation in Heath-Carter somatotype (ST) components (endomorphy, mesomorphy and ectomorphy). Multivariate path analysis on twin data. Eight hundred and three members of 424 adult Flemish twin pairs (18-34 years of age). The results indicate the significance of sex differences and the significance of the covariation between the three ST components. After age-regression, variation of the population in ST components and their covariation is explained by additive genetic sources of variance (A), shared (familial) environment (C) and unique environment (E). In men, additive genetic sources of variance explain 28.0% (CI 8.7-50.8%), 86.3% (71.6-90.2%) and 66.5% (37.4-85.1%) for endomorphy, mesomorphy and ectomorphy, respectively. For women, corresponding values are 32.3% (8.9-55.6%), 82.0% (67.7-87.7%) and 70.1% (48.9-81.8%). For all components in men and women, more than 70% of the total variation was explained by sources of variance shared between the three components, emphasising the importance of analysing the ST in a multivariate way. The findings suggest that the high heritabilities for mesomorphy and ectomorphy reported in earlier twin studies in adolescence are maintained in adulthood. For endomorphy, which represents a relative measure of subcutaneous adipose tissue, however, the results suggest heritability may be considerably lower than most values reported in earlier studies on adolescent twins. The heritability is also lower than values reported for, for example, body mass index (BMI), which next to the weight of organs and adipose tissue also includes muscle and bone tissue. Considering the differences in heritability between musculoskeletal robustness (mesomorphy) and subcutaneous adipose tissue (endomorphy) it may be questioned whether studying the genetics of BMI will eventually lead to a better understanding of the genetics of fatness, obesity and overweight.

  7. Environmental variation partitioned into separate heritable components.

    Science.gov (United States)

    Ørsted, Michael; Rohde, Palle Duun; Hoffmann, Ary Anthony; Sørensen, Peter; Kristensen, Torsten Nygaard

    2018-01-01

    Trait variation is normally separated into genetic and environmental components, yet genetic factors also control the expression of environmental variation, encompassing plasticity across environmental gradients and within-environment responses. We defined four components of environmental variation: plasticity across environments, variability in plasticity, variation within environments, and differences in within-environment variation across environments. We assessed these components for cold tolerance across five rearing temperatures using the Drosophila melanogaster Genetic Reference Panel (DGRP). The four components were found to be heritable, and genetically correlated to different extents. By whole genome single marker regression, we detected multiple candidate genes controlling the four components and showed limited overlap in genes affecting them. Using the binary UAS-GAL4 system, we functionally validated the effects of a subset of candidate genes affecting each of the four components of environmental variation and also confirmed the genetic and phenotypic correlations obtained from the DGRP in distinct genetic backgrounds. We delineate selection targets associated with environmental variation and the constraints acting upon them, providing a framework for evolutionary and applied studies on environmental sensitivity. Based on our results we suggest that the traditional quantitative genetic view of environmental variation and genotype-by-environment interactions needs revisiting. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  8. Variance components for body weight in Japanese quails (Coturnix japonica

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    RO Resende

    2005-03-01

    Full Text Available The objective of this study was to estimate the variance components for body weight in Japanese quails by Bayesian procedures. The body weight at hatch (BWH and at 7 (BW07, 14 (BW14, 21 (BW21 and 28 days of age (BW28 of 3,520 quails was recorded from August 2001 to June 2002. A multiple-trait animal model with additive genetic, maternal environment and residual effects was implemented by Gibbs sampling methodology. A single Gibbs sampling with 80,000 rounds was generated by the program MTGSAM (Multiple Trait Gibbs Sampling in Animal Model. Normal and inverted Wishart distributions were used as prior distributions for the random effects and the variance components, respectively. Variance components were estimated based on the 500 samples that were left after elimination of 30,000 rounds in the burn-in period and 100 rounds of each thinning interval. The posterior means of additive genetic variance components were 0.15; 4.18; 14.62; 27.18 and 32.68; the posterior means of maternal environment variance components were 0.23; 1.29; 2.76; 4.12 and 5.16; and the posterior means of residual variance components were 0.084; 6.43; 22.66; 31.21 and 30.85, at hatch, 7, 14, 21 and 28 days old, respectively. The posterior means of heritability were 0.33; 0.35; 0.36; 0.43 and 0.47 at hatch, 7, 14, 21 and 28 days old, respectively. These results indicate that heritability increased with age. On the other hand, after hatch there was a marked reduction in the maternal environment variance proportion of the phenotypic variance, whose estimates were 0.50; 0.11; 0.07; 0.07 and 0.08 for BWH, BW07, BW14, BW21 and BW28, respectively. The genetic correlation between weights at different ages was high, except for those estimates between BWH and weight at other ages. Changes in body weight of quails can be efficiently achieved by selection.

  9. Human sexual orientation has a heritable component.

    Science.gov (United States)

    Pillard, R C; Bailey, J M

    1998-04-01

    We present an overview of behavioral genetics research on homosexual and heterosexual orientation. Family, twin, and adoptee studies indicate that homosexuality and thus heterosexuality run in families. Sibling, twin, and adoptee concordance rates are compatible with the hypothesis that genes account for at least half of the variance in sexual orientation. We note observations of homosexual behavior in animal species, but the analogy to human sexual orientation is unclear. We discuss the reproductive disadvantage of a homosexual orientation and present possible mechanisms that could maintain a balanced polymorphism in human populations.

  10. Heterogeneidade dos componentes de variância na produção de leite e seus efeitos nas estimativas de herdabilidade e repetibilidade Heterogeneity of variance components in milk production and their effects on estimates of heritability and repeatability

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    Elmer Francisco Valencia Tapia

    2011-06-01

    Full Text Available Avaliou-se a heterogeneidade dos componentes de variância e seu efeito nas estimativas de herdabilidade e repetibilidade da produção de leite de bovinos da raça Holandesa. Os rebanhos foram agrupados de acordo com o nível de produção (baixo, médio e alto e avaliados na escala não transformada, raiz quadrada e logarítmica. Os componentes de variância foram estimados pelo método de máxima verossimilhança restrita. O modelo animal incluiu os efeitos fixos de rebanho-ano-estação e das covariáveis duração da lactação (efeito linear e idade da vaca ao parto (efeito linear e quadrático e os efeitos aleatórios genético aditivo direto, de ambiente permanente e residual. Na escala não transformada, todos os componentes de variância foram heterogêneos entre os três níveis de produção. Nesta escala, a variância residual e a fenotípica estavam associadas positivamente com o nível de produção enquanto que na escala logarítmica a associação foi negativa. A heterogeneidade da variância fenotípica e de seus componentes afetou mais as estimativas de herdabilidade que as da repetibilidade. A eficiência do processo de seleção para produção de leite poderá ser afetada pelo nível de produção em que forem estimados os parâmetros genéticos.It was evaluated the heterogeneity of components of phenotypic variance and its effects on the heritability and repeatability estimates for milk yield in Holstein cattle. The herds were grouped according to their level of production (low, medium and high and evaluated in the non-transformed, square-root and logarithmic scale. Variance components were estimated using a restricted maximum likelihood method based on an animal model that included fixed effects of herd-year-season, and as covariates the linear effect of lactation duration and the linear and quadratic effects of cow's age at calving and the random direct additive genetic, permanent environment and residual effects. In the

  11. Environmental variation partitioned into separate heritable components

    DEFF Research Database (Denmark)

    Ørsted, Michael; Rohde, Palle Duun; Hoffmann, Ary A

    2018-01-01

    : plasticity across environments, variability in plasticity, variation within environments, and differences in within-environment variation across environments. We assessed these components for cold tolerance across five rearing temperatures using the Drosophila melanogaster Genetic Reference Panel (DGRP...... functionally validated the effects of a subset of candidate genes affecting each of the four components of environmental variation and also confirmed the genetic and phenotypic correlations obtained from the DGRP in distinct genetic backgrounds. We delineate selection targets associated with environmental...

  12. Heritability, variance components and genetic advance of some ...

    African Journals Online (AJOL)

    Awolie

    2013-09-04

    Sep 4, 2013 ... indicated the usefulness of selection for these traits in the genetic material used for future improvement ... through selection. This study reveals that greater yield response could be obtained through direct selection scheme in finger millet landraces. ..... Barley (Hordium vulgare L.) landraces and crosses.

  13. Variance component and heritability estimates for growth traits in the ...

    African Journals Online (AJOL)

    Limousin; Shh = Shorthorn;. Sim = Simmental b = a vector of fixed effects consisting of year of birth, sex and the linear and quadratic regression of age of dam on year of birth,. Z,t Zz = known incidence matrices relating elements of a and m to y,.

  14. Variance component estimates for alternative litter size traits in swine.

    Science.gov (United States)

    Putz, A M; Tiezzi, F; Maltecca, C; Gray, K A; Knauer, M T

    2015-11-01

    Litter size at d 5 (LS5) has been shown to be an effective trait to increase total number born (TNB) while simultaneously decreasing preweaning mortality. The objective of this study was to determine the optimal litter size day for selection (i.e., other than d 5). Traits included TNB, number born alive (NBA), litter size at d 2, 5, 10, 30 (LS2, LS5, LS10, LS30, respectively), litter size at weaning (LSW), number weaned (NW), piglet mortality at d 30 (MortD30), and average piglet birth weight (BirthWt). Litter size traits were assigned to biological litters and treated as a trait of the sow. In contrast, NW was the number of piglets weaned by the nurse dam. Bivariate animal models included farm, year-season, and parity as fixed effects. Number born alive was fit as a covariate for BirthWt. Random effects included additive genetics and the permanent environment of the sow. Variance components were plotted for TNB, NBA, and LS2 to LS30 using univariate animal models to determine how variances changed over time. Additive genetic variance was minimized at d 7 in Large White and at d 14 in Landrace pigs. Total phenotypic variance for litter size traits decreased over the first 10 d and then stabilized. Heritability estimates increased between TNB and LS30. Genetic correlations between TNB, NBA, and LS2 to LS29 with LS30 plateaued within the first 10 d. A genetic correlation with LS30 of 0.95 was reached at d 4 for Large White and at d 8 for Landrace pigs. Heritability estimates ranged from 0.07 to 0.13 for litter size traits and MortD30. Birth weight had an h of 0.24 and 0.26 for Large White and Landrace pigs, respectively. Genetic correlations among LS30, LSW, and NW ranged from 0.97 to 1.00. In the Large White breed, genetic correlations between MortD30 with TNB and LS30 were 0.23 and -0.64, respectively. These correlations were 0.10 and -0.61 in the Landrace breed. A high genetic correlation of 0.98 and 0.97 was observed between LS10 and NW for Large White and

  15. Estimation models of variance components for farrowing interval in swine

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    Aderbal Cavalcante Neto

    2009-02-01

    Full Text Available The main objective of this study was to evaluate the importance of including maternal genetic, common litter environmental and permanent environmental effects in estimation models of variance components for the farrowing interval trait in swine. Data consisting of 1,013 farrowing intervals of Dalland (C-40 sows recorded in two herds were analyzed. Variance components were obtained by the derivative-free restricted maximum likelihood method. Eight models were tested which contained the fixed effects(contemporary group and covariables and the direct genetic additive and residual effects, and varied regarding the inclusion of the maternal genetic, common litter environmental, and/or permanent environmental random effects. The likelihood-ratio test indicated that the inclusion of these effects in the model was unnecessary, but the inclusion of the permanent environmental effect caused changes in the estimates of heritability, which varied from 0.00 to 0.03. In conclusion, the heritability values obtained indicated that this trait appears to present no genetic gain as response to selection. The common litter environmental and the maternal genetic effects did not present any influence on this trait. The permanent environmental effect, however, should be considered in the genetic models for this trait in swine, because its presence caused changes in the additive genetic variance estimates.Este trabalho teve como objetivo principal avaliar a importância da inclusão dos efeitos genético materno, comum de leitegada e de ambiente permanente no modelo de estimação de componentes de variância para a característica intervalo de parto em fêmeas suínas. Foram utilizados dados que consistiam de 1.013 observações de fêmeas Dalland (C-40, registradas em dois rebanhos. As estimativas dos componentes de variância foram realizadas pelo método da máxima verossimilhança restrita livre de derivadas. Foram testados oito modelos, que continham os efeitos

  16. Familial resemblance for physique: heritabilities for somatotype components.

    Science.gov (United States)

    Katzmarzyk, P T; Malina, R M; Pérusse, L; Rice, T; Province, M A; Rao, D C; Bouchard, C

    2000-01-01

    To examine familial resemblance in the Heath-Carter anthropometric somatotype in a sample of 328 participants from 103 nuclear families in Northern Ontario (Canada). The three somatotype components (endomorphy, mesomorphy, ectomorphy) were subjected to principal components analysis and the resulting first principal component (PCI) was used as an additional index of physique. The four phenotypes were adjusted for age, sex and generation effects, while each of the three somatotype components was further adjusted for the effects of the other two components using regression procedures. A familial correlation model was fit to the data and used to estimate the degree of familial resemblance in somatotype. For all somatotype variables, the most parsimonious model was one in which there was no spouse resemblance and no sex or generation effects in the familial correlations. Maximal heritabilities were 56%, 68%, 56% and 64% for endomorphy, mesomorphy, ectomorphy and PCI, respectively, indicating significant familial resemblance for the Heath-Carter anthropometric somatotype. Further, the pattern of familial correlations suggests the role of genetic factors in explaining variation in human physique. In general, a pattern of no spouse but significant parent-child correlations implicates the role of genes on human physique, provided that mating is random with regard to these traits.

  17. Heritability of the somatotype components in Biscay families.

    Science.gov (United States)

    Rebato, E; Jelenkovic, A; Salces, I

    2007-01-01

    The anthropometric somatotype is a quantitative description of body shape and composition. Familial studies indicate the existence of a familial resemblance for this phenotype and they suggest a substantial action by genetic factors on this aggregation. The aim of this study is to examine the degree of familial resemblance of the somatotype components and of a factor of shape, in a sample of Biscay nuclear families (Basque Country, Spain). One thousand three hundred and thirty nuclear families were analysed. The anthropometric somatotype components [Carter, J.E.L., Heath, B.H., 1990. Somatotyping. Development and applications. Cambridge University Press, Cambridge, p. 503] were computed. Each component was fitted for the other two through a stepwise multiple regression, and also fitted through the LMS method [Cole, T., 1988. Fitting smoothed centile curves to reference data. J. Roy. Stat. Soc. 151, 385-418] in order to eliminate the age, sex and generation effects. The three raw components were introduced in a PCA from which a shape factor (PC1) was extracted for each generation. The correlations analysis was performed with the SEGPATH package [Province, M.A., Rao, D.C., 1995. General purpose model and computer programme for combined segregation and path analysis (SEGPATH): automatically creating computer from symbolic language model specifications. Genet. Epidemiol. 12, 203-219]. A general model of transmission and nine reduced models were tested. Maximal heritability was estimated with the formula of [Rice, T., Warwick, D.E., Gagnon, J., Bouchard, C., Leon, A.S., Skinner, J.S., Wilmore, J.H., Rao, D.C., 1997. Familial resemblance for body composition measures: the HERITAGE family study. Obes. Res. 5, 557-562]. The correlations were higher between offspring than in parents and offspring and a significant resemblance between mating partners existed. Maximum heritabilities were 55%, 52% and 46% for endomorphy, mesomorphy and ectomorphy, respectively, and 52% for PC1

  18. Components of genetic variability and heritability of grain yield of silage maize

    Directory of Open Access Journals (Sweden)

    Sečanski Mile D.

    2004-01-01

    Full Text Available The aim of the present study was to evaluate the following parameters for the grain yield of silage maize: variability of inbred lines and their diallel hybrids, superior-parent heterosis and components of genetic variability and heritability on the basis of the diallel set. The two-year four-replicate trial was set up according to the randomized complete-block design at Zemun Polje. It was determined that a genotype, year and their interaction significantly affected variability of this trait. The highest. i.e. the lowest grain yield, on the average for both investigation years. was recorded in the silage maize inbred lines ZPLB402 and ZPLB405. respectively. The analysis of components of genetic variance for grain yield shows that the additive component (D was lower than the dominant (H1 and H2 genetic variance, while a positive component F and the frequency of dominant (u and recessive (v genes for this observed trait point to prevalence of dominant genes over recessive ones. Furthermore. this is confirmed by the ratio of dominant to recessive genes in parental genotypes for grain yield (Kd/Kr> 1 that is greater than unity in both years of investigation. The estimated value of the average degree of dominance (H1/D1/2 exceeds unity, pointing out to superdominance in inheritance of this trait in both years of investigation. Results of Vr/Vr regression analysis indicate superdominance in inheritance of grain yield. Moreover. a registered presence of non-allelic interaction points out to the need to study effects of epistasis, as it can have a greater significance in certain hybrids. A greater value of dominant than additive variance resulted in high values of broad-sense heritability for grain yield in both investigation years (98.71%, i.e. 97.19% in 1997, i.e. 1998, respectively. and low values of narrow-sense heritability (11.9% in 1997 and 12.2% in 1998.

  19. Direct and maternal variance component estimates for clean fleece ...

    African Journals Online (AJOL)

    ... -3.17o en -2.47o vir LG, SVG en GVD, respektiewelik. Daar word tot die gevolgtrekking gekom dat die maternale komponent weens die relatiewe klein effek op hierdie eienskappe, geigno- reer kan word. Keywords: Merino sheep, maternal variance, variance components. *To whom correspondence should be addressed.

  20. Heritability of blood pressure traits and the genetic contribution to blood pressure variance explained by four blood-pressure-related genes.

    NARCIS (Netherlands)

    Rijn, M.J. van; Schut, A.F.; Aulchenko, Y.S.; Deinum, J.; Sayed-Tabatabaei, F.A.; Yazdanpanah, M.; Isaacs, A.; Axenovich, T.I.; Zorkoltseva, I.V.; Zillikens, M.C.; Pols, H.A.; Witteman, J.C.; Oostra, B.A.; Duijn, C.M. van

    2007-01-01

    OBJECTIVE: To study the heritability of four blood pressure traits and the proportion of variance explained by four blood-pressure-related genes. METHODS: All participants are members of an extended pedigree from a Dutch genetically isolated population. Heritability and genetic correlations of

  1. Heritabilities of somatotype components in a population from rural Mozambique.

    Science.gov (United States)

    Saranga, Sílvio Pedro José; Prista, António; Nhantumbo, Leonardo; Beunen, Gaston; Rocha, Jorge; Williams-Blangero, Sarah; Maia, José A

    2008-01-01

    There have been few genetic studies of normal variation in body size and composition conducted in Africa. In particular, the genetic determinants of somatotype remain to be established for an African population. (1) To estimate the heritabilities of aspects of somatotype and (2) to compare the quantitative genetic effects in an African population to those that have been assessed in European and American populations. The sample composed of 329 subjects (173 males and 156 females) aged 7-17 years, belonging to 132 families. The sibships in the sample ranged in size from two to seven individuals. All sampled individuals were residents of the Calanga region, an area located to the north of Maputo in Mozambique. Somatotype was assessed using the Heath-Carter technique. Herit abilities were estimated using SAGE software. Moderate heritabilities were determined for each trait. Between 30 and 40% of the variation in each somatotype measure was attributable to genetic factors. The heritability of ectomorphy was 31%. Mesomorphy was similarly moderately heritable, with approximately 30% of the variationattributable to genetic factors. The heritability of endomorph was higher in the Calanga population (h(2) = 0.40). Quantitative genetic analyses of somatotype variation among siblings indicate that genetic factors significantly influence endomorphy, mesomorhpy, and ectomorphy. However, environmental factors also have significant effects on the variation in physique present in the population of Calanga. Lack of proper nutrition, housing, medical assistance, and primary health care, together with very demanding and sex-specific daily chores may contribute to the environmental effects on these traits.

  2. Genetic heterogeneity of residual variance - estimation of variance components using double hierarchical generalized linear models

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    Fikse Freddy

    2010-03-01

    Full Text Available Abstract Background The sensitivity to microenvironmental changes varies among animals and may be under genetic control. It is essential to take this element into account when aiming at breeding robust farm animals. Here, linear mixed models with genetic effects in the residual variance part of the model can be used. Such models have previously been fitted using EM and MCMC algorithms. Results We propose the use of double hierarchical generalized linear models (DHGLM, where the squared residuals are assumed to be gamma distributed and the residual variance is fitted using a generalized linear model. The algorithm iterates between two sets of mixed model equations, one on the level of observations and one on the level of variances. The method was validated using simulations and also by re-analyzing a data set on pig litter size that was previously analyzed using a Bayesian approach. The pig litter size data contained 10,060 records from 4,149 sows. The DHGLM was implemented using the ASReml software and the algorithm converged within three minutes on a Linux server. The estimates were similar to those previously obtained using Bayesian methodology, especially the variance components in the residual variance part of the model. Conclusions We have shown that variance components in the residual variance part of a linear mixed model can be estimated using a DHGLM approach. The method enables analyses of animal models with large numbers of observations. An important future development of the DHGLM methodology is to include the genetic correlation between the random effects in the mean and residual variance parts of the model as a parameter of the DHGLM.

  3. Application of variance components estimation to calibrate geoid error models.

    Science.gov (United States)

    Guo, Dong-Mei; Xu, Hou-Ze

    2015-01-01

    The method of using Global Positioning System-leveling data to obtain orthometric heights has been well studied. A simple formulation for the weighted least squares problem has been presented in an earlier work. This formulation allows one directly employing the errors-in-variables models which completely descript the covariance matrices of the observables. However, an important question that what accuracy level can be achieved has not yet to be satisfactorily solved by this traditional formulation. One of the main reasons for this is the incorrectness of the stochastic models in the adjustment, which in turn allows improving the stochastic models of measurement noises. Therefore the issue of determining the stochastic modeling of observables in the combined adjustment with heterogeneous height types will be a main focus point in this paper. Firstly, the well-known method of variance component estimation is employed to calibrate the errors of heterogeneous height data in a combined least square adjustment of ellipsoidal, orthometric and gravimetric geoid. Specifically, the iterative algorithms of minimum norm quadratic unbiased estimation are used to estimate the variance components for each of heterogeneous observations. Secondly, two different statistical models are presented to illustrate the theory. The first method directly uses the errors-in-variables as a priori covariance matrices and the second method analyzes the biases of variance components and then proposes bias-corrected variance component estimators. Several numerical test results show the capability and effectiveness of the variance components estimation procedure in combined adjustment for calibrating geoid error model.

  4. Using extended genealogy to estimate components of heritability for 23 quantitative and dichotomous traits.

    Directory of Open Access Journals (Sweden)

    Noah Zaitlen

    2013-05-01

    Full Text Available Important knowledge about the determinants of complex human phenotypes can be obtained from the estimation of heritability, the fraction of phenotypic variation in a population that is determined by genetic factors. Here, we make use of extensive phenotype data in Iceland, long-range phased genotypes, and a population-wide genealogical database to examine the heritability of 11 quantitative and 12 dichotomous phenotypes in a sample of 38,167 individuals. Most previous estimates of heritability are derived from family-based approaches such as twin studies, which may be biased upwards by epistatic interactions or shared environment. Our estimates of heritability, based on both closely and distantly related pairs of individuals, are significantly lower than those from previous studies. We examine phenotypic correlations across a range of relationships, from siblings to first cousins, and find that the excess phenotypic correlation in these related individuals is predominantly due to shared environment as opposed to dominance or epistasis. We also develop a new method to jointly estimate narrow-sense heritability and the heritability explained by genotyped SNPs. Unlike existing methods, this approach permits the use of information from both closely and distantly related pairs of individuals, thereby reducing the variance of estimates of heritability explained by genotyped SNPs while preventing upward bias. Our results show that common SNPs explain a larger proportion of the heritability than previously thought, with SNPs present on Illumina 300K genotyping arrays explaining more than half of the heritability for the 23 phenotypes examined in this study. Much of the remaining heritability is likely to be due to rare alleles that are not captured by standard genotyping arrays.

  5. Using extended genealogy to estimate components of heritability for 23 quantitative and dichotomous traits.

    Science.gov (United States)

    Zaitlen, Noah; Kraft, Peter; Patterson, Nick; Pasaniuc, Bogdan; Bhatia, Gaurav; Pollack, Samuela; Price, Alkes L

    2013-05-01

    Important knowledge about the determinants of complex human phenotypes can be obtained from the estimation of heritability, the fraction of phenotypic variation in a population that is determined by genetic factors. Here, we make use of extensive phenotype data in Iceland, long-range phased genotypes, and a population-wide genealogical database to examine the heritability of 11 quantitative and 12 dichotomous phenotypes in a sample of 38,167 individuals. Most previous estimates of heritability are derived from family-based approaches such as twin studies, which may be biased upwards by epistatic interactions or shared environment. Our estimates of heritability, based on both closely and distantly related pairs of individuals, are significantly lower than those from previous studies. We examine phenotypic correlations across a range of relationships, from siblings to first cousins, and find that the excess phenotypic correlation in these related individuals is predominantly due to shared environment as opposed to dominance or epistasis. We also develop a new method to jointly estimate narrow-sense heritability and the heritability explained by genotyped SNPs. Unlike existing methods, this approach permits the use of information from both closely and distantly related pairs of individuals, thereby reducing the variance of estimates of heritability explained by genotyped SNPs while preventing upward bias. Our results show that common SNPs explain a larger proportion of the heritability than previously thought, with SNPs present on Illumina 300K genotyping arrays explaining more than half of the heritability for the 23 phenotypes examined in this study. Much of the remaining heritability is likely to be due to rare alleles that are not captured by standard genotyping arrays.

  6. Variance components and genetic parameters for body weight and ...

    African Journals Online (AJOL)

    Variance components resulting from direct additive genetic effects, maternal additive genetic effects, maternal permanent environmental effects, as well as the relationship between direct and maternal genetic effects for several body weight and fleece traits, were estimated by DFREML procedures. Traits analysed included ...

  7. (co) variance components and genetic parameters for live weight ...

    African Journals Online (AJOL)

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    Against this background the present study estimated the (co)variance components as well as the genetic, phenotypic, environmental and maternal correlations for 16-months live weight and objectively measured wool traits in a South African Merino flock. Materials and Methods. The experimental flock is maintained on the ...

  8. Genetic variance components for residual feed intake and feed ...

    African Journals Online (AJOL)

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    South African Society for Animal Science. 257. Genetic variance components for residual feed intake and feed conversion ratio and their correlations with other production traits in beef bulls. R.R. van der Westhuizen. #. , J. van der Westhuizen and S.J. Schoeman. 1. ARC-Animal Improvement Institute, Private Bag X2, Irene ...

  9. Variance component estimation on female fertility traits in beef cattle

    African Journals Online (AJOL)

    Unknown

    sasas.co.za/Sajas.html. 131. Review Article. Variance component estimation on female fertility traits in beef cattle. T. Rust. 1# and E. Groeneveld. 2. 1 ARC Animal Improvement Institute, Irene 0062, South Africa; 2 Institute of Animal Husbandry and ...

  10. Combining abilities and components of variance for ear height in silage maize

    Directory of Open Access Journals (Sweden)

    Sečanski Mile

    2007-01-01

    Full Text Available The aim of this study was to evaluate the following parameters for the ear height of silage maize: variability of inbred lines and their diallel hybrids, superior-parent heterosis, components of genetic variability, heritability and combining ability on the basis of a diallel set. The two-year four-replicate trail was set up according to the randomized block design in the location of Zemun Polje. The analysis of components of genetic variance for ear height indicates that the additive components (D were lower than dominant components (H1 and H2 of genetic variance, while the frequency of dominant (u and recessive genes (v for this observed trait shows that dominant genes prevailed. The results of the Vr/Wr regression analysis point out to superdominance of ear height inheritance. The analysis of variance of combining abilities shows that there were highly significantly positive values of GCA and SCA for ear height in both years of investigation. Non-additive gene effects played an important role in inheritance of this trait, which was illustrated by the GCS to SCA ratio < 1.

  11. 8Wambi heritability.pmd

    African Journals Online (AJOL)

    ACSS

    as a percentage of the mean (GAM) and heritability were estimated using variance components. Phenotypic. Coefficient of Variation ... exhibited moderate GCV values. Broad and narrow sense heritability estimates for GRD disease score ..... in some faba bean genotypes (Vicia faba L.) grown in Northwestern Ethiopia.

  12. Heritability of somatotype components from early adolescence into young adulthood: a multivariate analysis on a longitudinal twin study.

    Science.gov (United States)

    Peeters, M W; Thomis, M A; Claessens, A L; Loos, R J F; Maes, H H M; Lysens, R; Vanden Eynde, B; Vlietinck, R; Beunen, G

    2003-01-01

    Several studies with different designs have attempted to estimate the heritability of somatotype components. However they often ignore the covariation between the three components as well as possible sex and age effects. Shared environmental factors are not always controlled for. This study explores the pattern of genetic and environmental determination of the variation in Heath-Carter somatotype components from early adolescence into young adulthood. Data from the Leuven Longitudinal Twin Study, a longitudinal sample of Belgian same-aged twins followed from 10 to 18 years (n = 105 pairs, equally divided over five zygosity groups), is entered into a multivariate path analysis. Thus the covariation between the somatotype components is taken into account, gender heterogeneity can be tested, common environmental influences can be distinguished from genetic effects and age effects are controlled for. Heritability estimates from 10 to 18 years range from 0.21 to 0.88, 0.46 to 0.76 and 0.16 to 0.73 for endomorphy, mesomorphy and ectomorphy in boys. In girls, heritability estimates range from 0.76 to 0.89, 0.36 to 0.57 and 0.57 to 0.76 for the respective somatotype components. Sex differences are significant from 14 years onwards. More than half of the variance in all somatotype components for both sexes at all time points is explained by factors the three components have in common. The finding of substantial genetic influence on the variability of somatotype components is further supported. The need to consider somatotype as a whole is stressed as well as the need for sex- and perhaps age-specific analyses. Further multivariate analyses are needed to confirm the present findings.

  13. Kriging with Unknown Variance Components for Regional Ionospheric Reconstruction

    Directory of Open Access Journals (Sweden)

    Ling Huang

    2017-02-01

    Full Text Available Ionospheric delay effect is a critical issue that limits the accuracy of precise Global Navigation Satellite System (GNSS positioning and navigation for single-frequency users, especially in mid- and low-latitude regions where variations in the ionosphere are larger. Kriging spatial interpolation techniques have been recently introduced to model the spatial correlation and variability of ionosphere, which intrinsically assume that the ionosphere field is stochastically stationary but does not take the random observational errors into account. In this paper, by treating the spatial statistical information on ionosphere as prior knowledge and based on Total Electron Content (TEC semivariogram analysis, we use Kriging techniques to spatially interpolate TEC values. By assuming that the stochastic models of both the ionospheric signals and measurement errors are only known up to some unknown factors, we propose a new Kriging spatial interpolation method with unknown variance components for both the signals of ionosphere and TEC measurements. Variance component estimation has been integrated with Kriging to reconstruct regional ionospheric delays. The method has been applied to data from the Crustal Movement Observation Network of China (CMONOC and compared with the ordinary Kriging and polynomial interpolations with spherical cap harmonic functions, polynomial functions and low-degree spherical harmonic functions. The statistics of results indicate that the daily ionospheric variations during the experimental period characterized by the proposed approach have good agreement with the other methods, ranging from 10 to 80 TEC Unit (TECU, 1 TECU = 1 × 1016 electrons/m2 with an overall mean of 28.2 TECU. The proposed method can produce more appropriate estimations whose general TEC level is as smooth as the ordinary Kriging but with a smaller standard deviation around 3 TECU than others. The residual results show that the interpolation precision of the

  14. Estimation of Variance Components and Genetic Parameters for Direct and Maternal Effects on Birth Weight in Brown Swiss Cattle

    Directory of Open Access Journals (Sweden)

    Ali Kaygisiz*, Galip Bakir1, Isa Yilmaz2 and Yusuf Vanli3

    2011-01-01

    Full Text Available The purpose of this study was to estimate the variance components and genetic parameters for birth weight in Brown Swiss cattle reared at Malya and Konuklar State Farms, Türkiye. The least square means of birth weight were 39.91±0.005 and 42.26±0.09kg for the calves raised at Malya and Konuklar State Farms, respectively. The effects of calving year, parity and calf sex on birth weight were significant (P<0.05. The effect of calving season on birth weight was highly significant (P<0.01 for Malya State Farm, while it was non-significant for Konuklar State Farm. Direct heritability (h2d, maternal heritability (h2m, total heritability (h2T and the fraction of variance due to maternal permanent environmental effects (c2 were 0.09, 0.04, 0.11 and 0.04, respectively for birth weights of the calves raised at Malya State Farms. The corresponding values of birth weight for calves raised at Konuklar State Farm were 0.39, 0.015, 0.29 and 0.018, respectively.

  15. Genetic variance components for residual feed intake and feed ...

    African Journals Online (AJOL)

    admin

    Genetic selection to improve feed efficiency aims to reduce feeding cost in beef cattle and thereby improve profitability. ... (reproduction or feedlot post-weaning growth efficiency). The heritability ... support reasoning that the inclusion of RFI will contribute towards both pre-weaning as well as post-weaning profitability in beef ...

  16. Estimation of variance components including competitive effects of Large White growing gilts.

    Science.gov (United States)

    Arango, J; Misztal, I; Tsuruta, S; Culbertson, M; Herring, W

    2005-06-01

    Records of on-test ADG of Large White gilts were analyzed to estimate variance components of direct and associative genetic effects. Models included the effects of contemporary group (farm-barn-batch), birth litter, pen group, and direct and associative additive genetic effects. The area of each pen was 14 m2. The additive genetic variance was a function of the number of competitors in a group, the additive relationships between the animal performing the record and its pen mates, and the additive relationships between pen mates. To partially account for differences in the number of pen mates, a covariable (qi = 1, 1/n, or 1/n(1/2)) was added to the associative genetic effect. There were 4,946 records from 2,409 litters and 362 pen groups. Pen group size ranged from 12 to 16 gilts. Analyses by REML converged very slowly. A grid search showed that the likelihood function was almost flat when the additive genetic associative effect was fitted. Estimates of direct and associative heritability were 0.15 and 0.03, respectively. Within the BLUPF90 family of programs, the mixed-model equations can be set up directly. For variance component estimation, simple programs (REMLF90 and GIBBSF90) worked without modifications, but more optimized programs did not. Estimates obtained using the three values of qi were similar. With the data structure available for this study and under an environment with relative low competition among animals, accurate estimation of associative genetic effects was not possible. Estimation of competitive effects with large pen size is difficult. The magnitude of competition effects may be larger in commercial populations, where housing is denser and food is limited.

  17. Variance components estimation for farrowing traits of three purebred pigs in Korea

    Directory of Open Access Journals (Sweden)

    Bryan Irvine Lopez

    2017-09-01

    Full Text Available Objective This study was conducted to estimate breed-specific variance components for total number born (TNB, number born alive (NBA and mortality rate from birth through weaning including stillbirths (MORT of three main swine breeds in Korea. In addition, the importance of including maternal genetic and service sire effects in estimation models was evaluated. Methods Records of farrowing traits from 6,412 Duroc, 18,020 Landrace, and 54,254 Yorkshire sows collected from January 2001 to September 2016 from different farms in Korea were used in the analysis. Animal models and the restricted maximum likelihood method were used to estimate variances in animal genetic, permanent environmental, maternal genetic, service sire and residuals. Results The heritability estimates ranged from 0.072 to 0.102, 0.090 to 0.099, and 0.109 to 0.121 for TNB; 0.087 to 0.110, 0.088 to 0.100, and 0.099 to 0.107 for NBA; and 0.027 to 0.031, 0.050 to 0.053, and 0.073 to 0.081 for MORT in the Duroc, Landrace and Yorkshire breeds, respectively. The proportion of the total variation due to permanent environmental effects, maternal genetic effects, and service sire effects ranged from 0.042 to 0.088, 0.001 to 0.031, and 0.001 to 0.021, respectively. Spearman rank correlations among models ranged from 0.98 to 0.99, demonstrating that the maternal genetic and service sire effects have small effects on the precision of the breeding value. Conclusion Models that include additive genetic and permanent environmental effects are suitable for farrowing traits in Duroc, Landrace, and Yorkshire populations in Korea. This breed-specific variance components estimates for litter traits can be utilized for pig improvement programs in Korea.

  18. Estimates of (co)variance components and genetic parameters for growth traits of Avikalin sheep.

    Science.gov (United States)

    Prince, Leslie Leo L; Gowane, Gopal R; Chopra, Ashish; Arora, Amrit L

    2010-08-01

    (Co)variance components and genetic parameters for various growth traits of Avikalin sheep maintained at Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, India, were estimated by Restricted Maximum Likelihood, fitting six animal models with various combinations of direct and maternal effects. Records of 3,840 animals descended from 257 sires and 1,194 dams were taken for this study over a period of 32 years (1977-2008). Direct heritability estimates (from best model as per likelihood ratio test) for weight at birth, weaning, 6 and 12 months of age, and average daily gain from birth to weaning, weaning to 6 months, and 6 to 12 months were 0.28 +/- 0.03, 0.20 +/- 0.03, 0.28 +/- 0.07, 0.15 +/- 0.04, 0.21 +/- 0.03, 0.16 and 0.03 +/- 0.03, respectively. Maternal heritability for traits declined as animal grows older and it was not at all evident at adult age and for post-weaning daily gain. Maternal permanent environmental effect (c(2)) declined significantly with advancement of age of animal. A small effect of c(2) on post-weaning weights was probably a carryover effect of pre-weaning maternal influence. A significant large negative genetic correlation was observed between direct and maternal genetic effects for all the traits, indicating antagonistic pleiotropy, which needs special care while formulating breeding plans. A fair rate of genetic progress seems possible in the flock by selection for all traits, but direct and maternal genetic correlation needs to be taken in to consideration.

  19. Genetic variance components for residual feed intake and feed ...

    African Journals Online (AJOL)

    Feeding costs of animals is a major determinant of profitability in livestock production enterprises. Genetic selection to improve feed efficiency aims to reduce feeding cost in beef cattle and thereby improve profitability. This study estimated genetic (co)variances between weaning weight and other production, reproduction ...

  20. Estimates of variance components for postweaning feed intake and ...

    African Journals Online (AJOL)

    The objective of this work was to evaluate alternative measures of feed efficiency for use in genetic evaluation. To meet this objective, genetic parameters were estimated for the components of efficiency. These parameters were then used in multiple-trait animal model genetic evaluations and alternative genetic predictors of ...

  1. Estimates of variance components for postweaning feed intake and ...

    African Journals Online (AJOL)

    Mike

    2013-03-09

    Mar 9, 2013 ... evaluate alternative measures of feed efficiency for use in genetic evaluation. To meet this objective, genetic parameters were estimated for the components of efficiency. These parameters were then used in multiple- trait animal model genetic evaluations and alternative genetic predictors of feed efficiency ...

  2. Principal component approach in variance component estimation for international sire evaluation

    Directory of Open Access Journals (Sweden)

    Jakobsen Jette

    2011-05-01

    Full Text Available Abstract Background The dairy cattle breeding industry is a highly globalized business, which needs internationally comparable and reliable breeding values of sires. The international Bull Evaluation Service, Interbull, was established in 1983 to respond to this need. Currently, Interbull performs multiple-trait across country evaluations (MACE for several traits and breeds in dairy cattle and provides international breeding values to its member countries. Estimating parameters for MACE is challenging since the structure of datasets and conventional use of multiple-trait models easily result in over-parameterized genetic covariance matrices. The number of parameters to be estimated can be reduced by taking into account only the leading principal components of the traits considered. For MACE, this is readily implemented in a random regression model. Methods This article compares two principal component approaches to estimate variance components for MACE using real datasets. The methods tested were a REML approach that directly estimates the genetic principal components (direct PC and the so-called bottom-up REML approach (bottom-up PC, in which traits are sequentially added to the analysis and the statistically significant genetic principal components are retained. Furthermore, this article evaluates the utility of the bottom-up PC approach to determine the appropriate rank of the (covariance matrix. Results Our study demonstrates the usefulness of both approaches and shows that they can be applied to large multi-country models considering all concerned countries simultaneously. These strategies can thus replace the current practice of estimating the covariance components required through a series of analyses involving selected subsets of traits. Our results support the importance of using the appropriate rank in the genetic (covariance matrix. Using too low a rank resulted in biased parameter estimates, whereas too high a rank did not result in

  3. A Cure for Variance Inflation in High Dimensional Kernel Principal Component Analysis

    DEFF Research Database (Denmark)

    Abrahamsen, Trine Julie; Hansen, Lars Kai

    2011-01-01

    Small sample high-dimensional principal component analysis (PCA) suffers from variance inflation and lack of generalizability. It has earlier been pointed out that a simple leave-one-out variance renormalization scheme can cure the problem. In this paper we generalize the cure in two directions...

  4. Tests and Confidence Intervals for an Extended Variance Component Using the Modified Likelihood Ratio Statistic

    DEFF Research Database (Denmark)

    Christensen, Ole Fredslund; Frydenberg, Morten; Jensen, Jens Ledet

    2005-01-01

    The large deviation modified likelihood ratio statistic is studied for testing a variance component equal to a specified value. Formulas are presented in the general balanced case, whereas in the unbalanced case only the one-way random effects model is studied. Simulation studies are presented, s......, showing that the normal approximation to the large deviation modified likelihood ratio statistic gives confidence intervals for variance components with coverage probabilities very close to the nominal confidence coefficient....

  5. Heritability of ocular component dimensions in chickens: genetic variants controlling susceptibility to experimentally induced myopia and pretreatment eye size are distinct.

    Science.gov (United States)

    Chen, Yen-Po; Prashar, Ankush; Erichsen, Jonathan T; To, Chi-Ho; Hocking, Paul M; Guggenheim, Jeremy A

    2011-06-08

    Purpose. To investigate the extent to which shared genetic variants control (1) multiple ocular component dimensions and (2) both normal eye length and susceptibility to visually induced myopic eye growth. Methods. Two laboratory-reared populations of chicks were examined. The first was a three-generation pedigree of White Leghorn (WL) birds used in a selective breeding experiment testing susceptibility to monocular deprivation of sharp vision (DSV). The chicks were assessed before (age, 4 days) and after 4 days of treatment with diffusers. The second was the 10th generation of an advanced intercross line (AIL) derived from a broiler-layer cross (age, 3 weeks). Variance components analysis was used to estimate heritability and to assess the evidence for shared genetic determination. Results. All measured ocular components were moderately or highly heritable (range, 0.36-0.61; all P shared across some ocular traits (corneal curvature, vitreous chamber depth, and axial length) but distinct for others (lens thickness and corneal thickness). The genetic variants controlling susceptibility to visually induced myopia in chicks are different from those controlling normal eye size.

  6. Estimates of Broad-Sense Heritability for Seed Yield and Yield Components of Grass Pea (Lathyrus sativus L.)

    OpenAIRE

    TÜRK, Mevlüt; Sebahattin ALBAYRAK; Necmettin ÇELİK

    2014-01-01

    This study was carried out to estimate the broad-sense heritability for seed yield and some yield components of 15 grass pea (Lathyrus sativus L.) genotypes in 2000-2002 at Bursa, in the Marmara region of Turkey. The experimental design was a randomized complete block design with 3 replications. The heritabilities for seed yield, plant height, pod number, seed number per pod, seed number per plant, 1000-seed weight, biologic yield, and harvest index were estimated as 30%, 42%, 61%, 19%, 56%, ...

  7. Technical Note: Introduction of variance component analysis to setup error analysis in radiotherapy.

    Science.gov (United States)

    Matsuo, Yukinori; Nakamura, Mitsuhiro; Mizowaki, Takashi; Hiraoka, Masahiro

    2016-09-01

    The purpose of this technical note is to introduce variance component analysis to the estimation of systematic and random components in setup error of radiotherapy. Balanced data according to the one-factor random effect model were assumed. Analysis-of-variance (anova)-based computation was applied to estimate the values and their confidence intervals (CIs) for systematic and random errors and the population mean of setup errors. The conventional method overestimates systematic error, especially in hypofractionated settings. The CI for systematic error becomes much wider than that for random error. The anova-based estimation can be extended to a multifactor model considering multiple causes of setup errors (e.g., interpatient, interfraction, and intrafraction). Variance component analysis may lead to novel applications to setup error analysis in radiotherapy.

  8. Two-Variance-Component Model Improves Genetic Prediction in Family Datasets.

    Science.gov (United States)

    Tucker, George; Loh, Po-Ru; MacLeod, Iona M; Hayes, Ben J; Goddard, Michael E; Berger, Bonnie; Price, Alkes L

    2015-11-05

    Genetic prediction based on either identity by state (IBS) sharing or pedigree information has been investigated extensively with best linear unbiased prediction (BLUP) methods. Such methods were pioneered in plant and animal-breeding literature and have since been applied to predict human traits, with the aim of eventual clinical utility. However, methods to combine IBS sharing and pedigree information for genetic prediction in humans have not been explored. We introduce a two-variance-component model for genetic prediction: one component for IBS sharing and one for approximate pedigree structure, both estimated with genetic markers. In simulations using real genotypes from the Candidate-gene Association Resource (CARe) and Framingham Heart Study (FHS) family cohorts, we demonstrate that the two-variance-component model achieves gains in prediction r(2) over standard BLUP at current sample sizes, and we project, based on simulations, that these gains will continue to hold at larger sample sizes. Accordingly, in analyses of four quantitative phenotypes from CARe and two quantitative phenotypes from FHS, the two-variance-component model significantly improves prediction r(2) in each case, with up to a 20% relative improvement. We also find that standard mixed-model association tests can produce inflated test statistics in datasets with related individuals, whereas the two-variance-component model corrects for inflation. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  9. How to assess intra- and inter-observer agreement with quantitative PET using variance component analysis

    DEFF Research Database (Denmark)

    Gerke, Oke; Vilstrup, Mie Holm; Segtnan, Eivind Antonsen

    2016-01-01

    BACKGROUND: Quantitative measurement procedures need to be accurate and precise to justify their clinical use. Precision reflects deviation of groups of measurement from another, often expressed as proportions of agreement, standard errors of measurement, coefficients of variation, or the Bland-A....... The involved linear mixed effects models require carefully considered sample sizes to account for the challenge of sufficiently accurately estimating variance components....

  10. Variability of indoor and outdoor VOC measurements: An analysis using variance components

    Science.gov (United States)

    Jia, Chunrong; Batterman, Stuart A.; Relyea, George E.

    2014-01-01

    This study examines concentrations of volatile organic compounds (VOCs) measured inside and outside of 162 residences in southeast Michigan, U.S.A. Nested analyses apportioned four sources of variation: city, residence, season, and measurement uncertainty. Indoor measurements were dominated by seasonal and residence effects, accounting for 50 and 31%, respectively, of the total variance. Contributions from measurement uncertainty (VOC concentrations can use multi-seasonal measurements at centralized locations. Error models showed that uncertainties at low concentrations might obscure effects of other factors. Variance component analyses can be used to interpret existing measurements, design effective exposure studies, and determine whether the instrumentation and protocols are satisfactory. PMID:21995872

  11. Resolution of Students t-tests, ANOVA and analysis of variance components from intermediary data.

    Science.gov (United States)

    Anders, Kallner

    2017-06-15

    Significance testing in comparisons is based on Student's t-tests for pairs and analysis of variance (ANOVA) for simultaneous comparison of several procedures. Access to the average, standard deviation and number of observations is sufficient for calculating the significance of differences using the Student's tests and the ANOVA. Once an ANOVA has been calculated, analysis of variance components from summary data becomes possible. Simple calculations based on summary data provide inference on significance testing. Examples are given from laboratory management and method comparisons. It is emphasized that the usual criteria of the underlying distribution of the raw data must be fulfilled.

  12. Analysis of experiments in square lattice with emphasis on variance components. i. Individual analysis

    OpenAIRE

    Silva,Heyder Diniz; Regazzi,Adair José; Cruz,Cosme Damião; Viana,José Marcelo Soriano

    1999-01-01

    This paper focused on four alternatives of analysis of experiments in square lattice as far as the estimation of variance components and some genetic parameters are concerned: 1) intra-block analysis with adjusted treatment and blocks within unadjusted repetitions; 2) lattice analysis as complete randomized blocks; 3) intrablock analysis with unadjusted treatment and blocks within adjusted repetitions; 4) lattice analysis as complete randomized blocks, by utilizing the adjusted means of treat...

  13. Dominance, epistasis, heritabilities and expected genetic gains

    Directory of Open Access Journals (Sweden)

    José Marcelo Soriano Viana

    2005-03-01

    Full Text Available Although epistasis is common in gene systems that determine quantitative traits, it is usually not possible to estimate the epistatic components of genotypic variance because experiments in breeding programs include only one type of progeny. As the study of this phenomenon is complex, there is a lack of theoretical knowledge on the contribution of the epistatic variances when predicting gains from selection and on the bias in estimating genetic parameters when fitting the additive-dominant model. The objective of this paper is to discuss these aspects. Regarding a non-inbred population, the genetic value due to dominance and the epistatic components of the genotypic value are not indicators of the number of favorable genes present in an individual. Thus, the efficiency of a selection process should be based on the narrow-sense heritability, a function only of additive variance. If there is no epistasis, generally it is satisfactory to assess the selection efficiency and to predict gain based on the broad-sense heritability. Regardless of the selection unit or type of epistasis, the bias in the estimate of the additive variance when assuming the additive-dominant model is considerable. This implies overestimation of the heritabilities at half sib family mean, plant within family and plant levels, and underestimation if the selection units are full sib progenies. The predicted gains will have a bias proportional to that of the heritability.

  14. A procedure for isolating social desirability variance in a three-way component analysis.

    Science.gov (United States)

    Lorenzo-Seva, Urbano; Ferrando, Pere J

    2012-02-01

    Three-way component analysis aims to summarize all the information in a three-way data set related, for example, to the responses of individuals to a set of items in a set of situations. The data are decomposed into three component matrices (person, item and situation components) and a core matrix. Such data are generally obtained by means of a situation-response questionnaire administered to a sample of participants. This paper proposes a preprocessing procedure for controlling social desirability in these kinds of questionnaires. The essential idea is to isolate the variance due to social desirability response bias and remove it from the data set. The procedure is demonstrated through its empirical application in the personality domain. Its performance is also assessed by means of a simulation study which shows that the presence of social desirability bias in a data set had different consequences: (1) the variance effect due to persons increased, and the effect of the triple interaction persons × items × situations decreased; (2) the person component and core matrix were partially distorted. However, the social desirability bias in the data set was successfully controlled by our preprocessing method. © 2011 The British Psychological Society.

  15. Estimation of variance components and prediction of breeding values in rubber tree breeding using the REML/BLUP procedure

    Directory of Open Access Journals (Sweden)

    Renata Capistrano Moreira Furlani

    2005-01-01

    Full Text Available The present paper deals with estimation of variance components, prediction of breeding values and selection in a population of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss. Müell.-Arg.] from Rio Branco, State of Acre, Brazil. The REML/BLUP (restricted maximum likelihood/best linear unbiased prediction procedure was applied. For this purpose, 37 rubber tree families were obtained and assessed in a randomized complete block design, with three unbalanced replications. The field trial was carried out at the Experimental Station of UNESP, located in Selvíria, State of Mato Grosso do Sul, Brazil. The quantitative traits evaluated were: girth (G, bark thickness (BT, number of latex vessel rings (NR, and plant height (PH. Given the unbalanced condition of the progeny test, the REML/BLUP procedure was used for estimation. The narrow-sense individual heritability estimates were 0.43 for G, 0.18 for BT, 0.01 for NR, and 0.51 for PH. Two selection strategies were adopted: one short-term (ST - selection intensity of 8.85% and the other long-term (LT - selection intensity of 26.56%. For G, the estimated genetic gains in relation to the population average were 26.80% and 17.94%, respectively, according to the ST and LT strategies. The effective population sizes were 22.35 and 46.03, respectively. The LT and ST strategies maintained 45.80% and 28.24%, respectively, of the original genetic diversity represented in the progeny test. So, it can be inferred that this population has potential for both breeding and ex situ genetic conservation as a supplier of genetic material for advanced rubber tree breeding programs.

  16. Principal variance component analysis of crop composition data: a case study on herbicide-tolerant cotton.

    Science.gov (United States)

    Harrison, Jay M; Howard, Delia; Malven, Marianne; Halls, Steven C; Culler, Angela H; Harrigan, George G; Wolfinger, Russell D

    2013-07-03

    Compositional studies on genetically modified (GM) and non-GM crops have consistently demonstrated that their respective levels of key nutrients and antinutrients are remarkably similar and that other factors such as germplasm and environment contribute more to compositional variability than transgenic breeding. We propose that graphical and statistical approaches that can provide meaningful evaluations of the relative impact of different factors to compositional variability may offer advantages over traditional frequentist testing. A case study on the novel application of principal variance component analysis (PVCA) in a compositional assessment of herbicide-tolerant GM cotton is presented. Results of the traditional analysis of variance approach confirmed the compositional equivalence of the GM and non-GM cotton. The multivariate approach of PVCA provided further information on the impact of location and germplasm on compositional variability relative to GM.

  17. Bayesian Variance Component Estimation Using the Inverse-Gamma Class of Priors in a Nested Generalizability Design

    Science.gov (United States)

    Arenson, Ethan A.

    2009-01-01

    One of the problems inherent in variance component estimation centers around inadmissible estimates. Such estimates occur when there is more variability within groups, relative to between groups. This paper suggests a Bayesian approach to resolve inadmissibility by placing noninformative inverse-gamma priors on the variance components, and…

  18. Components of behavioural impulsivity and automatic cue approach predict unique variance in hazardous drinking.

    Science.gov (United States)

    Christiansen, Paul; Cole, Jon C; Goudie, Andrew J; Field, Matt

    2012-01-01

    Hazardous drinking is associated with both increased impulsivity and automatic approach tendencies elicited by alcohol-related cues. However, impulsivity is a multi-factorial construct, and it is currently unclear if all components of impulsivity are associated with heavy drinking. Furthermore, emerging evidence suggests that the relationships between hazardous drinking and automatic alcohol cognitions may be moderated by individual differences in impulsivity. The aim of this study was to investigate the independence of measures of impulsivity and their association with hazardous drinking, and to examine if the relationship between hazardous drinking and automatic alcohol approach tendencies would be moderated by individual differences in impulsivity. Ninety-seven social drinkers (65 female) completed questionnaire measures of trait impulsivity, alcohol consumption and hazardous drinking. Participants also completed computerised measures of automatic alcohol approach tendencies (stimulus-response compatibility (SRC) task), and two behavioural measures of impulsivity (Go/No-go and delay discounting tasks). Principal component analysis revealed that the two measures of behavioural impulsivity were distinct from each other and from self-reported trait impulsivity, although self-reported non-planning impulsivity loaded on to two factors (trait impulsivity and delay discounting). Furthermore, all measures of impulsivity predicted unique variance in hazardous drinking as did automatic alcohol approach tendencies, although the latter relationship was not moderated by impulsivity. These results indicate that multiple components of impulsivity and automatic alcohol approach tendencies explain unique variance in hazardous drinking.

  19. SNP based heritability estimation using a Bayesian approach

    DEFF Research Database (Denmark)

    Krag, Kristian; Janss, Luc; Mahdi Shariati, Mohammad

    2013-01-01

    of 0.05, all models had difficulties in estimating the true heritability. The two Bayesian models were compared with a restricted maximum likelihood (REML) approach using a genomic relationship matrix. The comparison showed that the Bayesian approaches performed equally well as the REML approach......Heritability is a central element in quantitative genetics. New molecular markers to assess genetic variance and heritability are continually under development. The availability of molecular single nucleotide polymorphism (SNP) markers can be applied for estimation of variance components....... Differences in family structure were in general not found to influence the estimation of the heritability. For the sample sizes used in this study, a 10-fold increase of SNP density did not improve precision estimates compared with set-ups with a less dense distribution of SNPs. The methods used in this study...

  20. The heritability of blood donation

    DEFF Research Database (Denmark)

    Pedersen, Ole Birger; Axel, Skytthe; Rostgaard, Klaus

    2015-01-01

    BACKGROUND: Voluntary blood donation is believed to be mostly motivated by altruism. Because studies have suggested that altruistic personality is determined by both genetic and environmental factors, we speculated that willingness to donate blood could also be governed by constitutional factors...... active Danish blood donors from 2002 to 2012, to establish blood donor status for Danish twins, who at age 17 years became eligible for donation in 2002 or later. Casewise concordance in monozygotic (MZ) and dizygotic (DZ) twins were presented and heritability was estimated in Mx by variance component...... to donate blood, respectively. CONCLUSION: Becoming a volunteer blood donor is determined by both genetic and environmental factors shared within families....

  1. Genetic variances, heritabilities and maternal effects on body weight, breast meat yield, meat quality traits and the shape of the growth curve in turkey birds

    Directory of Open Access Journals (Sweden)

    Ducro Bart J

    2011-01-01

    Full Text Available Abstract Background Turkey is an important agricultural species and is largely used as a meat bird. In 2004, turkey represented 6.5% of the world poultry meat production. The world-wide turkey population has rapidly grown due to increased commercial farming. Due to the high demand for turkey meat from both consumers and industry global turkey stocks increased from 100 million in 1970 to over 276 million in 2004. This rapidly increasing importance of turkeys was a reason to design this study for the estimation of genetic parameters that control body weight, body composition, meat quality traits and parameters that shape the growth curve in turkey birds. Results The average heritability estimate for body weight traits was 0.38, except for early weights that were strongly affected by maternal effects. This study showed that body weight traits, upper asymptote (a growth curve trait, percent breast meat and redness of meat had high heritability whereas heritabilities of breast length, breast width, percent drip loss, ultimate pH, lightness and yellowness of meat were medium to low. We found high positive genetic and phenotypic correlations between body weight, upper asymptote, most breast meat yield traits and percent drip loss but percent drip loss was found strongly negatively correlated with ultimate pH. Percent breast meat, however, showed genetic correlations close to zero with body weight traits and upper asymptote. Conclusion The results of this analysis and the growth curve from the studied population of turkey birds suggest that the turkey birds could be selected for breeding between 60 and 80 days of age in order to improve overall production and the production of desirable cuts of meat. The continuous selection of birds within this age range could promote high growth rates but specific attention to meat quality would be needed to avoid a negative impact on the quality of meat.

  2. Genetic variances, heritabilities and maternal effects on body weight, breast meat yield, meat quality traits and the shape of the growth curve in turkey birds.

    Science.gov (United States)

    Aslam, Muhammad L; Bastiaansen, John Wm; Crooijmans, Richard Pma; Ducro, Bart J; Vereijken, Addie; Groenen, Martien Am

    2011-01-25

    Turkey is an important agricultural species and is largely used as a meat bird. In 2004, turkey represented 6.5% of the world poultry meat production. The world-wide turkey population has rapidly grown due to increased commercial farming. Due to the high demand for turkey meat from both consumers and industry global turkey stocks increased from 100 million in 1970 to over 276 million in 2004. This rapidly increasing importance of turkeys was a reason to design this study for the estimation of genetic parameters that control body weight, body composition, meat quality traits and parameters that shape the growth curve in turkey birds. The average heritability estimate for body weight traits was 0.38, except for early weights that were strongly affected by maternal effects. This study showed that body weight traits, upper asymptote (a growth curve trait), percent breast meat and redness of meat had high heritability whereas heritabilities of breast length, breast width, percent drip loss, ultimate pH, lightness and yellowness of meat were medium to low. We found high positive genetic and phenotypic correlations between body weight, upper asymptote, most breast meat yield traits and percent drip loss but percent drip loss was found strongly negatively correlated with ultimate pH. Percent breast meat, however, showed genetic correlations close to zero with body weight traits and upper asymptote. The results of this analysis and the growth curve from the studied population of turkey birds suggest that the turkey birds could be selected for breeding between 60 and 80 days of age in order to improve overall production and the production of desirable cuts of meat. The continuous selection of birds within this age range could promote high growth rates but specific attention to meat quality would be needed to avoid a negative impact on the quality of meat.

  3. Cooperative Localization Algorithm for Multiple Mobile Robot System in Indoor Environment Based on Variance Component Estimation

    Directory of Open Access Journals (Sweden)

    Qian Sun

    2017-06-01

    Full Text Available The Multiple Mobile Robot (MMR cooperative system is becoming a focus of study in various fields due to its advantages, such as high efficiency and good fault tolerance. However, the uncertainty and nonlinearity problems severely limit the cooperative localization accuracy of the MMR system. Thus, to solve the problems mentioned above, this manuscript presents a cooperative localization algorithm for MMR systems based on Cubature Kalman Filter (CKF and adaptive Variance Component Estimation (VCE methods. In this novel algorithm, a nonlinear filter named CKF is used to enhance the cooperative localization accuracy and reduce the computational load. On the other hand, the adaptive VCE method is introduced to eliminate the effects of unknown system noise. Furthermore, the performance of the proposed algorithm is compared with that of the cooperative localization algorithm based on normal CKF by utilizing the real experiment data. In addition, the results demonstrate that the proposed algorithm outperforms the CKF cooperative localization algorithm both in accuracy and consistency.

  4. Partitioning within-species variance in behaviour to within- and between-population components for understanding evolution.

    Science.gov (United States)

    Garamszegi, László Zsolt; Møller, Anders Pape

    2017-05-01

    Phenotypes vary at multiple hierarchical levels, of which the interspecific variance is the primary focus of phylogenetic comparative studies. However, the evolutionary role of particular within-species variance components (between-population, between- or within-individual variances) remains neglected. Here, we partition the variance in an anti-predator behaviour, flight initiation distance (FID), and assess how its within- and between-population variance are related to life history, distribution, dispersal and habitat ecology. Although the composition of within-species variance in FID depended on the phylogeny, most variance occurred within populations. When accounting for allometry, density-dependence, uncertainty in the phylogenetic hypothesis and heterogeneity in data quality, within-population variance was significantly associated with habitat diversity and population size. Between-population variance was a significant predictor of natal dispersal, senescence and habitat diversity. Accordingly, not only species-specific mean values of a behavioural trait, but also its variance within and among populations can shape the evolutionary ecology of species. © 2017 John Wiley & Sons Ltd/CNRS.

  5. Genome-wide estimation of heritability and its functional components for flowering, defense, ionomics, and developmental traits in a geographically diverse population of Arabidopsis thaliana.

    Science.gov (United States)

    Yang, Rong-Cai

    2017-07-01

    Narrow-sense heritability (portion of the total phenotypic variation attributable to additive genetic effect, h 2 ) is a critical parameter in plant breeding and genetics, but its estimation is difficult for populations with unknown pedigree information. This study applied a marker-based linear mixed model (LMM) analysis to estimate narrow-sense heritability and its seven functional components corresponding to SNPs in coding and noncoding regions for each of 107 flowering, defense, ionomics, and developmental traits in an Arabidopsis (Arabidopsis thaliana) population of 199 inbred lines with unknown genetic relatedness. Genetic relationship matrix (GRM) based on 214 051 SNPs and component GRMs based on seven subsets of SNPs were computed for LMM estimation of h 2 and functional components contributing to h 2 , respectively. The h 2 estimates for flowering traits were higher than those for defense, ionomics, and developmental traits, supporting a general view that the fitness-related traits have lower heritabilities than other traits. The function component owing to SNPs in coding (exon) regions was the least contributor to h 2 . Our LMM analysis provides an opportunity to gain a comprehensive view on heritability and its functional components for populations with unknown structure but with genome-wide DNA markers.

  6. Contrasting regional architectures of schizophrenia and other complex diseases using fast variance components analysis

    DEFF Research Database (Denmark)

    Loh, Po-Ru; Bhatia, Gaurav; Gusev, Alexander

    2015-01-01

    Heritability analyses of genome-wide association study (GWAS) cohorts have yielded important insights into complex disease architecture, and increasing sample sizes hold the promise of further discoveries. Here we analyze the genetic architectures of schizophrenia in 49,806 samples from the PGC...... and nine complex diseases in 54,734 samples from the GERA cohort. For schizophrenia, we infer an overwhelmingly polygenic disease architecture in which ≥71% of 1-Mb genomic regions harbor ≥1 variant influencing schizophrenia risk. We also observe significant enrichment of heritability in GC-rich regions...... and in higher-frequency SNPs for both schizophrenia and GERA diseases. In bivariate analyses, we observe significant genetic correlations (ranging from 0.18 to 0.85) for several pairs of GERA diseases; genetic correlations were on average 1.3 tunes stronger than the correlations of overall disease liabilities...

  7. Estimation of variance components for somatic cell counts to determine thresholds for uninfected quarters.

    Science.gov (United States)

    Schepers, A J; Lam, T J; Schukken, Y H; Wilmink, J B; Hanekamp, W J

    1997-08-01

    The objective of this study was to determine the factors affecting somatic cell count (SCC), to estimate variance components of these factors, and to calculate and evaluate the thresholds for intramammary infection based on SCC. The infection status from 22,467 quarter milk samples from 544 cows in seven herds was determined. Infections status was the most important factor affecting SCC. The increase in SCC was more pronounced for major pathogens than for minor pathogens. Even after adjustment for infection status, the interaction between stage of lactation and parity was significant. For culture-negative samples within a lactation, the shape of the SCC curve was inversely related to the shape of the milk production curve. The shape of the SCC curve was flat for first lactation cows compared with the shape of the SCC curve for cows in subsequent lactations. The effect of clinical mastitis on SCC was significant. The use of SCC thresholds for specific parities and stages of lactation to detect intramammary infection improved quality parameters only slightly over a fixed threshold of 200,000 cells/ml.

  8. Accuracy and precision of variance components in occupational posture recordings: a simulation study of different data collection strategies

    Directory of Open Access Journals (Sweden)

    Liv Per

    2012-06-01

    Full Text Available Abstract Background Information on exposure variability, expressed as exposure variance components, is of vital use in occupational epidemiology, including informed risk control and efficient study design. While accurate and precise estimates of the variance components are desirable in such cases, very little research has been devoted to understanding the performance of data sampling strategies designed specifically to determine the size and structure of exposure variability. The aim of this study was to investigate the accuracy and precision of estimators of between-subjects, between-days and within-day variance components obtained by sampling strategies differing with respect to number of subjects, total sampling time per subject, number of days per subject and the size of individual sampling periods. Methods Minute-by-minute values of average elevation, percentage time above 90° and percentage time below 15° were calculated in a data set consisting of measurements of right upper arm elevation during four full shifts from each of 23 car mechanics. Based on this parent data, bootstrapping was used to simulate sampling with 80 different combinations of the number of subjects (10, 20, total sampling time per subject (60, 120, 240, 480 minutes, number of days per subject (2, 4, and size of sampling periods (blocks within days (1, 15, 60, 240 minutes. Accuracy (absence of bias and precision (prediction intervals of the variance component estimators were assessed for each simulated sampling strategy. Results Sampling in small blocks within days resulted in essentially unbiased variance components. For a specific total sampling time per subject, and in particular if this time was small, increasing the block size resulted in an increasing bias, primarily of the between-days and the within-days variance components. Prediction intervals were in general wide, and even more so at larger block sizes. Distributing sampling time across more days gave in

  9. Odor measurements according to EN 13725: A statistical analysis of variance components

    Science.gov (United States)

    Klarenbeek, Johannes V.; Ogink, Nico W. M.; van der Voet, Hilko

    2014-04-01

    In Europe, dynamic olfactometry, as described by the European standard EN 13725, has become the preferred method for evaluating odor emissions emanating from industrial and agricultural sources. Key elements of this standard are the quality criteria for trueness and precision (repeatability). Both are linked to standard values of n-butanol in nitrogen. It is assumed in this standard that whenever a laboratory complies with the overall sensory quality criteria for n-butanol, the quality level is transferable to other, environmental, odors. Although olfactometry is well established, little has been done to investigate inter laboratory variance (reproducibility). Therefore, the objective of this study was to estimate the reproducibility of odor laboratories complying with EN 13725 as well as to investigate the transferability of n-butanol quality criteria to other odorants. Based upon the statistical analysis of 412 odor measurements on 33 sources, distributed in 10 proficiency tests, it was established that laboratory, panel and panel session are components of variance that significantly differ between n-butanol and other odorants (α = 0.05). This finding does not support the transferability of the quality criteria, as determined on n-butanol, to other odorants and as such is a cause for reconsideration of the present single reference odorant as laid down in EN 13725. In case of non-butanol odorants, repeatability standard deviation (sr) and reproducibility standard deviation (sR) were calculated to be 0.108 and 0.282 respectively (log base-10). The latter implies that the difference between two consecutive single measurements, performed on the same testing material by two or more laboratories under reproducibility conditions, will not be larger than a factor 6.3 in 95% of cases. As far as n-butanol odorants are concerned, it was found that the present repeatability standard deviation (sr = 0.108) compares favorably to that of EN 13725 (sr = 0.172). It is therefore

  10. Estimation of variance components including competitive effects of Large White growing gilts

    National Research Council Canada - National Science Library

    Arango, J; Misztal, I; Tsuruta, S; Culbertson, M; Herring, W

    2005-01-01

    .... The area of each pen was 14 m 2 . The additive genetic variance was a function of the number of competitors in a group, the additive relationships between the animal performing the record and its pen mates, and the additive...

  11. How Reliable Are Students' Evaluations of Teaching Quality? A Variance Components Approach

    Science.gov (United States)

    Feistauer, Daniela; Richter, Tobias

    2017-01-01

    The inter-rater reliability of university students' evaluations of teaching quality was examined with cross-classified multilevel models. Students (N = 480) evaluated lectures and seminars over three years with a standardised evaluation questionnaire, yielding 4224 data points. The total variance of these student evaluations was separated into the…

  12. Estimates for Genetic Variance Components in Reciprocal Recurrent Selection in Populations Derived from Maize Single-Cross Hybrids

    Directory of Open Access Journals (Sweden)

    Matheus Costa dos Reis

    2014-01-01

    Full Text Available This study was carried out to obtain the estimates of genetic variance and covariance components related to intra- and interpopulation in the original populations (C0 and in the third cycle (C3 of reciprocal recurrent selection (RRS which allows breeders to define the best breeding strategy. For that purpose, the half-sib progenies of intrapopulation (P11 and P22 and interpopulation (P12 and P21 from populations 1 and 2 derived from single-cross hybrids in the 0 and 3 cycles of the reciprocal recurrent selection program were used. The intra- and interpopulation progenies were evaluated in a 10×10 triple lattice design in two separate locations. The data for unhusked ear weight (ear weight without husk and plant height were collected. All genetic variance and covariance components were estimated from the expected mean squares. The breakdown of additive variance into intrapopulation and interpopulation additive deviations (στ2 and the covariance between these and their intrapopulation additive effects (CovAτ found predominance of the dominance effect for unhusked ear weight. Plant height for these components shows that the intrapopulation additive effect explains most of the variation. Estimates for intrapopulation and interpopulation additive genetic variances confirm that populations derived from single-cross hybrids have potential for recurrent selection programs.

  13. Two-Variance-Component Model Improves Genetic Prediction in Family Datasets

    OpenAIRE

    Tucker, George; Loh, Po-Ru; MacLeod, Iona M.; Hayes, Ben J.; Goddard, Michael E.; Berger, Bonnie; Price, Alkes L.

    2015-01-01

    Genetic prediction based on either identity by state (IBS) sharing or pedigree information has been investigated extensively with best linear unbiased prediction (BLUP) methods. Such methods were pioneered in plant and animal-breeding literature and have since been applied to predict human traits, with the aim of eventual clinical utility. However, methods to combine IBS sharing and pedigree information for genetic prediction in humans have not been explored. We introduce a two-variance-compo...

  14. Bias Reduction in Estimating Variance Components of Phytoplankton Existence at Na Thap River Based on Logistics Linear Mixed Models

    Science.gov (United States)

    Arisanti, R.; Notodiputro, K. A.; Sadik, K.; Lim, A.

    2017-03-01

    There are two approaches in estimating variance components, i.e. linearity and integral approaches. However the estimates of variance components produced by both methods are known to be biased. Firth (1993) has introduced parameter estimation for correcting the bias of the maximum likelihood estimates. This method is within the class of linear models, especially the Restricted Maximum Likelihood (REML) method, and the resulting estimator is known as the Firth estimator. In this paper we discuss the bias correction method applied to a logistic linear mixed model in analyzing the existence of Synedra phytoplankton along Na Thap river in Thailand. The Firth adjusted Maximum Likelihood Estimation (MLE) is similar to REML but it shows the characteristic of generalized linear mixed model. We evaluated the Firth adjustment method by means of simulations and the result showed that the unadjusted MLE produced 95% confidence intervals which were narrower when compare to the Firth method. However, the probability coverage of the interval for unadjusted MLE was lower than 95%, whereas for the Firth method the probability coverage is approximately 95%. These results were also consistent with the variance estimation of the Synedra phytoplankton existence. It was shown that the variance estimates of Firth adjusted MLE was lower than the unadjusted MLE.

  15. Partitioning Heritability of Regulatory and Cell-Type-Specific Variants across 11 Common Diseases

    DEFF Research Database (Denmark)

    Gusev, Alexander; Lee, S Hong; Trynka, Gosia

    2014-01-01

    Regulatory and coding variants are known to be enriched with associations identified by genome-wide association studies (GWASs) of complex disease, but their contributions to trait heritability are currently unknown. We applied variance-component methods to imputed genotype data for 11 common...... diseases to partition the heritability explained by genotyped SNPs (hg(2)) across functional categories (while accounting for shared variance due to linkage disequilibrium). Extensive simulations showed that in contrast to current estimates from GWAS summary statistics, the variance-component approach...... partitions heritability accurately under a wide range of complex-disease architectures. Across the 11 diseases DNaseI hypersensitivity sites (DHSs) from 217 cell types spanned 16% of imputed SNPs (and 24% of genotyped SNPs) but explained an average of 79% (SE = 8%) of hg(2) from imputed SNPs (5.1× enrichment...

  16. Heritability of bipolar affective disorder: Family study

    Directory of Open Access Journals (Sweden)

    Obradović Tanja

    2011-01-01

    Full Text Available Background/Aim. Bipolar affective disorder is mental disorder with polygenic type of heredity. Heritability - relation between genetic and environmental variance is used to estimate the level of influence of genetic variance to phenotype variance. Study results show decreasing trend in the value of heritability of bipolar affective disorder, thus indicating that this disorder is a complex behavioral threshold characteristic. Therefore, the aim of this study was to estimate the contribution of genetic variance to phenotype variance of bipolar affective disorder, i.e. to estimate heritability of this disorder. Methods. By the use of a questionnaire, 80 patients with over crossed threshold for bipolar affective disorder were asked for functional information about the members of their families belonging to the first degree of relation (fathers, mothers and full- sibs. By using ”Applet for calculating heritability for threshold traits (disease“, and regression analysis, heritability of bipolar affective disorder as well as its statistical significance, were estimated (χ2 test. Results. Heritability and relationship of genetic and environmental variance of bipolar affective disorder is 0.2 with statistically significant difference from zero (p < 0.001. Conclusion. The estimated contribution of genetic variance to phenotype variance of bipolar affective disorder is low being 20%, while the contribution of environmental variance is 80%. This result contributes to the understanding of bipolar affective disorder as a complex behavioral threshold trait.

  17. Components of variance in brain perfusion and the design of studies of individual differences: the baseline study.

    Science.gov (United States)

    Viviani, Roberto; Sim, Eun-Jin; Lo, Hanna; Richter, Sven; Haffer, Sebastian; Osterfeld, Nadine; Thöne, Jan; Beschoner, Petra

    2009-05-15

    Simple baseline studies correlate average perfusion levels measured at rest with individual variables, or contrast subject groups as in case-control studies. In this methodological work, we summarize some formal properties of the design of these studies, and investigate the sources of variance that characterize data acquired with the arterial spin labeling technique, with the purpose of alerting users to the main sources of variation that determine background variance and affect the power of statistical tests. This design typology is characterized by two variance components: between acquisitions and between subjects. We show that variation between acquisitions is affected by the presence of large vessels and venous sinuses, with potential adverse effects especially in the temporal and insular regions, and provide maps of the number of acquisitions or subjects required to reach the desired estimate precision. Furthermore, we show that the largest source of variation between subjects is captured by global perfusion levels, and can in principle be removed by adjusting the data. Significance levels, however, are not always only improved by the adjustment procedure; we provide an example in the correlation with age, and attempt to explain the consequences of the adjustment with the help of a principal component analysis of the data. We also show the existence of variation between subjects in the perfusion in the territory of the posterior cerebral artery and in hemispheric asymmetry.

  18. Genetic variance and covariance components related to intra- and interpopulation recurrent selection in maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Arias Carlos Alberto Arrabal

    1998-01-01

    Full Text Available New genetic variance and covariance components related to intra- and interpopulational recurrent selection methods have been theoretically developed by Souza Jr. (Rev. Bras. Genet. 16: 91-105, 1993 to explain the failure of these methods to concomitantly develop hybrid and per se populations. Intra- and interpopulation half-sib progenies of 100 genotypes were sampled from maize (Zea mays L. populations BR-106 and BR-105 to estimate variance and covariance components and to compare the expected responses to reciprocal (RRS, intrapopulational (HSS, and modified (MRS recurrent selection in interpopulation hybrid, populations per se, and to determine heterosis. Four sets of 100 progenies, two intra- and two interpopulational, were evaluated in partially balanced 10 x 10 lattices arranged in split-blocks with two replications in two years (1991/92 and 1992/93 and two locations in Piracicaba, SP. Data for ear weight, plant and ear height, and ear by plant height ratio were recorded. Populations and interpopulation crosses were high yielding and showed high breeding potential for production of hybrids from inbred lines. Mid parent and the highest parent heterosis were relatively high, but lower than values reported for these populations under other environmental conditions. Additive variance estimates of populations per se and interpopulation crosses confirmed the high potential of these materials. The magnitude of the variance estimates for the deviations from intra- and interpopulation additive effects ( for BR-106 and for BR-105 and covariance between additive effects with these deviations ( for BR-106 and for BR-105 indicated that these new components can significantly influence the effectiveness of breeding methods. Genetic component estimates for BR-105 had relatively small errors, with negative for all traits. Estimates of and had relatively larger errors for BR-106. The MRS method was more effective than the RRS and HSS methods in producing

  19. On the Estimation of Heritability with Family-Based and Population-Based Samples

    Directory of Open Access Journals (Sweden)

    Youngdoe Kim

    2015-01-01

    Full Text Available For a family-based sample, the phenotypic variance-covariance matrix can be parameterized to include the variance of a polygenic effect that has then been estimated using a variance component analysis. However, with the advent of large-scale genomic data, the genetic relationship matrix (GRM can be estimated and can be utilized to parameterize the variance of a polygenic effect for population-based samples. Therefore narrow sense heritability, which is both population and trait specific, can be estimated with both population- and family-based samples. In this study we estimate heritability from both family-based and population-based samples, collected in Korea, and the heritability estimates from the pooled samples were, for height, 0.60; body mass index (BMI, 0.32; log-transformed triglycerides (log TG, 0.24; total cholesterol (TCHL, 0.30; high-density lipoprotein (HDL, 0.38; low-density lipoprotein (LDL, 0.29; systolic blood pressure (SBP, 0.23; and diastolic blood pressure (DBP, 0.24. Furthermore, we found differences in how heritability is estimated—in particular the amount of variance attributable to common environment in twins can be substantial—which indicates heritability estimates should be interpreted with caution.

  20. Heritability in inflammatory bowel disease

    DEFF Research Database (Denmark)

    Gordon, Hannah; Trier Moller, Frederik; Andersen, Vibeke

    2015-01-01

    estimation regard genetic and environmental variance as separate entities, although it is now understood that there is a complex multidirectional interplay between genetic are environmental factors mediated by the microbiota, the epigenome, and the innate and acquired immune systems. Due to the limitations...... of heritability estimates, it is unlikely that a true value for heritability will be reached. Further work aimed at quantifying the variance explained across GWAS, epigenome-wide, and microbiota-wide association studies will help to define factors leading to inflammatory bowel disease....

  1. Using variance components to estimate power in a hierarchically nested sampling design improving monitoring of larval Devils Hole pupfish

    Science.gov (United States)

    Dzul, Maria C.; Dixon, Philip M.; Quist, Michael C.; Dinsomore, Stephen J.; Bower, Michael R.; Wilson, Kevin P.; Gaines, D. Bailey

    2013-01-01

    We used variance components to assess allocation of sampling effort in a hierarchically nested sampling design for ongoing monitoring of early life history stages of the federally endangered Devils Hole pupfish (DHP) (Cyprinodon diabolis). Sampling design for larval DHP included surveys (5 days each spring 2007–2009), events, and plots. Each survey was comprised of three counting events, where DHP larvae on nine plots were counted plot by plot. Statistical analysis of larval abundance included three components: (1) evaluation of power from various sample size combinations, (2) comparison of power in fixed and random plot designs, and (3) assessment of yearly differences in the power of the survey. Results indicated that increasing the sample size at the lowest level of sampling represented the most realistic option to increase the survey's power, fixed plot designs had greater power than random plot designs, and the power of the larval survey varied by year. This study provides an example of how monitoring efforts may benefit from coupling variance components estimation with power analysis to assess sampling design.

  2. The contribution of dominance and inbreeding depression in estimating variance components for litter size in Pannon White rabbits.

    Science.gov (United States)

    Nagy, I; Gorjanc, G; Curik, I; Farkas, J; Kiszlinger, H; Szendrő, Zs

    2013-08-01

    In a synthetic closed population of Pannon White rabbits, additive (VA ), dominance (VD ) and permanent environmental (VPe ) variance components as well as doe (bF d ) and litter (bF l ) inbreeding depression were estimated for the number of kits born alive (NBA), number of kits born dead (NBD) and total number of kits born (TNB). The data set consisted of 18,398 kindling records of 3883 does collected from 1992 to 2009. Six models were used to estimate dominance and inbreeding effects. The most complete model estimated VA and VD to contribute 5.5 ± 1.1% and 4.8 ± 2.4%, respectively, to total phenotypic variance (VP ) for NBA; the corresponding values for NBD were 1.9 ± 0.6% and 5.3 ± 2.4%, for TNB, 6.2 ± 1.0% and 8.1 ± 3.2% respectively. These results indicate the presence of considerable VD . Including dominance in the model generally reduced VA and VPe estimates, and had only a very small effect on inbreeding depression estimates. Including inbreeding covariates did not affect estimates of any variance component. A 10% increase in doe inbreeding significantly increased NBD (bF d  = 0.18 ± 0.07), while a 10% increase in litter inbreeding significantly reduced NBA (bF l  = -0.41 ± 0.11) and TNB (bF l  = -0.34 ± 0.10). These findings argue for including dominance effects in models of litter size traits in populations that exhibit significant dominance relationships. © 2012 Blackwell Verlag GmbH.

  3. Detecting parent of origin and dominant QTL in a two-generation commercial poultry pedigree using variance component methodology

    Directory of Open Access Journals (Sweden)

    Haley Christopher S

    2009-01-01

    Full Text Available Abstract Introduction Variance component QTL methodology was used to analyse three candidate regions on chicken chromosomes 1, 4 and 5 for dominant and parent-of-origin QTL effects. Data were available for bodyweight and conformation score measured at 40 days from a two-generation commercial broiler dam line. One hundred dams were nested in 46 sires with phenotypes and genotypes on 2708 offspring. Linear models were constructed to simultaneously estimate fixed, polygenic and QTL effects. Different genetic models were compared using likelihood ratio test statistics derived from the comparison of full with reduced or null models. Empirical thresholds were derived by permutation analysis. Results Dominant QTL were found for bodyweight on chicken chromosome 4 and for bodyweight and conformation score on chicken chromosome 5. Suggestive evidence for a maternally expressed QTL for bodyweight and conformation score was found on chromosome 1 in a region corresponding to orthologous imprinted regions in the human and mouse. Conclusion Initial results suggest that variance component analysis can be applied within commercial populations for the direct detection of segregating dominant and parent of origin effects.

  4. Heritability of flight and resting metabolic rates in the Glanville fritillary butterfly.

    Science.gov (United States)

    Mattila, A L K; Hanski, I

    2014-08-01

    Dispersal capacity is a key life-history trait especially in species inhabiting fragmented landscapes. Evolutionary models predict that, given sufficient heritable variation, dispersal rate responds to natural selection imposed by habitat loss and fragmentation. Here, we estimate phenotypic variance components and heritability of flight and resting metabolic rates (RMRs) in an ecological model species, the Glanville fritillary butterfly, in which flight metabolic rate (FMR) is known to correlate strongly with dispersal rate. We modelled a two-generation pedigree with the animal model to distinguish additive genetic variance from maternal and common environmental effects. The results show that FMR is significantly heritable, with additive genetic variance accounting for about 40% of total phenotypic variance; thus, FMR has the potential to respond to selection on dispersal capacity. Maternal influences on flight metabolism were negligible. Heritability of flight metabolism was context dependent, as in stressful thermal conditions, environmentally induced variation dominated over additive genetic effects. There was no heritability in RMR, which was instead strongly influenced by maternal effects. This study contributes to a mechanistic understanding of the evolution of dispersal-related traits, a pressing question in view of the challenges posed to many species by changing climate and fragmentation of natural habitats. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  5. Heritability of physical activity traits in Brazilian families: the Baependi Heart Study

    Directory of Open Access Journals (Sweden)

    Horimoto Andréa RVR

    2011-11-01

    Full Text Available Abstract Background It is commonly recognized that physical activity has familial aggregation; however, the genetic influences on physical activity phenotypes are not well characterized. This study aimed to (1 estimate the heritability of physical activity traits in Brazilian families; and (2 investigate whether genetic and environmental variance components contribute differently to the expression of these phenotypes in males and females. Methods The sample that constitutes the Baependi Heart Study is comprised of 1,693 individuals in 95 Brazilian families. The phenotypes were self-reported in a questionnaire based on the WHO-MONICA instrument. Variance component approaches, implemented in the SOLAR (Sequential Oligogenic Linkage Analysis Routines computer package, were applied to estimate the heritability and to evaluate the heterogeneity of variance components by gender on the studied phenotypes. Results The heritability estimates were intermediate (35% for weekly physical activity among non-sedentary subjects (weekly PA_NS, and low (9-14% for sedentarism, weekly physical activity (weekly PA, and level of daily physical activity (daily PA. Significant evidence for heterogeneity in variance components by gender was observed for the sedentarism and weekly PA phenotypes. No significant gender differences in genetic or environmental variance components were observed for the weekly PA_NS trait. The daily PA phenotype was predominantly influenced by environmental factors, with larger effects in males than in females. Conclusions Heritability estimates for physical activity phenotypes in this sample of the Brazilian population were significant in both males and females, and varied from low to intermediate magnitude. Significant evidence for heterogeneity in variance components by gender was observed. These data add to the knowledge of the physical activity traits in the Brazilian study population, and are concordant with the notion of significant

  6. Variance components of aggressive behavior in genetically highly connected Pietrain populations kept under two different housing conditions.

    Science.gov (United States)

    Appel, Anne K; Voß, Barbara; Tönepöhl, Björn; König von Borstel, Uta; Gauly, Matthias

    2013-12-01

    Mixing of unfamiliar pigs is a standard management procedure in commercial pig production and is often associated with a period of intense and physically damaging aggression. Aggression is considered a problem for animal welfare and production. The objective of the present paper was to investigate the genetic background of aggressive behavior traits at mixing of unfamiliar gilts under 2 different housing conditions. Therefore, a total of 543 purebred Pietrain gilts, from 2 nucleus farms (farm A: n = 302; farm B: n = 241) of 1 breeding company, were tested at an average age of 214 d (SD 12.2 d) for aggressive behavior by 1 observer. Observations included the frequencies of aggressive attack and reciprocal fighting during mixing with unfamiliar gilts. On farm A 41% of the gilts were purebred Pietrains, whereas 59% were purebred Landrace or Duroc gilts. On the farm B 42% of the gilts were purebred Pietrains, and 58% purebred Large White gilts. The average size of the newly mixed groups of gilts was 28 animals on farm A and 18 animals on farm B. The Pietrain gilts from the 2 herds were genetically closely linked. They were the offspring of 96 sires, with 64% of these sires having tested progeny in both farms. There were clear differences in the housing of the animals between the 2 farms. The test pen on farm A had a solid concrete floor littered with wooden shavings and was equipped with a dry feeder. On farm B there was a partly slatted floor, and the gilts were fed by an electronic sow feeder. Mean space allowance was 2.6 m(2)/gilt on farm A and 3.9 m(2)/gilt on farm B. Although large interindividual differences existed, gilts from farm B performed numerically more aggressive attack (mean 1.12, SD 1.42 vs. mean 0.71, SD 1.20) and reciprocal fighting (mean 0.78, SD 0.98 vs. mean 0.44, SD 0.82) when compared with gilts from farm A. The heritabilities and additive genetic variances for behavioral traits were estimated with a linear animal model and were on a low level

  7. Estimates of Genotype x Environment Interactions and Heritability of Black Point in Durum Wheat

    Directory of Open Access Journals (Sweden)

    Hasan Hasan KILIÇ

    2009-12-01

    Full Text Available Experiments were carried out in four different locations with 14 durum wheat genotypes in two successful seasons of 1999- 2000 and 2000-2001. Black point disease of genotypes was evaluated by interactions of genotypes and environment as well as heritability (h2. It was found that black point disease affected differently in different locations and growing seasons. This indicates that the genotypes have different adaptation ability for traits studied in different locations. Heritability rate that variance analyzes accepted means squares calculated was found as phenotypic variance rate of genotypic variance was found as 49%. Variance of genotype x location x year was bigger than other variance components. Genotype x year variance was bigger than genotype x location variance too. The heritability of black point disease was founded moderate. In addition to one of factors on the black point disease genotype also environment x genotype interactions were found effective. According to evaluation of black point disease, the highest value was obtained from ‘Sorgül’ (2.7%, ‘Dicle-74’ (2.56% and ‘Gidara-II’ (2.32% varieties; the least value was obtained from ‘Balcali-2000’ variety (0.64%. Alternaria spp., Phoma sp, Fusarium spp., Helminthosporium spp., and Stemphylium spp., fungi were isolated from the grain affected by black point diseases.

  8. Genotype by environment interactions, stability, and heritability of ...

    African Journals Online (AJOL)

    Genotype x location x year interaction variances were also found significant at all the traits except first pod height. The estimates of heritabilities with limited phenotypic variance definition were ... Moderate or low heritabilities estimated for all the traits showed that family selection method could be used instead of individual ...

  9. Heterogeneity of variance components for preweaning growth in Romane sheep due to the number of lambs reared

    Directory of Open Access Journals (Sweden)

    Poivey Jean-Paul

    2011-09-01

    Full Text Available Abstract Background The pre-weaning growth rate of lambs, an important component of meat market production, is affected by maternal and direct genetic effects. The French genetic evaluation model takes into account the number of lambs suckled by applying a multiplicative factor (1 for a lamb reared as a single, 0.7 for twin-reared lambs to the maternal genetic effect, in addition to including the birth*rearing type combination as a fixed effect, which acts on the mean. However, little evidence has been provided to justify the use of this multiplicative model. The two main objectives of the present study were to determine, by comparing models of analysis, 1 whether pre-weaning growth is the same trait in single- and twin-reared lambs and 2 whether the multiplicative coefficient represents a good approach for taking this possible difference into account. Methods Data on the pre-weaning growth rate, defined as the average daily gain from birth to 45 days of age on 29,612 Romane lambs born between 1987 and 2009 at the experimental farm of La Sapinière (INRA-France were used to compare eight models that account for the number of lambs per dam reared in various ways. Models were compared using the Akaike information criteria. Results The model that best fitted the data assumed that 1 direct (maternal effects correspond to the same trait regardless of the number of lambs reared, 2 the permanent environmental effects and variances associated with the dam depend on the number of lambs reared and 3 the residual variance depends on the number of lambs reared. Even though this model fitted the data better than a model that included a multiplicative coefficient, little difference was found between EBV from the different models (the correlation between EBV varied from 0.979 to 0.999. Conclusions Based on experimental data, the current genetic evaluation model can be improved to better take into account the number of lambs reared. Thus, it would be of

  10. Removing an intersubject variance component in a general linear model improves multiway factoring of event-related spectral perturbations in group EEG studies.

    Science.gov (United States)

    Spence, Jeffrey S; Brier, Matthew R; Hart, John; Ferree, Thomas C

    2013-03-01

    Linear statistical models are used very effectively to assess task-related differences in EEG power spectral analyses. Mixed models, in particular, accommodate more than one variance component in a multisubject study, where many trials of each condition of interest are measured on each subject. Generally, intra- and intersubject variances are both important to determine correct standard errors for inference on functions of model parameters, but it is often assumed that intersubject variance is the most important consideration in a group study. In this article, we show that, under common assumptions, estimates of some functions of model parameters, including estimates of task-related differences, are properly tested relative to the intrasubject variance component only. A substantial gain in statistical power can arise from the proper separation of variance components when there is more than one source of variability. We first develop this result analytically, then show how it benefits a multiway factoring of spectral, spatial, and temporal components from EEG data acquired in a group of healthy subjects performing a well-studied response inhibition task. Copyright © 2011 Wiley Periodicals, Inc.

  11. Joint analysis of beef growth and carcass quality traits through calculation of co-variance components and correlations.

    Science.gov (United States)

    Mirzaei, H R; Verbyla, A P; Pitchford, W S

    2011-03-15

    A joint growth-carcass model using random regression was used to estimate the (co)variance components of beef cattle body weights and carcass quality traits and correlations between them. During a four-year period (1994-1997) of the Australian "southern crossbreeding project", mature Hereford cows (N = 581) were mated to 97 sires of Jersey, Wagyu, Angus, Hereford, South Devon, Limousin, and Belgian Blue breeds, resulting in 1141 calves. Data included 13 (for steers) and 8 (for heifers) body weight measurements approximately every 50 days from birth until slaughter and four carcass quality traits: hot standard carcass weight, rump fat depth, rib eye muscle area, and intramuscular fat content. The mixed model included fixed effects of sex, sire breed, age (linear, quadratic and cubic), and their interactions between sex and sire breed with age. Random effects were sire, dam, management (birth location, year, post-weaning groups), and permanent environmental effects, and their interactions with linear, quadratic and cubic growth, when possible. Phenotypic, sire and dam correlations between body weights and hot standard carcass weight and rib eye muscle area were positive and moderate to high from birth to feedlot period. Management variation accounted for the largest proportion of total variation in both growth and carcass traits. Management correlations between carcass traits were high, except between rump fat depth and intramuscular fat (r = 0.26). Management correlations between body weight and carcass traits during the pre-weaning period were positive except for intramuscular fat. The correlations were low from birth to weaning, then increased dramatically and were high during the feedlot period.

  12. Variance and covariance estimates for weaning weight of Senepol cattle.

    Science.gov (United States)

    Wright, D W; Johnson, Z B; Brown, C J; Wildeus, S

    1991-10-01

    Variance and covariance components were estimated for weaning weight from Senepol field data for use in the reduced animal model for a maternally influenced trait. The 4,634 weaning records were used to evaluate 113 sires and 1,406 dams on the island of St. Croix. Estimates of direct additive genetic variance (sigma 2A), maternal additive genetic variance (sigma 2M), covariance between direct and maternal additive genetic effects (sigma AM), permanent maternal environmental variance (sigma 2PE), and residual variance (sigma 2 epsilon) were calculated by equating variances estimated from a sire-dam model and a sire-maternal grandsire model, with and without the inverse of the numerator relationship matrix (A-1), to their expectations. Estimates were sigma 2A, 139.05 and 138.14 kg2; sigma 2M, 307.04 and 288.90 kg2; sigma AM, -117.57 and -103.76 kg2; sigma 2PE, -258.35 and -243.40 kg2; and sigma 2 epsilon, 588.18 and 577.72 kg2 with and without A-1, respectively. Heritability estimates for direct additive (h2A) were .211 and .210 with and without A-1, respectively. Heritability estimates for maternal additive (h2M) were .47 and .44 with and without A-1, respectively. Correlations between direct and maternal (IAM) effects were -.57 and -.52 with and without A-1, respectively.

  13. Heritability of performance deficit accumulation during acute sleep deprivation in twins.

    Science.gov (United States)

    Kuna, Samuel T; Maislin, Greg; Pack, Frances M; Staley, Bethany; Hachadoorian, Robert; Coccaro, Emil F; Pack, Allan I

    2012-09-01

    To determine if the large and highly reproducible interindividual differences in rates of performance deficit accumulation during sleep deprivation, as determined by the number of lapses on a sustained reaction time test, the Psychomotor Vigilance Task (PVT), arise from a heritable trait. Prospective, observational cohort study. Academic medical center. There were 59 monozygotic (mean age 29.2 ± 6.8 [SD] yr; 15 male and 44 female pairs) and 41 dizygotic (mean age 26.6 ± 7.6 yr; 15 male and 26 female pairs) same-sex twin pairs with a normal polysomnogram. Thirty-eight hr of monitored, continuous sleep deprivation. Patients performed the 10-min PVT every 2 hr during the sleep deprivation protocol. The primary outcome was change from baseline in square root transformed total lapses (response time ≥ 500 ms) per trial. Patient-specific linear rates of performance deficit accumulation were separated from circadian effects using multiple linear regression. Using the classic approach to assess heritability, the intraclass correlation coefficients for accumulating deficits resulted in a broad sense heritability (h(2)) estimate of 0.834. The mean within-pair and among-pair heritability estimates determined by analysis of variance-based methods was 0.715. When variance components of mixed-effect multilevel models were estimated by maximum likelihood estimation and used to determine the proportions of phenotypic variance explained by genetic and nongenetic factors, 51.1% (standard error = 8.4%, P performance deficit accumulations on PVT during sleep deprivation.

  14. Heritability assessment of cartilage metabolism. A twin study on circulating procollagen IIA N-terminal propeptide (PIIANP)

    DEFF Research Database (Denmark)

    Munk, H L; Svendsen, A J; Hjelmborg, J V B

    2014-01-01

    OBJECTIVE: The aim of this investigation was to estimate the heritability of circulating collagen IIA N-terminal propeptide (PIIANP) by studying mono- and dizygotic healthy twin pairs at different age and both genders. DESIGN: 598 monozygotic (MZ) and dizygotic (DZ) twin individuals aged 18......-59 years were recruited from the Danish Twin Registry. PIIANP was measured by competitive ELISA. The similarity of circulating PIIANP among MZ and DZ twins was assessed by intraclass correlations according to traits. The heritability was estimated by variance component analysis accounting for additive...... genetic impact on PIIANP in serum. Additive genetic effects explained 45% (21-70%), shared environment 24% (7-53%) and non-shared environment 31% (24-39%) of the total variance. The heritability estimate did not differ across ages and between genders. CONCLUSIONS: The study shows that approximately 45...

  15. The heritability of glaucoma-related traits corneal hysteresis, central corneal thickness, intraocular pressure, and choroidal blood flow pulsatility.

    Science.gov (United States)

    Freeman, Ellen E; Roy-Gagnon, Marie-Hélène; Descovich, Denise; Massé, Hugues; Lesk, Mark R

    2013-01-01

    The purpose of this work was to investigate the heritability of potential glaucoma endophenotypes. We estimated for the first time the heritability of the pulsatility of choroidal blood flow. We also sought to confirm the heritability of corneal hysteresis, central corneal thickness, and 3 ways of measuring intraocular pressure. Measurements were performed on 96 first-degree relatives recruited from Maisonneuve-Rosemont Hospital in Montreal. Corneal hysteresis was determined using the Reichert Ocular Response Analyser. Central corneal thickness was measured with an ultrasound pachymeter. Three measures of intraocular pressure were obtained: Goldmann-correlated and corneal compensated intraocular pressure using the Ocular Response Analyser, and Pascal intraocular pressure using the Pascal Dynamic Contour Tonometer. The pulsatility of choroidal blood velocity and flow were measured in the sub-foveolar choroid using single-point laser Doppler flowmetry (Oculix). We estimated heritability using maximum-likelihood variance components methods implemented in the SOLAR software. No significant heritability was detected for the pulsatility of choroidal blood flow or velocity. The Goldman-correlated, corneal compensated, and Pascal measures of intraocular pressure measures were all significantly heritable at 0.94, 0.79, and 0.53 after age and sex adjustment (p = 0.0003, p = 0.0023, p = 0.0239). Central corneal thickness was significantly heritable at 0.68 (p = 0.0078). Corneal hysteresis was highly heritable but the estimate was at the upper boundary of 1.00 preventing us from giving a precise estimate. Corneal hysteresis, central corneal thickness, and intraocular pressure are all heritable and may be suitable as glaucoma endophenotypes. The pulsatility of choroidal blood flow and blood velocity were not significantly heritable in this sample.

  16. The heritability of glaucoma-related traits corneal hysteresis, central corneal thickness, intraocular pressure, and choroidal blood flow pulsatility.

    Directory of Open Access Journals (Sweden)

    Ellen E Freeman

    Full Text Available PURPOSE: The purpose of this work was to investigate the heritability of potential glaucoma endophenotypes. We estimated for the first time the heritability of the pulsatility of choroidal blood flow. We also sought to confirm the heritability of corneal hysteresis, central corneal thickness, and 3 ways of measuring intraocular pressure. METHODS: Measurements were performed on 96 first-degree relatives recruited from Maisonneuve-Rosemont Hospital in Montreal. Corneal hysteresis was determined using the Reichert Ocular Response Analyser. Central corneal thickness was measured with an ultrasound pachymeter. Three measures of intraocular pressure were obtained: Goldmann-correlated and corneal compensated intraocular pressure using the Ocular Response Analyser, and Pascal intraocular pressure using the Pascal Dynamic Contour Tonometer. The pulsatility of choroidal blood velocity and flow were measured in the sub-foveolar choroid using single-point laser Doppler flowmetry (Oculix. We estimated heritability using maximum-likelihood variance components methods implemented in the SOLAR software. RESULTS: No significant heritability was detected for the pulsatility of choroidal blood flow or velocity. The Goldman-correlated, corneal compensated, and Pascal measures of intraocular pressure measures were all significantly heritable at 0.94, 0.79, and 0.53 after age and sex adjustment (p = 0.0003, p = 0.0023, p = 0.0239. Central corneal thickness was significantly heritable at 0.68 (p = 0.0078. Corneal hysteresis was highly heritable but the estimate was at the upper boundary of 1.00 preventing us from giving a precise estimate. CONCLUSION: Corneal hysteresis, central corneal thickness, and intraocular pressure are all heritable and may be suitable as glaucoma endophenotypes. The pulsatility of choroidal blood flow and blood velocity were not significantly heritable in this sample.

  17. Estimation of Genetic Variance Components Including Mutation and Epistasis using Bayesian Approach in a Selection Experiment on Body Weight in Mice

    DEFF Research Database (Denmark)

    Widyas, Nuzul; Jensen, Just; Nielsen, Vivi Hunnicke

    Selection experiment was performed for weight gain in 13 generations of outbred mice. A total of 18 lines were included in the experiment. Nine lines were allotted to each of the two treatment diets (19.3 and 5.1 % protein). Within each diet three lines were selected upwards, three lines were...... selected downwards and three lines were kept as controls. Bayesian statistical methods are used to estimate the genetic variance components. Mixed model analysis is modified including mutation effect following the methods by Wray (1990). DIC was used to compare the model. Models including mutation effect...... have better fit compared to the model with only additive effect. Mutation as direct effect contributes 3.18% of the total phenotypic variance. While in the model with interactions between additive and mutation, it contributes 1.43% as direct effect and 1.36% as interaction effect of the total variance...

  18. Genetic and environmental variance components for physical activity patterns of twins. Exploring the possibilities of approximate entropy

    Directory of Open Access Journals (Sweden)

    José António Ribeiro Maia

    2010-06-01

    Full Text Available The main objective of this study was to estimate the contribution of genetic factorsto physical activity patterns (PAPs in twins using approximate entropy (ApEn statistics. Thesample consisted of 162 monozygotic and dizygotic twins from Portugal aged 6 to 18 years.Physical activity was measured with a Tritrac-RT3 triaxial accelerometer over 5 days of a usualweek. PAPs were described by ApEn using the Cine Wizard software. Zygosity was assessed bydirect DNA analysis. Data were analyzed using the SYSTAT 10, STATA 10 and Twinan92softwares. PAPs were estimated for 5, 3 and 2 days. In addition, structural equation modelingwas used to compute different sources of variance genetic, common environmental and uniqueenvironmental variance.The level of significance was set at 5%. Sibling aggregation was identifiedby ApEn analysis, with monozygotic twins showing greater homogeneity. In conclusion, geneticfactors accounted for 44 to 89% of the total variation in PAP.

  19. Growth Performance and Initial Heritability Estimates for Growth Traits in Juvenile Sea Urchin Tripneustes gratilla

    Directory of Open Access Journals (Sweden)

    Ma. Josefa Pante

    2007-06-01

    Full Text Available Genetic improvement of performance traits of maricultured species is becoming an important concern. Improvement of performance traits is important for two reasons: it enhances the growth and survival of the animals and it translates to economic gains to the fish farmer. In the sea urchin, Tripneustes gratilla, growth performance of the different families and heritabilities for wet weight, test diameter and test height were estimated from 1,020 offspring from a mating of each of the 15 males with 1 or 2 females. Measurements were done monthly starting at the grow-out stage or four months after hatching. There were significant family differences for the performance traits in sea urchin reared in tanks at the BML hatchery as revealed by ANOVA. Estimates of heritabilities based on the sire component of variance were low for wet weight (0.027, test diameter (0.033 and zero for test height. Heritabilities estimated from the dam component of variance were low for wet weight (0.063, moderate for test diameter (0.286 and test height (0.227. The results indicate that test diameter and wet weight have lowly heritable traits, which means that mass or individual selection may not be the best method for improving the traits for sea urchin populations in Bolinao. Other methods such as family and combined family selection should be explored.

  20. Heritability of neck pain

    DEFF Research Database (Denmark)

    Fejer, R; Hartvigsen, J; Kyvik, K O

    2006-01-01

    OBJECTIVES: To determine the heritability of neck pain in a large population-based study of twins. METHODS: Data on lifetime prevalence of neck pain from a population-based cross-sectional survey of Danish twins were used. To assess twin similarity, the probandwise concordance rates, zygosity......-specific odds ratios and tetrachoric correlations were calculated and compared for monozygotic and dizygotic twins. Using biometric modelling (structural equation modelling), the genetic and environmental contributions of the liability to neck pain were estimated. RESULTS: A total of 33,794 twins (response rate...... 73%) answered the questions regarding neck pain. Probandwise concordance rates, zygosity-specific odds ratios and tetrachoric correlations showed a significant genetic effect on neck pain. An overall additive genetic component of 44% was found. The genetic effect decreased with age, accounting...

  1. Comparison of multipoint linkage analyses for quantitative traits in the CEPH data: parametric LOD scores, variance components LOD scores, and Bayes factors.

    Science.gov (United States)

    Sung, Yun Ju; Di, Yanming; Fu, Audrey Q; Rothstein, Joseph H; Sieh, Weiva; Tong, Liping; Thompson, Elizabeth A; Wijsman, Ellen M

    2007-01-01

    We performed multipoint linkage analyses with multiple programs and models for several gene expression traits in the Centre d'Etude du Polymorphisme Humain families. All analyses provided consistent results for both peak location and shape. Variance-components (VC) analysis gave wider peaks and Bayes factors gave fewer peaks. Among programs from the MORGAN package, lm_multiple performed better than lm_markers, resulting in less Markov-chain Monte Carlo (MCMC) variability between runs, and the program lm_twoqtl provided higher LOD scores by also including either a polygenic component or an additional quantitative trait locus.

  2. variation, correlation and heritability of interest characters

    African Journals Online (AJOL)

    ACSS

    2016-05-17

    May 17, 2016 ... fruit weight, leaf blade length and width, and height at flowering. In addition, genetic and phenotypic variances were high for the number of seed, fruit weight, plant height at flowering and days to 50% flowering. High heritability estimates were recorded for all traits. Fruit weight showed a positive association ...

  3. Test day-milk yields variance component estimation using repeatability or random regression models in the Rendena breed

    Directory of Open Access Journals (Sweden)

    Roberto Mantovani

    2010-01-01

    Full Text Available This study has aimed to compare Repeatability (RP-TDm and Random-Regression Test Day models (RR-TDm in genetic evaluations of milk (M, fat (F and protein (P yields in Rendena breed. Variance estimations for Milk (M, Fat (F and Protein (P were obtained on a sample of 43,842 TD belonging to 2,692 animals controlled over 15 years (1990-2005. RP-TDm estimates of h2 were of 0.21 for M and 0.17 for both F and P, whereas RR-TDM provided a trend of h2 ranging from 0.15-0.34 for M, 0.15-0.31 for F and 0.10-0.24 for P. Both RP-TDm and RR-TDm results agreed with literature, even though RR-TDm provided a pattern of h2 along the lactation different from other studies, with the lowest h2 at the beginning and at the end of lactation. PSB, MAD and -2Log L parameters revealed lower power of RP-TDm as compare with the RR-TDm.

  4. Heritability of arterial stiffness in a Brazilian population: Baependi Heart Study.

    Science.gov (United States)

    Alvim, Rafael O; Horimoto, Andréa R V R; Oliveira, Camila M; Bortolotto, Luiz A; Krieger, José E; Pereira, Alexandre C

    2017-01-01

    Increased arterial stiffness is an important determinant of cardiovascular disease risk. In addition, it has been recognized that arterial stiffness has familial aggregation; however, there are no studies involving Brazilian families. Thus, the aim of this study was to evaluate the heritability of arterial stiffness in a Brazilian population. In this study, 1675 eligible individuals (both sexes and aged 18-102 years) were distributed in 125 families resident in the municipality of Baependi, a city located in the southeast of Brazil. Carotid-femoral pulse wave velocity (PWV) was measured with a noninvasive automatic device (Complior; Artech Medical, Pantin, France). Variance component approaches, implemented in the SOLAR computer package (San Antonio, Texas, USA), were applied to estimate the heritability of the studied phenotype under different statistical models. Heritability estimates for carotid-femoral PWV stratified by age ranging from 11 to 35% (higher in individuals aged ≤45 years and lower in individuals aged 18-102 years). Age and hypertension showed significant effects on the PWV trait and significantly affect heritability estimates in all models. We conclude that the heritability of carotid-femoral PWV in a Brazilian population is intermediate, and therefore genetic studies evolving arterial stiffness phenotypes should be encouraged.

  5. Heritability estimates of the Big Five personality traits based on common genetic variants.

    Science.gov (United States)

    Power, R A; Pluess, M

    2015-07-14

    According to twin studies, the Big Five personality traits have substantial heritable components explaining 40-60% of the variance, but identification of associated genetic variants has remained elusive. Consequently, knowledge regarding the molecular genetic architecture of personality and to what extent it is shared across the different personality traits is limited. Using genomic-relatedness-matrix residual maximum likelihood analysis (GREML), we here estimated the heritability of the Big Five personality factors (extraversion, agreeableness, conscientiousness, neuroticism and openness for experience) in a sample of 5011 European adults from 527,469 single-nucleotide polymorphisms across the genome. We tested for the heritability of each personality trait, as well as for the genetic overlap between the personality factors. We found significant and substantial heritability estimates for neuroticism (15%, s.e. = 0.08, P = 0.04) and openness (21%, s.e. = 0.08, P Big Five personality traits using the GREML approach. Findings should be considered exploratory and suggest that detectable heritability estimates based on common variants is shared between neuroticism and openness to experiences.

  6. Sexual variation in heritability and genetic correlations of morphological traits in house sparrow (Passer domesticus).

    Science.gov (United States)

    Jensen, H; Saether, B E; Ringsby, T H; Tufto, J; Griffith, S C; Ellegren, H

    2003-11-01

    Estimates of genetic components are important for our understanding of how individual characteristics are transferred between generations. We show that the level of heritability varies between 0.12 and 0.68 in six morphological traits in house sparrows (Passer domesticus L.) in northern Norway. Positive and negative genetic correlations were present among traits, suggesting evolutionary constraints on the evolution of some of these characters. A sexual difference in the amount of heritable genetic variation was found in tarsus length, wing length, bill depth and body condition index, with generally higher heritability in females. In addition, the structure of the genetic variance-covariance matrix for the traits differed between the sexes. Genetic correlations between males and females for the morphological traits were however large and not significantly different from one, indicating that sex-specific responses to selection will be influenced by intersexual differences in selection differentials. Despite this, some traits had heritability above 0.1 in females, even after conditioning on the additive genetic covariance between sexes and the additive genetic variances in males. Moreover, a meta-analysis indicated that higher heritability in females than in males may be common in birds. Thus, this indicates sexual differences in the genetic architecture of birds. Consequently, as in house sparrows, the evolutionary responses to selection will often be larger in females than males. Hence, our results suggest that sex-specific additive genetic variances and covariances, although ignored in most studies, should be included when making predictions of evolutionary changes from standard quantitative genetic models.

  7. Heritability of Performance Deficit Accumulation During Acute Sleep Deprivation in Twins

    Science.gov (United States)

    Kuna, Samuel T.; Maislin, Greg; Pack, Frances M.; Staley, Bethany; Hachadoorian, Robert; Coccaro, Emil F.; Pack, Allan I.

    2012-01-01

    Study Objectives: To determine if the large and highly reproducible interindividual differences in rates of performance deficit accumulation during sleep deprivation, as determined by the number of lapses on a sustained reaction time test, the Psychomotor Vigilance Task (PVT), arise from a heritable trait. Design: Prospective, observational cohort study. Setting: Academic medical center. Participants: There were 59 monozygotic (mean age 29.2 ± 6.8 [SD] yr; 15 male and 44 female pairs) and 41 dizygotic (mean age 26.6 ± 7.6 yr; 15 male and 26 female pairs) same-sex twin pairs with a normal polysomnogram. Interventions: Thirty-eight hr of monitored, continuous sleep deprivation. Measurements and Results: Patients performed the 10-min PVT every 2 hr during the sleep deprivation protocol. The primary outcome was change from baseline in square root transformed total lapses (response time ≥ 500 ms) per trial. Patient-specific linear rates of performance deficit accumulation were separated from circadian effects using multiple linear regression. Using the classic approach to assess heritability, the intraclass correlation coefficients for accumulating deficits resulted in a broad sense heritability (h2) estimate of 0.834. The mean within-pair and among-pair heritability estimates determined by analysis of variance-based methods was 0.715. When variance components of mixed-effect multilevel models were estimated by maximum likelihood estimation and used to determine the proportions of phenotypic variance explained by genetic and nongenetic factors, 51.1% (standard error = 8.4%, P sleep deprivation. Citation: Kuna ST; Maislin G; Pack FM; Staley B; Hachadoorian R; Coccaro EF; Pack AI. Heritability of performance deficit accumulation during acute sleep deprivation in twins. SLEEP 2012;35(9):1223-1233. PMID:22942500

  8. Heritability, parental transmission and environment correlation of pediatric-onset type 2 diabetes mellitus and metabolic syndrome-related traits.

    Science.gov (United States)

    Miranda-Lora, América L; Vilchis-Gil, Jenny; Molina-Díaz, Mario; Flores-Huerta, Samuel; Klünder-Klünder, Miguel

    2017-04-01

    To estimate the heritability, parental transmission and environmental contributions to the phenotypic variation in type 2 diabetes mellitus and metabolic syndrome-related traits in families of Mexican children and adolescents. We performed a cross-sectional study of 184 tri-generational pedigrees with a total of 1160 individuals (99 families with a type 2 diabetes mellitus proband before age 19). The family history of type 2 diabetes mellitus in three generations was obtained by interview. Demographic, anthropometric, biochemical and lifestyle information was corroborated in parents and offspring. We obtained correlations for metabolic traits between relative pairs, and variance component methods were used to determine the heritability and environmental components. The heritability of early-onset of type 2 diabetes mellitus was 0.50 (p0.50) for blood pressure, HbA1c and HDL-cholesterol after multivariate adjustment (pdiabetes mellitus and insulin resistance, were significantly correlated only through the mother and others, such as hypertriglyceridemia, were significantly correlated only through the father. This study demonstrates that type 2 diabetes mellitus and metabolic syndrome-related traits are highly heritable among Mexican children and adolescents. Furthermore, several cardiometabolic factors have strong heritability and/or high environmental contributions that highlight the complex architecture of these alterations. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Heritability of antisocial behaviour

    NARCIS (Netherlands)

    Kretschmer, Tina; DeLisi, Matt

    2016-01-01

    This chapter reviews important strands of research on the heritability of antisocial behavior and crime, including both quantitative genetic studies using twin or adoption designs as well as molecular genetic approaches. Study designs are introduced and findings discussed. Contemporary avenues

  10. Heritability of markers of bone metabolism

    Science.gov (United States)

    Smith, Scott M.; Zwart, S. R.; Hargens, A. R.

    2005-01-01

    Several classic twin studies show genetic effects on markers of bone health, including bone mineral density and parathyroid hormone (PTH). This study was performed to assess the relative contribution of genetics to biochemical markers of bone metabolism. Fifteen sets of identical twins (8 male, 7 female) were housed in a clinical research center where diet was controlled (15% protein, 55% carbohydrate, 30% fat) for 3 consecutive days. Each day, 24-h urine pools were collected and N-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and serum PTH were measured. The broad-sense heritability factor (H2) is an estimation of the portion of the total variance of a given phenotype that is attributable to genetic variance. H2 was estimated from the correlation coefficient of the phenotype data. H2 for NTX was 94% for males and 80% for females, DPD was 88% for males and 97% for females, urinary calcium excretion was 97% for males and 90% for females, and PTH was 92% for males and 79% for females. Since environmental variability was minimized for the 3 days of data collection, these heritability factors are likely overestimated. Nonetheless, the data support the concept that PTH is a predominantly heritable trait, and suggest that NTX, DPD, and calcium excretion are as well. These biochemical data support the previously documented heritability of bone health.

  11. Heritability of chronic venous disease

    Science.gov (United States)

    Krusche, Petra; Wolf, Andreas; Krawczak, Michael; Timm, Birgitt; Nikolaus, Susanna; Frings, Norbert; Schreiber, Stefan

    2010-01-01

    Varicose veins without skin changes have a prevalence of approximately 20% in Northern and Western Europe whereas advanced chronic venous insufficiency affects about 3% of the population. Genetic risk factors are thought to play an important role in the aetiology of both these chronic venous diseases (CVD). We evaluated the relative genetic and environmental impact upon CVD risk by estimating the heritability of the disease in 4,033 nuclear families, comprising 16,434 individuals from all over Germany. Upon clinical examination, patients were classified according to the CEAP guidelines as either C2 (simple varicose veins), C3 (oedema), C4 (skin changes without ulceration), C5 (healed ulceration), or C6 (active ulcers). The narrow-sense heritability (h2) of CVD equals 17.3% (standard error 2.5%, likelihood ratio test P = 1.4 × 10−13). The proportion of disease risk attributable to age (at ascertainment) and sex, the two main risk factors for CVD, was estimated as 10.7% (Kullback–Leibler deviance R2). The heritability of CVD is high, thereby suggesting a notable genetic component in the aetiology of the disease. Systematic population-based searches for CVD susceptibility genes are therefore warranted. PMID:20354728

  12. Heritability of cardiovascular and personality traits in 6,148 Sardinians.

    Directory of Open Access Journals (Sweden)

    Giuseppe Pilia

    2006-08-01

    Full Text Available In family studies, phenotypic similarities between relatives yield information on the overall contribution of genes to trait variation. Large samples are important for these family studies, especially when comparing heritability between subgroups such as young and old, or males and females. We recruited a cohort of 6,148 participants, aged 14-102 y, from four clustered towns in Sardinia. The cohort includes 34,469 relative pairs. To extract genetic information, we implemented software for variance components heritability analysis, designed to handle large pedigrees, analyze multiple traits simultaneously, and model heterogeneity. Here, we report heritability analyses for 98 quantitative traits, focusing on facets of personality and cardiovascular function. We also summarize results of bivariate analyses for all pairs of traits and of heterogeneity analyses for each trait. We found a significant genetic component for every trait. On average, genetic effects explained 40% of the variance for 38 blood tests, 51% for five anthropometric measures, 25% for 20 measures of cardiovascular function, and 19% for 35 personality traits. Four traits showed significant evidence for an X-linked component. Bivariate analyses suggested overlapping genetic determinants for many traits, including multiple personality facets and several traits related to the metabolic syndrome; but we found no evidence for shared genetic determinants that might underlie the reported association of some personality traits and cardiovascular risk factors. Models allowing for heterogeneity suggested that, in this cohort, the genetic variance was typically larger in females and in younger individuals, but interesting exceptions were observed. For example, narrow heritability of blood pressure was approximately 26% in individuals more than 42 y old, but only approximately 8% in younger individuals. Despite the heterogeneity in effect sizes, the same loci appear to contribute to variance

  13. Heritability of Cardiovascular and Personality Traits in 6,148 Sardinians

    Science.gov (United States)

    Scuteri, Angelo; Orrú, Marco; Albai, Giuseppe; Dei, Mariano; Lai, Sandra; Usala, Gianluca; Lai, Monica; Loi, Paola; Mameli, Cinzia; Vacca, Loredana; Deiana, Manila; Olla, Nazario; Masala, Marco; Cao, Antonio; Najjar, Samer S; Terracciano, Antonio; Nedorezov, Timur; Sharov, Alexei; Zonderman, Alan B; Abecasis, Gonçalo R; Costa, Paul; Lakatta, Edward; Schlessinger, David

    2006-01-01

    In family studies, phenotypic similarities between relatives yield information on the overall contribution of genes to trait variation. Large samples are important for these family studies, especially when comparing heritability between subgroups such as young and old, or males and females. We recruited a cohort of 6,148 participants, aged 14–102 y, from four clustered towns in Sardinia. The cohort includes 34,469 relative pairs. To extract genetic information, we implemented software for variance components heritability analysis, designed to handle large pedigrees, analyze multiple traits simultaneously, and model heterogeneity. Here, we report heritability analyses for 98 quantitative traits, focusing on facets of personality and cardiovascular function. We also summarize results of bivariate analyses for all pairs of traits and of heterogeneity analyses for each trait. We found a significant genetic component for every trait. On average, genetic effects explained 40% of the variance for 38 blood tests, 51% for five anthropometric measures, 25% for 20 measures of cardiovascular function, and 19% for 35 personality traits. Four traits showed significant evidence for an X-linked component. Bivariate analyses suggested overlapping genetic determinants for many traits, including multiple personality facets and several traits related to the metabolic syndrome; but we found no evidence for shared genetic determinants that might underlie the reported association of some personality traits and cardiovascular risk factors. Models allowing for heterogeneity suggested that, in this cohort, the genetic variance was typically larger in females and in younger individuals, but interesting exceptions were observed. For example, narrow heritability of blood pressure was approximately 26% in individuals more than 42 y old, but only approximately 8% in younger individuals. Despite the heterogeneity in effect sizes, the same loci appear to contribute to variance in young and old

  14. Genetic Variance in Homophobia: Evidence from Self- and Peer Reports.

    Science.gov (United States)

    Zapko-Willmes, Alexandra; Kandler, Christian

    2018-01-01

    The present twin study combined self- and peer assessments of twins' general homophobia targeting gay men in order to replicate previous behavior genetic findings across different rater perspectives and to disentangle self-rater-specific variance from common variance in self- and peer-reported homophobia (i.e., rater-consistent variance). We hypothesized rater-consistent variance in homophobia to be attributable to genetic and nonshared environmental effects, and self-rater-specific variance to be partially accounted for by genetic influences. A sample of 869 twins and 1329 peer raters completed a seven item scale containing cognitive, affective, and discriminatory homophobic tendencies. After correction for age and sex differences, we found most of the genetic contributions (62%) and significant nonshared environmental contributions (16%) to individual differences in self-reports on homophobia to be also reflected in peer-reported homophobia. A significant genetic component, however, was self-report-specific (38%), suggesting that self-assessments alone produce inflated heritability estimates to some degree. Different explanations are discussed.

  15. Dietary patterns and heritability of food choice in a UK female twin cohort.

    Science.gov (United States)

    Teucher, Birgit; Skinner, Jane; Skidmore, Paula M L; Cassidy, Aedin; Fairweather-Tait, Susan J; Hooper, Lee; Roe, Mark A; Foxall, Robert; Oyston, Sarah L; Cherkas, Lynn F; Perks, Ursula C; Spector, Tim D; MacGregor, Alex J

    2007-10-01

    To examine the contribution of genetic factors to food choice, we determined dietary patterns from food frequency questionnaires in 3262 UK female twins aged 18 to 79 years. Five distinct dietary patterns were identified (fruit and vegetable, high alcohol, traditional English, dieting, low meat) that accounted for 22% of the total variance. These patterns are similar to those found in other singleton Western populations, and were related to body mass index, smoking status, physical activity and deprivation scores. Older subjects had higher scores on the fruit and vegetable and traditional English patterns, while lower social deprivation was associated with higher scores for fruit and vegetable, and lower scores for traditional English patterns. All 5 patterns were heritable, with estimates ranging from 41% to 48%. Among individual dietary components, a strongly heritable component was identified for garlic (46%), coffee (41%), fruit and vegetable sources (49%), and red meat (39%). Our results indicate that genetic factors have an important influence in determining food choice and dietary habits in Western populations. The relatively high heritability of specific dietary components implicates taste perception as a possible target for future genetic studies.

  16. Aorta measurements are heritable and influenced by bicuspid aortic valve

    Directory of Open Access Journals (Sweden)

    Lisa J Martin

    2011-09-01

    Full Text Available Abstract: Word Count 266, 1609 charactersObjectives: To determine whether the contributions of genetics and bicuspid aortic valve (BAV independently influence aortic (Ao dimensions.Background: Ao dilation is a risk factor for aneurysm, dissection, and sudden cardiac death. Frequent association of BAV with Ao dilation implicates a common underlying defect possibly due to genetic factors. Methods: Families enriched for BAV underwent standardized transthoracic echocardiography. In addition to BAV status, echocardiographic measures of Ao (annulus to descending Ao, pulmonary artery and mitral valve annulus diameters were obtained. Using variance components analysis, heritability was estimated with and without BAV status. Additionally, bivariate genetic analyses between Ao dimensions and BAV were performed.Results: Our cohort was obtained from 209 families enriched for BAV. After adjusting for age, body surface area and sex, individuals with BAV had a statistically significant increase in all echocardiographic measurements (p < 0.006 except descending Ao and mitral valve annulus. Individuals with BAV were at greater odds of having Ao dilation (OR = 4.44, 95% CI 2.93 – 6.72 than family members without BAV. All echocardiographic measurements exhibited moderate to strong heritability (0.25 to 0.53, and these estimates were not influenced by inclusion of BAV as a covariate. Bivariate genetic analyses supported that the genetic correlation between BAV and echo measures were not significantly different from zero.Conclusions: We show for the first time that echocardiographic measurements of Ao, pulmonary artery and mitral valve annulus diameters are quantitative traits that exhibit significant heritability. In addition, our results suggest the presence of BAV independently influences the proximal Ao and pulmonary artery measures but not those in the descending Ao or mitral valve annulus.

  17. Methodological Considerations in Estimation of Phenotype Heritability Using Genome-Wide SNP Data, Illustrated by an Analysis of the Heritability of Height in a Large Sample of African Ancestry Adults.

    Directory of Open Access Journals (Sweden)

    Fang Chen

    Full Text Available Height has an extremely polygenic pattern of inheritance. Genome-wide association studies (GWAS have revealed hundreds of common variants that are associated with human height at genome-wide levels of significance. However, only a small fraction of phenotypic variation can be explained by the aggregate of these common variants. In a large study of African-American men and women (n = 14,419, we genotyped and analyzed 966,578 autosomal SNPs across the entire genome using a linear mixed model variance components approach implemented in the program GCTA (Yang et al Nat Genet 2010, and estimated an additive heritability of 44.7% (se: 3.7% for this phenotype in a sample of evidently unrelated individuals. While this estimated value is similar to that given by Yang et al in their analyses, we remain concerned about two related issues: (1 whether in the complete absence of hidden relatedness, variance components methods have adequate power to estimate heritability when a very large number of SNPs are used in the analysis; and (2 whether estimation of heritability may be biased, in real studies, by low levels of residual hidden relatedness. We addressed the first question in a semi-analytic fashion by directly simulating the distribution of the score statistic for a test of zero heritability with and without low levels of relatedness. The second question was addressed by a very careful comparison of the behavior of estimated heritability for both observed (self-reported height and simulated phenotypes compared to imputation R2 as a function of the number of SNPs used in the analysis. These simulations help to address the important question about whether today's GWAS SNPs will remain useful for imputing causal variants that are discovered using very large sample sizes in future studies of height, or whether the causal variants themselves will need to be genotyped de novo in order to build a prediction model that ultimately captures a large fraction of the

  18. Methodological Considerations in Estimation of Phenotype Heritability Using Genome-Wide SNP Data, Illustrated by an Analysis of the Heritability of Height in a Large Sample of African Ancestry Adults

    Science.gov (United States)

    Chen, Fang; He, Jing; Zhang, Jianqi; Chen, Gary K.; Thomas, Venetta; Ambrosone, Christine B.; Bandera, Elisa V.; Berndt, Sonja I.; Bernstein, Leslie; Blot, William J.; Cai, Qiuyin; Carpten, John; Casey, Graham; Chanock, Stephen J.; Cheng, Iona; Chu, Lisa; Deming, Sandra L.; Driver, W. Ryan; Goodman, Phyllis; Hayes, Richard B.; Hennis, Anselm J. M.; Hsing, Ann W.; Hu, Jennifer J.; Ingles, Sue A.; John, Esther M.; Kittles, Rick A.; Kolb, Suzanne; Leske, M. Cristina; Monroe, Kristine R.; Murphy, Adam; Nemesure, Barbara; Neslund-Dudas, Christine; Nyante, Sarah; Ostrander, Elaine A; Press, Michael F.; Rodriguez-Gil, Jorge L.; Rybicki, Ben A.; Schumacher, Fredrick; Stanford, Janet L.; Signorello, Lisa B.; Strom, Sara S.; Stevens, Victoria; Van Den Berg, David; Wang, Zhaoming; Witte, John S.; Wu, Suh-Yuh; Yamamura, Yuko; Zheng, Wei; Ziegler, Regina G.; Stram, Alexander H.; Kolonel, Laurence N.; Marchand, Loïc Le; Henderson, Brian E.; Haiman, Christopher A.; Stram, Daniel O.

    2015-01-01

    Height has an extremely polygenic pattern of inheritance. Genome-wide association studies (GWAS) have revealed hundreds of common variants that are associated with human height at genome-wide levels of significance. However, only a small fraction of phenotypic variation can be explained by the aggregate of these common variants. In a large study of African-American men and women (n = 14,419), we genotyped and analyzed 966,578 autosomal SNPs across the entire genome using a linear mixed model variance components approach implemented in the program GCTA (Yang et al Nat Genet 2010), and estimated an additive heritability of 44.7% (se: 3.7%) for this phenotype in a sample of evidently unrelated individuals. While this estimated value is similar to that given by Yang et al in their analyses, we remain concerned about two related issues: (1) whether in the complete absence of hidden relatedness, variance components methods have adequate power to estimate heritability when a very large number of SNPs are used in the analysis; and (2) whether estimation of heritability may be biased, in real studies, by low levels of residual hidden relatedness. We addressed the first question in a semi-analytic fashion by directly simulating the distribution of the score statistic for a test of zero heritability with and without low levels of relatedness. The second question was addressed by a very careful comparison of the behavior of estimated heritability for both observed (self-reported) height and simulated phenotypes compared to imputation R2 as a function of the number of SNPs used in the analysis. These simulations help to address the important question about whether today's GWAS SNPs will remain useful for imputing causal variants that are discovered using very large sample sizes in future studies of height, or whether the causal variants themselves will need to be genotyped de novo in order to build a prediction model that ultimately captures a large fraction of the variability

  19. Heritability of caffeine metabolism

    DEFF Research Database (Denmark)

    Matthaei, Johannes; Tzvetkov, Mladen V; Strube, Jakob

    2016-01-01

    Heritability of caffeine pharmacokinetics and CYP1A2 activity is controversial. Here we analyzed the pharmacokinetics of caffeine, an in vivo probe drug for CYP1A2 and arylamine N-acetyltransferase 2 (NAT2) activity, in monozygotic and dizygotic twins. In the entire group, common and unique envir...

  20. The heritability of perceived stress.

    NARCIS (Netherlands)

    Federenko, I.S.; Schlotz, W.; Kirschbaum, C.; Bartels, M.; Hellhammer, D.H.; Wüst, S.

    2006-01-01

    Background. Exploration of the degree to which perceived chronic stress is heritable is important as these self-reports have been linked to stress-related health outcomes. The aims of this study were to estimate whether perceived stress is a heritable condition and to assess whether heritability

  1. Heritability of attractiveness to mosquitoes.

    Science.gov (United States)

    Fernández-Grandon, G Mandela; Gezan, Salvador A; Armour, John A L; Pickett, John A; Logan, James G

    2015-01-01

    Female mosquitoes display preferences for certain individuals over others, which is determined by differences in volatile chemicals produced by the human body and detected by mosquitoes. Body odour can be controlled genetically but the existence of a genetic basis for differential attraction to insects has never been formally demonstrated. This study investigated heritability of attractiveness to mosquitoes by evaluating the response of Aedes aegypti (=Stegomyia aegypti) mosquitoes to odours from the hands of identical and non-identical twins in a dual-choice assay. Volatiles from individuals in an identical twin pair showed a high correlation in attractiveness to mosquitoes, while non-identical twin pairs showed a significantly lower correlation. Overall, there was a strong narrow-sense heritability of 0.62 (SE 0.124) for relative attraction and 0.67 (0.354) for flight activity based on the average of ten measurements. The results demonstrate an underlying genetic component detectable by mosquitoes through olfaction. Understanding the genetic basis for attractiveness could create a more informed approach to repellent development.

  2. Heritability of attractiveness to mosquitoes.

    Directory of Open Access Journals (Sweden)

    G Mandela Fernández-Grandon

    Full Text Available Female mosquitoes display preferences for certain individuals over others, which is determined by differences in volatile chemicals produced by the human body and detected by mosquitoes. Body odour can be controlled genetically but the existence of a genetic basis for differential attraction to insects has never been formally demonstrated. This study investigated heritability of attractiveness to mosquitoes by evaluating the response of Aedes aegypti (=Stegomyia aegypti mosquitoes to odours from the hands of identical and non-identical twins in a dual-choice assay. Volatiles from individuals in an identical twin pair showed a high correlation in attractiveness to mosquitoes, while non-identical twin pairs showed a significantly lower correlation. Overall, there was a strong narrow-sense heritability of 0.62 (SE 0.124 for relative attraction and 0.67 (0.354 for flight activity based on the average of ten measurements. The results demonstrate an underlying genetic component detectable by mosquitoes through olfaction. Understanding the genetic basis for attractiveness could create a more informed approach to repellent development.

  3. Partitioning the heritability of Tourette syndrome and obsessive compulsive disorder reveals differences in genetic architecture

    NARCIS (Netherlands)

    Davis, L.K.; Yu, D.; Keenan, C.L.; Gamazon, E.R.; Konkashbaev, A.I.; Derks, E.M.; Neale, B.M.; Yang, J.; Lee, S.H.; Evans, P.; Barr, C.L.; Bellodi, L.; Benarroch, F.; Berrio, G.B.; Bienvenu, O.J.; Bloch, M.H.; Blom, R.M.; Bruun, R.D.; Budman, C.L.; Camarena, B.; Campbell, D.; Cappi, C.; Cardona Silgado, J.C.; Cath, D.C.; Cavallini, M.C.; Chavira, D.A.; Chouinard, S.; Conti, D.V.; Cook, E.H.; Coric, V.; Cullen, B.A.; Deforce, D.; Delorme, R.; Dion, Y.; Edlund, C.K.; Egberts, K.; Falkai, P.; Fernandez, T.V.; Gallagher, P.J.; Garrido, H.; Geller, D.; Girard, S.L.; Grabe, H.J.; Grados, M.A.; Greenberg, B.D.; Gross-Tsur, V.; Haddad, S.; Heiman, G.A.; Hemmings, S.M.; Hounie, A.G.; Illmann, C.; Jankovic, J.; Jenike, M.A.; Kennedy, J.L.; King, R.A.; Kremeyer, B.; Kurlan, R.; Lanzagorta, N.; Leboyer, M.; Leckman, J.F.; Lennertz, L.; Liu, C.; Lochner, C.; Lowe, T.L.; Macciardi, F.; McCracken, J.T.; McGrath, L.M.; Mesa Restrepo, S.C.; Moessner, R.; Morgan, J.; Muller, H.; Murphy, D.L.; Naarden, A.L.; Ochoa, W.C.; Ophoff, R.A.; Osiecki, L.; Pakstis, A.J.; Pato, M.T.; Piacentini, J.; Pittenger, C.; Pollak, Y.; Rauch, S.L.; Renner, T.J.; Reus, V.I.; Richter, M.A.; Riddle, M.A.; Robertson, M.M.; Romero, R.; Rosàrio, M.C.; Rosenberg, D.; Rouleau, G.A.; Ruhrmann, S.; Ruiz-Linares, A.; Sampaio, A.S.; Samuels, J.; Sandor, P.; Sheppard, B.; Singer, H.S.; Smit, J.H.; Stein, D.J.; Strengman, E.; Tischfield, J.A.; Valencia Duarte, A.V.; Vallada, H.; van Nieuwerburgh, F.; Veenstra-Vanderweele, J.; Walitza, S.; Wang, Y.; Wendland, J.R.; Westenberg, H.G.; Shugart, Y.Y.; Miguel, E.C.; McMahon, W.; Wagner, M.; Nicolini, H.; Posthuma, D.; Hanna, G.L.; Heutink, P.; Denys, D.; Arnold, P.D.; Oostra, B.A.; Nestadt, G.; Freimer, N.B.; Pauls, D.L.; Wray, N.R.; Stewart, S.E.; Mathews, C.A.; Knowles, J.A.; Cox, N.J.; Scharf, J.M.

    2013-01-01

    The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease

  4. Partitioning the Heritability of Tourette Syndrome and Obsessive Compulsive Disorder Reveals Differences in Genetic Architecture

    NARCIS (Netherlands)

    Davis, Lea K.; Yu, Dongmei; Keenan, Clare L.; Gamazon, Eric R.; Konkashbaev, Anuar I.; Derks, Eske M.; Neale, Benjamin M.; Yang, Jian; Lee, S. Hong; Evans, Patrick; Barr, Cathy L.; Bellodi, Laura; Benarroch, Fortu; Berrio, Gabriel Bedoya; Bienvenu, Oscar J.; Bloch, Michael H.; Blom, Rianne M.; Bruun, Ruth D.; Budman, Cathy L.; Camarena, Beatriz; Campbell, Desmond; Cappi, Carolina; Cardona Silgado, Julio C.; Cath, Danielle C.; Cavallini, Maria C.; Chavira, Denise A.; Chouinard, Sylvain; Conti, David V.; Cook, Edwin H.; Coric, Vladimir; Cullen, Bernadette A.; Deforce, Dieter; Delorme, Richard; Dion, Yves; Edlund, Christopher K.; Egberts, Karin; Falkai, Peter; Fernandez, Thomas V.; Gallagher, Patience J.; Garrido, Helena; Geller, Daniel; Girard, Simon L.; Grabe, Hans J.; Grados, Marco A.; Greenberg, Benjamin D.; Gross-Tsur, Varda; Haddad, Stephen; Heiman, Gary A.; Hemmings, Sian M. J.; Hounie, Ana G.; Illmann, Cornelia; Jankovic, Joseph; Jenike, Michael A.; Kennedy, James L.; King, Robert A.; Kremeyer, Barbara; Kurlan, Roger; Lanzagorta, Nuria; Leboyer, Marion; Leckman, James F.; Lennertz, Leonhard; Liu, Chunyu; Lochner, Christine; Lowe, Thomas L.; Macciardi, Fabio; McCracken, James T.; McGrath, Lauren M.; Mesa Restrepo, Sandra C.; Moessner, Rainald; Morgan, Jubel; Muller, Heike; Murphy, Dennis L.; Naarden, Allan L.; Ochoa, William Cornejo; Ophoff, Roel A.; Osiecki, Lisa; Pakstis, Andrew J.; Pato, Michele T.; Pato, Carlos N.; Piacentini, John; Pittenger, Christopher; Pollak, Yehuda; Rauch, Scott L.; Renner, Tobias J.; Reus, Victor I.; Richter, Margaret A.; Riddle, Mark A.; Robertson, Mary M.; Romero, Roxana; Rosàrio, Maria C.; Rosenberg, David; Rouleau, Guy A.; Ruhrmann, Stephan; Ruiz-Linares, Andres; Sampaio, Aline S.; Samuels, Jack; Sandor, Paul; Sheppard, Brooke; Singer, Harvey S.; Smit, Jan H.; Stein, Dan J.; Strengman, E.; Tischfield, Jay A.; Valencia Duarte, Ana V.; Vallada, Homero; van Nieuwerburgh, Filip; Veenstra-Vanderweele, Jeremy; Walitza, Susanne; Wang, Ying; Wendland, Jens R.; Westenberg, Herman G. M.; Shugart, Yin Yao; Miguel, Euripedes C.; McMahon, William; Wagner, Michael; Nicolini, Humberto; Posthuma, Danielle; Hanna, Gregory L.; Heutink, Peter; Denys, Damiaan; Arnold, Paul D.; Oostra, Ben A.; Nestadt, Gerald; Freimer, Nelson B.; Pauls, David L.; Wray, Naomi R.; Stewart, S. Evelyn; Mathews, Carol A.; Knowles, James A.; Cox, Nancy J.; Scharf, Jeremiah M.

    2013-01-01

    The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease

  5. Effect of Box-Cox transformation on power of Haseman-Elston and maximum-likelihood variance components tests to detect quantitative trait Loci.

    Science.gov (United States)

    Etzel, C J; Shete, S; Beasley, T M; Fernandez, J R; Allison, D B; Amos, C I

    2003-01-01

    Non-normality of the phenotypic distribution can affect power to detect quantitative trait loci in sib pair studies. Previously, we observed that Winsorizing the sib pair phenotypes increased the power of quantitative trait locus (QTL) detection for both Haseman-Elston (HE) least-squares tests [Hum Hered 2002;53:59-67] and maximum likelihood-based variance components (MLVC) analysis [Behav Genet (in press)]. Winsorizing the phenotypes led to a slight increase in type 1 error in H-E tests and a slight decrease in type I error for MLVC analysis. Herein, we considered transforming the sib pair phenotypes using the Box-Cox family of transformations. Data were simulated for normal and non-normal (skewed and kurtic) distributions. Phenotypic values were replaced by Box-Cox transformed values. Twenty thousand replications were performed for three H-E tests of linkage and the likelihood ratio test (LRT), the Wald test and other robust versions based on the MLVC method. We calculated the relative nominal inflation rate as the ratio of observed empirical type 1 error divided by the set alpha level (5, 1 and 0.1% alpha levels). MLVC tests applied to non-normal data had inflated type I errors (rate ratio greater than 1.0), which were controlled best by Box-Cox transformation and to a lesser degree by Winsorizing. For example, for non-transformed, skewed phenotypes (derived from a chi2 distribution with 2 degrees of freedom), the rates of empirical type 1 error with respect to set alpha level=0.01 were 0.80, 4.35 and 7.33 for the original H-E test, LRT and Wald test, respectively. For the same alpha level=0.01, these rates were 1.12, 3.095 and 4.088 after Winsorizing and 0.723, 1.195 and 1.905 after Box-Cox transformation. Winsorizing reduced inflated error rates for the leptokurtic distribution (derived from a Laplace distribution with mean 0 and variance 8). Further, power (adjusted for empirical type 1 error) at the 0.01 alpha level ranged from 4.7 to 17.3% across all tests

  6. Low heritability in pharmacokinetics of talinolol

    DEFF Research Database (Denmark)

    Matthaei, Johannes; Tzvetkov, Mladen V; Gal, Valerie

    2016-01-01

    BACKGROUND: Efflux transporters like MDR1 and MRP2 may modulate the pharmacokinetics of about 50 % of all drugs. It is currently unknown how much of the variation in the activities of important drug membrane transporters like MDR1 or MRP2 is determined by genetic or by environmental factors...... of talinolol was predefined as the primary parameter. Heritability was analyzed by structural equation modeling and by within- and between-subject variance and talinolol clearance was correlated with polymorphisms in MDR1, MRP2, BCRP, MDR5, OATP1B1, and OCT1. RESULTS: Talinolol clearance varied approximately...

  7. Heritability of short-scale natal dispersal in a large-scale foraging bird, the wandering albatross.

    Science.gov (United States)

    Charmantier, A; Buoro, M; Gimenez, O; Weimerskirch, H

    2011-07-01

    Natal dispersal is a key life history trait for the evolution and adaptation of wild populations. Although its evolution has repeatedly been related to the social and environmental context faced by individuals, parent-offspring regressions have also highlighted a possible heritable component. In this study, we explore heritability of natal dispersal, at the scale of the sub-Antarctic Possession Island, for a large-scale foraging seabird, the Wandering albatross Diomedea exulans, exploiting a pedigree spanning over four decades and a maximum of four generations. The comparison of three different methods shows that heritability on the liability scale can vary drastically depending on the type of model (heritability from 6% to 86%), with a notable underestimation by restricted maximum likelihood animal models (6%) compared to Bayesian animal models (36%). In all cases, however, our results point to significant additive genetic variance in the individual propensity to disperse, after controlling for substantial effects of sex and natal colony. These results reveal promising evolutionary potential for short-scale natal dispersal, which could play a critical role for the long-term persistence of this species on the long run. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  8. Polygenic risk score and heritability estimates reveals a genetic relationship between ASD and OCD.

    Science.gov (United States)

    Guo, W; Samuels, J F; Wang, Y; Cao, H; Ritter, M; Nestadt, P S; Krasnow, J; Greenberg, B D; Fyer, A J; McCracken, J T; Geller, D A; Murphy, D L; Knowles, J A; Grados, M A; Riddle, M A; Rasmussen, S A; McLaughlin, N C; Nurmi, E L; Askland, K D; Cullen, B A; Piacentini, J; Pauls, D L; Bienvenu, O J; Stewart, S E; Goes, F S; Maher, B; Pulver, A E; Valle, D; Mattheisen, M; Qian, J; Nestadt, G; Shugart, Y Y

    2017-07-01

    Obsessive-compulsive disorder (OCD) and Autism spectrum disorder (ASD) are both highly heritable neurodevelopmental disorders that conceivably share genetic risk factors. However, the underlying genetic determinants remain largely unknown. In this work, the authors describe a combined genome-wide association study (GWAS) of ASD and OCD. The OCD dataset includes 2998 individuals in nuclear families. The ASD dataset includes 6898 individuals in case-parents trios. GWAS summary statistics were examined for potential enrichment of functional variants associated with gene expression levels in brain regions. The top ranked SNP is rs4785741 (chromosome 16) with P value=6.9×10-7 in our re-analysis. Polygenic risk score analyses were conducted to investigate the genetic relationship within and across the two disorders. These analyses identified a significant polygenic component of ASD, predicting 0.11% of the phenotypic variance in an independent OCD data set. In addition, we examined the genomic architecture of ASD and OCD by estimating heritability on different chromosomes and different allele frequencies, analyzing genome-wide common variant data by using the Genome-wide Complex Trait Analysis (GCTA) program. The estimated global heritability of OCD is 0.427 (se=0.093) and 0.174 (se=0.053) for ASD in these imputed data. Published by Elsevier B.V.

  9. Heritability of audiometric shape parameters and familial aggregation of presbycusis in an elderly Flemish population.

    Science.gov (United States)

    Demeester, Kelly; van Wieringen, Astrid; Hendrickx, Jan-jaap; Topsakal, Vedat; Huyghe, Jeroen; Fransen, Erik; Van Laer, Lut; Van Camp, Guy; Van de Heyning, Paul

    2010-06-14

    This study describes the heritability of audiometric shape parameters and the familial aggregation of different types of presbycusis in a healthy, otologically screened population between 50 and 75 years old. About 342 siblings of 64 families (average family-size: 5.3) were recruited through population registries. Audiometric shape was mathematically quantified by objective parameters developed to measure size, slope, concavity, percentage of frequency-dependent and frequency-independent hearing loss and Bulge Depth. The heritability of each parameter was calculated using a variance components model. Logistic regression models were used to estimate the odds ratios (ORs). Estimates of sibling recurrence risk ratios (lambda(s)) are also provided. Heritability estimates were generally higher compared to previous studies. ORs and lambda(s) for the parameters Total Hearing Loss (size), Uniform Hearing Loss (percentage of frequency-dependent hearing loss) and Bulge Depth suggest a higher heredity for severe types of presbycusis compared to moderate or mild types. Our results suggest that the separation of the parameter 'Total Hearing Loss' into the two parameters 'Uniform Hearing Loss' and 'Non-uniform Hearing Loss' could lead to the discovery of different genetic subtypes of presbycusis. The parameter 'Bulge Depth', instead of 'Concavity', seemed to be an important parameter for classifying subjects into 'susceptible' or 'resistant' to societal or intensive environmental exposure. 2010 Elsevier B.V. All rights reserved.

  10. Heritability and Genome-Wide Association Studies for Hair Color in a Dutch Twin Family Based Sample

    Science.gov (United States)

    Lin, Bochao Danae; Mbarek, Hamdi; Willemsen, Gonneke; Dolan, Conor V.; Fedko, Iryna O.; Abdellaoui, Abdel; de Geus, Eco J.; Boomsma, Dorret I.; Hottenga, Jouke-Jan

    2015-01-01

    Hair color is one of the most visible and heritable traits in humans. Here, we estimated heritability by structural equation modeling (N = 20,142), and performed a genome wide association (GWA) analysis (N = 7091) and a GCTA study (N = 3340) on hair color within a large cohort of twins, their parents and siblings from the Netherlands Twin Register (NTR). Self-reported hair color was analyzed as five binary phenotypes, namely “blond versus non-blond”, “red versus non-red”, “brown versus non-brown”, “black versus non-black”, and “light versus dark”. The broad-sense heritability of hair color was estimated between 73% and 99% and the genetic component included non-additive genetic variance. Assortative mating for hair color was significant, except for red and black hair color. From GCTA analyses, at most 24.6% of the additive genetic variance in hair color was explained by 1000G well-imputed SNPs. Genome-wide association analysis for each hair color showed that SNPs in the MC1R region were significantly associated with red, brown and black hair, and also with light versus dark hair color. Five other known genes (HERC2, TPCN2, SLC24A4, IRF4, and KITLG) gave genome-wide significant hits for blond, brown and light versus dark hair color. We did not find and replicate any new loci for hair color. PMID:26184321

  11. Heritability and Genome-Wide Association Studies for Hair Color in a Dutch Twin Family Based Sample

    Directory of Open Access Journals (Sweden)

    Bochao Danae Lin

    2015-07-01

    Full Text Available Hair color is one of the most visible and heritable traits in humans. Here, we estimated heritability by structural equation modeling (N = 20,142, and performed a genome wide association (GWA analysis (N = 7091 and a GCTA study (N = 3340 on hair color within a large cohort of twins, their parents and siblings from the Netherlands Twin Register (NTR. Self-reported hair color was analyzed as five binary phenotypes, namely “blond versus non-blond”, “red versus non-red”, “brown versus non-brown”, “black versus non-black”, and “light versus dark”. The broad-sense heritability of hair color was estimated between 73% and 99% and the genetic component included non-additive genetic variance. Assortative mating for hair color was significant, except for red and black hair color. From GCTA analyses, at most 24.6% of the additive genetic variance in hair color was explained by 1000G well-imputed SNPs. Genome-wide association analysis for each hair color showed that SNPs in the MC1R region were significantly associated with red, brown and black hair, and also with light versus dark hair color. Five other known genes (HERC2, TPCN2, SLC24A4, IRF4, and KITLG gave genome-wide significant hits for blond, brown and light versus dark hair color. We did not find and replicate any new loci for hair color.

  12. Twin Study of the Heritability of Recognition Thresholds for Sour and Salty Taste

    Science.gov (United States)

    Wise, Paul M.; Hansen, Jonathan L.; Reed, Danielle R.; Breslin, Paul A. S.

    2007-01-01

    Seventy-four pairs of monozygotic (identical) twins and 35 pairs of dizygotic (fraternal) twins provided recognition thresholds (modified Harris–Kalmus test) for the sourness of citric acid and the saltiness of sodium chloride during the Twins Days Festival in Twinsburg, OH. Variance components (ACE) models were applied to the data: total variation = additive genetic (A) + common environment (C) + nonshared environment (E). The best-fit model of variation in recognition thresholds for sourness included an additive genetic factor, accounting for 53% of the variance, but no common environment component. This level of heritability, on par with that of sensitivity to the bitter compounds 6-n-propylthiouracil and phenylthiocarbamide, strongly suggests that genetic factors play a larger role than shared environment in determining individual differences in recognition thresholds for sourness. In contrast, the best-fit model for saltiness recognition included a common environment component, accounting for 22% of the variance in thresholds, but no additive component. This result suggests that environment plays a larger role than genetics in determining individual differences in recognition thresholds for saltiness. PMID:17623712

  13. Heritability, family, school and academic achievement in adolescence.

    Science.gov (United States)

    Pokropek, Artur; Sikora, Joanna

    2015-09-01

    We demonstrate how genetically informed designs can be applied to administrative exam data to study academic achievement. ACE mixture latent class models have been used with Year 6 and 9 exam data for seven cohorts of Polish students which include 24,285 pairs of twins. Depending on a learning domain and classroom environment history, from 58% to 88% of variance in exam results is attributable to heritability, up to 34% to shared environment and from 8% to 15% depends on unique events in students' lives. Moreover, between 54% and 66% of variance in students' learning gains made between Years 6 and 9 is explained by heritability. The unique environment accounts for between 34% and 46% of that variance. However, we find no classroom effects on student progress made between Years 6 and 9. We situate this finding against the view that classroom peer groups and teachers matter for adolescent learning. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Beyond missing heritability: prediction of complex traits.

    Directory of Open Access Journals (Sweden)

    Robert Makowsky

    2011-04-01

    Full Text Available Despite rapid advances in genomic technology, our ability to account for phenotypic variation using genetic information remains limited for many traits. This has unfortunately resulted in limited application of genetic data towards preventive and personalized medicine, one of the primary impetuses of genome-wide association studies. Recently, a large proportion of the "missing heritability" for human height was statistically explained by modeling thousands of single nucleotide polymorphisms concurrently. However, it is currently unclear how gains in explained genetic variance will translate to the prediction of yet-to-be observed phenotypes. Using data from the Framingham Heart Study, we explore the genomic prediction of human height in training and validation samples while varying the statistical approach used, the number of SNPs included in the model, the validation scheme, and the number of subjects used to train the model. In our training datasets, we are able to explain a large proportion of the variation in height (h(2 up to 0.83, R(2 up to 0.96. However, the proportion of variance accounted for in validation samples is much smaller (ranging from 0.15 to 0.36 depending on the degree of familial information used in the training dataset. While such R(2 values vastly exceed what has been previously reported using a reduced number of pre-selected markers (<0.10, given the heritability of the trait (∼ 0.80, substantial room for improvement remains.

  15. Heritability of MMPI-2 scales in the UCSF family alcoholism study.

    Science.gov (United States)

    Gizer, Ian R; Seaton-Smith, Kimberley L; Ehlers, Cindy L; Vieten, Cassandra; Wilhelmsen, Kirk C

    2010-01-01

    The current study evaluated the heritability of personality traits and psychopathology symptoms assessed by the Minnesota Multiphasic Personality Inventory 2nd Edition (MMPI-2) in a family-based sample selected for alcohol dependence. Participants included 950 probands and 1,204 first-degree relatives recruited for the University of California at San Francisco (UCSF) Family Alcoholism Study. Heritability estimates for MMPI-2 scales ranged from .25 to .49. When alcohol dependence was used as a covariate, heritability estimates remained significant but generally declined. However, when the MMPI-2 scales were used as covariates to estimate the heritability of alcohol dependence, the scales measuring antisocial behavior, depressive symptoms, and addictive behavior led to moderate increases in the heritability of alcohol dependence. This suggests that the scales may explain some of the non-genetic variance in the alcohol dependence diagnosis in this population when used as covariates, and thus may serve to produce a more homogeneous and heritable alcohol-dependence phenotype.

  16. Equality in Educational Policy and the Heritability of Educational Attainment.

    Science.gov (United States)

    Colodro-Conde, Lucía; Rijsdijk, Frühling; Tornero-Gómez, María J; Sánchez-Romera, Juan F; Ordoñana, Juan R

    2015-01-01

    Secular variation in the heritability of educational attainment are proposed to be due to the implementation of more egalitarian educational policies leading to increased equality in educational opportunities in the second part of the 20th century. The action of effect is hypothesized to be a decrease of shared environmental (e.g., family socioeconomic status or parents' education) influences on educational attainment, giving more room for genetic differences between individuals to impact on the variation of the trait. However, this hypothesis has not yet found consistent evidence. Support for this effect relies mainly on comparisons between countries adopting different educational systems or between different time periods within a country reflecting changes in general policy. Using a population-based sample of 1271 pairs of adult twins, we analyzed the effect of the introduction of a specific educational policy in Spain in 1970. The shared-environmental variance decreased, leading to an increase in heritability in the post-reform cohort (44 vs. 67%) for males. Unstandardized estimates of genetic variance were of a similar magnitude (.56 vs. .57) between cohorts, while shared environmental variance decreased from .56 to .04. Heritability remained in the same range for women (40 vs. 34%). Our results support the role of educational policy in affecting the relative weight of genetic and environmental factors on educational attainment, such that increasing equality in educational opportunities increases heritability estimates by reducing variation of non-genetic familial origin.

  17. Equality in Educational Policy and the Heritability of Educational Attainment

    Science.gov (United States)

    Colodro-Conde, Lucía; Rijsdijk, Frühling; Tornero-Gómez, María J.; Sánchez-Romera, Juan F.; Ordoñana, Juan R.

    2015-01-01

    Secular variation in the heritability of educational attainment are proposed to be due to the implementation of more egalitarian educational policies leading to increased equality in educational opportunities in the second part of the 20th century. The action of effect is hypothesized to be a decrease of shared environmental (e.g., family socioeconomic status or parents’ education) influences on educational attainment, giving more room for genetic differences between individuals to impact on the variation of the trait. However, this hypothesis has not yet found consistent evidence. Support for this effect relies mainly on comparisons between countries adopting different educational systems or between different time periods within a country reflecting changes in general policy. Using a population-based sample of 1271 pairs of adult twins, we analyzed the effect of the introduction of a specific educational policy in Spain in 1970. The shared-environmental variance decreased, leading to an increase in heritability in the post-reform cohort (44 vs. 67%) for males. Unstandardized estimates of genetic variance were of a similar magnitude (.56 vs. .57) between cohorts, while shared environmental variance decreased from .56 to .04. Heritability remained in the same range for women (40 vs. 34%). Our results support the role of educational policy in affecting the relative weight of genetic and environmental factors on educational attainment, such that increasing equality in educational opportunities increases heritability estimates by reducing variation of non-genetic familial origin. PMID:26618539

  18. Heritability of OSA in a Rural Population.

    Science.gov (United States)

    de Paula, Lilian K G; Alvim, Rafael O; Pedrosa, Rodrigo P; Horimoto, Andrea R V R; Krieger, José E; Oliveira, Camila M; Pereira, Alexandre C; Lorenzi-Filho, Geraldo

    2016-01-01

    OSA has a familial aggregation pattern indicating that it can be partially caused by a genetic component. However, the heritability of OSA has been estimated based on the study of families of obese probands of urban populations with established OSA diagnosis. The objective of this genetic-epidemiologic study is to study families ascertained from a general rural population to determine an unbiased estimate of OSA heritability. We studied a sample of families living in Baependi, a small rural southeastern Brazilian city. Participants were assessed for anthropometric measurements, physical examination, Epworth Sleepiness Scale, blood samples for glucose and cholesterol determination, and overnight home portable monitoring. We studied 587 participants (399 women) from 91 families, with a median (interquartile range [IQR]) of 4 (2-8) participants per family. The median age of the population was 44 years (IQR, 29-55 years) and median BMI was 25.0 kg/m(2) (IQR, 22.1-28.6 kg/m(2)). OSA, defined by apnea-hypopnea index (AHI) > 5/h, was diagnosed in 18.6% of the sample. Two polygenic models, model I (no covariate effects) and model II (with covariate effects), were fitted to the data in all analyses. Heritability estimates for AHI were 0.23 and 0.25 for model I and II, respectively. Covariates (age, sex, and BMI) showed no significant effects on the heritability estimate for AHI. The heritability of AHI in a rural population with low levels of obesity is intermediate (25%). Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  19. Heritability and genome-wide linkage scan of subjective happiness.

    Science.gov (United States)

    Bartels, Meike; Saviouk, Viatcheslav; de Moor, Marleen H M; Willemsen, Gonneke; van Beijsterveldt, Toos C E M; Hottenga, Jouke-Jan; de Geus, Eco J C; Boomsma, Dorret I

    2010-04-01

    Causes of individual differences in happiness, as assessed with the Subjective Happiness Scale, are investigated in a large of sample twins and siblings from the Netherlands Twin Register. Over 12,000 twins and siblings, average age 24.7 years (range 12 to 88), took part in the study. A genetic model with an age by sex design was fitted to the data with structural equation modeling in Mx. The heritability of happiness was estimated at 22% for males and 41% in females. No effect of age was observed. To identify the genomic regions contributing to this heritability, a genome-wide linkage study for happiness was conducted in sibling pairs. A subsample of 1157 offspring from 441 families was genotyped with an average of 371 micro-satellite markers per individual. Phenotype and genotype data were analyzed in MERLIN with multipoint variance component linkage analysis and age and sex as covariates. A linkage signal (logarithm of odds score 2.73, empirical p value 0.095) was obtained at the end of the long arm of chromosome 19 for marker D19S254 at 110 cM. A second suggestive linkage peak was found at the short arm of chromosome 1 (LOD of 2.37) at 153 cM, marker D1S534 (empirical p value of .209). These two regions of interest are not overlapping with the regions found for contrasting phenotypes (such as depression, which is negatively associated with happiness). Further linkage and future association studies are warranted.

  20. Comparison between multitrait and unitrait analysis in the heritability estimate of electrical conductivity of milk

    Directory of Open Access Journals (Sweden)

    Daniella Flavia Vilas Boas

    2012-12-01

    Full Text Available Electrical conductivity of milk is an indirect method for diagnosis of mastitis that can be used as criterion of selection in breeding programs, to obtain more resistant animals to infection. Data from 9,302 records of electrical conductivity from the morning milking (ECM, 13,070 milk yield records (MY and 11,560 records of milking time (MT, of 1,129 first lactation Holstein cows, calving from 2001 to 2011, were used in statistical analysis. Data of eight herds of Southeast region of Brazil were obtained by the WESTFALIA® electronic milking machines, with “Dairyplan” management system. Two analysis were performed: a multitrait, including MY, MT and ECM, and an unitrait, considering only test-day morning electrical conductivity. The model included additive genetic, permanent environmental and residual effects as random. Additionally, contemporary groups (CG, the age of cow at calving (AGC and days in milk (DIM (linear and quadratic regression were included as fixed effects. The CG was composed by herd, year and month of test. DIM classes were formed with weekly intervals, constituting a total of 42 classes. The variance components were estimated by Restricted Maximum Likelihood Method (REML, using the Wombat software. The average and standard deviation of ECM were 4.80 mS cm-1 and 0.54 mS cm-1, respectively. The heritability estimates by multitrait model and their standard errors were 0.33 (0.05, 0.15 (0.03 and 0.22 (0.03 for ECM, MY and MT, respectively. Genetic correlation was 0.74 for MY and MT, 0.37 for MY and ECM and -0.09 for MY and ECM. In the unitrait analysis, the heritability estimate for ECM was 0.35 with a standard error of 0.05. These results agree with the literature that reported heritability estimates for electrical conductivity ranging from 0.26 to 0.39. Although the estimates were close, the heritability estimated by unitrait analysis was slightly higher that estimated by multtrait probably because the pedigree file was the

  1. Social Networks and the Heritability of Migratory Behavior.

    Science.gov (United States)

    Napierala, Jeffrey S; Gage, Timothy

    2016-01-01

    A small but growing body of literature examines the relationship between genetics and human migration. These studies suggest that some DRD4 alleles, particularly 7R+, are related to migration. This is surprising from a sociological perspective, which views migration largely as a product of social and economic forces. However, social relationships with migrants, which have been theorized to influence migration by providing access to migration-specific information and resources, can also be viewed as proxies for genetic relatedness within households. This study computed intraclass correlations for five relatedness groups, along with narrow-sense heritability and environmental correlations, using a large survey of Mexicans. Shared and independent variance components were estimated using multilevel models for the relatedness groups simultaneously with sex and age components. The results indicate that strong environmental influences are exerted on young family members and, to a lesser extent, males. On the other hand, genetic relatedness plays a large role in determining migration for older migrants and females; surprisingly, this is true for both domestic and international migrants.

  2. Components of Variance when Assessing the Reproducibility of Body Composition Measurements using Bio-Impedance and the Hologic QDR-2000 DXA Scanner

    DEFF Research Database (Denmark)

    Jensen, Martin Bach; Hermann, Anne Pernille; Hessov, Ib

    1997-01-01

    whether sheets and pillows significantly altered the DXA results. Fifty-one healthy volunteers aged 20-61 years were examined before and after repositioning (n = 20), removal of the sheets (n = 10), addition of two foam pillows (n = 11) or a regular pillow (n = 10). One to 7 days later a re...... for the other measurements the day to day variation could be accounted for by just measurement variance. Pillows systematically changed the estimates of bone mineral and soft tissue, but sheets did not....

  3. Heritability and genetic correlation between GERD symptoms severity, metabolic syndrome, and inflammation markers in families living in Mexico City.

    Science.gov (United States)

    Reding-Bernal, Arturo; Sánchez-Pedraza, Valentin; Moreno-Macías, Hortensia; Sobrino-Cossio, Sergio; Tejero-Barrera, María Elizabeth; Burguete-García, Ana Isabel; León-Hernández, Mireya; Serratos-Canales, María Fabiola; Duggirala, Ravindranath; López-Alvarenga, Juan Carlos

    2017-01-01

    The aim of this study was to estimate the heritability (h2) and genetic correlation (ρG) between GERD symptoms severity, metabolic syndrome components, and inflammation markers in Mexican families. Cross-sectional study which included 32 extended families resident in Mexico City. GERD symptoms severity was assessed by the ReQuest in Practice questionnaire. Heritability and genetic correlation were determined using the Sequential Oligogenic Linkage Analysis Routines software. 585 subjects were included, the mean age was 42 (±16.7) years, 57% were women. The heritability of the severity of some GERD symptoms was h2 = 0.27, 0.27, 0.37, and 0.34 (p-value syndrome components ranged from 0.40 for fasting plasma glucose to 0.61 for body mass index and diabetes mellitus. The heritability for fibrinogen and C-reactive protein was 0.64 and 0.38, respectively. Statistically significant genetic correlations were found between acidity complaints and fasting plasma glucose (ρG = 0.40); sleep disturbances and fasting plasma glucose (ρG = 0.36); acidity complaints and diabetes mellitus (ρG = 0.49) and between total ReQuest score and fasting plasma glucose (ρG = 0.43). The rest of metabolic syndrome components did not correlate with GERD symptoms. Genetic factors substantially explain the phenotypic variance of the severity of some GERD symptoms, metabolic syndrome components and inflammation markers. Observed genetic correlations suggest that these phenotypes share common genes. These findings suggest conducting further investigation, as the determination of a linkage analysis in order to identify regions of susceptibility for developing of GERD and metabolic syndrome.

  4. Group differences in the heritability of items and test scores

    Science.gov (United States)

    Wicherts, Jelte M.; Johnson, Wendy

    2009-01-01

    It is important to understand potential sources of group differences in the heritability of intelligence test scores. On the basis of a basic item response model we argue that heritabilities which are based on dichotomous item scores normally do not generalize from one sample to the next. If groups differ in mean ability, the functioning of items at different ability levels may result in group differences in the heritability of items, even when these items function equivalently across groups and the heritability of the underlying ability is equal across groups. We illustrate this graphically, by computer simulation, and by focusing on several problems associated with a recent study by Rushton et al. who argued that the heritability estimates of items of Raven's Progressive Matrices test in North-American twin samples generalized to other population groups, and hence that the population group differences on this test of general mental ability (or intelligence) had a substantial genetic component. Our results show that item heritabilities are strongly dependent on the group on which the heritabilities were based. Rushton et al.'s results were artefactual and do not speak to the nature of population group differences in intelligence test performance. PMID:19403538

  5. Kernel-based variance component estimation and whole-genome prediction of pre-corrected phenotypes and progeny tests for dairy cow health traits

    Science.gov (United States)

    Morota, Gota; Boddhireddy, Prashanth; Vukasinovic, Natascha; Gianola, Daniel; DeNise, Sue

    2014-01-01

    Prediction of complex trait phenotypes in the presence of unknown gene action is an ongoing challenge in animals, plants, and humans. Development of flexible predictive models that perform well irrespective of genetic and environmental architectures is desirable. Methods that can address non-additive variation in a non-explicit manner are gaining attention for this purpose and, in particular, semi-parametric kernel-based methods have been applied to diverse datasets, mostly providing encouraging results. On the other hand, the gains obtained from these methods have been smaller when smoothed values such as estimated breeding value (EBV) have been used as response variables. However, less emphasis has been placed on the choice of phenotypes to be used in kernel-based whole-genome prediction. This study aimed to evaluate differences between semi-parametric and parametric approaches using two types of response variables and molecular markers as inputs. Pre-corrected phenotypes (PCP) and EBV obtained for dairy cow health traits were used for this comparison. We observed that non-additive genetic variances were major contributors to total genetic variances in PCP, whereas additivity was the largest contributor to variability of EBV, as expected. Within the kernels evaluated, non-parametric methods yielded slightly better predictive performance across traits relative to their additive counterparts regardless of the type of response variable used. This reinforces the view that non-parametric kernels aiming to capture non-linear relationships between a panel of SNPs and phenotypes are appealing for complex trait prediction. However, like past studies, the gain in predictive correlation was not large for either PCP or EBV. We conclude that capturing non-additive genetic variation, especially epistatic variation, in a cross-validation framework remains a significant challenge even when it is important, as seems to be the case for health traits in dairy cows. PMID:24715901

  6. Kernel-based variance component estimation and whole-genome prediction of pre-corrected phenotypes and progeny tests for dairy cow health traits

    Directory of Open Access Journals (Sweden)

    Gota eMorota

    2014-03-01

    Full Text Available Prediction of complex trait phenotypes in the presence of unknown gene action is an ongoing challenge in animals, plants, and humans. Development of flexible predictive models that perform well irrespective of genetic and environmental architectures is desirable. Methods that can address non-additive variation in a non-explicit manner are gaining attention for this purpose and, in particular, semi-parametric kernel-based methods have been applied to diverse datasets, mostly providing encouraging results. On the other hand, the gains obtained from these methods have been smaller when smoothed values such as estimated breeding value (EBV have been used as response variables. However, less emphasis has been placed on the choice of phenotypes to be used in kernel-based whole-genome prediction. This study aimed to evaluate differences between semi-parametric and parametric approaches using two types of response variables and molecular markers as inputs. Pre-corrected phenotypes (PCP and EBV obtained for dairy cow health traits were used for this comparison. We observed that non-additive genetic variances were major contributors to total genetic variances in PCP, whereas additivity was the largest contributor to variability of EBV, as expected. Within the kernels evaluated, non-parametric methods yielded slightly better predictive performance across traits relative to their additive counterparts regardless of the type of response variable used. This reinforces the view that non-parametric kernels aiming to capture non-linear relationships between a panel of SNPs and phenotypes are appealing for complex trait prediction. However, like past studies, the gain in predictive correlation was not large for either PCP or EBV. We conclude that capturing non-additive genetic variation, especially epistatic variation, in a cross-validation framework remains a significant challenge even when it is important, as seems to be the case for health traits in dairy cows.

  7. Heritable Disorders of Connective Tissue

    Science.gov (United States)

    ... rare. Common heritable disorders of connective tissue include: Ehlers-Danlos syndrome mostly affects the skin and joints. Connective ... of America, Inc. Website: https://www.debra.org Ehlers-Danlos National Foundation Website: https://www.ednf.org/ National ...

  8. Pregnancy failure and heritable thrombophilia

    NARCIS (Netherlands)

    Middeldorp, Saskia

    2007-01-01

    Heritable thrombophilia is associated with an increased risk for pregnancy failure, defined as sporadic and recurrent miscarriage, late fetal loss, and other vascular pregnancy complications such as preeclampsia and intrauterine growth retardation. The pathogenesis is likely to include effects on

  9. Repeatability and Heritability of Behavioural Types in a Social Cichlid

    Directory of Open Access Journals (Sweden)

    Noémie Chervet

    2011-01-01

    Full Text Available Aim. The quantitative genetics underlying correlated behavioural traits (‘‘animal personality’’ have hitherto been studied mainly in domesticated animals. Here we report the repeatability ( and heritability (ℎ2 of behavioural types in the highly social cichlid fish Neolamprologus pulcher. Methods. We tested 1779 individuals repeatedly and calculated the ℎ2 of behavioural types by variance components estimation (GLMM REML, using 1327 offspring from 162 broods from 74 pairs. Results. Repeatability of behavioural types was significant and considerable (0.546, but declined from 0.83 between tests conducted on the same day, to 0.19 on tests conducted up to 1201 days apart. All ℎ2 estimates were significant but low (e.g., pair identity ℎ2=0.15±0.03 SE. Additionally, we found significant variation between broods nested within the parent(s, but these were not related to several environmental factors tested. Conclusions. We conclude that despite a considerable , ℎ2 in this cichlid species is low, and variability in behavioural type appears to be strongly affected by other (nongenetic effects.

  10. High Heritability Is Compatible with the Broad Distribution of Set Point Viral Load in HIV Carriers

    Science.gov (United States)

    Bonhoeffer, Sebastian; Fraser, Christophe; Leventhal, Gabriel E.

    2015-01-01

    Set point viral load in HIV patients ranges over several orders of magnitude and is a key determinant of disease progression in HIV. A number of recent studies have reported high heritability of set point viral load implying that viral genetic factors contribute substantially to the overall variation in viral load. The high heritability is surprising given the diversity of host factors associated with controlling viral infection. Here we develop an analytical model that describes the temporal changes of the distribution of set point viral load as a function of heritability. This model shows that high heritability is the most parsimonious explanation for the observed variance of set point viral load. Our results thus not only reinforce the credibility of previous estimates of heritability but also shed new light onto mechanisms of viral pathogenesis. PMID:25658741

  11. High heritability is compatible with the broad distribution of set point viral load in HIV carriers.

    Directory of Open Access Journals (Sweden)

    Sebastian Bonhoeffer

    2015-02-01

    Full Text Available Set point viral load in HIV patients ranges over several orders of magnitude and is a key determinant of disease progression in HIV. A number of recent studies have reported high heritability of set point viral load implying that viral genetic factors contribute substantially to the overall variation in viral load. The high heritability is surprising given the diversity of host factors associated with controlling viral infection. Here we develop an analytical model that describes the temporal changes of the distribution of set point viral load as a function of heritability. This model shows that high heritability is the most parsimonious explanation for the observed variance of set point viral load. Our results thus not only reinforce the credibility of previous estimates of heritability but also shed new light onto mechanisms of viral pathogenesis.

  12. Heritability of strabismus: genetic influence is specific to eso-deviation and independent of refractive error.

    Science.gov (United States)

    Sanfilippo, Paul G; Hammond, Christopher J; Staffieri, Sandra E; Kearns, Lisa S; Melissa Liew, S H; Barbour, Julie M; Hewitt, Alex W; Ge, Dongliang; Snieder, Harold; Mackinnon, Jane R; Brown, Shayne A; Lorenz, Birgit; Spector, Tim D; Martin, Nicholas G; Wilmer, Jeremy B; Mackey, David A

    2012-10-01

    Strabismus represents a complex oculomotor disorder characterized by the deviation of one or both eyes and poor vision. A more sophisticated understanding of the genetic liability of strabismus is required to guide searches for associated molecular variants. In this classical twin study of 1,462 twin pairs, we examined the relative influence of genes and environment in comitant strabismus, and the degree to which these influences can be explained by factors in common with refractive error. Participants were examined for the presence of latent ('phoria') and manifest ('tropia') strabismus using cover-uncover and alternate cover tests. Two phenotypes were distinguished: eso-deviation (esophoria and esotropia) and exo-deviation (exophoria and exotropia). Structural equation modeling was subsequently employed to partition the observed phenotypic variation in the twin data into specific variance components. The prevalence of eso-deviation and exo-deviation was 8.6% and 20.7%, respectively. For eso-deviation, the polychoric correlation was significantly greater in monozygotic (MZ) (r = 0.65) compared to dizygotic (DZ) twin pairs (r = 0.33), suggesting a genetic role (p = .003). There was no significant difference in polychoric correlation between MZ (r = 0.55) and DZ twin pairs (r = 0.53) for exo-deviation (p = .86), implying that genetic factors do not play a significant role in the etiology of exo-deviation. The heritability of an eso-deviation was 0.64 (95% CI 0.50-0.75). The additive genetic correlation for eso-deviation and refractive error was 0.13 and the bivariate heritability (i.e., shared variance) was less than 1%, suggesting negligible shared genetic effect. This study documents a substantial heritability of 64% for eso-deviation, yet no corresponding heritability for exo-deviation, suggesting that the genetic contribution to strabismus may be specific to eso-deviation. Future studies are now needed to identify the genes associated with eso-deviation and

  13. Analisis Ragam dan Peragam Bobot Badan Kambing Peranakan Etawa (ANALYSIS VARIANCE AND COVARIANCE OF BODY WEIGHT OF ETTAWA GRADE GOAT

    Directory of Open Access Journals (Sweden)

    Siti Hidayati

    2015-05-01

    Full Text Available The aims of this study were (1 to analyze the phenotypic performance of Ettawa Grade (EG goat; (2to estimate the heritability of birth weight (BW, weaning weight (WW, yearling weight (YW, and geneticcorrelation between two body weights on the third different period; and (3 to analyze the variance andcovariance component of body weight. The material used were the exiting records of 437 EG goats in BalaiPembibitan Ternak Unggul dan Hijauan Pakan Ternak Pelaihari, South Kalimantan. These goats originatedfrom the crossing between 19 males and 216 females from periods of 2009 - 2012. Nested Design methodwas used to etimate the phenotypic correlation, heritability and genetic correlation. Variance componentswere determined from heritability estimation, while covariance components were determined from geneticcerrelation estimation. Phenotypic correlation between BW and WW, between BW and YW, and betweenWW and YW were 0.19 (low; 0.31 (medium; 0.65 (high; respectively. Heritability of BW, WW, and YW were0.43±0.23 (high; WW 0.27±0.19 (medium; and YW 1.01±0.38 (excludeof the h2 value, respectively.Genetic correlation between BW and WW, between BW and YW, and between WW and YW were -0.04(negative low; 0.49 (positive medium; and -0.41 (negative medium, respectively. Variance components ofbuck, ewes, and kid for BW were 10.76%; 37.16%; and 52.09%, respectively, for WW were 6.67%; 38.52%;and 54.81%, respectively, and for YW were 25.15%; 58.37%; and 16.43%, respectively. Covariancecomponents of buck, ewes, and kid between BW and WW were -3.91%; 66.45%; and 37.46%, respectively,between BW and YW were 65.68%; 16.50%; and 17.82, and between WW and YW were -5.14%; 83.87%; and21.28%, respectively. In conclusions variance component of ewes and kid were high in body weight at birthand weaning time. Therefore, selection should be conducted for body weight at birth and weaning time.

  14. On the heritability of psoriatic arthritis. Disease concordance among monozygotic and dizygotic twins

    DEFF Research Database (Denmark)

    Pedersen, Ole Birger; Svendsen, Anders Jørgen; Ejstrup, Leif

    2008-01-01

    OBJECTIVE: In a nationwide unselected twin population to estimate the relative importance of genetic and environmental effectors in the etiopathogenesis of psoriatic arthritis (PsA). METHODS: The study comprised three Danish nationwide twin cohorts. In 1994 and 2002 a total of 37,388 and 46......,418 Danish twin individuals respectively were asked by questionnaire if they had PsA. Twins reporting PsA were invited to participate in a clinical examination. Patients were classified according to the Moll and Wright (M&W) and the CASPAR criteria. Heritability was estimated by probandwise concordance rates...... and variance component analysis. RESULTS: 228 twin individuals reported PsA. Following diagnostic validation in 184 (81%), 50 probands were diagnosed with PsA according to the M&W criteria. Five of their co-twins were either dead, had emigrated, or did not participate in the twin study and nine did not respond...

  15. Assumption-free estimation of heritability from genome-wide identity-by-descent sharing between full siblings.

    Directory of Open Access Journals (Sweden)

    2006-03-01

    Full Text Available The study of continuously varying, quantitative traits is important in evolutionary biology, agriculture, and medicine. Variation in such traits is attributable to many, possibly interacting, genes whose expression may be sensitive to the environment, which makes their dissection into underlying causative factors difficult. An important population parameter for quantitative traits is heritability, the proportion of total variance that is due to genetic factors. Response to artificial and natural selection and the degree of resemblance between relatives are all a function of this parameter. Following the classic paper by R. A. Fisher in 1918, the estimation of additive and dominance genetic variance and heritability in populations is based upon the expected proportion of genes shared between different types of relatives, and explicit, often controversial and untestable models of genetic and non-genetic causes of family resemblance. With genome-wide coverage of genetic markers it is now possible to estimate such parameters solely within families using the actual degree of identity-by-descent sharing between relatives. Using genome scans on 4,401 quasi-independent sib pairs of which 3,375 pairs had phenotypes, we estimated the heritability of height from empirical genome-wide identity-by-descent sharing, which varied from 0.374 to 0.617 (mean 0.498, standard deviation 0.036. The variance in identity-by-descent sharing per chromosome and per genome was consistent with theory. The maximum likelihood estimate of the heritability for height was 0.80 with no evidence for non-genetic causes of sib resemblance, consistent with results from independent twin and family studies but using an entirely separate source of information. Our application shows that it is feasible to estimate genetic variance solely from within-family segregation and provides an independent validation of previously untestable assumptions. Given sufficient data, our new paradigm will

  16. Heritability of objectively assessed daily physical activity and sedentary behavior.

    Science.gov (United States)

    den Hoed, Marcel; Brage, Søren; Zhao, Jing Hua; Westgate, Kate; Nessa, Ayrun; Ekelund, Ulf; Spector, Tim D; Wareham, Nicholas J; Loos, Ruth J F

    2013-11-01

    Twin and family studies that estimated the heritability of daily physical activity have been limited by poor measurement quality and a small sample size. We examined the heritability of daily physical activity and sedentary behavior assessed objectively by using combined heart rate and movement sensing in a large twin study. Physical activity traits were assessed in daily life for a mean (± SD) 6.7 ± 1.1 d in 1654 twins from 420 monozygotic and 352 dizygotic same-sex twin pairs aged 56.3 ± 10.4 y with body mass index (in kg/m(2)) of 26.1 ± 4.8. We estimated the average daily movement, physical activity energy expenditure, and time spent in moderate-to-vigorous intensity physical activity and sedentary behavior from heart rate and acceleration data. We used structural equation modeling to examine the contribution of additive genetic, shared environmental, and unique environmental factors to between-individual variation in traits. Additive genetic factors (ie, heritability) explained 47% of the variance in physical activity energy expenditure (95% CI: 23%, 53%) and time spent in moderate-to-vigorous intensity physical activity (95% CI: 29%, 54%), 35% of the variance in acceleration of the trunk (95% CI: 0%, 44%), and 31% of the variance in the time spent in sedentary behavior (95% CI: 9%, 51%). The remaining variance was predominantly explained by unique environmental factors and random error, whereas shared environmental factors played only a marginal role for all traits with a range of 0-15%. The between-individual variation in daily physical activity and sedentary behavior is mainly a result of environmental influences. Nevertheless, genetic factors explain up to one-half of the variance, suggesting that innate biological processes may be driving some of our daily physical activity.

  17. Heritability and Genetic Advance among Chili Pepper Genotypes for Heat Tolerance and Morphophysiological Characteristics

    Directory of Open Access Journals (Sweden)

    Magaji G. Usman

    2014-01-01

    Full Text Available High temperature tolerance is an important component of adaptation to arid and semiarid cropping environment in chili pepper. Two experiments were carried out to study the genetic variability among chili pepper for heat tolerance and morphophysiological traits and to estimate heritability and genetic advance expected from selection. There was a highly significant variation among the genotypes in response to high temperature (CMT, photosynthesis rate, plant height, disease incidence, fruit length, fruit weight, number of fruits, and yield per plant. At 5% selection intensity, high genetic advance as percent of the mean (>20% was observed for CMT, photosynthesis rate, fruit length, fruit weight, number of fruits, and yield per plant. Similarly, high heritability (>60% was also observed indicating the substantial effect of additive gene more than the environmental effect. Yield per plant showed strong to moderately positive correlations (r=0.23–0.56 at phenotypic level while at genotypic level correlation coefficient ranged from 0.16 to 0.72 for CMT, plant height, fruit length, and number of fruits. Cluster analysis revealed eight groups and Group VIII recorded the highest CMT and yield. Group IV recorded 13 genotypes while Groups II, VII, and VIII recorded one each. The results showed that the availability of genetic variance could be useful for exploitation through selection for further breeding purposes.

  18. Sequential recruitment of study participants may inflate genetic heritability estimates.

    Science.gov (United States)

    Noce, Damia; Gögele, Martin; Schwienbacher, Christine; Caprioli, Giulia; De Grandi, Alessandro; Foco, Luisa; Platzgummer, Stefan; Pramstaller, Peter P; Pattaro, Cristian

    2017-06-01

    After the success of genome-wide association studies to uncover complex trait loci, attempts to explain the remaining genetic heritability (h (2)) are mainly focused on unraveling rare variant associations and gene-gene or gene-environment interactions. Little attention is paid to the possibility that h (2) estimates are inflated as a consequence of the epidemiological study design. We studied the time series of 54 biochemical traits in 4373 individuals from the Cooperative Health Research In South Tyrol (CHRIS) study, a pedigree-based study enrolling ten participants/day over several years, with close relatives preferentially invited within the same day. We observed distributional changes of measured traits over time. We hypothesized that the combination of such changes with the pedigree structure might generate a shared-environment component with consequent h (2) inflation. We performed variance components (VC) h (2) estimation for all traits after accounting for the enrollment period in a linear mixed model (two-stage approach). Accounting for the enrollment period caused a median h (2) reduction of 4%. For 9 traits, the reduction was of >20%. Results were confirmed by a Bayesian Markov chain Monte Carlo analysis with all VCs included at the same time (one-stage approach). The electrolytes were the traits most affected by the enrollment period. The h (2) inflation was independent of the h (2) magnitude, laboratory protocol changes, and length of the enrollment period. The enrollment process may induce shared-environment effects even under very stringent and standardized operating procedures, causing h (2) inflation. Including the day of participation as a random effect is a sensitive way to avoid overestimation.

  19. Paramutation: Heritable in trans effects

    NARCIS (Netherlands)

    Stam, M.; Louwers, M.; Bennetzen, J.L.; Hake, S.

    2009-01-01

    Paramutation is the heritable transfer of epigenetic information from one allele of a gene to another allele of the same gene. In general, the consequence of this trans-communication is a change in gene expression. Paramutation has been observed in plants, fungi and mammals, but is most extensively

  20. heterosis and heritability estimates of purine alkaloids and ...

    African Journals Online (AJOL)

    ACSS

    to disease and to insect pest, or to climatic rigours. (Rhode etal., 2004; Korn et al., 2008). Despite the fact that purine alkaloids and flavanols are signature component in cocoa beans, little information is available on heterosis of these traits in cocoa. Another important genetic factor used by breeders is heritability. This term ...

  1. Heritability and intrafamilial aggregation of arterial characteristics

    Science.gov (United States)

    Seidlerová, Jitka; Bochud, Murielle; Staessen, Jan A.; Cwynar, Marcin; Dolejšová, Milena; Kuznetsova, Tatiana; Nawrot, Tim; Olszanecka, Agnieszka; Stolarz, Katarzyna; Thijs, Lutgarde; Wojciechowska, Wiktoria; Struijker-Boudier, Harry A.; Kawecka-Jaszcz, Kalina; Elston, Robert C.; Fagard, Robert; Filipovský, Jan

    2013-01-01

    Background We investigated the heritability and familial aggregation of various indexes of arterial stiffness and wave reflection and we partitioned the phenotypic correlation between these traits into shared genetic and environmental components. Methods Using a family-based population sample, we recruited 204 parents (mean age, 51.7 years) and 290 offspring (29.4 years) from the population in Cracow, Poland (62 families), Hechtel-Eksel, Belgium (36), and Pilsen, the Czech Republic (50). We measured peripheral pulse pressure (PPp) sphygmomanometrically at the brachial artery; central pulse pressure (PPc), the peripheral augmentation indexes (PAIxs) and central augmentation indexes (CAIxs) by applanation tonometry at the radial artery; and aortic pulse wave velocity (PWV) by tonometry or ultrasound. In multivariate-adjusted analyses, we used the ASSOC and PROC GENMOD procedures as implemented in SAGE and SAS, respectively. Results We found significant heritability for PAIx, CAIx, PPc and mean arterial pressure ranging from 0.37 to 0.41; P ≤ 0.0001. The method of intrafamilial concordance confirmed these results; intrafamilial correlation coefficients were significant for all arterial indexes (r > ≥ 0.12; P < ≤ 0.02) with the exception of PPc (r = −0.007; P = 0.90) in parent–offspring pairs. The sib–sib correlations were also significant for CAIx (r = 0.22; P = 0.001). The genetic correlation between PWV and the other arterial indexes were significant (ρG ≥ 0.29; P < 0.0001). The corresponding environmental correlations were only significantly positive for PPp (ρE = 0.10, P = 0.03). Conclusion The observation of significant intrafamilial concordance and heritability of various indexes of arterial stiffness as well as the genetic correlations among arterial phenotypes strongly support the search for shared genetic determinants underlying these traits. PMID:18327082

  2. Sex-specific heritability of spontaneous lipid levels in an extended pedigree of Indian-origin rhesus macaques (Macaca mulatta.

    Directory of Open Access Journals (Sweden)

    Amanda Vinson

    Full Text Available The rhesus macaque is an important model for human atherosclerosis but genetic determinants of relevant phenotypes have not yet been investigated in this species. Because lipid levels are well-established and heritable risk factors for human atherosclerosis, our goal was to assess the heritability of lipoprotein cholesterol and triglyceride levels in a single, extended pedigree of 1,289 Indian-origin rhesus macaques. Additionally, because increasing evidence supports sex differences in the genetic architecture of lipid levels and lipid metabolism in humans and macaques, we also explored sex-specific heritability for all lipid measures investigated in this study. Using standard methods, we measured lipoprotein cholesterol and triglyceride levels from fasted plasma in a sample of 193 pedigreed rhesus macaques selected for membership in large, paternal half-sib cohorts, and maintained on a low-fat, low cholesterol chow diet. Employing a variance components approach, we found moderate heritability for total cholesterol (h²=0.257, P=0.032, LDL cholesterol (h²=0.252, P=0.030, and triglyceride levels (h²=0.197, P=0.034 in the full sample. However, stratification by sex (N=68 males, N=125 females revealed substantial sex-specific heritability for total cholesterol (0.644, P=0.004, females only, HDL cholesterol (0.843, P=0.0008, females only, VLDL cholesterol (0.482, P=0.018, males only, and triglyceride levels (0.705, P=0.001, males only that was obscured or absent when sexes were combined in the full sample. We conclude that genes contribute to spontaneous variation in circulating lipid levels in the Indian-origin rhesus macaque in a sex-specific manner, and that the rhesus macaque is likely to be a valuable model for sex-specific genetic effects on lipid risk factors for human atherosclerosis. These findings are a first-ever report of heritability for cholesterol levels in this species, and support the need for expanded analysis of these traits in

  3. Heritability and familial aggregation of diverticular disease

    DEFF Research Database (Denmark)

    Strate, Lisa L; Erichsen, Rune; Baron, John A

    2013-01-01

    Little is known about the role of heritable factors in diverticular disease. We evaluated the contribution of heritable factors to the development of diverticular disease diagnosed at a hospitalization or outpatient visit.......Little is known about the role of heritable factors in diverticular disease. We evaluated the contribution of heritable factors to the development of diverticular disease diagnosed at a hospitalization or outpatient visit....

  4. Heritability of working memory brain activation.

    Science.gov (United States)

    Blokland, Gabriëlla A M; McMahon, Katie L; Thompson, Paul M; Martin, Nicholas G; de Zubicaray, Greig I; Wright, Margaret J

    2011-07-27

    Although key to understanding individual variation in task-related brain activation, the genetic contribution to these individual differences remains largely unknown. Here we report voxel-by-voxel genetic model fitting in a large sample of 319 healthy, young adult, human identical and fraternal twins (mean ± SD age, 23.6 ± 1.8 years) who performed an n-back working memory task during functional magnetic resonance imaging (fMRI) at a high magnetic field (4 tesla). Patterns of task-related brain response (BOLD signal difference of 2-back minus 0-back) were significantly heritable, with the highest estimates (40-65%) in the inferior, middle, and superior frontal gyri, left supplementary motor area, precentral and postcentral gyri, middle cingulate cortex, superior medial gyrus, angular gyrus, superior parietal lobule, including precuneus, and superior occipital gyri. Furthermore, high test-retest reliability for a subsample of 40 twins indicates that nongenetic variance in the fMRI brain response is largely due to unique environmental influences rather than measurement error. Individual variations in activation of the working memory network are therefore significantly influenced by genetic factors. By establishing the heritability of cognitive brain function in a large sample that affords good statistical power, and using voxel-by-voxel analyses, this study provides the necessary evidence for task-related brain activation to be considered as an endophenotype for psychiatric or neurological disorders, and represents a substantial new contribution to the field of neuroimaging genetics. These genetic brain maps should facilitate discovery of gene variants influencing cognitive brain function through genome-wide association studies, potentially opening up new avenues in the treatment of brain disorders.

  5. Neutral theory for life histories and individual variability in fitness components.

    Science.gov (United States)

    Steiner, Ulrich Karl; Tuljapurkar, Shripad

    2012-03-20

    Individuals within populations can differ substantially in their life span and their lifetime reproductive success but such realized individual variation in fitness components need not reflect underlying heritable fitness differences visible to natural selection. Even so, biologists commonly argue that large differences in fitness components are likely adaptive, resulting from and driving evolution by natural selection. To examine this argument we use unique formulas to compute exactly the variance in life span and in lifetime reproductive success among individuals with identical (genotypic) vital rates (assuming a common genotype for all individuals). Such individuals have identical fitness but vary substantially in their realized individual fitness components. We show by example that our computed variances and corresponding simulated distribution of fitness components match those observed in real populations. Of course, (genotypic) vital rates in real populations are expected to differ by small but evolutionarily important amounts among genotypes, but we show that such differences only modestly increase variances in fitness components. We conclude that observed differences in fitness components may likely be evolutionarily neutral, at least to the extent that they are indistinguishable from distributions generated by neutral processes. Important consequences of large neutral variation are the following: Heritabilities for fitness components are likely to be small (which is in fact the case), small selective differences in life histories will be hard to measure, and the effects of random drift will be amplified in natural populations by the large variances among individuals.

  6. Prediction of Breeding Values and Selection Responses With Genetic Heterogeneity of Environmental Variance

    Science.gov (United States)

    Mulder, H. A.; Bijma, P.; Hill, W. G.

    2007-01-01

    There is empirical evidence that genotypes differ not only in mean, but also in environmental variance of the traits they affect. Genetic heterogeneity of environmental variance may indicate genetic differences in environmental sensitivity. The aim of this study was to develop a general framework for prediction of breeding values and selection responses in mean and environmental variance with genetic heterogeneity of environmental variance. Both means and environmental variances were treated as heritable traits. Breeding values and selection responses were predicted with little bias using linear, quadratic, and cubic regression on individual phenotype or using linear regression on the mean and within-family variance of a group of relatives. A measure of heritability was proposed for environmental variance to standardize results in the literature and to facilitate comparisons to “conventional” traits. Genetic heterogeneity of environmental variance can be considered as a trait with a low heritability. Although a large amount of information is necessary to accurately estimate breeding values for environmental variance, response in environmental variance can be substantial, even with mass selection. The methods developed allow use of the well-known selection index framework to evaluate breeding strategies and effects of natural selection that simultaneously change the mean and the variance. PMID:17277375

  7. Aphid Heritable Symbiont Exploits Defensive Mutualism.

    Science.gov (United States)

    Doremus, Matthew R; Oliver, Kerry M

    2017-04-15

    Insects and other animals commonly form symbioses with heritable bacteria, which can exert large influences on host biology and ecology. The pea aphid, Acyrthosiphon pisum , is a model for studying effects of infection with heritable facultative symbionts (HFS), and each of its seven common HFS species has been reported to provide resistance to biotic or abiotic stresses. However, one common HFS, called X-type, rarely occurs as a single infection in field populations and instead typically superinfects individual aphids with Hamiltonella defensa , another HFS that protects aphids against attack by parasitic wasps. Using experimental aphid lines comprised of all possible infection combinations in a uniform aphid genotype, we investigated whether the most common strain of X-type provides any of the established benefits associated with aphid HFS as a single infection or superinfection with H. defensa We found that X-type does not confer protection to any tested threats, including parasitoid wasps, fungal pathogens, or thermal stress. Instead, component fitness assays identified large costs associated with X-type infection, costs which were ameliorated in superinfected aphids. Together these findings suggest that X-type exploits the aphid/ H. defensa mutualism and is maintained primarily as a superinfection by "hitchhiking" via the mutualistic benefits provided by another HFS. Exploitative symbionts potentially restrict the functions and distributions of mutualistic symbioses with effects that extend to other community members. IMPORTANCE Maternally transmitted bacterial symbionts are widespread and can have major impacts on the biology of arthropods, including insects of medical and agricultural importance. Given that host fitness and symbiont fitness are tightly linked, inherited symbionts can spread within host populations by providing beneficial services. Many insects, however, are frequently infected with multiple heritable symbiont species, providing potential

  8. Partitioning the Heritability of Tourette Syndrome and Obsessive Compulsive Disorder Reveals Differences in Genetic Architecture

    Science.gov (United States)

    Davis, Lea K.; Yu, Dongmei; Keenan, Clare L.; Gamazon, Eric R.; Konkashbaev, Anuar I.; Derks, Eske M.; Neale, Benjamin M.; Yang, Jian; Lee, S. Hong; Evans, Patrick; Barr, Cathy L.; Bellodi, Laura; Benarroch, Fortu; Berrio, Gabriel Bedoya; Bienvenu, Oscar J.; Bloch, Michael H.; Blom, Rianne M.; Bruun, Ruth D.; Budman, Cathy L.; Camarena, Beatriz; Campbell, Desmond; Cappi, Carolina; Cardona Silgado, Julio C.; Cath, Danielle C.; Cavallini, Maria C.; Chavira, Denise A.; Chouinard, Sylvain; Conti, David V.; Cook, Edwin H.; Coric, Vladimir; Cullen, Bernadette A.; Deforce, Dieter; Delorme, Richard; Dion, Yves; Edlund, Christopher K.; Egberts, Karin; Falkai, Peter; Fernandez, Thomas V.; Gallagher, Patience J.; Garrido, Helena; Geller, Daniel; Girard, Simon L.; Grabe, Hans J.; Grados, Marco A.; Greenberg, Benjamin D.; Gross-Tsur, Varda; Haddad, Stephen; Heiman, Gary A.; Hemmings, Sian M. J.; Hounie, Ana G.; Illmann, Cornelia; Jankovic, Joseph; Jenike, Michael A.; Kennedy, James L.; King, Robert A.; Kremeyer, Barbara; Kurlan, Roger; Lanzagorta, Nuria; Leboyer, Marion; Leckman, James F.; Lennertz, Leonhard; Liu, Chunyu; Lochner, Christine; Lowe, Thomas L.; Macciardi, Fabio; McCracken, James T.; McGrath, Lauren M.; Mesa Restrepo, Sandra C.; Moessner, Rainald; Morgan, Jubel; Muller, Heike; Murphy, Dennis L.; Naarden, Allan L.; Ochoa, William Cornejo; Ophoff, Roel A.; Osiecki, Lisa; Pakstis, Andrew J.; Pato, Michele T.; Pato, Carlos N.; Piacentini, John; Pittenger, Christopher; Pollak, Yehuda; Rauch, Scott L.; Renner, Tobias J.; Reus, Victor I.; Richter, Margaret A.; Riddle, Mark A.; Robertson, Mary M.; Romero, Roxana; Rosàrio, Maria C.; Rosenberg, David; Rouleau, Guy A.; Ruhrmann, Stephan; Ruiz-Linares, Andres; Sampaio, Aline S.; Samuels, Jack; Sandor, Paul; Sheppard, Brooke; Singer, Harvey S.; Smit, Jan H.; Stein, Dan J.; Strengman, E.; Tischfield, Jay A.; Valencia Duarte, Ana V.; Vallada, Homero; Van Nieuwerburgh, Filip; Veenstra-VanderWeele, Jeremy; Walitza, Susanne; Wang, Ying; Wendland, Jens R.; Westenberg, Herman G. M.; Shugart, Yin Yao; Miguel, Euripedes C.; McMahon, William; Wagner, Michael; Nicolini, Humberto; Posthuma, Danielle; Hanna, Gregory L.; Heutink, Peter; Denys, Damiaan; Arnold, Paul D.; Oostra, Ben A.; Nestadt, Gerald; Freimer, Nelson B.; Pauls, David L.; Wray, Naomi R.

    2013-01-01

    The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease explained by all SNPs for two phenotypically-related neurobehavioral disorders, obsessive-compulsive disorder (OCD) and Tourette Syndrome (TS), using GCTA. Our analysis yielded a heritability point estimate of 0.58 (se = 0.09, p = 5.64e-12) for TS, and 0.37 (se = 0.07, p = 1.5e-07) for OCD. In addition, we conducted multiple genomic partitioning analyses to identify genomic elements that concentrate this heritability. We examined genomic architectures of TS and OCD by chromosome, MAF bin, and functional annotations. In addition, we assessed heritability for early onset and adult onset OCD. Among other notable results, we found that SNPs with a minor allele frequency of less than 5% accounted for 21% of the TS heritability and 0% of the OCD heritability. Additionally, we identified a significant contribution to TS and OCD heritability by variants significantly associated with gene expression in two regions of the brain (parietal cortex and cerebellum) for which we had available expression quantitative trait loci (eQTLs). Finally we analyzed the genetic correlation between TS and OCD, revealing a genetic correlation of 0.41 (se = 0.15, p = 0.002). These results are very close to previous heritability estimates for TS and OCD based on twin and family studies, suggesting that very little, if any, heritability is truly missing (i.e., unassayed) from TS and OCD GWAS studies of common variation. The results also indicate that there is some genetic overlap between these two phenotypically-related neuropsychiatric disorders, but suggest that the two disorders have distinct genetic architectures. PMID:24204291

  9. Partitioning the heritability of Tourette syndrome and obsessive compulsive disorder reveals differences in genetic architecture.

    Directory of Open Access Journals (Sweden)

    Lea K Davis

    2013-10-01

    Full Text Available The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease explained by all SNPs for two phenotypically-related neurobehavioral disorders, obsessive-compulsive disorder (OCD and Tourette Syndrome (TS, using GCTA. Our analysis yielded a heritability point estimate of 0.58 (se = 0.09, p = 5.64e-12 for TS, and 0.37 (se = 0.07, p = 1.5e-07 for OCD. In addition, we conducted multiple genomic partitioning analyses to identify genomic elements that concentrate this heritability. We examined genomic architectures of TS and OCD by chromosome, MAF bin, and functional annotations. In addition, we assessed heritability for early onset and adult onset OCD. Among other notable results, we found that SNPs with a minor allele frequency of less than 5% accounted for 21% of the TS heritability and 0% of the OCD heritability. Additionally, we identified a significant contribution to TS and OCD heritability by variants significantly associated with gene expression in two regions of the brain (parietal cortex and cerebellum for which we had available expression quantitative trait loci (eQTLs. Finally we analyzed the genetic correlation between TS and OCD, revealing a genetic correlation of 0.41 (se = 0.15, p = 0.002. These results are very close to previous heritability estimates for TS and OCD based on twin and family studies, suggesting that very little, if any, heritability is truly missing (i.e., unassayed from TS and OCD GWAS studies of common variation. The results also indicate that there is some genetic overlap between these two phenotypically-related neuropsychiatric disorders, but suggest that the two disorders have distinct genetic architectures.

  10. Evidence for a heritable unidimensional symptom factor underlying obsessionality.

    Science.gov (United States)

    Mathews, Carol A; Greenwood, Tiffany; Wessel, Jennifer; Azzam, Amin; Garrido, Helena; Chavira, Denise A; Chandavarkar, Uma; Bagnarello, Monica; Stein, Murray; Schork, Nicholas J

    2008-09-05

    The division of obsessive-compulsive symptoms (OCS) into specific factors is now widely accepted. However, the utility of these categories for genetic studies remains unclear, as studies examining their heritability have been inconsistent. Less attention has been paid to the possibility that clinically significant obsessionality is primarily determined by a "core" group of OCS that crosses the boundaries between symptom subgroups. The aim of this study is to determine whether such a core group exists, and to compare its heritability to that of the more traditionally derived symptom factors. We examined the properties and heritability of obsessive-compulsive symptoms in college students, medical students, and obsessive-compulsive disorder (OCD) families using the Leyton Obsessional Inventory. In each of the three samples, we identified a core group of symptoms that comprised a single unique construct and accounted for over 90% of the variation of the four more traditional symptom factors. This core construct was highly correlated with OCD in our families and had a heritability estimate of 0.19 when OCD was not included as a covariate and 0.49 when OCD was included as a covariate. In contrast, the four symptom factors were not heritable. There appears to be an underlying unidimensional component to obsessionality, both in non-clinical and clinical samples. This component, which is heritable, accounts for the majority of the variation of the more traditionally derived symptom factors in our sample, and is composed of OCS that are not specific to any of the symptom subgroups. 2007 Wiley-Liss, Inc.

  11. Heritability estimates and correlations between production and ...

    African Journals Online (AJOL)

    p4263707

    All the effects were significant (P <0.05) and hence they were included in the animal model. (Co)Variance components and correlations were estimated from an animal model in a bivariate analysis using the restricted maximum likelihood method (WOMBAT program of Meyer, 2006). Three different animal models were used.

  12. Reporting explained variance

    Science.gov (United States)

    Good, Ron; Fletcher, Harold J.

    The importance of reporting explained variance (sometimes referred to as magnitude of effects) in ANOVA designs is discussed in this paper. Explained variance is an estimate of the strength of the relationship between treatment (or other factors such as sex, grade level, etc.) and dependent variables of interest to the researcher(s). Three methods that can be used to obtain estimates of explained variance in ANOVA designs are described and applied to 16 studies that were reported in recent volumes of this journal. The results show that, while in most studies the treatment accounts for a relatively small proportion of the variance in dependent variable scores., in., some studies the magnitude of the treatment effect is respectable. The authors recommend that researchers in science education report explained variance in addition to the commonly reported tests of significance, since the latter are inadequate as the sole basis for making decisions about the practical importance of factors of interest to science education researchers.

  13. Heritability of chronic venous disease

    OpenAIRE

    Fiebig, Andreas; Krusche, Petra; De Wolf, Andreas; Krawczak, Michael; Timm, Birgitt; Nikolaus, Susanna; Frings, Norbert; Schreiber, Stefan

    2010-01-01

    Varicose veins without skin changes have a prevalence of approximately 20% in Northern and Western Europe whereas advanced chronic venous insufficiency affects about 3% of the population. Genetic risk factors are thought to play an important role in the aetiology of both these chronic venous diseases (CVD). We evaluated the relative genetic and environmental impact upon CVD risk by estimating the heritability of the disease in 4,033 nuclear families, comprising 16,434 individuals from all ove...

  14. Estimação de componentes de (covariâncias e predição de DEP's para características de crescimento pós-desmama de bovinos da raça Nelore, usando diferentes modelos estatísticos Variance components and breeding values for post weaning growth traits of Nellore cattle, from different statistical models

    Directory of Open Access Journals (Sweden)

    T.C.C. Bittencourt

    2002-06-01

    Full Text Available Foram estimados parâmetros genéticos, fenotípicos e valores genéticos de pesos padronizados aos 365 (P365 e 455 (P455 dias de idade de animais pertencentes ao programa de melhoramento genético da raça Nelore, desenvolvido pelo Departamento de Genética da USP. Quatro modelos foram utilizados para obter estimativas de parâmetros genéticos REML: o modelo 1 incluiu apenas os efeitos genético direto e residual; o 2, incluiu o efeito de ambiente permanente e os efeitos incluídos no modelo 1; o modelo 3 incluiu o efeito genético materno e os efeitos incluídos no modelo 1; o modelo 4 é o completo, com a inclusão dos efeitos genéticos direto e materno e de ambiente permanente. Para P365, as herdabilidades obtidas foram: 0,48, 0,32, 0,28 e 0,27 para os modelos 1, 2, 3 e 4, respectivamente. Para P455, os valores observados foram: 0,48, 0,38, 0,35 e 0,34 para os modelos 1, 2, 3 e 4, respectivamente. A comparação entre os modelos indicou que os efeitos maternos não foram importantes na variação do P455, mas podem ter alguma importância no peso aos 365 dias de idade.Data from the Genetic Improvement Program of the Nellore Breed of Genetic Department-USP were used to estimate genetic parameters and breeding values for weights at 365 (P365 and 455 (P455 days of age. Four animal models were used to obtain REML estimates of genetic parameters aiming to evaluate the effect of the inclusion of a random maternal genetic effect and a permanent environmental effect on variance component estimates. The model 1 included genetic and residual random effects; model 2 and model 3 were based on model 1 but included permanent environmental (2 and maternal genetic (3 effects; model 4 included genetic, maternal and permanent environmental effects. The heritability estimates for P365 were 0.48, 0.32, 0.28 and 0.27 using models 1, 2, 3 and 4, respectively. For P455, the values were 0.48, 0.38, 0.35 e 0.34 with the same models. The results suggest that

  15. An investigation into heterogeneity of variance for milk and fat yields of Holstein cows in Brazilian herd environments

    Directory of Open Access Journals (Sweden)

    Costa Claudio Napolis

    1999-01-01

    Full Text Available Heterogeneity of variance in Brazilian herd environments was studied using first-lactation 305-day mature equivalent (ME milk and fat records of Holstein cows. Herds were divided into two categories, according to low or high herd-year phenotypic standard deviation for ME milk (HYSD. There were 330 sires with daughter records in both HYSD categories. Components of (covariance, heritability, and genetic correlations for milk and fat yields were estimated using a sire model from bivariate analyses with a restricted maximum likelihood (REML derivative-free algorithm. Sire and residual variances for milk yield in low HYSD herds were 79 and 57% of those obtained in high HYSD herd. For fat yield they were 67 and 60%, respectively. Heritabilities for milk and fat yields in low HYSD herds were larger (0.30 and 0.22 than in high HYSD herds (0.23 and 0.20. Genetic correlation between expression in low and high HYSD herds was 0.997 for milk yield and 0.985 for fat yield. Expected correlated response in low HYSD herds based on sires selected on half-sister information from high HYSD was 0.89 kg/kg for milk and 0.80 kg/kg for fat yield. Genetic evaluations in Brazil need to account for heterogeneity of variances to increase the accuracy of evaluations and the selection efficiency for milk and fat yields of Holstein cows. Selection response will be lower in low variance herds than in high variance herds because of reduced differences in daughter response and among breeding values of sires in low HYSD herds. Genetic investments in sire selection to improve production are more likely to be successful in high HYSD herds than in low HYSD Brazilian herds.

  16. Heritable influence of DBH on adrenergic and renal function: twin and disease studies.

    Directory of Open Access Journals (Sweden)

    Dalal N Pasha

    Full Text Available Elevated sympathetic activity is associated with kidney dysfunction. Here we used twin pairs to probe heritability of GFR and its genetic covariance with other traits.We evaluated renal and adrenergic phenotypes in twins. GFR was estimated by CKD-EPI algorithm. Heritability and genetic covariance of eGFR and associated risk traits were estimated by variance-components. Meta-analysis probed reproducibility of DBH genetic effects. Effect of DBH genetic variation on renal disease was tested in the NIDDK-AASK cohort.Norepinephrine secretion rose across eGFR tertiles while eGFR fell (p<0.0001. eGFR was heritable, at h(2 = 67.3±4.7% (p = 3.0E-18, as were secretion of norepinephrine (h(2 = 66.5±5.0%, p = 3.2E-16 and dopamine (h(2 = 56.5±5.6%, p = 1.8E-13, and eGFR displayed genetic co-determination (covariance with norepinephrine (ρG = -0.557±0.088, p = 1.11E-08 as well as dopamine (ρG = -0.223±0.101, p = 2.3E-02. Since dopamine β-hydroxylase (DBH catalyzes conversion of dopamine to norepinephrine, we studied functional variation at DBH; DBH promoter haplotypes predicted transcriptional activity (p<0.001, plasma DBH (p<0.0001 and norepinephrine (p = 0.0297 secretion; transcriptional activity was inversely (p<0.0001 associated with basal eGFR. Meta-analysis validated DBH haplotype effects on eGFR across 3 samples. In NIDDK-AASK, we established a role for DBH promoter variation in long-term renal decline rate (GFR slope, p = 0.003.The heritable GFR trait shares genetic determination with catecholamines, suggesting new pathophysiologic, diagnostic and therapeutic approaches towards disorders of GFR as well as CKD. Adrenergic activity may play a role in progressive renal decline, and genetic variation at DBH may assist in profiling subjects for rational preventive treatment.

  17. Component

    Directory of Open Access Journals (Sweden)

    Tibor Tot

    2011-01-01

    Full Text Available A unique case of metaplastic breast carcinoma with an epithelial component showing tumoral necrosis and neuroectodermal stromal component is described. The tumor grew rapidly and measured 9 cm at the time of diagnosis. No lymph node metastases were present. The disease progressed rapidly and the patient died two years after the diagnosis from a hemorrhage caused by brain metastases. The morphology and phenotype of the tumor are described in detail and the differential diagnostic options are discussed.

  18. Longitudinal Analysis of Residual Feed Intake in Mink using Random Regression with Heterogeneous Residual Variance

    DEFF Research Database (Denmark)

    Shirali, Mahmoud; Nielsen, Vivi Hunnicke; Møller, Steen Henrik

    at the end compared to the early growing period suggesting that heterogeneous residual variance should be considered for analyzing feed efficiency data in mink. This study suggests random regression methods are suitable for analyzing feed efficiency and that genetic selection for RFI in mink is promising.......Heritability of residual feed intake (RFI) increased from low to high over the growing period in male and female mink. The lowest heritability for RFI (male: 0.04 ± 0.01 standard deviation (SD); female: 0.05 ± 0.01 SD) was in early and the highest heritability (male: 0.33 ± 0.02; female: 0.34 ± 0...

  19. Heritability of Malaria in Africa.

    Directory of Open Access Journals (Sweden)

    2005-11-01

    Full Text Available BACKGROUND: While many individual genes have been identified that confer protection against malaria, the overall impact of host genetics on malarial risk remains unknown. METHODS AND FINDINGS: We have used pedigree-based genetic variance component analysis to determine the relative contributions of genetic and other factors to the variability in incidence of malaria and other infectious diseases in two cohorts of children living on the coast of Kenya. In the first, we monitored the incidence of mild clinical malaria and other febrile diseases through active surveillance of 640 children 10 y old or younger, living in 77 different households for an average of 2.7 y. In the second, we recorded hospital admissions with malaria and other infectious diseases in a birth cohort of 2,914 children for an average of 4.1 y. Mean annual incidence rates for mild and hospital-admitted malaria were 1.6 and 0.054 episodes per person per year, respectively. Twenty-four percent and 25% of the total variation in these outcomes was explained by additively acting host genes, and household explained a further 29% and 14%, respectively. The haemoglobin S gene explained only 2% of the total variation. For nonmalarial infections, additive genetics explained 39% and 13% of the variability in fevers and hospital-admitted infections, while household explained a further 9% and 30%, respectively. CONCLUSION: Genetic and unidentified household factors each accounted for around one quarter of the total variability in malaria incidence in our study population. The genetic effect was well beyond that explained by the anticipated effects of the haemoglobinopathies alone, suggesting the existence of many protective genes, each individually resulting in small population effects. While studying these genes may well provide insights into pathogenesis and resistance in human malaria, identifying and tackling the household effects must be the more efficient route to reducing the burden

  20. Heterogeneity of variance and its implications on dairy cattle breeding

    African Journals Online (AJOL)

    ... and evaluated for within herd variation using univariate animal model procedures. Variance components were estimated by derivative free REML algorithm, and significance tests done using the Fmax procedure. Phenotypic, additive genetic and residual variances were heterogeneous across production environments.

  1. The Genealogical Consequences of Fecundity Variance Polymorphism

    Science.gov (United States)

    Taylor, Jesse E.

    2009-01-01

    The genealogical consequences of within-generation fecundity variance polymorphism are studied using coalescent processes structured by genetic backgrounds. I show that these processes have three distinctive features. The first is that the coalescent rates within backgrounds are not jointly proportional to the infinitesimal variance, but instead depend only on the frequencies and traits of genotypes containing each allele. Second, the coalescent processes at unlinked loci are correlated with the genealogy at the selected locus; i.e., fecundity variance polymorphism has a genomewide impact on genealogies. Third, in diploid models, there are infinitely many combinations of fecundity distributions that have the same diffusion approximation but distinct coalescent processes; i.e., in this class of models, ancestral processes and allele frequency dynamics are not in one-to-one correspondence. Similar properties are expected to hold in models that allow for heritable variation in other traits that affect the coalescent effective population size, such as sex ratio or fecundity and survival schedules. PMID:19433628

  2. Will Big Data Close the Missing Heritability Gap?

    Science.gov (United States)

    Kim, Hwasoon; Grueneberg, Alexander; Vazquez, Ana I; Hsu, Stephen; de Los Campos, Gustavo

    2017-11-01

    Despite the important discoveries reported by genome-wide association (GWA) studies, for most traits and diseases the prediction R-squared (R-sq.) achieved with genetic scores remains considerably lower than the trait heritability. Modern biobanks will soon deliver unprecedentedly large biomedical data sets: Will the advent of big data close the gap between the trait heritability and the proportion of variance that can be explained by a genomic predictor? We addressed this question using Bayesian methods and a data analysis approach that produces a surface response relating prediction R-sq. with sample size and model complexity (e.g., number of SNPs). We applied the methodology to data from the interim release of the UK Biobank. Focusing on human height as a model trait and using 80,000 records for model training, we achieved a prediction R-sq. in testing (n = 22,221) of 0.24 (95% C.I.: 0.23-0.25). Our estimates show that prediction R-sq. increases with sample size, reaching an estimated plateau at values that ranged from 0.1 to 0.37 for models using 500 and 50,000 (GWA-selected) SNPs, respectively. Soon much larger data sets will become available. Using the estimated surface response, we forecast that larger sample sizes will lead to further improvements in prediction R-sq. We conclude that big data will lead to a substantial reduction of the gap between trait heritability and the proportion of interindividual differences that can be explained with a genomic predictor. However, even with the power of big data, for complex traits we anticipate that the gap between prediction R-sq. and trait heritability will not be fully closed. Copyright © 2017 by the Genetics Society of America.

  3. Heritability of the morphology of optic nerve head and surrounding structures: The Healthy Twin Study.

    Directory of Open Access Journals (Sweden)

    Jong Chul Han

    Full Text Available Optic nerve head (ONH and surrounding structures such as β-zone peripapillary atrophy (PPA are important structures in glaucomatous pathogenesis. Thus, for understanding genetic components in glaucoma pathogenesis, it is necessary to evaluate the heritability of ONH and surrounding structures. The present study investigated the genetic influences on ONH and surrounding structures such as β-zone PPA and retinal vessels.A total of 1,205 adult twins and their family members (362 monozygotic (MZ twin subjects (181 pairs, 64 dizygotic (DZ twin subjects (32 pairs, and 779 singletons from 261 families, were part of the Korean Healthy Twin Study. ONH parameters including the vertical cup-to-disc ratio, the presence, the area and the location of β-zone PPA and the angular location of retinal vein were measured. The genetic influences on the structures were evaluated using variance-component methods.The intraclass correlation coefficient (ICC values of axial length were highest among the parameters. The ICCs of the area and location of PPA were similar to those of vertical cup-to-disc ratio. However, retinal vessel angular locations showed low ICC values even in MZ twins. After age and sex adjustment, for axial length, vertical cup-to-disc ratio, the presence, area and location of PPA, the estimated narrow-sense heritability was 0.85, 0.48, 0.76, 0.50 and 0.65 in the right eye and 0.84, 0.47, 0.72, 0.46 and 0.72 in the left eye, respectively. The estimated narrow-sense heritability of angular location of the superior and inferior vein was 0.17 and 0.12 in the right eye and 0.13 and 0.05 in the left eye, respectively.ONH and surrounding structures such as vertical cup-to-disc ratio and the presence, the area and the location of β-zone PPA seemed to be determined by the substantial genetic influence, whereas the venous angular location did not.

  4. Heritability of Recurrent Exertional Rhabdomyolysis in Standardbred and Thoroughbred Racehorses Derived From SNP Genotyping Data

    Science.gov (United States)

    Norton, Elaine M.; Mickelson, James R.; Binns, Matthew M.; Blott, Sarah C.; Caputo, Paul; Isgren, Cajsa M.; McCoy, Annette M.; Moore, Alison; Piercy, Richard J.; Swinburne, June E.; Vaudin, Mark

    2016-01-01

    Recurrent exertional rhabdomyolysis (RER) in Thoroughbred and Standardbred racehorses is characterized by episodes of muscle rigidity and cell damage that often recur upon strenuous exercise. The objective was to evaluate the importance of genetic factors in RER by obtaining an unbiased estimate of heritability in cohorts of unrelated Thoroughbred and Standardbred racehorses. Four hundred ninety-one Thoroughbred and 196 Standardbred racehorses were genotyped with the 54K or 74K SNP genotyping arrays. Heritability was calculated from genome-wide SNP data with a mixed linear and Bayesian model, utilizing the standard genetic relationship matrix (GRM). Both the mixed linear and Bayesian models estimated heritability of RER in Thoroughbreds to be approximately 0.34 and in Standardbred racehorses to be approximately 0.45 after adjusting for disease prevalence and sex. To account for potential differences in the genetic architecture of the underlying causal variants, heritability estimates were adjusted based on linkage disequilibrium weighted kinship matrix, minor allele frequency and variant effect size, yielding heritability estimates that ranged between 0.41–0.46 (Thoroughbreds) and 0.39–0.49 (Standardbreds). In conclusion, between 34–46% and 39–49% of the variance in RER susceptibility in Thoroughbred and Standardbred racehorses, respectively, can be explained by the SNPs present on these 2 genotyping arrays, indicating that RER is moderately heritable. These data provide further rationale for the investigation of genetic mutations associated with RER susceptibility. PMID:27489252

  5. Characterization of the Infant BMI Peak: Sex Differences, Birth Year Cohort Effects, Association with Concurrent Adiposity, and Heritability

    Science.gov (United States)

    Johnson, William; Choh, Audrey C.; Lee, Miryoung; Towne, Bradford; Czerwinski, Stefan A.; Demerath, Ellen W.

    2014-01-01

    Objectives To characterize an early trait in the BMI-for-age curve, the infant BMI peak. Methods BMI-for-age curves were produced for 747 non-Hispanic, white Fels Longitudinal Study participants, from which individual age (AgePeak) and BMI (BMIPeak) at maximum infant BMI were estimated. Multivariable general linear regression was used to examine the effects of sex and birth year cohort (1929–1950, 1951–1970, and 1971–2010) on AgePeak and BMIPeak, with associations between BMIPeak and concurrent sum of four skinfold thicknesses assessed in a subsample (N = 155). Heritability (h2) of AgePeak and BMIPeak was estimated using maximum-likelihood variance components analysis. Results AgePeak occurred at 9 months of age in both sexes, but BMIPeak was 0.4 kg/m2 higher for boys than for girls (P-value adiposity, AgePeak appears to occur later than does the well-documented peak in infant fat mass and BMIPeak does not capture known sex differences in infant adiposity. Strong heritability of these infant BMI traits suggests investigation of genetic control, and validation of their relationship to body composition is greatly needed. PMID:23606227

  6. Heritability and genome-wide association analysis of renal sinus fat accumulation in the Framingham Heart Study

    Directory of Open Access Journals (Sweden)

    Foster Meredith C

    2011-11-01

    Full Text Available Abstract Background Ectopic fat accumulation in the renal sinus is associated with chronic kidney disease and hypertension. The genetic contributions to renal sinus fat accumulation in humans have not been well characterized. Methods The present analysis consists of participants from the Framingham Offspring and Third Generation who underwent computed tomography; renal sinus fat and visceral adipose tissue (VAT were quantified. Renal sinus fat was natural log transformed and sex- and cohort-specific residuals were created, adjusted for (1 age, (2 age and body mass index (BMI, and (3 age and VAT. Residuals were pooled and used to calculate heritability using variance-components analysis in SOLAR. A genome-wide association study (GWAS for renal sinus fat was performed using an additive model with approximately 2.5 million imputed single nucleotide polymorphisms (SNPs. Finally, we identified the associations of renal sinus fat in our GWAS results with validated SNPs for renal function (n = 16, BMI (n = 32, and waist-to-hip ratio (WHR, n = 14, and applied a multi-SNP genetic risk score method to determine if the SNPs for each renal and obesity trait were in aggregate associated with renal sinus fat. Results The heritability of renal sinus fat was 39% (p Conclusions Renal sinus fat is a heritable trait, even after accounting for generalized and abdominal adiposity. This provides support for further research into the genetic determinants of renal sinus fat. While our study was underpowered to detect genome-wide significant loci, our candidate gene BMI risk score results suggest that variability in renal sinus fat may be associated with SNPs previously known to be associated with generalized adiposity.

  7. Portfolio optimization with mean-variance model

    Science.gov (United States)

    Hoe, Lam Weng; Siew, Lam Weng

    2016-06-01

    Investors wish to achieve the target rate of return at the minimum level of risk in their investment. Portfolio optimization is an investment strategy that can be used to minimize the portfolio risk and can achieve the target rate of return. The mean-variance model has been proposed in portfolio optimization. The mean-variance model is an optimization model that aims to minimize the portfolio risk which is the portfolio variance. The objective of this study is to construct the optimal portfolio using the mean-variance model. The data of this study consists of weekly returns of 20 component stocks of FTSE Bursa Malaysia Kuala Lumpur Composite Index (FBMKLCI). The results of this study show that the portfolio composition of the stocks is different. Moreover, investors can get the return at minimum level of risk with the constructed optimal mean-variance portfolio.

  8. variation, correlation and heritability of interest characters

    African Journals Online (AJOL)

    ACSS

    2016-05-17

    May 17, 2016 ... The objective of this study was to determine genetic variability, strength of association and level of heritability among agronomic interest traits. Phenotypic and genotypic variations and heritability of 14 traits were estimated in 61 accessions at Institut de Développement Rural (IDR), Gampela in Burkina Faso ...

  9. Heritability estimates derived from threshold analyses for ...

    African Journals Online (AJOL)

    Heritability estimates derived from threshold analyses for reproduction and stayability traits in a beef cattle herd. ... South African Journal of Animal Science ... The object of this study was to estimate heritabilities and sire breeding values for stayability and reproductive traits in a composite multibreed beef cattle herd using a ...

  10. Heritability estimates derived from threshold analyses for ...

    African Journals Online (AJOL)

    Unknown

    Abstract. The object of this study was to estimate heritabilities and sire breeding values for stayability and reproductive traits in a composite multibreed beef cattle herd using a threshold model. A GFCAT set of programmes was used to analyse reproductive data. Heritabilities and product-moment correlations between.

  11. The heritability of leucocyte telomere length dynamics

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob B; Dalgård, Christine; Möller, Sören

    2015-01-01

    BACKGROUND: Leucocyte telomere length (LTL) is a complex trait associated with ageing and longevity. LTL dynamics are defined by LTL and its age-dependent attrition. Strong, but indirect evidence suggests that LTL at birth and its attrition during childhood largely explains interindividual LTL...... variation among adults. A number of studies have estimated the heritability of LTL, but none has assessed the heritability of age-dependent LTL attrition. METHODS: We examined the heritability of LTL dynamics based on a longitudinal evaluation (an average follow-up of 12 years) in 355 monozygotic and 297...... dizygotic same-sex twins (aged 19-64 years at baseline). RESULTS: Heritability of LTL at baseline was estimated at 64% (95% CI 39% to 83%) with 22% (95% CI 6% to 49%) of shared environmental effects. Heritability of age-dependent LTL attrition rate was estimated at 28% (95% CI 16% to 44%). Individually...

  12. Partitioning of genomic variance using biological pathways

    DEFF Research Database (Denmark)

    Edwards, Stefan McKinnon; Janss, Luc; Madsen, Per

    -data and trait phenotypes and can account for a much larger fraction of the heritable component. A disadvantage is that this “black-box” modelling approach conceals the biological mechanisms underlying the trait. We propose to open the “black-box” by building SNP-set genomic models that evaluate the collective...... action of multiple SNPs in genes, biological pathways or other external findings on the trait phenotype. As proof of concept we have tested the modelling framework on several traits in dairy cattle....

  13. Short communication: Heritability estimates for susceptibility to Mycobacterium avium subspecies paratuberculosis infection defined by ELISA and fecal culture test results in Jersey cattle.

    Science.gov (United States)

    Zare, Y; Shook, G E; Collins, M T; Kirkpatrick, B W

    2014-07-01

    Paratuberculosis (Johne's disease), an enteric disorder in ruminants caused by Mycobacterium avium ssp. paratuberculosis, causes economic losses in excess of $200 million annually to the US dairy industry. Costly diagnostic testing, cumbersome control programs, incurability, and ineffective vaccination all make M. avium ssp. paratuberculosis susceptibility a good candidate for genetic studies and genetic selection a potentially useful adjunct to management-based control programs. No report has been published for heritability of susceptibility to M. avium ssp. paratuberculosis infection in Jersey cattle. The objective of this study was to estimate variance components and heritability for susceptibility to M. avium ssp. paratuberculosis infection in US Jersey cattle. Data consisted of complete serum ELISA and partial fecal culture results on a total of 2,861 Jersey cows from 23 commercial herds throughout the United States after editing. Four M. avium ssp. paratuberculosis susceptibility phenotypes were defined using (1) ELISA sample-to-positive ratios as a continuous trait, (2) ELISA results as a binary trait (positive=1, negative=0), (3) ELISA results as an ordered categorical trait, and (4) a combined test in which ELISA and fecal culture results were both taken into account in a binary analysis. Three statistical models, including linear, binary threshold, and ordered threshold sire models, were used to analyze the data. All analyses were executed using the restricted maximum likelihood method in ASReml 3 software. The heritability estimates were low to moderate and ranged from 0.08 (±0.03) to 0.27 (±0.11) based on different trait definitions. The nonzero heritability indicates that susceptibility to M. avium ssp. paratuberculosis infection in Jersey cattle is influenced by genetic factors. Therefore, selection of the least susceptible animals could decrease genetic predisposition to M. avium ssp. paratuberculosis infection in Jersey populations in future

  14. Heritability of compulsive Internet use in adolescents.

    Science.gov (United States)

    Vink, Jacqueline M; van Beijsterveldt, Toos C E M; Huppertz, Charlotte; Bartels, Meike; Boomsma, Dorret I

    2016-03-01

    Over the past decades, Internet use has grown substantially, and it now serves people as a supportive tool that is used regularly and-in large parts of the world-inevitably. Some people develop problematic Internet use, which may lead to addictive behavior and it is becoming important to explore the risk factors for compulsive Internet use. Data were analyzed on compulsive Internet use [with the Compulsive Internet Use Scale (CIUS)] from 5247 monozygotic (MZ) and dizygotic (DZ) adolescent twins registered with the Netherlands Twin Register. The participants form a sample that is informative for genetic analyses, allowing the investigation of the causes of individual differences in compulsive Internet use. The internal consistency of the instrument was high and the 1.6-year test-retest correlation in a subsample (n = 902) was 0.55. CIUS scores increased slightly with age. Remarkably, gender did not explain variation in CIUS scores, as mean scores on the CIUS were the same in boys and girls. However, the time spent on specific Internet activities differed: boys spent more time on gaming, whereas girls spent more time on social network sites and chatting. The heritability estimates were the same for boys and girls: 48 percent of the individual differences in CIUS score were influenced by genetic factors. The remaining variance (52 percent) was due to environmental influences that were not shared between family members. Because a life without Internet is almost impossible nowadays, it is important to further explore the determinants of compulsive Internet use, including genetic risk factors. © 2015 The Authors. Addiction Biology published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

  15. Heritability of compulsive Internet use in adolescents

    Science.gov (United States)

    van Beijsterveldt, Toos C. E. M.; Huppertz, Charlotte; Bartels, Meike; Boomsma, Dorret I.

    2015-01-01

    Abstract Over the past decades, Internet use has grown substantially, and it now serves people as a supportive tool that is used regularly and—in large parts of the world—inevitably. Some people develop problematic Internet use, which may lead to addictive behavior and it is becoming important to explore the risk factors for compulsive Internet use. Data were analyzed on compulsive Internet use [with the Compulsive Internet Use Scale (CIUS)] from 5247 monozygotic (MZ) and dizygotic (DZ) adolescent twins registered with the Netherlands Twin Register. The participants form a sample that is informative for genetic analyses, allowing the investigation of the causes of individual differences in compulsive Internet use. The internal consistency of the instrument was high and the 1.6‐year test–retest correlation in a subsample (n = 902) was 0.55. CIUS scores increased slightly with age. Remarkably, gender did not explain variation in CIUS scores, as mean scores on the CIUS were the same in boys and girls. However, the time spent on specific Internet activities differed: boys spent more time on gaming, whereas girls spent more time on social network sites and chatting. The heritability estimates were the same for boys and girls: 48 percent of the individual differences in CIUS score were influenced by genetic factors. The remaining variance (52 percent) was due to environmental influences that were not shared between family members. Because a life without Internet is almost impossible nowadays, it is important to further explore the determinants of compulsive Internet use, including genetic risk factors. PMID:25582809

  16. Heritability of nestling begging intensity in the house sparrow (Passer domesticus).

    Science.gov (United States)

    Dor, Roi; Lotem, Arnon

    2009-03-01

    Evolutionary theory of parent-offspring conflict assumes that offspring food solicitation behavior, known as begging, and parental response to begging are subjected to selection and coevolution. This assumption implies that begging intensity should be heritable, at least to some degree. Although some studies have suggested that begging is heritable, the evidence for this is rare and mostly indirect. To assess the heritability of begging we used artificial selection, sibling analysis, and the monitoring of begging intensity in four generations of cross-fostered captive house sparrow nestlings. We also contrasted the heritability of begging with that of morphological traits, known to be heritable in this species. Our results show that adult wing length and body mass were heritable as expected. The heritability estimates of the visual and vocal components of nestling begging (standardized for food deprivation and body mass) were low to moderate, as expected for behavioral traits in general, and lower than previously reported for passerine birds. Our sibling analysis shows that common environment had much greater effect on begging than genetic origin, suggesting that begging evolution may be strongly influenced by gene-environment interaction, probably through the mechanisms that adjust begging response to environmental and social conditions.

  17. Familial Risk and Heritability of Cancer Among Twins in Nordic Countries

    Science.gov (United States)

    Mucci, Lorelei A.; Hjelmborg, Jacob B.; Harris, Jennifer R.; Czene, Kamila; Havelick, David J.; Scheike, Thomas; Graff, Rebecca E.; Holst, Klaus; Möller, Sören; Unger, Robert H.; McIntosh, Christina; Nuttall, Elizabeth; Brandt, Ingunn; Penney, Kathryn L.; Hartman, Mikael; Kraft, Peter; Parmigiani, Giovanni; Christensen, Kaare; Koskenvuo, Markku; Holm, Niels V.; Heikkilä, Kauko; Pukkala, Eero; Skytthe, Axel; Adami, Hans-Olov; Kaprio, Jaakko

    2017-01-01

    Importance Estimates of familial cancer risk from population-based studies are essential components of cancer risk prediction. Objective To estimate familial risk and heritability of cancer types in a large twin cohort. Design, Setting, and Participants Prospective study of 80 309 monozygotic and 123 382 same-sex dizygotic twin individuals (N = 203 691) within the population-based registers of Denmark, Finland, Norway, and Sweden. Twins were followed up a median of 32 years between 1943 and 2010. There were 50 990 individuals who died of any cause, and 3804 who emigrated and were lost to follow-up. Exposures Shared environmental and heritable risk factors among pairs of twins. Main Outcomes and Measures The main outcome was incident cancer. Time-to-event analyses were used to estimate familial risk (risk of cancer in an individual given a twin's development of cancer) and heritability (proportion of variance in cancer risk due to interindividual genetic differences) with follow-up via cancer registries. Statistical models adjusted for age and follow-up time, and accounted for censoring and competing risk of death. Results A total of 27 156 incident cancers were diagnosed in 23 980 individuals, translating to a cumulative incidence of 32%. Cancer was diagnosed in both twins among 1383 monozygotic (2766 individuals) and 1933 dizygotic (2866 individuals) pairs. Of these, 38% of monozygotic and 26% of dizygotic pairs were diagnosed with the same cancer type. There was an excess cancer risk in twins whose co-twin was diagnosed with cancer, with estimated cumulative risks that were an absolute 5% (95% CI, 4%-6%) higher in dizygotic (37%; 95% CI, 36%-38%) and an absolute 14% (95% CI, 12%-16%) higher in monozygotic twins (46%; 95% CI, 44%-48%) whose twin also developed cancer compared with the cumulative risk in the overall cohort (32%). For most cancer types, there were significant familial risks and the cumulative risks were higher in monozygotic than dizygotic twins

  18. Spectral Ambiguity of Allan Variance

    Science.gov (United States)

    Greenhall, C. A.

    1996-01-01

    We study the extent to which knowledge of Allan variance and other finite-difference variances determines the spectrum of a random process. The variance of first differences is known to determine the spectrum. We show that, in general, the Allan variance does not. A complete description of the ambiguity is given.

  19. Smaller, scale-free gene networks increase quantitative trait heritability and result in faster population recovery.

    Directory of Open Access Journals (Sweden)

    Jacob W Malcom

    Full Text Available One of the goals of biology is to bridge levels of organization. Recent technological advances are enabling us to span from genetic sequence to traits, and then from traits to ecological dynamics. The quantitative genetics parameter heritability describes how quickly a trait can evolve, and in turn describes how quickly a population can recover from an environmental change. Here I propose that we can link the details of the genetic architecture of a quantitative trait--i.e., the number of underlying genes and their relationships in a network--to population recovery rates by way of heritability. I test this hypothesis using a set of agent-based models in which individuals possess one of two network topologies or a linear genotype-phenotype map, 16-256 genes underlying the trait, and a variety of mutation and recombination rates and degrees of environmental change. I find that the network architectures introduce extensive directional epistasis that systematically hides and reveals additive genetic variance and affects heritability: network size, topology, and recombination explain 81% of the variance in average heritability in a stable environment. Network size and topology, the width of the fitness function, pre-change additive variance, and certain interactions account for ∼75% of the variance in population recovery times after a sudden environmental change. These results suggest that not only the amount of additive variance, but importantly the number of loci across which it is distributed, is important in regulating the rate at which a trait can evolve and populations can recover. Taken in conjunction with previous research focused on differences in degree of network connectivity, these results provide a set of theoretical expectations and testable hypotheses for biologists working to span levels of organization from the genotype to the phenotype, and from the phenotype to the environment.

  20. A simple algorithm to estimate genetic variance in an animal threshold model using Bayesian inference Genetics Selection Evolution 2010, 42:29

    DEFF Research Database (Denmark)

    Ødegård, Jørgen; Meuwissen, Theo HE; Heringstad, Bjørg

    2010-01-01

    Background In the genetic analysis of binary traits with one observation per animal, animal threshold models frequently give biased heritability estimates. In some cases, this problem can be circumvented by fitting sire- or sire-dam models. However, these models are not appropriate in cases where...... individual records exist on parents. Therefore, the aim of our study was to develop a new Gibbs sampling algorithm for a proper estimation of genetic (co)variance components within an animal threshold model framework. Methods In the proposed algorithm, individuals are classified as either "informative...... data sets, the standard animal threshold model failed to produce useful results since samples of genetic variance always drifted towards infinity, while the new algorithm produced proper parameter estimates essentially identical to the results from a sire-dam model (given the fact that no individual...

  1. Lessons on the pathogenesis of aneurysm from heritable conditions

    Science.gov (United States)

    Lindsay, Mark E.; Dietz, Harry C.

    2013-01-01

    Aortic aneurysm is common, accounting for 1–2% of all deaths in industrialized countries. Early theories of the causes of human aneurysm mostly focused on inherited or acquired defects in components of the extracellular matrix in the aorta. Although several mutations in the genes encoding extracellular matrix proteins have been recognized, more recent discoveries have shown important perturbations in cytokine signalling cascades and intracellular components of the smooth muscle contractile apparatus. The modelling of single-gene heritable aneurysm disorders in mice has shown unexpected involvement of the transforming growth factor-β cytokine pathway in aortic aneurysm, highlighting the potential for new therapeutic strategies. PMID:21593863

  2. Further results on variances of local stereological estimators

    DEFF Research Database (Denmark)

    Pawlas, Zbynek; Jensen, Eva B. Vedel

    2006-01-01

    in the particle population. It turns out that these two variance components can be estimated separately, from sectional data. We present further results on the variances that can be used to determine the variance by numerical integration for particular choices of particle shapes.......In the present paper the statistical properties of local stereological estimators of particle volume are studied. It is shown that the variance of the estimators can be decomposed into the variance due to the local stereological estimation procedure and the variance due to the variability...

  3. Estimates of repeatability and heritability of productive and reproductive traits in a herd of Jersey cattle

    Directory of Open Access Journals (Sweden)

    Roman R.M.

    2000-01-01

    Full Text Available Estimates of the repeatability and heritability of 19 measures of performance in Jersey cows were obtained using an animal model with a relationship matrix and a derivative-free restricted maximum likelihood algorithm. The data consisted of 935 records for 374 cows by 69 sires over the period 1969-1987. The estimates were similar to those obtained by ordinary least squares methods reported for the same data set and in other studies, but had smaller error variances. A likelihood ratio test showed agreement between these heritability estimates and those in the literature. The heritability estimates of milk, fat, protein, lactose-mineral, solids-not-fat, and total solids yields were about 0.25; for the corresponding percentages, and for the protein to fat and solids-not-fat to fat ratios, the estimates were 0.50. Heritability estimates were 0.10 or less for the time from parturition to first breeding and for three measures of somatic cell counts. These estimates of heritability in a dairy cattle population in a subtropical environment were not different from those of populations in temperate climates.

  4. The Evolution of Human Intelligence and the Coefficient of Additive Genetic Variance in Human Brain Size

    Science.gov (United States)

    Miller, Geoffrey F.; Penke, Lars

    2007-01-01

    Most theories of human mental evolution assume that selection favored higher intelligence and larger brains, which should have reduced genetic variance in both. However, adult human intelligence remains highly heritable, and is genetically correlated with brain size. This conflict might be resolved by estimating the coefficient of additive genetic…

  5. Introduction to variance estimation

    CERN Document Server

    Wolter, Kirk M

    2007-01-01

    We live in the information age. Statistical surveys are used every day to determine or evaluate public policy and to make important business decisions. Correct methods for computing the precision of the survey data and for making inferences to the target population are absolutely essential to sound decision making. Now in its second edition, Introduction to Variance Estimation has for more than twenty years provided the definitive account of the theory and methods for correct precision calculations and inference, including examples of modern, complex surveys in which the methods have been used successfully. The book provides instruction on the methods that are vital to data-driven decision making in business, government, and academe. It will appeal to survey statisticians and other scientists engaged in the planning and conduct of survey research, and to those analyzing survey data and charged with extracting compelling information from such data. It will appeal to graduate students and university faculty who...

  6. Dominant-lethal mutations and heritable translocations in mice

    Energy Technology Data Exchange (ETDEWEB)

    Generoso, W.M.

    1983-01-01

    Chromosome aberrations are a major component of radiation or chemically induced genetic damage in mammalian germ cells. The types of aberration produced are dependent upon the mutagen used and the germ-cell stage treated. For example, in male meiotic and postmeiotic germ cells certain alkylating chemicals induce both dominant-lethal mutations and heritable translocations while others induce primarily dominant-lethal mutations. Production of these two endpoints appears to be determined by the stability of alkylation products with the chromosomes. If the reaction products are intact in the male chromosomes at the time of sperm entry, they may be repaired in fertilized eggs. If repair is not effected and the alkylation products persist to the time of pronuclear chromosome replication, they lead to chromatid-type aberrations and eventually to dominant-lethality. The production of heritable translocations, on the other hand, requires a transformation of unstable alkylation products into suitable intermediate lesions. The process by which these lesions are converted into chromosome exchange within the male genome takes place after sperm enters the egg but prior to the time of pronuclear chromosome replication (i.e., chromosome-type). Thus, dominant-lethal mutations result from both chromatid- and chromosome-type aberrations while heritable translocations result primarily from the latter type. DNA target sites associated with the production of these two endpoints are discussed.

  7. Phenome-wide heritability analysis of the UK Biobank

    OpenAIRE

    Tian Ge; Chia-Yen Chen; Neale, Benjamin M; Sabuncu, Mert R.; Smoller, Jordan W.

    2017-01-01

    Heritability estimation provides important information about the relative contribution of genetic and environmental factors to phenotypic variation, and provides an upper bound for the utility of genetic risk prediction models. Recent technological and statistical advances have enabled the estimation of additive heritability attributable to common genetic variants (SNP heritability) across a broad phenotypic spectrum. Here, we present a computationally and memory efficient heritability estima...

  8. Phenotypic variance, plasticity and heritability estimates of critical thermal limits depend on methodological context

    DEFF Research Database (Denmark)

    Chown, Steven L.; Jumbam, Keafon R.; Sørensen, Jesper Givskov

    2009-01-01

    1.  Biologists have long been concerned with measuring thermal performance curves and limits because of their significance to fitness. Basic experimental design may have a marked effect on the outcome of such measurements, and this is true especially of the experimental rates of temperature chang...

  9. Genomic Heritability: What Is It?

    DEFF Research Database (Denmark)

    de los Campos, Gustavo; Sorensen, Daniel; Gianola, Daniel

    2015-01-01

    of phenotypic variance that can be explained by regression on molecular markers. This is so even though some of the assumptions commonly adopted for data analysis are at odds with important quantitative genetic concepts. In this article we develop theory that leads to a precise definition of parameters arising...... of consistency of likelihood (or Bayesian) estimates. This situation can be encountered if the individuals in the sample are distantly related and linkage disequilibrium spans over short regions. This bias does not negate the use of whole-genome regression models as predictive machines; however, our results...

  10. Ethyl methane sulphonate induced genetic variability and heritability in macrosperma and microsperma lentils.

    Science.gov (United States)

    Rana, Aman; Solanki, I S

    2015-09-01

    Dry and healthy seeds of two lentil cultivars, LH90-54 (macrosperma) and LH89-48 (microsperma) were treated with three doses of ethyl methane sulphonate (0.1, 0.2 and 0.4 %). In both the cultivars, all the M, plants with sufficient seed from each treatment and control were taken to raise independent M2 plant progenies. Wider range of means in both positive and negative directions along with overall positive shift in mean for all the polygenic traits, except pod-initiation height and 100-seed weight, were observed in different treatments in M2 generation. In both the cultivars, medium dose induced highest amount of variation. The estimates of variance, GCV and PCV for different polygenic traits increased significantly over control values in all the treatments of both the cultivars. Higher estimates of heritability and genetic advance in M2 population indicated tremendous scope for the improvement of seed yield and its component traits through selection in the mutagenized material.

  11. Late Language Emergence in 24-Month-Old Twins: Heritable and Increased Risk for Late Language Emergence in Twins

    Science.gov (United States)

    Rice, Mabel L.; Zubrick, Stephen R.; Taylor, Catherine L.; Gayán, Javier; Bontempo, Daniel E.

    2014-01-01

    Purpose: This study investigated the etiology of late language emergence (LLE) in 24-month-old twins, considering possible twinning, zygosity, gender, and heritability effects for vocabulary and grammar phenotypes. Method: A population-based sample of 473 twin pairs participated. Multilevel modeling estimated means and variances of vocabulary and…

  12. Using transformation algorithms to estimate (co)variance ...

    African Journals Online (AJOL)

    ... to multiple traits by the use of canonical transformations. A computing strategy is developed for use on large data sets employing two different REML algorithms for the estimation of (co)variance components. Results from a simulation study indicate that (co)variance components can be estimated efficiently at a low cost on ...

  13. Data Sparseness and Variance in Accounting Profitability

    NARCIS (Netherlands)

    S. Stavropoulos (Spyridon); M.J. Burger (Martijn); D. Skuras (Dimitris)

    2015-01-01

    markdownabstract__Abstract__ A central question in strategic management is why some firms perform better than others. One approach to addressing this question empirically is to decompose the variance in firm-level profitability into firm, industry, location, and year components. Although it is

  14. The Variance Composition of Firm Growth Rates

    Directory of Open Access Journals (Sweden)

    Luiz Artur Ledur Brito

    2009-04-01

    Full Text Available Firms exhibit a wide variability in growth rates. This can be seen as another manifestation of the fact that firms are different from one another in several respects. This study investigated this variability using the variance components technique previously used to decompose the variance of financial performance. The main source of variation in growth rates, responsible for more than 40% of total variance, corresponds to individual, idiosyncratic firm aspects and not to industry, country, or macroeconomic conditions prevailing in specific years. Firm growth, similar to financial performance, is mostly unique to specific firms and not an industry or country related phenomenon. This finding also justifies using growth as an alternative outcome of superior firm resources and as a complementary dimension of competitive advantage. This also links this research with the resource-based view of strategy. Country was the second source of variation with around 10% of total variance. The analysis was done using the Compustat Global database with 80,320 observations, comprising 13,221 companies in 47 countries, covering the years of 1994 to 2002. It also compared the variance structure of growth to the variance structure of financial performance in the same sample.

  15. Heritable and non-heritable genetic effects on retained placenta in Meuse-Rhine-Yssel cattle

    NARCIS (Netherlands)

    Benedictus, L.; Koets, A.P.; Kuijpers, F.H.J.; Joosten, I.; Eldik, van P.; Heuven, H.C.M.

    2013-01-01

    Failure of the timely expulsion of the fetal membranes, called retained placenta, leads to reduced fertility, increased veterinary costs and reduced milk yields. The objectives of this study were to concurrently look at the heritable and non-heritable genetic effects on retained placenta and test

  16. Heritability of Choroidal Thickness in the Amish.

    Science.gov (United States)

    Sardell, Rebecca J; Nittala, Muneeswar G; Adams, Larry D; Laux, Reneé A; Cooke Bailey, Jessica N; Fuzzell, Denise; Fuzzell, Sarada; Reinhart-Mercer, Lori; Caywood, Laura J; Horst, Violet; Mackay, Tine; Dana, Debbie; Sadda, SriniVas R; Scott, William K; Stambolian, Dwight; Haines, Jonathan L; Pericak-Vance, Margaret A

    2016-12-01

    To evaluate the heritability of choroidal thickness and its relationship to age-related macular degeneration (AMD). Cohort study. Six hundred eighty-nine individuals from Amish families with early or intermediate AMD. Ocular coherence tomography was used to quantify choroidal thickness, and fundus photography was used to classify eyes into categories using a modified Clinical Age-Related Maculopathy Staging (CARMS) system. Repeatability and heritability of choroidal thickness and its phenotypic and genetic correlations with the AMD phenotype (CARMS category) were estimated using a generalized linear mixed model (GLMM) approach that accounted for relatedness, repeated measures (left and right eyes), and the effects of age, gender, and refraction. Heritability of choroidal thickness and its phenotypic and genetic correlation with the AMD phenotype (CARMS category). Phenotypic correlation between choroidal thickness and CARMS category was moderate (Spearman's rank correlation, rs = -0.24; n = 1313 eyes) and significant (GLMM posterior mean, -4.27; 95% credible interval [CI], -7.88 to -0.79; P = 0.02) after controlling for relatedness, age, gender, and refraction. Eyes with advanced AMD had thinner choroids than eyes without AMD (posterior mean, -73.8; 95% CI, -94.7 to -54.6; P < 0.001; n = 1178 eyes). Choroidal thickness was highly repeatable within individuals (repeatability, 0.78; 95% CI, 0.68 to 0.89) and moderately heritable (heritability, 0.40; 95% CI, 0.14 to 0.51), but did not show significant genetic correlation with CARMS category, although the effect size was moderate (genetic correlation, -0.18; 95% CI, -0.49 to 0.16). Choroidal thickness also varied with age, gender, and refraction. The CARMS category showed moderate heritability (heritability, 0.49; 95% CI, 0.26 to 0.72). We quantify the heritability of choroidal thickness for the first time, highlighting a heritable, quantitative trait that is measurable in all individuals regardless of AMD

  17. Double decomposition: decomposing the variance in subcomponents of male extra-pair reproductive success.

    Science.gov (United States)

    Losdat, Sylvain; Arcese, Peter; Reid, Jane M

    2015-09-01

    1. Extra-pair reproductive success (EPRS) is a key component of male fitness in socially monogamous systems and could cause selection on female extra-pair reproduction if extra-pair offspring (EPO) inherit high value for EPRS from their successful extra-pair fathers. However, EPRS is itself a composite trait that can be fully decomposed into subcomponents of variation, each of which can be further decomposed into genetic and environmental variances. However, such decompositions have not been implemented in wild populations, impeding evolutionary inference. 2. We first show that EPRS can be decomposed into the product of three life-history subcomponents: the number of broods available to a focal male to sire EPO, the male's probability of siring an EPO in an available brood and the number of offspring in available broods. This decomposition of EPRS facilitates estimation from field data because all subcomponents can be quantified from paternity data without need to quantify extra-pair matings. Our decomposition also highlights that the number of available broods, and hence population structure and demography, might contribute substantially to variance in male EPRS and fitness. 3. We then used 20 years of complete genetic paternity and pedigree data from wild song sparrows (Melospiza melodia) to partition variance in each of the three subcomponents of EPRS, and thereby estimate their additive genetic variance and heritability conditioned on effects of male coefficient of inbreeding, age and social status. 4. All three subcomponents of EPRS showed some degree of within-male repeatability, reflecting combined permanent environmental and genetic effects. Number of available broods and offspring per brood showed low additive genetic variances. The estimated additive genetic variance in extra-pair siring probability was larger, although the 95% credible interval still converged towards zero. Siring probability also showed inbreeding depression and increased with male age

  18. Agronomic performance and Heritability of some components of ...

    African Journals Online (AJOL)

    The present investigation evaluates the performance of newly identified clones in the major coffee growing zones of Kagera region, Tanzania. Five clones namely MS1/95. MS2/95. MS3/95, MS5/95. MS6/95 selected from individual trees in farmers fields and FS a control variety, were grown in farmers fields in March 1998 a ...

  19. Genetic variability and heritability of grain yield components and ...

    African Journals Online (AJOL)

    Pearl millet (Pennisetum glaucum (L.) R. Br.) is an important cereal in semi-arid tropics in Africa and India. Conventionally, millet has good amounts of grain minerals compared to other cereals. Estimation of genetic parameters would be useful in developing appropriate breeding and selection strategies. The present study ...

  20. The effect of trait type and strength of selection on heritability and evolvability in an island bird population.

    Science.gov (United States)

    Wheelwright, Nathaniel T; Keller, Lukas F; Postma, Erik

    2014-11-01

    The heritability (h(2) ) of fitness traits is often low. Although this has been attributed to directional selection having eroded genetic variation in direct proportion to the strength of selection, heritability does not necessarily reflect a trait's additive genetic variance and evolutionary potential ("evolvability"). Recent studies suggest that the low h(2) of fitness traits in wild populations is caused not by a paucity of additive genetic variance (VA ) but by greater environmental or nonadditive genetic variance (VR ). We examined the relationship between h(2) and variance-standardized selection intensities (i or βσ ), and between evolvability (IA :VA divided by squared phenotypic trait mean) and mean-standardized selection gradients (βμ ). Using 24 years of data from an island population of Savannah sparrows, we show that, across diverse traits, h(2) declines with the strength of selection, whereas IA and IR (VR divided by squared trait mean) are independent of the strength of selection. Within trait types (morphological, reproductive, life-history), h(2) , IA , and IR are all independent of the strength of selection. This indicates that certain traits have low heritability because of increased residual variance due to the age at which they are expressed or the multiple factors influencing their expression, rather than their association with fitness. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  1. Heritability of adult body height

    DEFF Research Database (Denmark)

    Silventoinen, Karri; Sammalisto, Sampo; Perola, Markus

    2003-01-01

    A major component of variation in body height is due to genetic differences, but environmental factors have a substantial contributory effect. In this study we aimed to analyse whether the genetic architecture of body height varies between affluent western societies. We analysed twin data from ei...

  2. Heritability of fear: Ukrainian experience

    Directory of Open Access Journals (Sweden)

    O.V. Filiptsova

    2014-10-01

    Conclusions: The conducted research demonstrated genetic component presence for nine types of fear – psychic disorder development, complications in personal life, making responsible decisions, senility, closed spaces, sexual dysfunction, suicide commission, speaking in public, and aggressive behavior possibility to relatives. It helps to consider these fear perspectives for further molecular-genetic analysis in Ukraine.

  3. Field heritability of a plant adaptation to fire in heterogeneous landscapes.

    Science.gov (United States)

    Castellanos, M C; González-Martínez, S C; Pausas, J G

    2015-11-01

    The strong association observed between fire regimes and variation in plant adaptations to fire suggests a rapid response to fire as an agent of selection. It also suggests that fire-related traits are heritable, a precondition for evolutionary change. One example is serotiny, the accumulation of seeds in unopened fruits or cones until the next fire, an important strategy for plant population persistence in fire-prone ecosystems. Here, we evaluate the potential of this trait to respond to natural selection in its natural setting. For this, we use a SNP marker approach to estimate genetic variance and heritability of serotiny directly in the field for two Mediterranean pine species. Study populations were large and heterogeneous in climatic conditions and fire regime. We first estimated the realized relatedness among trees from genotypes, and then partitioned the phenotypic variance in serotiny using Bayesian animal models that incorporated environmental predictors. As expected, field heritability was smaller (around 0.10 for both species) than previous estimates under common garden conditions (0.20). An estimate on a subset of stands with more homogeneous environmental conditions was not different from that in the complete set of stands, suggesting that our models correctly captured the environmental variation at the spatial scale of the study. Our results highlight the importance of measuring quantitative genetic parameters in natural populations, where environmental heterogeneity is a critical aspect. The heritability of serotiny, although not high, combined with high phenotypic variance within populations, confirms the potential of this fire-related trait for evolutionary change in the wild. © 2015 John Wiley & Sons Ltd.

  4. Fixed effects analysis of variance

    CERN Document Server

    Fisher, Lloyd; Birnbaum, Z W; Lukacs, E

    1978-01-01

    Fixed Effects Analysis of Variance covers the mathematical theory of the fixed effects analysis of variance. The book discusses the theoretical ideas and some applications of the analysis of variance. The text then describes topics such as the t-test; two-sample t-test; the k-sample comparison of means (one-way analysis of variance); the balanced two-way factorial design without interaction; estimation and factorial designs; and the Latin square. Confidence sets, simultaneous confidence intervals, and multiple comparisons; orthogonal and nonorthologonal designs; and multiple regression analysi

  5. A review and meta-analysis of the heritability of specific phobia subtypes and corresponding fears.

    Science.gov (United States)

    Van Houtem, C M H H; Laine, M L; Boomsma, D I; Ligthart, L; van Wijk, A J; De Jongh, A

    2013-05-01

    Evidence from twin studies suggests that genetic factors contribute to the risk of developing a fear or a phobia. The aim of the present study was to review the current literature regarding twin studies describing the genetic basis of specific phobias and their corresponding fears. The analysis included five twin studies on fears and ten twin studies on specific phobias. Heritability estimates of fear subtypes and specific phobia subtypes both varied widely, even within the subtypes. A meta-analysis performed on the twin study results indicated that fears and specific phobias are moderately heritable. The highest mean heritability (±SEM) among fear subtypes was found for animal fear (45%±0.004), and among specific phobias for the blood-injury-injection phobia (33%±0.06). For most phenotypes, variance could be explained solely by additive genetic and unique environmental effects. Given the dearth of independent data on the heritability of specific phobias and fears, additional research is needed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  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...

  7. IQ Heritability: A Checklist of Methodological Fallacies

    Science.gov (United States)

    Taylor, Howard F.

    1976-01-01

    Presents a brief, quick-reference check list of methodological errors, fallacies, mistakes, and instances of out-and-out trickery that are found in recent well-known studies of IQ, IQ heritability, and race differences, focusing primarily upon the works of psychologist Jensen, Herrnstein, Eysenck, including selected works of William Shockley and…

  8. Assessing the heritability of attentional networks

    Directory of Open Access Journals (Sweden)

    Fossella John A

    2001-09-01

    Full Text Available Abstract Background Current efforts to study the genetics of higher functions have been lacking appropriate phenotypes to describe cognition. One of the problems is that many cognitive concepts for which there is a single word (e.g. attention have been shown to be related to several anatomical networks. Recently we have developed an Attention Network Test (ANT that provides a separate measure for each of three anatomically defined attention networks. In this small scale study, we ran 26 pairs of MZ and DZ twins in an effort to determine if any of these networks show sufficient evidence of heritability to warrant further exploration of their genetic basis. Results The efficiency of the executive attention network, that mediates stimulus and response conflict, shows sufficient heritability to warrant further study. Alerting and overall reaction time show some evidence for heritability and in our study the orienting network shows no evidence of heritability. Conclusions These results suggest that genetic variation contributes to normal individual differences in higher order executive attention involving dopamine rich frontal areas including the anterior cingulate. At least the executive portion of the ANT may serve as a valid endophenotype for larger twin studies and subsequent molecular genetic analysis in normal subject populations.

  9. Drosophila Modeling of Heritable Neurodevelopmental Disorders

    OpenAIRE

    Gatto, Cheryl L.; Broadie, Kendal

    2011-01-01

    Heritable neurodevelopmental disorders are multifaceted disease conditions encompassing a wide range of symptoms including intellectual disability, cognitive dysfunction, autism and myriad other behavioral impairments. In cases where single, causative genetic defects have been identified, such as Angelman syndrome, Rett syndrome, Neurofibromatosis Type 1 and Fragile X syndrome, the classical Drosophila genetic system has provided fruitful disease models. Recent Drosophila studies have advance...

  10. Heritability estimates and correlations between subjectively ...

    African Journals Online (AJOL)

    PavarniN

    exceptions were positive genetic correlations of fibre diameter (FD) and coefficient of variation of FD with staple formation score and belly and points score. Genetic progress in subjective traits thus appears possible, if desired in a selection strategy. Keywords: Correlations, heritabilities, linearly assessed traits, subjective ...

  11. Genotypic Variability, Heritability, Genetic Advance and Associations ...

    African Journals Online (AJOL)

    %) and kernel yield plant-1 (12.3%). Broad sense heritability were high for spike length (89.2%), plant height (87.1%) and thousand kernels weight (80.2%), indicating that these characters were predominantly controlled by genetic factors.

  12. Heritability of Polycystic Ovary Syndrome in a Dutch Twin-family study

    NARCIS (Netherlands)

    Vink, J.M.; Sadrzadeh, S.; Lambalk, C.B.; Boomsma, D.I.

    2006-01-01

    Background: Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders among women of reproductive age. There is evidence for a genetic component in PCOS based on familial clustering of cases. Objective: In the present study, the heritability of PCOS was estimated.

  13. Association Between Mortality and Heritability of the Scale of Aging Vigor in Epidemiology

    DEFF Research Database (Denmark)

    Sanders, Jason L; Singh, Jatinder; Minster, Ryan L

    2016-01-01

    OBJECTIVES: To investigate the association between mortality and heritability of a rescaled Fried frailty index, the Scale of Aging Vigor in Epidemiology (SAVE), to determine its value for genetic analyses. DESIGN: Longitudinal, community-based cohort study. SETTING: The Long Life Family Study......, suggesting a genetic component to age-related vigor and frailty and supporting its use for further genetic analyses....

  14. Familial aggregation and heritability of Loa loa microfilaremia.

    Science.gov (United States)

    Eyebe, Serge; Sabbagh, Audrey; Pion, Sébastien D; Nana-Djeunga, Hugues C; Kamgno, Joseph; Boussinesq, Michel; Chesnais, Cédric B

    2017-10-10

    For a given prevalence of Loa loa microfilaremia, the proportion of people with high densities varies significantly between communities. We hypothesized that this variation is related to the existence of familial clusters of hypermicrofilaremic individuals that would be the consequence of a genetic predisposition to present high L. loa microfilarial densities. A familial study was performed in 10 villages in the Okola Health District of Cameroon. Intra-familial correlation coefficients and heritability estimates were assessed for both the presence of L. loa microfilaremia and individual microfilarial densities by controlling for age, sex, Mansonella perstans coinfection and household effects. Pedigrees were constructed for 1,126 individuals. A significant familial susceptibility to be microfilaremic for L. loa was found for first-degree relatives (ρ = 0.08, P < .05; heritability = 0.23). Regarding individual microfilarial densities, a significant familial aggregation was demonstrated (ρ = 0.36 for first- and 0.27 for second-degree relatives). For first-degree relatives, the highest coefficient was found between mothers and daughters (ρ = 0.57). Overall heritability estimate for L. loa microfilarial density was 0.24 (P = .003). A significant genetic component governs L. loa microfilarial density. This supports the hypothesis that a genetic predisposition to be hypermicrofilaremic exists, leading to the presence of familial clusters of individuals at risk for post-ivermectin severe adverse events. This finding should be taken into account while developing sampling strategies (including a household-level sampling) to identify villages where community-directed treatment with ivermectin cannot be applied.

  15. Heritable and non-heritable pathways to early callous-unemotional behaviors

    Science.gov (United States)

    Hyde, Luke W.; Waller, Rebecca; Trentacosta, Christopher J.; Shaw, Daniel S.; Neiderhiser, Jenae M.; Ganiban, Jody M.; Reiss, David; Leve, Leslie D.

    2016-01-01

    Objective Callous-unemotional behaviors in early childhood identify children at high risk for severe trajectories of antisocial behavior and callous-unemotional traits that culminate in later diagnoses of conduct disorder, antisocial personality disorder, and psychopathy. Studies have demonstrated high heritability of callous-unemotional traits, but little research has examined specific heritable pathways to earlier callous-unemotional behaviors. Additionally, studies indicate that positive parenting protects against the development of callous-unemotional traits, but genetically informed designs have not been used to confirm that these relationships are not the product of gene-environment correlations. Method Using an adoption cohort of 561 families, biological mothers reported their history of severe antisocial behavior. Observations of adoptive mother positive reinforcement at 18 months were examined as predictors of callous-unemotional behaviors when children were 27 months old. Results Biological mother antisocial behavior predicted early callous-unemotional behaviors despite having no or limited contact with offspring. Adoptive mother positive reinforcement protected against early callous-unemotional behaviors in children not genetically related to the parent. High levels of adoptive mother positive reinforcement buffered the effects of heritable risk for callous-unemotional behaviors posed by biological mother antisocial behavior. Conclusions The findings elucidate heritable and non-heritable pathways to early callous-unemotional behaviors. The results provide a specific heritable pathway to callous-unemotional behaviors and compelling evidence that parenting is an important non-heritable factor in the development of callous-unemotional behaviors. As positive reinforcement buffered heritable risk for callous-unemotional behaviors, these findings have important translational implications for the prevention of trajectories to serious antisocial behavior. PMID

  16. Fundamentals of exploratory analysis of variance

    CERN Document Server

    Hoaglin, David C; Tukey, John W

    2009-01-01

    The analysis of variance is presented as an exploratory component of data analysis, while retaining the customary least squares fitting methods. Balanced data layouts are used to reveal key ideas and techniques for exploration. The approach emphasizes both the individual observations and the separate parts that the analysis produces. Most chapters include exercises and the appendices give selected percentage points of the Gaussian, t, F chi-squared and studentized range distributions.

  17. Heritability of Retinal Vascular Fractals

    DEFF Research Database (Denmark)

    Vergmann, Anna Stage; Broe, Rebecca; Kessel, Line

    2017-01-01

    , the branching pattern of the retinal vessels demonstrated a higher structural similarity in monozygotic than in dizygotic twin pairs. The retinal vascular fractal dimension was mainly determined by genetic factors, which accounted for 54% of the variation. The genetically predetermination of the retinal......Purpose: To determine the genetic contribution to the pattern of retinal vascular branching expressed by its fractal dimension. Methods: This was a cross-sectional study of 50 monozygotic and 49 dizygotic, same-sex twin pairs aged 20 to 46 years. In 50°, disc-centered fundus photographs......, the retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficients. Falconer's formula and quantitative genetic models were used to determine the genetic component of variation. Results: The mean...

  18. Heritability of Drought Adaptive Traits and Relationships with Grain ...

    African Journals Online (AJOL)

    estimate: (i) broad-sense heritability of each tested trait; and (ii) relationships between grain yield and drought adaptive traits. The broad sense heritabilities of flowering traits were relatively high across all growing conditions. In contrast, the heritability for number of ears per plant (EPP) increased with increasing plant ...

  19. Human-directed social behaviour in dogs shows significant heritability.

    Science.gov (United States)

    Persson, M E; Roth, L S V; Johnsson, M; Wright, D; Jensen, P

    2015-04-01

    Through domestication and co-evolution with humans, dogs have developed abilities to attract human attention, e.g. in a manner of seeking assistance when faced with a problem solving task. The aims of this study were to investigate within breed variation in human-directed contact seeking in dogs and to estimate its genetic basis. To do this, 498 research beagles, bred and kept under standardized conditions, were tested in an unsolvable problem task. Contact seeking behaviours recorded included both eye contact and physical interactions. Behavioural data was summarized through a principal component analysis, resulting in four components: test interactions, social interactions, eye contact and physical contact. Females scored significantly higher on social interactions and physical contact and age had an effect on eye contact scores. Narrow sense heritabilities (h(2) ) of the two largest components were estimated at 0.32 and 0.23 but were not significant for the last two components. These results show that within the studied dog population, behavioural variation in human-directed social behaviours was sex dependent and that the utilization of eye contact seeking increased with age and experience. Hence, heritability estimates indicate a significant genetic contribution to the variation found in human-directed social interactions, suggesting that social skills in dogs have a genetic basis, but can also be shaped and enhanced through individual experiences. This research gives the opportunity to further investigate the genetics behind dogs' social skills, which could also play a significant part into research on human social disorders such as autism. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  20. Heritability of some quantitative characters in five varieties of maize ...

    African Journals Online (AJOL)

    The experiment was laid out in a randomized complete block design, and replicated three times. The genotype × different levels of nitrogen fertilizer (G × N) influenced the expression of the ear height and yield component. Analysis of variance for plant height revealed highly significant differences among varieties with ...

  1. Small Drinking Water System Variances

    Science.gov (United States)

    Small system variances allow a small system to install and maintain technology that can remove a contaminant to the maximum extent that is affordable and protective of public health in lieu of technology that can achieve compliance with the regulation.

  2. Blending of heritable recognition cues among ant nestmates creates distinct colony gestalt odours but prevents within-colony nepotism

    DEFF Research Database (Denmark)

    van Zweden, Jelle Stijn; Brask, Josefine B.; Christensen, Jan H.

    2010-01-01

    members to create a Gestalt odour. Although earlier studies have established that hydrocarbon profiles are influenced by heritable factors, transfer among nestmates and additional environmental factors, no studies have quantified these relative contributions for separate compounds. Here, we use the ant...... Formica rufibarbis in a cross-fostering design to test the degree to which hydrocarbons are heritably synthesized by young workers and transferred by their foster workers. Bioassays show that nestmate recognition has a significant heritable component. Multivariate quantitative analyses based on 38...... discrimination or as nestmate recognition cues. These results indicate that heritable compounds are suitable for establishing a genetic Gestalt for efficient nestmate recognition, but that recognition cues within colonies are insufficiently distinct to allow nepotistic kin discrimination....

  3. Novel Molecular Therapies for Heritable Skin Disorders

    Science.gov (United States)

    Uitto, Jouni; Christiano, Angela M.; Irwin McLean, W. H.; McGrath, John A.

    2013-01-01

    Tremendous progress has been made in the past two decades in molecular genetics of heritable skin diseases, and pathogenic mutations have been identified in as many as 500 distinct human genes. This progress has resulted in improved diagnosis with prognostic implications, refined genetic counseling, and has formed the basis for prenatal and presymptomatic testing as well as preimplantation genetic diagnosis. However, there has been relatively little progress in developing effective and specific treatments for these often devastating diseases. Very recently, however, a number of novel molecular strategies, including gene therapy, cell-based approaches, and protein replacement therapy have been explored for treatment of these conditions. This overview will focus on the prototypic heritable blistering disorders, epidermolysis bullosa and related keratinopathies, in which significant progress has been recently made towards treatment, and illustrate how some of the translational research therapies have already entered the clinical arena. PMID:22158553

  4. Heritable change caused by transient transcription errors.

    Directory of Open Access Journals (Sweden)

    Alasdair J E Gordon

    2013-06-01

    Full Text Available Transmission of cellular identity relies on the faithful transfer of information from the mother to the daughter cell. This process includes accurate replication of the DNA, but also the correct propagation of regulatory programs responsible for cellular identity. Errors in DNA replication (mutations and protein conformation (prions can trigger stable phenotypic changes and cause human disease, yet the ability of transient transcriptional errors to produce heritable phenotypic change ('epimutations' remains an open question. Here, we demonstrate that transcriptional errors made specifically in the mRNA encoding a transcription factor can promote heritable phenotypic change by reprogramming a transcriptional network, without altering DNA. We have harnessed the classical bistable switch in the lac operon, a memory-module, to capture the consequences of transient transcription errors in living Escherichia coli cells. We engineered an error-prone transcription sequence (A9 run in the gene encoding the lac repressor and show that this 'slippery' sequence directly increases epigenetic switching, not mutation in the cell population. Therefore, one altered transcript within a multi-generational series of many error-free transcripts can cause long-term phenotypic consequences. Thus, like DNA mutations, transcriptional epimutations can instigate heritable changes that increase phenotypic diversity, which drives both evolution and disease.

  5. A simple algorithm to estimate genetic variance in an animal threshold model using Bayesian inference

    Directory of Open Access Journals (Sweden)

    Heringstad Bjørg

    2010-07-01

    Full Text Available Abstract Background In the genetic analysis of binary traits with one observation per animal, animal threshold models frequently give biased heritability estimates. In some cases, this problem can be circumvented by fitting sire- or sire-dam models. However, these models are not appropriate in cases where individual records exist on parents. Therefore, the aim of our study was to develop a new Gibbs sampling algorithm for a proper estimation of genetic (covariance components within an animal threshold model framework. Methods In the proposed algorithm, individuals are classified as either "informative" or "non-informative" with respect to genetic (covariance components. The "non-informative" individuals are characterized by their Mendelian sampling deviations (deviance from the mid-parent mean being completely confounded with a single residual on the underlying liability scale. For threshold models, residual variance on the underlying scale is not identifiable. Hence, variance of fully confounded Mendelian sampling deviations cannot be identified either, but can be inferred from the between-family variation. In the new algorithm, breeding values are sampled as in a standard animal model using the full relationship matrix, but genetic (covariance components are inferred from the sampled breeding values and relationships between "informative" individuals (usually parents only. The latter is analogous to a sire-dam model (in cases with no individual records on the parents. Results When applied to simulated data sets, the standard animal threshold model failed to produce useful results since samples of genetic variance always drifted towards infinity, while the new algorithm produced proper parameter estimates essentially identical to the results from a sire-dam model (given the fact that no individual records exist for the parents. Furthermore, the new algorithm showed much faster Markov chain mixing properties for genetic parameters (similar to

  6. Impact of family structure and common environment on heritability estimation for neuroimaging genetics studies using Sequential Oligogenic Linkage Analysis Routines.

    Science.gov (United States)

    Koran, Mary Ellen; Thornton-Wells, Tricia A; Jahanshad, Neda; Glahn, David C; Thompson, Paul M; Blangero, John; Nichols, Thomas E; Kochunov, Peter; Landman, Bennett A

    2014-06-27

    Imaging genetics is an emerging methodological field that combines genetic information with medical imaging-derived metrics to understand how genetic factors impact observable phenotypes. In order for a trait to be a reasonable phenotype in an imaging genetics study, it must be heritable: at least some proportion of its variance must be due to genetic influences. The Sequential Oligogenic Linkage Analysis Routines (SOLAR) imaging genetics software can estimate the heritability of a trait in complex pedigrees. We investigate the ability of SOLAR to accurately estimate heritability and common environmental effects on simulated imaging phenotypes in various family structures. We found that heritability is reliably estimated with small family-based studies of 40 to 80 individuals, though subtle differences remain between the family structures. In an imaging application analysis, we found that with 80 subjects in any of the family structures, estimated heritability of white matter fractional anisotropy was biased by <10% for every region of interest. Results from these studies can be used when investigators are evaluating power in planning genetic analyzes.

  7. Genetic parameters of yield components and pomologic properties in raspberry seedlings

    Directory of Open Access Journals (Sweden)

    Fotirić-Akšić Milica

    2011-01-01

    Full Text Available Over a three-year period yield components and pomologic properties were studied in 20 raspberry seedlings obtained by open pollination of Meeker`s yellow clone. The primary goals of this research were to determine its variability components, coefficients of genetic and phenotypic variation and coefficient of heritability in a broader sense. The analysis of the components of total variance evidenced that higher proportion of genotypic variance was found with fruit shape index (30.84% and sucrose content (35.61%. The results revealed that genotypic coefficient of variation were less than its corresponding estimates of phenotypic coefficient of variation for all traits which indicated significant role of environment in the expression of these characters. The values of heritability coefficients, in a broader sense, were high except for number of flowers per inflorescens (9.47%, titratable acidity (6.38% and inverted sugar content (28.88%. Nine characters had h2 in interval from 50 to 80% but for fruit weight and fruit length was greater than 80% which implies the high potential of genetic improvement in those traits.

  8. Finding missing heritability in less significant Loci and allelic heterogeneity: genetic variation in human height.

    Directory of Open Access Journals (Sweden)

    Ge Zhang

    Full Text Available Genome-wide association studies (GWAS have identified many common variants associated with complex traits in human populations. Thus far, most reported variants have relatively small effects and explain only a small proportion of phenotypic variance, leading to the issues of 'missing' heritability and its explanation. Using height as an example, we examined two possible sources of missing heritability: first, variants with smaller effects whose associations with height failed to reach genome-wide significance and second, allelic heterogeneity due to the effects of multiple variants at a single locus. Using a novel analytical approach we examined allelic heterogeneity of height-associated loci selected from SNPs of different significance levels based on the summary data of the GIANT (stage 1 studies. In a sample of 1,304 individuals collected from an island population of the Adriatic coast of Croatia, we assessed the extent of height variance explained by incorporating the effects of less significant height loci and multiple effective SNPs at the same loci. Our results indicate that approximately half of the 118 loci that achieved stringent genome-wide significance (p-value<5×10(-8 showed evidence of allelic heterogeneity. Additionally, including less significant loci (i.e., p-value<5×10(-4 and accounting for effects of allelic heterogeneity substantially improved the variance explained in height.

  9. Estimadores de componentes de variância em delineamento de blocos aumentados com tratamentos novos de uma ou mais populações Estimators of variance components in the augmented block design with new treatments from one or more populations

    Directory of Open Access Journals (Sweden)

    João Batista Duarte

    2001-09-01

    Full Text Available O objetivo do trabalho foi comparar, por meio de simulação, as estimativas de componentes de variância produzidas pelos métodos ANOVA (análise da variância, ML (máxima verossimilhança, REML (máxima verossimilhança restrita e MIVQUE(0 (estimador quadrático não viesado de variância mínima, no delineamento de blocos aumentados com tratamentos adicionais (progênies de uma ou mais procedências (cruzamentos. Os resultados indicaram superioridade relativa do método MIVQUE(0. O método ANOVA, embora não tendencioso, apresentou as estimativas de menor precisão. Os métodos de máxima verossimilhança, sobretudo ML, tenderam a subestimar a variância do erro experimental ( e a superestimar as variâncias genotípicas (, em especial nos experimentos de menor tamanho (n/>0,5. Contudo, o método produziu as piores estimativas de variâncias genotípicas quando as progênies vieram de diferentes cruzamentos e os experimentos foram pequenos.This work compares by simulation estimates of variance components produced by the ANOVA (analysis of variance, ML (maximum likelihood, REML (restricted maximum likelihood, and MIVQUE(0 (minimum variance quadratic unbiased estimator methods for augmented block design with additional treatments (progenies stemming from one or more origins (crosses. Results showed the superiority of the MIVQUE(0 estimation. The ANOVA method, although unbiased, showed estimates with lower precision. The ML and REML methods produced downwards biased estimates for error variance (, and upwards biased estimates for genotypic variances (, particularly the ML method. Biases for the REML estimation became negligible when progenies were derived from a single cross, and experiments were of larger size with ratios />0.5. This method, however, provided the worst estimates for genotypic variances when progenies were derived from several crosses and the experiments were of small size (n<120 observations.

  10. Estimating heritability for cause specific mortality based on twin studies

    DEFF Research Database (Denmark)

    Scheike, Thomas; Holst, Klaus K.; Hjelmborg, Jacob B.

    2014-01-01

    There has been considerable interest in studying the magnitude and type of inheritance of specific diseases. This is typically derived from family or twin studies, where the basic idea is to compare the correlation for different pairs that share different amount of genes. We here consider data from...... the Danish twin registry and discuss how to define heritability for cancer occurrence. The key point is that this should be done taking censoring as well as competing risks due to e.g.  death into account. We describe the dependence between twins on the probability scale and show that various models can...... be used to achieve sensible estimates of the dependence within monozygotic and dizygotic twin pairs that may vary over time. These dependence measures can subsequently be decomposed into a genetic and environmental component using random effects models. We here present several novel models that in essence...

  11. Revision: Variance Inflation in Regression

    Directory of Open Access Journals (Sweden)

    D. R. Jensen

    2013-01-01

    the intercept; and (iv variance deflation may occur, where ill-conditioned data yield smaller variances than their orthogonal surrogates. Conventional VIFs have all regressors linked, or none, often untenable in practice. Beyond these, our models enable the unlinking of regressors that can be unlinked, while preserving dependence among those intrinsically linked. Moreover, known collinearity indices are extended to encompass angles between subspaces of regressors. To reaccess ill-conditioned data, we consider case studies ranging from elementary examples to data from the literature.

  12. Inferring the trajectory of genetic variance in the course of artificial selection.

    Science.gov (United States)

    Sorensen, D; Fernando, R; Gianola, D

    2001-02-01

    A method is proposed to infer genetic parameters within a cohort, using data from all individuals in an experiment. An application is the study of changes in additive genetic variance over generations, employing data from all generations. Inferences about the genetic variance in a given generation are based on its marginal posterior distribution, estimated via Markov chain Monte Carlo methods. As defined, the additive genetic variance within the group is directly related to the amount of selection response to be expected if parents are chosen within the group. Results from a simulated selection experiment are used to illustrate properties of the method. Four sets of data are analysed: directional selection with and without environmental trend, and random selection, with and without environmental trend. In all cases, posterior credibility intervals of size 95% assign relatively high density to values of the additive genetic variance and heritability in the neighbourhood of the true values. Properties and generalizations of the method are discussed.

  13. Six low-penetrance SNPs for the estimation of breast cancer heritability: A family-based study in Caucasian Italian patients.

    Science.gov (United States)

    De Summa, Simona; Graziano, Francesca; Pilato, Brunella; Pinto, Rosamaria; Danza, Katia; Lacalamita, Rosanna; Serratì, Simona; Sambiasi, Domenico; Grassi, Mario; Tommasi, Stefania

    2017-10-01

    Breast cancer is a malignancy with a strong heritable component. Genetic counseling has been principally focused on families carrying high-penetrance breast cancer 1/2, early onset genes. Current modeling suggests that the majority of the unexplained fraction of familial risk is likely to be explained by a polygenic model. The aim of the present study was to estimate the heritability (h 2 ) of breast cancer susceptibility through the analysis of 6 single nucleotide polymorphisms (SNPs), nuclear mitotic apparatus protein 1, cyclin D1, cytochrome C oxidase copper chaperone, fibroblast growth factor receptor 2, TOX high mobility group box family member 3 and solute carrier family 4 member 7. These 6 SNPs, previously identified by genome-wide association studies, were considered to evaluate the additive and common environmental components that contribute to the development of breast cancer in nuclear (pedigrees including only first degree relationships) and in extended families (with at most third degree relationships). A total of 22 extended pedigrees, subsequently split into 52 nuclear pedigrees were analyzed. An example of splitting process from extended to nuclear pedigree is shown in Fig. 1. Firstly, an underline latent continuous trait ( Y *) using breast cancer status and information of 6 breast cancer-associated SNPs was calculated. This novel trait summarized the susceptibility of breast cancer in each individual. Secondly, the h 2 of Y * was estimated using an additive polygenic-common environment-unique error model. h 2 was evaluated in extended and immediate pedigrees, obtaining comparable results. h 2 accounts for ~40% of the total phenotypic variance, indicating a fairly strong additive genetic effect of breast cancer susceptibility. The present study indicated the importance of the evaluation and consideration of these six SNPs, which can be used as instrumental variables in order to obtain improved genetic models that are useful for h 2 analysis.

  14. Blending of heritable recognition cues among ant nestmates creates distinct colony gestalt odours but prevents within-colony nepotism.

    Science.gov (United States)

    van Zweden, J S; Brask, J B; Christensen, J H; Boomsma, J J; Linksvayer, T A; d'Ettorre, P

    2010-07-01

    The evolution of sociality is facilitated by the recognition of close kin, but if kin recognition is too accurate, nepotistic behaviour within societies can dissolve social cohesion. In social insects, cuticular hydrocarbons act as nestmate recognition cues and are usually mixed among colony members to create a Gestalt odour. Although earlier studies have established that hydrocarbon profiles are influenced by heritable factors, transfer among nestmates and additional environmental factors, no studies have quantified these relative contributions for separate compounds. Here, we use the ant Formica rufibarbis in a cross-fostering design to test the degree to which hydrocarbons are heritably synthesized by young workers and transferred by their foster workers. Bioassays show that nestmate recognition has a significant heritable component. Multivariate quantitative analyses based on 38 hydrocarbons reveal that a subset of branched alkanes are heritably synthesized, but that these are also extensively transferred among nestmates. In contrast, especially linear alkanes are less heritable and little transferred; these are therefore unlikely to act as cues that allow within-colony nepotistic discrimination or as nestmate recognition cues. These results indicate that heritable compounds are suitable for establishing a genetic Gestalt for efficient nestmate recognition, but that recognition cues within colonies are insufficiently distinct to allow nepotistic kin discrimination.

  15. The power of regional heritability analysis for rare and common variant detection: simulations and application to eye biometrical traits

    Directory of Open Access Journals (Sweden)

    Yoshinobu eUemoto

    2013-11-01

    Full Text Available Genome-wide association studies (GWAS have provided valuable insights into the genetic basis of complex traits. However, they have explained relatively little trait heritability. Recently, we proposed a new analytical approach called regional heritability mapping (RHM that captures more of the missing genetic variation. This method is applicable both to related and unrelated populations. Here, we demonstrate the power of RHM in comparison with single-SNP GWAS and gene-based association approaches under a wide range of scenarios with variable numbers of quantitative trait loci (QTLs with common and rare causal variants in a narrow genomic region. Simulations based on real genotype data were performed to assess power to capture QTL variance, and we demonstrate that RHM has greater power to detect rare variants and/or multiple alleles in a region than other approaches. In addition, we show that RHM can capture more accurately the QTL variance, when it is caused by multiple independent effects and/or rare variants. We applied RHM to analyze three biometrical eye traits for which single-SNP GWAS have been published or performed to evaluate the effectiveness of this method in real data analysis and detected some additional loci which were not detected by other GWAS methods. RHM has the potential to explain some of missing heritability by capturing variance caused by QTL with low MAF and multiple independent QTLs in a region, not captured by other GWAS methods.

  16. Familial aggregation and heritability of pyloric stenosis.

    Science.gov (United States)

    Krogh, Camilla; Fischer, Thea K; Skotte, Line; Biggar, Robert J; Øyen, Nina; Skytthe, Axel; Goertz, Sanne; Christensen, Kaare; Wohlfahrt, Jan; Melbye, Mads

    2010-06-16

    Pyloric stenosis is the most common condition requiring surgery in the first months of life. Case reports have suggested familial aggregation, but to what extent this is caused by common environment or inheritance is unknown. To investigate familial aggregation of pyloric stenosis from monozygotic twins to fourth-generation relatives according to sex and maternal and paternal contributions and to estimate disease heritability. Population-based cohort study of 1,999,738 children born in Denmark between 1977 and 2008 and followed up for the first year of life, during which 3362 children had surgery for pyloric stenosis. Familial aggregation of pyloric stenosis, evaluated by rate ratios. The incidence rate (per 1000 person-years) of pyloric stenosis in the first year of life was 1.8 for singletons and 3.1 for twins. The rate ratios of pyloric stenosis were 182 (95% confidence interval [CI], 70.7-467) for monozygotic twins, 29.4 (95% CI, 9.45-91.5) for dizygotic twins, 18.5 (95% CI, 13.7-25.1) for siblings, 4.99 (95% CI, 2.59-9.65) for half-siblings, 3.06 (95% CI, 2.10-4.44) for cousins, and 1.60 (95% CI, 0.51-4.99) for half-cousins. We found no difference in rate ratios for maternal and paternal relatives of children with pyloric stenosis and no difference according to sex of cohort member or sex of relative. The heritability of pyloric stenosis was 87%. Pyloric stenosis in Danish children shows strong familial aggregation and heritability.

  17. Drosophila modeling of heritable neurodevelopmental disorders.

    Science.gov (United States)

    Gatto, Cheryl L; Broadie, Kendal

    2011-12-01

    Heritable neurodevelopmental disorders are multifaceted disease conditions encompassing a wide range of symptoms including intellectual disability, cognitive dysfunction, autism and myriad other behavioral impairments. In cases where single, causative genetic defects have been identified, such as Angelman syndrome, Rett syndrome, Neurofibromatosis Type 1 and Fragile X syndrome, the classical Drosophila genetic system has provided fruitful disease models. Recent Drosophila studies have advanced our understanding of UBE3A, MECP2, NF1 and FMR1 function, respectively, in genetic, biochemical, anatomical, physiological and behavioral contexts. Investigations in Drosophila continue to provide the essential mechanistic understanding required to facilitate the conception of rational therapeutic treatments. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Familial aggregation and heritability of pyloric stenosis

    DEFF Research Database (Denmark)

    Krogh, Camilla; Fischer, Thea K; Skotte, Line

    2010-01-01

    for the first year of life, during which 3362 children had surgery for pyloric stenosis. MAIN OUTCOME MEASURE: Familial aggregation of pyloric stenosis, evaluated by rate ratios. RESULTS: The incidence rate (per 1000 person-years) of pyloric stenosis in the first year of life was 1.8 for singletons and 3......CONTEXT: Pyloric stenosis is the most common condition requiring surgery in the first months of life. Case reports have suggested familial aggregation, but to what extent this is caused by common environment or inheritance is unknown. OBJECTIVES: To investigate familial aggregation of pyloric...... familial aggregation and heritability....

  19. Heritability of the Effective Connectivity in the Resting-State Default Mode Network.

    Science.gov (United States)

    Xu, Junhai; Yin, Xuntao; Ge, Haitao; Han, Yan; Pang, Zengchang; Liu, Baolin; Liu, Shuwei; Friston, Karl

    2016-11-23

    The default mode network (DMN) is thought to reflect endogenous neural activity, which is considered as one of the most intriguing phenomena in cognitive neuroscience. Previous studies have found that key regions within the DMN are highly interconnected. Here, we characterized the genetic influences on causal or directed information flow within the DMN during the resting state. In this study, we recruited 46 pairs of twins and collected fMRI imaging data using a 3.0 T scanner. Dynamic causal modeling was conducted for each participant, and a structural equation model was used to calculate the heritability of DMN in terms of its effective connectivity. Model comparison favored a full-connected model. Structural equal modeling was used to estimate the additive genetics (A), common environment (C) and unique environment (E) contributions to variance for the DMN effective connectivity. The ACE model was preferred in the comparison of structural equation models. Heritability of DMN effective connectivity was 0.54, suggesting that the genetic made a greater contribution to the effective connectivity within DMN. Establishing the heritability of default-mode effective connectivity endorses the use of resting-state networks as endophenotypes or intermediate phenotypes in the search for the genetic basis of psychiatric or neurological illnesses. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Estimation of variation and correlation analysis for yield components in black currant cultivars

    Directory of Open Access Journals (Sweden)

    Rakonjac Vera

    2015-01-01

    Full Text Available Creating genotypes that will be characterized by high yields, good quality and other favorable agronomic characters is a major objective of most currant breeding programs worldwide. For easier and faster achievement of these goals and identification of superior genotypes suitable for use as parents in future hybridization programs, study of genetic parameters seems to be obligatory. In this regard, the aims of our study were to estimate components of variability and heritability, and do correlation analysis for yield components in order to determine efficient strategies for improving yield in black currant breeding programs. Significant differences between cultivars were established for all studied traits. A high proportion of genotypic variance was found with bush width, no. of shoots per bush, bunch weight and berry weight indicating that genetic improvement for these traits through breeding was achievable. Opposite, seasonal variance was high for bush height, no. of bunch per bush and yield. The high heritability coefficients (0.80-0.94 detected for all traits studied reflect the close agreement between their phenotypic and genotypic values. Also, most pairs of traits were similarly correlated at both phenotypic and genotypic levels. So, yield was significantly and positively correlated with bush height, no of bunch per bush and bunch weight. These results imply a rapid response of black currants to selection. [Projekat Ministarstva nauke Republike Srbije, br. 46013 i FP7 Project AREA 316004

  1. Partitioning of genomic variance using prior biological information

    DEFF Research Database (Denmark)

    Edwards, Stefan McKinnon; Janss, Luc; Madsen, Per

    to open the “black box” by building SNP set genomic models that evaluate the collective action of multiple SNPs in genes, biological pathways or other external biological findings on the trait phenotype. As a proof of concept we have tested the modelling framework on susceptibility to mastitis in dairy...... of single nucleotide polymorphism (SNP) data and trait phenotypes and can account for a much larger fraction of the heritable component of the trait. A disadvantage is that this “black box” modelling approach does not provide any insight into the biological mechanisms underlying the trait. We propose...

  2. Age at fatherhood: heritability and associations with psychiatric disorders.

    Science.gov (United States)

    Frans, E M; Lichtenstein, P; Hultman, C M; Kuja-Halkola, R

    2016-10-01

    Advancing paternal age has been linked to psychiatric disorders. These associations might be caused by the increased number of de novo mutations transmitted to offspring of older men. It has also been suggested that the associations are confounded by a genetic liability for psychiatric disorders in parents. The aim of this study was to indirectly test the confounding hypotheses by examining if there is a genetic component to advancing paternal age and if men with a genetic liability for psychiatric disorders have children at older ages. We examined the genetic component to advancing paternal age by utilizing the twin model in a cohort of male twins (N = 14 679). We also studied ages at childbirth in men with or without schizophrenia, bipolar disorder and/or autism spectrum disorder. Ages were examined in: (1) healthy men, (2) affected men, (3) healthy men with an affected sibling, (4) men with healthy spouses, (5) men with affected spouses, and (6) men with healthy spouses with an affected sibling. The twin analyses showed that late fatherhood is under genetic influence (heritability = 0.33). However, affected men or men with affected spouses did not have children at older ages. The same was found for healthy individuals with affected siblings. Instead, these men were generally having children at younger ages. Although there is a genetic component influencing late fatherhood, our data suggest that the associations are not explained by psychiatric disorders or a genetic liability for psychiatric disorders in the parent.

  3. Multi-Trait analysis of growth traits: fitting reduced rank models using principal components for Simmental beef cattle

    Directory of Open Access Journals (Sweden)

    Rodrigo Reis Mota

    2016-09-01

    Full Text Available ABSTRACT: The aim of this research was to evaluate the dimensional reduction of additive direct genetic covariance matrices in genetic evaluations of growth traits (range 100-730 days in Simmental cattle using principal components, as well as to estimate (covariance components and genetic parameters. Principal component analyses were conducted for five different models-one full and four reduced-rank models. Models were compared using Akaike information (AIC and Bayesian information (BIC criteria. Variance components and genetic parameters were estimated by restricted maximum likelihood (REML. The AIC and BIC values were similar among models. This indicated that parsimonious models could be used in genetic evaluations in Simmental cattle. The first principal component explained more than 96% of total variance in both models. Heritability estimates were higher for advanced ages and varied from 0.05 (100 days to 0.30 (730 days. Genetic correlation estimates were similar in both models regardless of magnitude and number of principal components. The first principal component was sufficient to explain almost all genetic variance. Furthermore, genetic parameter similarities and lower computational requirements allowed for parsimonious models in genetic evaluations of growth traits in Simmental cattle.

  4. Variance decomposition in stochastic simulators

    KAUST Repository

    Le Maître, O. P.

    2015-06-28

    This work aims at the development of a mathematical and computational approach that enables quantification of the inherent sources of stochasticity and of the corresponding sensitivities in stochastic simulations of chemical reaction networks. The approach is based on reformulating the system dynamics as being generated by independent standardized Poisson processes. This reformulation affords a straightforward identification of individual realizations for the stochastic dynamics of each reaction channel, and consequently a quantitative characterization of the inherent sources of stochasticity in the system. By relying on the Sobol-Hoeffding decomposition, the reformulation enables us to perform an orthogonal decomposition of the solution variance. Thus, by judiciously exploiting the inherent stochasticity of the system, one is able to quantify the variance-based sensitivities associated with individual reaction channels, as well as the importance of channel interactions. Implementation of the algorithms is illustrated in light of simulations of simplified systems, including the birth-death, Schlögl, and Michaelis-Menten models.

  5. Variance based OFDM frame synchronization

    Directory of Open Access Journals (Sweden)

    Z. Fedra

    2012-04-01

    Full Text Available The paper deals with a new frame synchronization scheme for OFDM systems and calculates the complexity of this scheme. The scheme is based on the computing of the detection window variance. The variance is computed in two delayed times, so a modified Early-Late loop is used for the frame position detection. The proposed algorithm deals with different variants of OFDM parameters including guard interval, cyclic prefix, and has good properties regarding the choice of the algorithm's parameters since the parameters may be chosen within a wide range without having a high influence on system performance. The verification of the proposed algorithm functionality has been performed on a development environment using universal software radio peripheral (USRP hardware.

  6. Monitoring structural change in variance

    OpenAIRE

    Carsoule, F.; Franses, Ph.H.B.F.

    1999-01-01

    In this paper we propose a sequential testing approach for a structural change in the variance of a time series, which amounts to a procedure with a controlled asymptotic size as we repeat the test. Our approach builds on that taken in Chu, Stinchcombe and White (1996) for structural change in the parameters of a linear regression model. We provide simulation evidence to examine the empirical size and power of our procedure. We apply our approach to 14 weekly observed European exchange rates ...

  7. Estimating the Modified Allan Variance

    Science.gov (United States)

    Greenhall, Charles

    1995-01-01

    The third-difference approach to modified Allan variance (MVAR) leads to a tractable formula for a measure of MVAR estimator confidence, the equivalent degrees of freedom (edf), in the presence of power-law phase noise. The effect of estimation stride on edf is tabulated. A simple approximation for edf is given, and its errors are tabulated. A theorem allowing conservative estimates of edf in the presence of compound noise processes is given.

  8. Heritability of hsp70 expression in the beetle Tenebrio molitor: Ontogenetic and environmental effects.

    Science.gov (United States)

    Lardies, Marco A; Arias, María Belén; Poupin, María Josefina; Bacigalupe, Leonardo D

    2014-08-01

    Ectotherms constitute the vast majority of terrestrial biodiversity and are especially likely to be vulnerable to climate warming because their basic physiological functions such as locomotion, growth, and reproduction are strongly influenced by environmental temperature. An integrated view about the effects of global warming will be reached not just establishing how the increase in mean temperature impacts the natural populations but also establishing the effects of the increase in temperature variance. One of the molecular responses that are activated in a cell under a temperature stress is the heat shock protein response (HSP). Some studies that have detected consistent differences among thermal treatments and ontogenetic stages in HSP70 expression have assumed that these differences had a genetic basis and consequently expression would be heritable. We tested for changes in quantitative genetic parameters of HSP70 expression in a half-sib design where individuals of the beetle Tenebrio molitor were maintained in constant and varying thermal environments. We estimated heritability of HSP70 expression using a linear mixed modelling approach in different ontogenetic stages. Expression levels of HSP70 were consistently higher in the variable environment and heritability estimates were low to moderate. The results imply that within each ontogenetic stage additive genetic variance was higher in the variable environment and in adults compared with constant environment and larvae stage, respectively. We found that almost all the genetic correlations across ontogenetic stages and environment were positive. These suggest that directional selection for higher levels of expression in one environment will result in higher expression levels of HSP70 on the other environment for the same ontogenetic stage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. The heritability of corneal hysteresis and ocular pulse amplitude: a twin study.

    Science.gov (United States)

    Carbonaro, Francis; Andrew, Toby; Mackey, David A; Spector, Tim D; Hammond, Chris J

    2008-09-01

    To examine the roles of genetic and environmental factors in corneal hysteresis and ocular pulse amplitude by performing a classic twin study. Cross-sectional twin study. Two hundred sixty-four twin pairs: 135 monozygotic (MZ) and 129 dizygotic (DZ). Corneal hysteresis was measured using the Reichert Ocular Response Analyzer (ORA; Reichert, Buffalo, NY), and ocular pulse amplitude was measured using the Pascal Dynamic Contour Tonometer (DCT; Swiss Microtechnology AG, Port, Switzerland). Contribution of genetic and environmental effects on corneal hysteresis and OPA among MZ and DZ twins. The mean corneal hysteresis was 10.24+/-1.54 mmHg and the mean ocular pulse amplitude was 2.88+/-0.97 mmHg. The MZ correlations were higher than DZ for both corneal hysteresis and ocular pulse amplitude (correlation coefficients, 0.75:0.42 and 0.59:0.32 for MZ:DZ twins, respectively). Modeling suggested heritability of corneal hysteresis of 0.77 (95% confidence interval [CI], 0.70-0.82), with the remaining proportion of variance because of individual environmental effects of 0.23 (95% CI, 0.18-0.30). For ocular pulse amplitude, the heritability was 0.62 (95% CI, 0.51-0.70), with the remaining proportion of variance the result of individual environmental effects of 0.38 (95% CI, 0.30-0.49). This study demonstrated that additive genetic influences explained most of the individual differences in corneal hysteresis and ocular pulse amplitude among these twins.

  10. Heritability of premature mitral valve disease in Cavalier King Charles spaniels.

    Science.gov (United States)

    Lewis, Tom; Swift, Simon; Woolliams, John A; Blott, Sarah

    2011-04-01

    Mixed model analysis of 1252 records of cardiac auscultation of 4- to 5-year-old Cavalier King Charles spaniels (CKCS) from 1991 to 2008 in conjunction with the Kennel Club pedigree records of all dogs registered from the mid 1980s to September 2007 was used to estimate variance parameters of premature mitral valve disease (MVD). Data were limited to dogs ≥4 and <5 years of age to ensure diagnostic distinction between early and late onset MVD. Cardiac murmurs were detected in 108/1252 (8.6%) dogs. Heritability estimates of 0.67 (standard error, SE 0.071) for the grade of murmur and 0.33 (SE 0.072) for the presence/absence of murmur were calculated. The variance due to clinician was 0.02 (SE 0.012) for grade and 0.03 (SE 0.017) for presence/absence of murmur. These results indicate that the presence and severity of MVD, as assessed by cardiac auscultation, in 4- to 5-year-old CKCS is highly heritable and that selection against the disease should be successful. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Confidence intervals for intraclass correlation coefficients in variance components models

    NARCIS (Netherlands)

    Demetrashvili, Nino; Wit, Ernst C.; van den Heuvel, Edwin R.

    2016-01-01

    Confidence intervals for intraclass correlation coefficients in agreement studies with continuous outcomes are model-specific and no generic approach exists. This paper provides two generic approaches for intraclass correlation coefficients of the form Sigma q=1 2). The first approach uses

  12. Variance components and genetic parameters for body weight and ...

    African Journals Online (AJOL)

    ) op l8 maande-ouderdom. Om die mees geskikte model vir elke eienskap te bepaal, is vier verskillende modelle gepas deur maternale genetiese en omgewingsef- fekte te ignoreer of in te sluit. WW en GFW6 is betekenisvol deur maternale ...

  13. Application of Test-day Models for Variance Components Estimation ...

    African Journals Online (AJOL)

    Julio Carvalheira

    the random effect of the animal, LTE is the random effect of the long-term environmental effects accounting for the autocorrelations generated by the cow across repeated lactations, STE is the random effect of short term environmental effects accounting for the autocorrelations due to cow within each lactation, and e is the.

  14. Variance component estimation of a female fertility trait in two ...

    African Journals Online (AJOL)

    USER

    Introduction. In current national genetic evaluations in Southern Africa, estimated breeding values (EBVs) for growth traits are reported without any indication of the reproductive ability of the animals. This void could lead to the assumption that differences between animals in genetic merit for reproduction and fitness traits.

  15. Estimates of variance components for postweaning feed intake and ...

    African Journals Online (AJOL)

    Mike

    2013-03-09

    Mar 9, 2013 ... examined, contained either EBV for: 1) ADG and DFI assuming relative economic values of 7 and 1, respectively; 2) MBW, ADG, and RFI; or 3) RDG and DFI. Results & Discussion. Means and phenotypic standard deviations (in parentheses) of MBW, ADG, and DFI were 79.7 (4.19) kg0.75, 1.74 (0.22) kg/d, ...

  16. (Co) variance Components and Genetic Parameter Estimates for Re

    African Journals Online (AJOL)

    Mapula

    generation interval which in turn hinders genetic improvement. Live animal ultrasound measures of carcass traits were recently introduced to supplement progeny testing programmes or for usage as sole source of carcass data in beef cattle breeding programmes (Crews et al., 2004; MacNeil & Northcutt, 2008). Ultrasonic.

  17. Direct and maternal variance component estimates for clean fleece ...

    African Journals Online (AJOL)

    fleece weight (CFW), body weight (BW) and mean fibre diameter (MFD) in the Grootfontein Merino stud. Direct herita- bilities were estimated as 0.381, ... South African Merino stud as far as management and selection procedures (until 1984) are concerned. ... ance and Progeny Testing Scheme: Body weight (BW) - taken ...

  18. Components of the metabolic syndrome: clustering and genetic variance

    NARCIS (Netherlands)

    Povel, C.M.

    2012-01-01

    Background Abdominal obesity, hyperglycemia, hypertriglyceridemia, low HDL cholesterol levels and hypertension frequently co-occur within individuals. The cluster of these features is referred to as the metabolic syndrome (MetS). The aim

  19. Genetic variability and heritability studies of some reproductive traits ...

    African Journals Online (AJOL)

    GRACE

    2006-07-03

    Jul 3, 2006 ... genotypic variability of some reproductive traits and their heritability in some selected cowpea varieties. Results of ... Broad-sense heritability estimate (h2) was 98.9% for 100-seed weight, 94% for duration of reproductive phase, 84.5% for .... days interval to control flowering-and post-flowering insect pests.

  20. Genetic components of litter size variability in sheep

    Directory of Open Access Journals (Sweden)

    Chevalet Claude

    2001-05-01

    Full Text Available Abstract Classical selection for increasing prolificacy in sheep leads to a concomitant increase in its variability, even though the objective of the breeder is to maximise the frequency of an intermediate litter size rather than the frequency of high litter sizes. For instance, in the Lacaune sheep breed raised in semi-intensive conditions, ewes lambing twins represent the economic optimum. Data for this breed, obtained from the national recording scheme, were analysed. Variance components were estimated in an infinitesimal model involving genes controlling the mean level as well as its environmental variability. Large heritability was found for the mean prolificacy, but a high potential for increasing the percentage of twins at lambing while reducing the environmental variability of prolificacy is also suspected. Quantification of the response to such a canalising selection was achieved.

  1. Heritability of the Severity of the Metabolic Syndrome in Whites and Blacks in 3 Large Cohorts.

    Science.gov (United States)

    Musani, Solomon K; Martin, Lisa J; Woo, Jessica G; Olivier, Michael; Gurka, Matthew J; DeBoer, Mark D

    2017-04-01

    Although dichotomous criteria for the metabolic syndrome (MetS) appear heritable, it is not known whether MetS severity as assessed by a continuous MetS score is heritable and whether this varies by race. We used SOLAR (Sequential Oligogenic Linkage Analysis Routines) to evaluate heritability of Adult Treatment Panel-III MetS and a sex- and race-specific MetS severity Z score among 3 large familial cohorts: the JHS (Jackson Heart Study, 1404 black participants), TOPS (Take Off Pounds Sensibly, 1947 white participants), and PLRS (Princeton Lipid Research Study, 229 black and 527 white participants). Heritability estimates were larger for Adult Treatment Panel-III MetS among black compared with white cohort members (JHS 0.48; 95% confidence interval [CI], 0.28-0.68 and PLRS blacks 0.93 [95% CI, 0.73-1.13] versus TOPS 0.21 [95% CI, -0.18 to 0.60] and PLRS whites 0.27 [95% CI, -0.04 to 0.58]). The difference by race narrowed when assessing heritability of the MetS severity score (JHS 0.52 [95% CI, 0.38, 0.66] and PLRS blacks 0.64 [95% CI, 0.13-1.15] versus TOPS 0.23 [95% CI, 0.15-0.31] and PLRS whites 0.60 [95% CI, 0.33-0.87]). There was a high degree of genetic and phenotypic correlation between MetS severity and the individual components of MetS among all groups, although the genetic correlations failed to reach statistical significance among PLRS blacks. Meta-analyses revealed a combined heritability estimate for Adult Treatment Panel-III MetS of 0.24 (95% CI, 0.11-0.36) and for the MetS severity score of 0.50 (95% CI, -0.05 to 0.99). MetS severity seems highly heritable among whites and blacks. This continuous MetS severity Z score may provide a more useful means of characterizing phenotypic MetS in genetic studies by minimizing racial differences. © 2017 American Heart Association, Inc.

  2. Heritable factors influence sexual orientation in women.

    Science.gov (United States)

    Bailey, J M; Pillard, R C; Neale, M C; Agyei, Y

    1993-03-01

    Homosexual female probands with monozygotic cotwins, dizygotic cotwins, or adoptive sisters were recruited using homophile publications. Sexual orientation of relatives was assessed either by asking relatives directly, or, when this was impossible, by asking the probands. Of the relatives whose sexual orientation could be confidently rated, 34 (48%) of 71 monozygotic cotwins, six (16%) of 37 dizygotic cotwins, and two (6%) of 35 adoptive sisters were homosexual. Probands also reported 10 (14%) nontwin biologic sisters to be homosexual, although those sisters were not contacted to confirm their orientations. Heritabilities were significant using a wide range of assumptions about both the base rate of homosexuality in the population and ascertainment bias. The likelihood that a monozygotic cotwin would also be homosexual was unrelated to measured characteristics of the proband such as self-reported history of childhood gender nonconformity. Concordant monozygotic twins reported similar levels of childhood gender nonconformity.

  3. Human somatic, germinal and heritable mutagenicity

    Energy Technology Data Exchange (ETDEWEB)

    Mendelsohn, M.L.

    1987-05-01

    This report deals with the general process of variant formation rather than with the consequences of a specific variant being present. It focusses on mutational mechanisms, mutagens, and the method for detecting de novo mutants and estimating mutation rate. It is to human genetics much like disease causation and prevention medicine are to medicine as a whole. The word ''mutagenicity'' is used in the title and throughout the text to connote the causation of all classes of genetic damage. Mutagenicity and the corresponding words mutation, mutagen and mutagenesis can have multiple meaning, sometimes relating to gene mutation, sometimes to heritable mutation, and somtimes to all types of genetic damage. 38 refs., 1 tab.

  4. Epigenetic variation, phenotypic heritability, and evolution

    DEFF Research Database (Denmark)

    Furrow, Robert E.; Christiansen, Freddy Bugge; Feldman, Marcus W.

    2014-01-01

    Familial aggregation of complex diseases may have many causes in addition to and apart from genetic predisposition due to common ancestry. For example, exposure to an environment that induces susceptibility to a disease may produce similar familial aggregations when the environment is shared...... by family members. In general, according to the principles of (Johannsen 1903), the emergence of a disease phenotype is the result of the combined effects of the genotype of the individual and the environment that it experiences during development. The heritability of a disease is a measure of familial...... of evolution. Darwin’s inspiration originated from the practical use of family resemblance in animal breeding. Animal breeders have long known that a major obstacle to progress in genetic improvement is the interaction between familial aggregation of environments and the effects of similar genetics within...

  5. Sex-differences in heritability of BMI

    DEFF Research Database (Denmark)

    Schousboe, K; Willemsen, G; Kyvik, Kirsten Ohm

    2003-01-01

    Body mass index (BMI), a simple anthropometric measure, is the most frequently used measure of adiposity and has been instrumental in documenting the worldwide increase in the prevalence of obesity witnessed during the last decades. Although this increase in overweight and obesity is thought...... to be mainly due to environmental changes, i.e., sedentary lifestyles and high caloric diets, consistent evidence from twin studies demonstrates high heritability and the importance of genetic differences for normal variation in BMI. We analysed self-reported data on BMI from approximately 37,000 complete twin...... factors that influence variation in BMI. These results encourage the continued search for genes of importance to the body composition and the development of obesity. Furthermore, they suggest that strategies to identify predisposing genes may benefit from taking into account potential sex specific effects....

  6. Heritability estimates of methane emissions from sheep.

    Science.gov (United States)

    Pinares-Patiño, C S; Hickey, S M; Young, E A; Dodds, K G; MacLean, S; Molano, G; Sandoval, E; Kjestrup, H; Harland, R; Hunt, C; Pickering, N K; McEwan, J C

    2013-06-01

    The objective of this study was to determine the genetic parameters of methane (CH4) emissions and their genetic correlations with key production traits. The trial measured the CH4 emissions, at 5-min intervals, from 1225 sheep placed in respiration chambers for 2 days, with repeat measurements 2 weeks later for another 2 days. They were fed in the chambers, based on live weight, a pelleted lucerne ration at 2.0 times estimated maintenance requirements. Methane outputs were calculated for g CH4/day and g CH4/kg dry matter intake (DMI) for each of the 4 days. Single trait models were used to obtain estimates of heritability and repeatability. Heritability of g CH4/day was 0.29 ± 0.05, and for g CH4/kg DMI 0.13 ± 0.03. Repeatability between measurements 14 days apart were 0.55 ± 0.02 and 0.26 ± 0.02, for the two traits. The genetic and phenotypic correlations of CH4 outputs with various production traits (weaning weight, live weight at 8 months of age, dag score, muscle depth and fleece weight at 12 months of age) measured in the first year of life, were estimated using bivariate models. With the exception of fleece weight, correlations were weak and not significantly different from zero for the g CH4/kg DMI trait. For fleece weight the phenotypic and genetic correlation estimates were -0.08 ± 0.03 and -0.32 ± 0.11 suggesting a low economically favourable relationship. These results indicate that there is genetic variation between animals for CH4 emission traits even after adjustment for feed intake and that these traits are repeatable. Current work includes the establishment of selection lines from these animals to investigate the physiological, microbial and anatomical changes, coupled with investigations into shorter and alternative CH4 emission measurement and breeding value estimation techniques; including genomic selection.

  7. Heritable Bovine Rumen Bacteria Are Phylogenetically Related and Correlated with the Cow's Capacity To Harvest Energy from Its Feed.

    Science.gov (United States)

    Sasson, Goor; Kruger Ben-Shabat, Sheerli; Seroussi, Eyal; Doron-Faigenboim, Adi; Shterzer, Naama; Yaacoby, Shamay; Berg Miller, Margret E; White, Bryan A; Halperin, Eran; Mizrahi, Itzhak

    2017-08-15

    Ruminants sustain a long-lasting obligatory relationship with their rumen microbiome dating back 50 million years. In this unique host-microbiome relationship, the host's ability to digest its feed is completely dependent on its coevolved microbiome. This extraordinary alliance raises questions regarding the dependent relationship between ruminants' genetics and physiology and the rumen microbiome structure, composition, and metabolism. To elucidate this relationship, we examined the association of host genetics with the phylogenetic and functional composition of the rumen microbiome. We accomplished this by studying a population of 78 Holstein-Friesian dairy cows, using a combination of rumen microbiota data and other phenotypes from each animal with genotypic data from a subset of 47 animals. We identified 22 operational taxonomic units (OTUs) whose abundances were associated with rumen metabolic traits and host physiological traits and which showed measurable heritability. The abundance patterns of these microbes can explain high proportions of variance in rumen metabolism and many of the host physiological attributes such as its energy-harvesting efficiency. Interestingly, these OTUs shared higher phylogenetic similarity between themselves than expected by chance, suggesting occupation of a specific ecological niche within the rumen ecosystem. The findings presented here suggest that ruminant genetics and physiology are correlated with microbiome structure and that host genetics may shape the microbiome landscape by enriching for phylogenetically related taxa that may occupy a unique niche. IMPORTANCE Dairy cows are an essential nutritional source for the world's population; as such, they are extensively farmed throughout our planet and subsequently impact our environment. The microbial communities that reside in the upper digestive tract of these animals in a compartment named the rumen degrade and ferment the plant biomass that the animal ingests. Our recent

  8. A Paradox of Genetic Variance in Epigamic Traits: Beyond "Good Genes" View of Sexual Selection.

    Science.gov (United States)

    Radwan, Jacek; Engqvist, Leif; Reinhold, Klaus

    Maintenance of genetic variance in secondary sexual traits, including bizarre ornaments and elaborated courtship displays, is a central problem of sexual selection theory. Despite theoretical arguments predicting that strong sexual selection leads to a depletion of additive genetic variance, traits associated with mating success show relatively high heritability. Here we argue that because of trade-offs associated with the production of costly epigamic traits, sexual selection is likely to lead to an increase, rather than a depletion, of genetic variance in those traits. Such trade-offs can also be expected to contribute to the maintenance of genetic variation in ecologically relevant traits with important implications for evolutionary processes, e.g. adaptation to novel environments or ecological speciation. However, if trade-offs are an important source of genetic variation in sexual traits, the magnitude of genetic variation may have little relevance for the possible genetic benefits of mate choice.

  9. What Explains the Heritability of Completed Fertility? Evidence from Two Large Twin Studies.

    Science.gov (United States)

    Briley, Daniel A; Tropf, Felix C; Mills, Melinda C

    2017-01-01

    In modern societies, individual differences in completed fertility are linked with genotypic differences between individuals. Explaining the heritability of completed fertility has been inconclusive, with alternative explanations centering on family formation timing, pursuit of education, or other psychological traits. We use the twin subsample from the Midlife Development in the United States study and the TwinsUK study to examine these issues. In total, 2606 adult twin pairs reported on their completed fertility, age at first birth and marriage, level of education, Big Five personality traits, and cognitive ability. Quantitative genetic Cholesky models were used to partition the variance in completed fertility into genetic and environmental variance that is shared with other phenotypes and residual variance. Genetic influences on completed fertility are strongly related to family formation timing and less strongly, but significantly, with psychological traits. Multivariate models indicate that family formation, demographic, and psychological phenotypes leave no residual genetic variance in completed fertility in either dataset. Results are largely consistent across U.S. and U.K. sociocultural contexts.

  10. Heritability of naevus patterns in an adult twin cohort from the Brisbane Twin Registry: a cross-sectional study.

    Science.gov (United States)

    Lee, S; Duffy, D L; McClenahan, P; Lee, K J; McEniery, E; Burke, B; Jagirdar, K; Martin, N G; Sturm, R A; Soyer, H P; Schaider, H

    2016-02-01

    Heritability of naevi counts is widely acknowledged as a potential surveillance parameter for prevention purposes. The contribution of heritability to the changes seen in naevus number and morphology over time and their corresponding dermoscopic characteristics is unknown, but is important to understand in order to account for adequate prevention measures. To identify naevus characteristics that are strongly influenced by heritability. This cross-sectional study included 220 individuals [76 monozygotic (MZ), 144 dizygotic (DZ)], recruited from the Brisbane Twin Naevus Study. Participants received full body imaging and dermoscopy of naevi ≥ 5 mm in diameter. Dermoscopic type, total naevus count (TNC), change in TNC with age, and naevus distribution, size, colour and profile were compared between MZ and DZ twins. Heritability of these traits was assessed via Falconer's estimate. Significant differences were found in comparing MZ and DZ twins for TNC, numbers of naevi 5·0-7·9 mm in diameter, counts of light-brown naevi, naevi on the back and sun-protected sites, and naevi with the 'nonspecific' dermoscopic pattern. This study strongly supports a heritable component to TNC, as well as changes in TNC, and the number of medium-sized naevi, light-brown naevi, specific sites and certain dermoscopic features in adults. These characteristics should be taken into account by naevus surveillance programmes and further studied to identify candidate gene associations for clinical and dermoscopic patterns in conjunction with melanoma risk stratification. © 2015 British Association of Dermatologists.

  11. The Multi-allelic Genetic Architecture of a Variance-Heterogeneity Locus for Molybdenum Concentration in Leaves Acts as a Source of Unexplained Additive Genetic Variance.

    Directory of Open Access Journals (Sweden)

    Simon K G Forsberg

    2015-11-01

    Full Text Available Genome-wide association (GWA analyses have generally been used to detect individual loci contributing to the phenotypic diversity in a population by the effects of these loci on the trait mean. More rarely, loci have also been detected based on variance differences between genotypes. Several hypotheses have been proposed to explain the possible genetic mechanisms leading to such variance signals. However, little is known about what causes these signals, or whether this genetic variance-heterogeneity reflects mechanisms of importance in natural populations. Previously, we identified a variance-heterogeneity GWA (vGWA signal for leaf molybdenum concentrations in Arabidopsis thaliana. Here, fine-mapping of this association reveals that the vGWA emerges from the effects of three independent genetic polymorphisms that all are in strong LD with the markers displaying the genetic variance-heterogeneity. By revealing the genetic architecture underlying this vGWA signal, we uncovered the molecular source of a significant amount of hidden additive genetic variation or "missing heritability". Two of the three polymorphisms underlying the genetic variance-heterogeneity are promoter variants for Molybdate transporter 1 (MOT1, and the third a variant located ~25 kb downstream of this gene. A fourth independent association was also detected ~600 kb upstream of MOT1. Use of a T-DNA knockout allele highlights Copper Transporter 6; COPT6 (AT2G26975 as a strong candidate gene for this association. Our results show that an extended LD across a complex locus including multiple functional alleles can lead to a variance-heterogeneity between genotypes in natural populations. Further, they provide novel insights into the genetic regulation of ion homeostasis in A. thaliana, and empirically confirm that variance-heterogeneity based GWA methods are a valuable tool to detect novel associations of biological importance in natural populations.

  12. A Wavelet Perspective on the Allan Variance.

    Science.gov (United States)

    Percival, Donald B

    2016-04-01

    The origins of the Allan variance trace back 50 years ago to two seminal papers, one by Allan (1966) and the other by Barnes (1966). Since then, the Allan variance has played a leading role in the characterization of high-performance time and frequency standards. Wavelets first arose in the early 1980s in the geophysical literature, and the discrete wavelet transform (DWT) became prominent in the late 1980s in the signal processing literature. Flandrin (1992) briefly documented a connection between the Allan variance and a wavelet transform based upon the Haar wavelet. Percival and Guttorp (1994) noted that one popular estimator of the Allan variance-the maximal overlap estimator-can be interpreted in terms of a version of the DWT now widely referred to as the maximal overlap DWT (MODWT). In particular, when the MODWT is based on the Haar wavelet, the variance of the resulting wavelet coefficients-the wavelet variance-is identical to the Allan variance when the latter is multiplied by one-half. The theory behind the wavelet variance can thus deepen our understanding of the Allan variance. In this paper, we review basic wavelet variance theory with an emphasis on the Haar-based wavelet variance and its connection to the Allan variance. We then note that estimation theory for the wavelet variance offers a means of constructing asymptotically correct confidence intervals (CIs) for the Allan variance without reverting to the common practice of specifying a power-law noise type a priori. We also review recent work on specialized estimators of the wavelet variance that are of interest when some observations are missing (gappy data) or in the presence of contamination (rogue observations or outliers). It is a simple matter to adapt these estimators to become estimators of the Allan variance. Finally we note that wavelet variances based upon wavelets other than the Haar offer interesting generalizations of the Allan variance.

  13. Impact of changing drug treatment and malaria endemicity on the heritability of malaria phenotypes in a longitudinal family-based cohort study.

    Directory of Open Access Journals (Sweden)

    Cheikh Loucoubar

    Full Text Available Despite considerable success of genome wide association (GWA studies in identifying causal variants for many human diseases, their success in unraveling the genetic basis to complex diseases has been more mitigated. Pathogen population structure may impact upon the infectious phenotype, especially with the intense short-term selective pressure that drug treatment exerts on pathogens. Rigorous analysis that accounts for repeated measures and disentangles the influence of genetic and environmental factors must be performed. Attempts should be made to consider whether pathogen diversity will impact upon host genetic responses to infection.We analyzed the heritability of two Plasmodium falciparum phenotypes, the number of clinical malaria episodes (PFA and the proportion of these episodes positive for gametocytes (Pfgam, in a family-based cohort followed for 19 years, during which time there were four successive drug treatment regimes, with documented appearance of drug resistance. Repeated measures and variance components analyses were performed with fixed environmental, additive genetic, intra-individual and maternal effects for each drug period. Whilst there was a significant additive genetic effect underlying PFA during the first drug period of study, this was lost in subsequent periods. There was no additive genetic effect for Pfgam. The intra-individual effect increased significantly in the chloroquine period.The loss of an additive genetic effect following novel drug treatment may result in significant loss of power to detect genes in a GWA study. Prior genetic analysis must be a pre-requisite for more detailed GWA studies. The temporal changes in the individual genetic and the intra-individual estimates are consistent with those expected if there were specific host-parasite interactions. The complex basis to the human response to malaria parasite infection likely includes dominance/epistatic genetic effects encompassed within the intra

  14. Heritability and repeatability of milk coagulation properties predicted by mid-infrared spectroscopy during routine data recording, and their relationships with milk yield and quality traits.

    Science.gov (United States)

    Tiezzi, F; Pretto, D; De Marchi, M; Penasa, M; Cassandro, M

    2013-10-01

    The aim of this study was to estimate (co)variance components for milk coagulation properties (MCP) predicted by mid-infrared spectroscopy (MIRS) during routine milk recording, and to assess their relationships with yield and quality traits. A total of 63 470 milk samples from Holstein-Friesian cows were analyzed for MCP, pH and quality characteristics using MIRS. Casein to protein and protein to fat ratios were calculated from information obtained by MIRS. Records were collected across 1 year on 16 089 cows in 345 herds. The model used for genetic analysis included fixed effects of parity and stage of lactation, and random effects of herd-test-day, cow permanent environmental, animal additive genetic and residual. (Co)variance components were assessed in a Bayesian framework using the Gibbs Sampler. Estimates of heritabilities were consistent with those reported in the literature, being moderate for MCP (0.210 and 0.238 for rennet coagulation time (RCT) and curd firmness (a30), respectively), milk contents (0.213 to 0.333) and pH (0.262), and low for somatic cell score (0.093) and yield traits (0.098 to 0.130). Repeatabilities were 0.391 and 0.434 for RCT and a30, respectively, and genetic correlations were generally low, with estimates greater than 0.30 (in absolute value) only for a30 with fat, protein and casein contents. Overall, results suggest that genetic evaluation for MCP predicted by MIRS is feasible at population level, and several repeated measures per cow during a lactation are required to estimate reliable breeding values for coagulation traits.

  15. Genetic variation and heritability of the antibody response to Mycobacterium avium subspecies paratuberculosis in Danish Hostein cows

    DEFF Research Database (Denmark)

    Mortensen, Hanne; Nielsen, Søren Saxmose; Berg, Peer

    2004-01-01

    The purpose of this study was to estimate the genetic variation and the heritability of the ability to establish an immune response by producing antibodies to Mycobacterium avium subsp. paratuberculosis. Antibody levels were determined using an ELISA and measuring optical density (OD) values from...... milk samples of 11,535 cows from 99 herds. The pedigree of the 11,535 cows and information about days in milk, parity, milk yield, and others were obtained from the Danish Cattle database. The statistical analyses were made using a bivariate mixed animal model. The bivariate model with daily milk yield...... and OD as dependent variables showed a significant heritability of the ability to produce Mycobacterium avium subsp. paratuberculosis antibodies of 0.102 (genetic variance = 0.054) and a nonsignificant genetic correlation of −0.037 between daily milk yield and OD. When a sire model was used...

  16. Heritability of plasma neopterin levels in the Old Order Amish.

    Science.gov (United States)

    Raheja, Uttam K; Fuchs, Dietmar; Lowry, Christopher A; Stephens, Sarah H; Pavlovich, Mary A; Mohyuddin, Hira; Yousufi, Hassaan; Ryan, Kathleen A; O'Connell, Jeff; Brenner, Lisa A; Punzalan, Cecile; Hoisington, Andrew J; Nijjar, Gursharon K; Groer, Maureen; Shuldiner, Alan R; Pollin, Toni I; Stiller, John W; Mitchell, Braxton D; Postolache, Teodor T

    2017-06-15

    We examined the heritability of neopterin, a biomarker for cell-mediated immunity and oxidative stress, and potentially for psychiatric disorders, in the Old Order Amish. Plasma neopterin levels were determined in 2015 Old Order Amish adults. Quantitative genetic procedures were used to estimate heritability of neopterin. Heritability of log-neopterin was estimated at 0.07 after adjusting for age, gender, and household (p=0.03). The shared household effect was 0.06 (pAmish. Copyright © 2017. Published by Elsevier B.V.

  17. Efficient and heritable transformation of Phalaenopsis orchids.

    Science.gov (United States)

    Hsing, Hong-Xian; Lin, Yi-Jyun; Tong, Chii-Gong; Li, Min-Jeng; Chen, Yun-Jin; Ko, Swee-Suak

    2016-12-01

    Phalaenopsis orchid (Phal. orchid) is visually attractive and it is important economic floriculture species. Phal. orchids have many unique biological features. However, investigation of these features and validation on their biological functions are limited due to the lack of an efficient transformation method. We developed a heritable and efficient Agrobacterium- mediated transformation using protocorms derived from tetraploid or diploid Phal. orchids. A T-DNA vector construct containing eGFP driven by ubiquitin promoter was subjected to transformation. An approximate 1.2-5.2 % transformation rate was achieved. Genomic PCR confirmed that hygromycin selection marker, HptII gene and target gene eGFP were integrated into the orchid genome. Southern blotting indicated a low T-DNA insertion number in the orchid genome of the transformants. Western blot confirmed the expression of eGFP protein in the transgenic orchids. Furthermore, the GFP signal was detected in the transgenic orchids under microscopy. After backcrossing the pollinia of the transgenic plants to four different Phal. orchid varieties, the BC1 progenies showed hygromycin resistance and all surviving BC1 seedlings were HptII positive in PCR and expressed GFP protein as shown by western blot. This study demonstrated a stable transformation system was generated for Phal. orchids. This useful transformation protocol enables functional genomics studies and molecular breeding.

  18. Genetic potential and heritability estimates of yield traits in F3 segregating populations of bread wheat

    Directory of Open Access Journals (Sweden)

    Soshma Jan

    2015-06-01

    Full Text Available An experiment comprising of 24 wheat genotypes was undertaken during 2011-12, at New Developmental Research Farm, The University of Agriculture Peshawar, to elucidate information on the nature and magnitude of genetic variability, index of transmissibility and assessing the level of genetic improvement of the quantitative characters. The experimental material comprising 19 F3 populations along with their 5 parents of bread wheat were evaluated in randomized complete block design (RCBD with three replications. Analysis of variance exhibited highly significant (P ≤ 0.01 differences among genotypes for all the traits studied. F3 population Ghaznavi-98 x Pirsabak-05 showed maximum mean value for 1000-grain weight (47.3 g and biological yield (11474.9 kg ha-1, whereas, maximum values for grain yield (4027.3 kg ha-1, and harvest index (48.1% were observed for Pirsabak-05 x AUP-4006. Moreover, maximum spike length (11 cm was recorded for cross combination Pirsabak-05 x Pirsabak-04 and Janbaz x Pirsabak-05, respectively. In addition, Pirsabak-04 showed maximum value for number of grains spike-1 (55.0. Genetic variances were of greater magnitude than environmental variances for all the traits except for spike length and 1000-grain weight. Heritability estimates were of higher magnitude ranged from 0.64 to 0.92 for harvest index, biological yield, grain yield, and grains spike-1. Moderate to low heritability (0.40-0.46 was observed for 1000-grain weight, and spike length, respectively. Genetic gain was for spike length (0.48 cm, grains spike-1 (8.57, 1000-grain weight (2.93 g, grain yield (639.87 kg ha-1, biological yield (1790.03 kg ha-1, and harvest index (5.32 %. From high values of heritability and genetic advance, it could be concluded that selection for traits like grains spike-1 suggested good selection criteria and could be effective for future breeding programs. DOI: http://dx.doi.org/10.3126/ije.v4i2.12630 International Journal of Environment

  19. Childhood and adolescent anxiety and depression: beyond heritability

    NARCIS (Netherlands)

    Franic, S.; Middeldorp, C.M.; Dolan, C.V.; Ligthart, L.; Boomsma, D.I.

    2010-01-01

    Objective: To review the methodology of behavior genetics studies addressing research questions that go beyond simple heritability estimation and illustrate these using representative research on childhood and adolescent anxiety and depression. Method: The classic twin design and its extensions may

  20. Childhood and Adolescent Anxiety and Depression: Beyond Heritability

    NARCIS (Netherlands)

    Franic, S.; Middeldorp, C.M.; Dolan, C.V.; Ligthart, R.S.L.; Boomsma, D.I.

    2010-01-01

    Objective: To review the methodology of behavior genetics studies addressing research questions that go beyond simple heritability estimation and illustrate these using representative research on childhood and adolescent anxiety and depression. Method: The classic twin design and its extensions may

  1. Heritability of wing-beat frequency in Anopheles quadrimaculatus.

    Science.gov (United States)

    Robertson, Shawn P; Caprio, Michael A; Faver, Marla K

    2002-12-01

    The repeatability of male wing-beat frequency measurements of Anopheles quadrimaculatus was determined by using mosquitoes allowed free flight in a confined space. Heritability of the wing-beat frequency trait was estimated for a laboratory and a wild-strain population of An. quadrimaculatus by using free-flight measurement with a parent-offspring regression of offspring on dams. Repeatability was 0.75 for free flight. Wing-beat frequency rose for the 1st day after adult emergence and then became steady. Female heritability of wing-beat frequency was 21.6% for colony and 24.0% for wild-strain mosquitoes. Male heritability was 57.2% for colony and 53.7% for wild-strain mosquitoes. Male heritability was significantly different from 0 when probabilities were combined across both populations.

  2. Tic symptom dimensions and their heritabilities in Tourette's syndrome

    NARCIS (Netherlands)

    de Haan, Marcel J; Delucchi, Kevin L; Mathews, Carol M; Cath, Danielle C

    INTRODUCTION: Gilles de la Tourette's syndrome (TS) is both genotypically and phenotypically heterogeneous. Gene-finding strategies have had limited success, possibly because of symptom heterogeneity. OBJECTIVE: This study aimed at specifically investigating heritabilities of tic symptom factors in

  3. Partitioning heritability by functional category using GWAS summary statistics

    DEFF Research Database (Denmark)

    Finucane, Hilary K.; Bulik-Sullivan, Brendan; Gusev, Alexander

    2015-01-01

    in genome-wide association studies (GWAS) of 17 complex diseases and traits with an average sample size of 73,599. To enable this analysis, we introduce a new method, stratified LD score regression, for partitioning heritability from GWAS summary statistics while accounting for linked markers. This new...... type-specific enrichments, including significant enrichment of central nervous system cell types in the heritability of body mass index, age at menarche, educational attainment and smoking behavior....

  4. Heritability of peripheral refraction in Chinese children and adolescents: the Guangzhou Twin Eye study.

    Science.gov (United States)

    Ding, Xiaohu; Lin, Zhi; Huang, Qunxiao; Zheng, Yingfeng; Congdon, Nathan; He, Mingguang

    2012-01-10

    To estimate the heritability of peripheral refraction in Chinese children and adolescents. The authors examined 72 monozygotic (MZ) twins and 48 dizygotic (DZ) twins aged 8 to 20 years from a population-based twin registry. Temporal and nasal peripheral refraction, each 40° from the visual axis, and axial refraction were measured using an autorefractor. Relative peripheral refractive error (RPRE) was defined as the peripheral refraction minus the axial refraction. Heritability was assessed by structural equation modeling after adjustment for age and sex. The mean and SD of temporal refraction (T(40)), nasal refraction (N(40)), RPRE-T(40), RPRE-N(40), and T(40)-N(40) asymmetry were -0.27 ± 2.0 D, 0.36 ± 2.19 D, 1.18 ± 1.39 D, 1.80 ± 1.69 D, and -0.62 ± 1.58 D, respectively. The intraclass correlations for T(40) refraction, N(40) refraction, RPRE-T(40), RPRE-N(40), and T(40)-N(40) asymmetry were 0.87, 0.83, 0.65, 0.74, and 0.58 for MZ pairs and 0.49, 0.42, 0.30, 0.41, and 0.32 for DZ pairs, respectively. A model with additive genetic and unique environmental effects was the most parsimonious, with heritability values estimated as 0.84, 0.76, 0.63, 0.70, and 0.55, respectively, for the peripheral refractive parameters. Additive genetic effects appear to explain most of the variance in peripheral refraction and relative peripheral refraction when adjusting for the effects of axial refraction.

  5. Single nucleotide polymorphisms (SNPs are inherited from parents and they measure heritable events

    Directory of Open Access Journals (Sweden)

    Hemminki Kari

    2005-01-01

    Full Text Available Abstract Single nucleotide polymorphisms (SNPs are extensively used in case-control studies of practically all cancer types. They are used for the identification of inherited cancer susceptibility genes and those that may interact with environmental factors. However, being genetic markers, they are applicable only on heritable conditions, which is often a neglected fact. Based on the data in the nationwide Swedish Family-Cancer Database, we review familial risks for all main cancers and discuss the evidence for a heritable component in cancer. The available evidence is not conclusive but it is consistent in pointing to a minor heritable etiology in cancer, which will hamper the success of SNP-based association studies. Empirical familial risks should be used as guidance for the planning of SNP studies. We provide calculations for the assessment of familial risks for assumed allele frequencies and gene effects (odds ratios for different modes of inheritance. Based on these data, we discuss the gene effects that could account for the unexplained proportion of familial breast and lung cancer. As a conclusion, we are concerned about the indiscriminate use of a genetic tool to cancers, which are mainly environmental in origin. We consider the likelihood of a successful application of SNPs in gene-environment studies small, unless established environmental risk factors are tested on proven candidate genes.

  6. Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for Thirteen Cancer Types

    NARCIS (Netherlands)

    Sampson, Joshua N; Wheeler, William A; Yeager, Meredith; Panagiotou, Orestis; Wang, Zhaoming; Berndt, Sonja I; Lan, Qing; Abnet, Christian C; Amundadottir, Laufey T; Figueroa, Jonine D; Landi, Maria Teresa; Mirabello, Lisa; Savage, Sharon A; Taylor, Philip R; Vivo, Immaculata De; McGlynn, Katherine A; Purdue, Mark P; Rajaraman, Preetha; Adami, Hans-Olov; Ahlbom, Anders; Albanes, Demetrius; Amary, Maria Fernanda; An, She-Juan; Andersson, Ulrika; Andriole, Gerald; Andrulis, Irene L; Angelucci, Emanuele; Ansell, Stephen M; Arici, Cecilia; Armstrong, Bruce K; Arslan, Alan A; Austin, Melissa A; Baris, Dalsu; Barkauskas, Donald A; Bassig, Bryan A; Becker, Nikolaus; Benavente, Yolanda; Benhamou, Simone; Berg, Christine; Van Den Berg, David; Bernstein, Leslie; Bertrand, Kimberly A; Birmann, Brenda M; Black, Amanda; Boeing, Heiner; Boffetta, Paolo; Boutron-Ruault, Marie-Christine; Bracci, Paige M; Brinton, Louise; Brooks-Wilson, Angela R; Bueno-de-Mesquita, H Bas; Burdett, Laurie; Buring, Julie; Butler, Mary Ann; Cai, Qiuyin; Cancel-Tassin, Geraldine; Canzian, Federico; Carrato, Alfredo; Carreon, Tania; Carta, Angela; Chan, John K C; Chang, Ellen T; Chang, Gee-Chen; Chang, I-Shou; Chang, Jiang; Chang-Claude, Jenny; Chen, Chien-Jen; Chen, Chih-Yi; Chen, Chu; Chen, Chung-Hsing; Chen, Constance; Chen, Hongyan; Chen, Kexin; Chen, Kuan-Yu; Chen, Kun-Chieh; Chen, Ying; Chen, Ying-Hsiang; Chen, Yi-Song; Chen, Yuh-Min; Chien, Li-Hsin; Chirlaque, María-Dolores; Choi, Jin Eun; Choi, Yi Young; Chow, Wong-Ho; Chung, Charles C; Clavel, Jacqueline; Clavel-Chapelon, Françoise; Cocco, Pierluigi; Colt, Joanne S; Comperat, Eva; Conde, Lucia; Connors, Joseph M; Conti, David; Cortessis, Victoria K; Cotterchio, Michelle; Cozen, Wendy; Crouch, Simon; Crous-Bou, Marta; Cussenot, Olivier; Davis, Faith G; Ding, Ti; Diver, W Ryan; Dorronsoro, Miren; Dossus, Laure; Duell, Eric J; Ennas, Maria Grazia; Erickson, Ralph L; Feychting, Maria; Flanagan, Adrienne M; Foretova, Lenka; Fraumeni, Joseph F; Freedman, Neal D; Beane Freeman, Laura E; Fuchs, Charles; Gago-Dominguez, Manuela; Gallinger, Steven; Gao, Yu-Tang; Gapstur, Susan M; Garcia-Closas, Montserrat; García-Closas, Reina; Gascoyne, Randy D; Gastier-Foster, Julie; Gaudet, Mia M; Gaziano, J Michael; Giffen, Carol; Giles, Graham G; Giovannucci, Edward; Glimelius, Bengt; Goggins, Michael; Gokgoz, Nalan; Goldstein, Alisa M; Gorlick, Richard; Gross, Myron; Grubb, Robert; Gu, Jian; Guan, Peng; Gunter, Marc; Guo, Huan; Habermann, Thomas M; Haiman, Christopher A; Halai, Dina; Hallmans, Goran; Hassan, Manal; Hattinger, Claudia; He, Qincheng; He, Xingzhou; Helzlsouer, Kathy; Henderson, Brian; Henriksson, Roger; Hjalgrim, Henrik; Hoffman-Bolton, Judith; Hohensee, Chancellor; Holford, Theodore R; Holly, Elizabeth A; Hong, Yun-Chul; Hoover, Robert N; Horn-Ross, Pamela L; Hosain, G M Monawar; Hosgood, H Dean; Hsiao, Chin-Fu; Hu, Nan; Hu, Wei; Hu, Zhibin; Huang, Ming-Shyan; Huerta, Jose-Maria; Hung, Jen-Yu; Hutchinson, Amy; Inskip, Peter D; Jackson, Rebecca D; Jacobs, Eric J; Jenab, Mazda; Jeon, Hyo-Sung; Ji, Bu-Tian; Jin, Guangfu; Jin, Li; Johansen, Christoffer; Johnson, Alison; Jung, Yoo Jin; Kaaks, Rudolph; Kamineni, Aruna; Kane, Eleanor; Kang, Chang Hyun; Karagas, Margaret R; Kelly, Rachel S; Khaw, Kay-Tee; Kim, Christopher; Kim, Hee Nam; Kim, Jin Hee; Kim, Jun Suk; Kim, Yeul Hong; Kim, Young Tae; Kim, Young-Chul; Kitahara, Cari M; Klein, Alison P; Klein, Robert J; Kogevinas, Manolis; Kohno, Takashi; Kolonel, Laurence N; Kooperberg, Charles; Kricker, Anne; Krogh, Vittorio; Kunitoh, Hideo; Kurtz, Robert C; Kweon, Sun-Seog; LaCroix, Andrea; Lawrence, Charles; Lecanda, Fernando; Lee, Victor Ho Fun; Li, Donghui; Li, Haixin; Li, Jihua; Li, Yao-Jen; Li, Yuqing; Liao, Linda M; Liebow, Mark; Lightfoot, Tracy; Lim, Wei-Yen; Lin, Chien-Chung; Lin, Dongxin; Lindstrom, Sara; Linet, Martha S; Link, Brian K; Liu, Chenwei; Liu, Jianjun; Liu, Li; Ljungberg, Börje; Lloreta, Josep; Lollo, Simonetta Di; Lu, Daru; Lund, Eiluv; Malats, Nuria; Mannisto, Satu; Marchand, Loic Le; Marina, Neyssa; Masala, Giovanna; Mastrangelo, Giuseppe; Matsuo, Keitaro; Maynadie, Marc; McKay, James; McKean-Cowdin, Roberta; Melbye, Mads; Melin, Beatrice S; Michaud, Dominique S; Mitsudomi, Tetsuya; Monnereau, Alain; Montalvan, Rebecca; Moore, Lee E; Mortensen, Lotte Maxild; Nieters, Alexandra; North, Kari E; Novak, Anne J; Oberg, Ann L; Offit, Kenneth; Oh, In-Jae; Olson, Sara H; Palli, Domenico; Pao, William; Park, In Kyu; Park, Jae Yong; Park, Kyong Hwa; Patiño-Garcia, Ana; Pavanello, Sofia; Peeters, Petra H M; Perng, Reury-Perng; Peters, Ulrike; Petersen, Gloria M; Picci, Piero; Pike, Malcolm C; Porru, Stefano; Prescott, Jennifer; Prokunina-Olsson, Ludmila; Qian, Biyun; Qiao, You-Lin; Rais, Marco; Riboli, Elio; Riby, Jacques; Risch, Harvey A; Rizzato, Cosmeri; Rodabough, Rebecca; Roman, Eve; Roupret, Morgan; Ruder, Avima M; Sanjose, Silvia de; Scelo, Ghislaine; Schned, Alan; Schumacher, Fredrick; Schwartz, Kendra; Schwenn, Molly; Scotlandi, Katia; Seow, Adeline; Serra, Consol; Serra, Massimo; Sesso, Howard D; Setiawan, Veronica Wendy; Severi, Gianluca; Severson, Richard K; Shanafelt, Tait D; Shen, Hongbing; Shen, Wei; Shin, Min-Ho; Shiraishi, Kouya; Shu, Xiao-Ou; Siddiq, Afshan; Sierrasesúmaga, Luis; Sihoe, Alan Dart Loon; Skibola, Christine F; Smith, Alex; Smith, Martyn T; Southey, Melissa C; Spinelli, John J; Staines, Anthony; Stampfer, Meir; Stern, Marianna C; Stevens, Victoria L; Stolzenberg-Solomon, Rachael S; Su, Jian; Su, Wu-Chou; Sund, Malin; Sung, Jae Sook; Sung, Sook Whan; Tan, Wen; Tang, Wei; Tardón, Adonina; Thomas, David; Thompson, Carrie A; Tinker, Lesley F; Tirabosco, Roberto; Tjønneland, Anne; Travis, Ruth C; Trichopoulos, Dimitrios; Tsai, Fang-Yu; Tsai, Ying-Huang; Tucker, Margaret; Turner, Jenny; Vajdic, Claire M; Vermeulen, Roel C H|info:eu-repo/dai/nl/216532620; Villano, Danylo J; Vineis, Paolo; Virtamo, Jarmo; Visvanathan, Kala; Wactawski-Wende, Jean; Wang, Chaoyu; Wang, Chih-Liang; Wang, Jiu-Cun; Wang, Junwen; Wei, Fusheng; Weiderpass, Elisabete; Weiner, George J; Weinstein, Stephanie; Wentzensen, Nicolas; White, Emily; Witzig, Thomas E; Wolpin, Brian M; Wong, Maria Pik; Wu, Chen; Wu, Guoping; Wu, Junjie; Wu, Tangchun; Wu, Wei; Wu, Xifeng; Wu, Yi-Long; Wunder, Jay S; Xiang, Yong-Bing; Xu, Jun; Xu, Ping; Yang, Pan-Chyr; Yang, Tsung-Ying; Ye, Yuanqing; Yin, Zhihua; Yokota, Jun; Yoon, Ho-Il; Yu, Chong-Jen; Yu, Herbert; Yu, Kai; Yuan, Jian-Min; Zelenetz, Andrew; Zeleniuch-Jacquotte, Anne; Zhang, Xu-Chao; Zhang, Yawei; Zhao, Xueying; Zhao, Zhenhong; Zheng, Hong; Zheng, Tongzhang; Zheng, Wei; Zhou, Baosen; Zhu, Meng; Zucca, Mariagrazia; Boca, Simina M; Cerhan, James R; Ferri, Giovanni M; Hartge, Patricia; Hsiung, Chao Agnes; Magnani, Corrado; Miligi, Lucia; Morton, Lindsay M; Smedby, Karin E; Teras, Lauren R; Vijai, Joseph; Wang, Sophia S; Brennan, Paul; Caporaso, Neil E; Hunter, David J; Kraft, Peter; Rothman, Nathaniel; Silverman, Debra T; Slager, Susan L; Chanock, Stephen J; Chatterjee, Nilanjan

    2015-01-01

    BACKGROUND: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites.

  7. Generalized analysis of molecular variance.

    Directory of Open Access Journals (Sweden)

    Caroline M Nievergelt

    2007-04-01

    Full Text Available Many studies in the fields of genetic epidemiology and applied population genetics are predicated on, or require, an assessment of the genetic background diversity of the individuals chosen for study. A number of strategies have been developed for assessing genetic background diversity. These strategies typically focus on genotype data collected on the individuals in the study, based on a panel of DNA markers. However, many of these strategies are either rooted in cluster analysis techniques, and hence suffer from problems inherent to the assignment of the biological and statistical meaning to resulting clusters, or have formulations that do not permit easy and intuitive extensions. We describe a very general approach to the problem of assessing genetic background diversity that extends the analysis of molecular variance (AMOVA strategy introduced by Excoffier and colleagues some time ago. As in the original AMOVA strategy, the proposed approach, termed generalized AMOVA (GAMOVA, requires a genetic similarity matrix constructed from the allelic profiles of individuals under study and/or allele frequency summaries of the populations from which the individuals have been sampled. The proposed strategy can be used to either estimate the fraction of genetic variation explained by grouping factors such as country of origin, race, or ethnicity, or to quantify the strength of the relationship of the observed genetic background variation to quantitative measures collected on the subjects, such as blood pressure levels or anthropometric measures. Since the formulation of our test statistic is rooted in multivariate linear models, sets of variables can be related to genetic background in multiple regression-like contexts. GAMOVA can also be used to complement graphical representations of genetic diversity such as tree diagrams (dendrograms or heatmaps. We examine features, advantages, and power of the proposed procedure and showcase its flexibility by

  8. A twin study of problematic internet use: its heritability and genetic association with effortful control.

    Science.gov (United States)

    Li, Mengjiao; Chen, Jie; Li, Naishi; Li, Xinying

    2014-08-01

    Our goal was to estimate genetic and environmental sources of influence on adolescent problematic internet use, and whether these individual differences can be explained by effortful control, an important aspect of self-regulation. A sample of 825 pairs of Chinese adolescent twins and their parents provided reports of problematic internet use and effortful control. Univariate analysis revealed that genetic factors explained 58-66% of variance in problematic internet use, with the rest explained by non-shared environmental factors. Sex difference was found, suggesting boys' problematic internet use was more influenced by genetic influences than girls' problematic internet use. Bivariate analysis indicated that effortful control accounted for a modest portion of the genetic and non-shared environmental variance in problematic internet use among girls. In contrast, among boys, effortful control explained between 6% (parent report) and 20% (self-report) of variance in problematic internet use through overlapping genetic pathways. Adolescent problematic internet use is heritable, and poor effortful control can partly explain adolescent problematic internet use, with effects stronger for boys. Implications for future research are discussed.

  9. DNA Repair Decline During Mouse Spermiogenesis Results in the Accumulation of Heritable DNA Damage

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Marchetti, Francesco; Wyrobek, Andrew J.

    2007-12-01

    The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7-1 dbf). Analysis of chromosomal aberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a linear response for both single and repeated exposures. These findings show that the differential DNA repair capacity of post-meioitic male germ cells has a major impact on the risk of paternally transmitted heritable damage and suggest that chronic exposures that may occur in the weeks prior to fertilization because of occupational or lifestyle factors (i.e, smoking) can lead to an accumulation of genetic damage in sperm and result in heritable chromosomal aberrations of paternal origin.

  10. DNA repair decline during mouse spermiogenesis results in the accumulation of heritable DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Marchetti, Francesco; Wryobek, Andrew J

    2008-02-21

    The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7- 1 dbf). Analysis of chromosomalaberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a linear response for both single and repeated exposures. These findings show that the differential DNA repair capacity of post-meioitic male germ cells has a major impact on the risk of paternally transmitted heritable damage and suggest that chronic exposures that may occur in the weeks prior to fertilization because of occupational or lifestyle factors (i.e, smoking) can lead to an accumulation of genetic damage in sperm and result in heritable chromosomal aberrations of paternal origin.

  11. HERDABILIDADES E CORRELAÇÕES DA PRODUÇÃO DO FEIJÃO E DOS SEUS COMPONENTES PRIMÁRIOS, NAS ÉPOCAS DE CULTIVO DA PRIMAVERA-VERÃO E DO VERÃO-OUTONO HERITABILITIES AND CORRELATIONS OF COMMON BEAN YIELD AND ITS PRIMARY COMPONENTS, IN THE SPRING-SUMMER AND SUMMER-FALL CULTIVATION SEASONS

    Directory of Open Access Journals (Sweden)

    Antônio Daniel Fernandes Coelho

    2002-04-01

    Full Text Available Este trabalho teve como objetivo estimar parâmetros genéticos em populações F2 do feijoeiro (Phaseolus vulgaris L., cultivadas em duas épocas tradicionais no Estado de Minas Gerais. Foi realizado o cruzamento entre os cultivares 'Ouro 1919' e 'Milionário 1732', e as populações genitoras, F1 e F2 foram cultivadas na primavera-verão e no verão-outono. Nas duas épocas, as estimativas de herdabilidades foram baixas para todos os caracteres e o número de vagens por planta apresentou as maiores correlações fenotípicas e de ambiente com a produção de grãos.This work aimed to estimate genetic parameters in F2 populations of the common bean (Phaseolus vulgaris L., cultivated in two traditional seasons in Minas Gerais State (Brazil. The cultivars 'Ouro 1919' and 'Milinário 1732' were crossed, and the parental, F1 and F2 populations were cultivated in the spring-summer and summer-fall. In the two cultivation seasons, the heritabilities were low for all characters, while the number of pods per plant showed the greatest phenotypic and environmental correlations with grain yield.

  12. Melhoramento do trigo: XX. Herdabilidades e correlações entre os componentes de produção em populações híbridas envolvendo fontes de nanismo Wheat breeding: XX. Heritabilities and correlations among yield components in hybrid populations involving different sources of dwarfism

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Oliveira Camargo

    1989-01-01

    semi-anão, com elevado potencial produtivo, alto número de grãos por espiga e de espigas por planta e elevado peso de cem grãos, desde que grandes populações segregantes sejam conduzidas para favorecer a identificação dos genótipos desejáveis originários das eventuais recombinações genéticas. Tal procedimento vem sendo adotado na seleção de cultivares de porte semi-anão para o Estado de São Paulo.Diallelic crosses were made involving the standard height cultivars BH-1146 and Atlas-66, the semidwarf cultivar Siete Cerros and the dwarf source Tordo. Parents, F1's, F2's and reciprocal backcrosses were tested for grain yield, plant height, number of heads per plant, number of kernels per head, and for weight of 100 kernels, in an experiment carried out at Hyslop Farm, Oregon, U.S.A., in 1978. Narrow sense heritability estimates for plant height were moderately high for the crosses BH-1146 x Atlas-66 (0.55, BH-1146 x Siete Cerros (0.60 and Atlas-66 x Siete Cerros (0.74, moderate for the crosses Atlas-66 x Tordo (0.43 and Tordo x Siete Cerros (0.41 and low for the cross BH-1146 x Tordo (0.24. Moderate values (0.43 to 0.58 were estimated for number of heads per plant for all crosses with exception of the crosses BH-1146 x Atlas-66 and Atlas-66 x Tordo which presented low values for the narrow sense heritability. The heritability values for weight of 100 grains were low for all crosses with exception of the crosses BH-1146 x Atlas-66 and BH-1146 x Siete Cerros which presented moderate levels (0.40 and 0.45, respectively. In relation to grain yield the narrow sense heritability estimates were low with exception of those for the crosses BH-1146 x Tordo (0.73 and BH-1146 x Siete Cerros (0.62. The phenotypic correlations between grain yield and number of heads per plant, plant height, number of grains per head and weight of 100 grains were positive and mostly highly significant, except for the correlation between grain yield and weight of 100 grains for the

  13. Heritability of dimensions of Eysenck's pen model and the alternative five-factor model of personality

    Directory of Open Access Journals (Sweden)

    Smederevac Snežana

    2006-01-01

    Full Text Available The main aim of this study is to estimate the heritability of AFFM and PEN dimensions, including 67 pairs of twins (34 monozygotic and 33 dizygotic of both genders, aged 18 - 44. The heritability has been estimated by the biometric method, two full (ACE and ADE and three reduced (AE, DE and CE models tested for each personality trait. Taking into consideration the AFFM dimensions, additive genetic factors and a non-shared environment contribute the most significantly to the phenotypic variation of activity, sociability and the impulsive sensation seeking; anxiety and aggressiveness are best accounted for by the dominant genetic effects. In the PEN domain, fit indicators suggest that ACE and the reduced AE models provide the best explanation for the phenotypic manifestations of neuroticism, while ACE and CE models account for the variation of L scale. Although the fit indicators calculated for extraversion and psychotic behavior are somewhat problematic, the parameter estimates show that extraversion is best accounted for by the additive genetic variance, shared environmental effects, and the non-shared environment, whereas psychotic behavior is the most adequately explained by both shared and non-shared environmental effects.

  14. Assessment of heritability and genetic advance for agronomic traits in durum wheat (Triticum durum Desf.

    Directory of Open Access Journals (Sweden)

    HASSAN NIKKHAHKOUCHAKSARAEI

    2017-09-01

    Full Text Available In order to evaluate the amount of heritability for desirable agronomic characteristics and the genetic progress associated with grain yield of durum wheat (Triticum durum Desf., a split plot experiment was carried out with four replications during three cropping seasons (2009-2012. Three sowing dates (as environmental factor and six durum wheat varieties (as genotypic factor were considered as main and sub factors respectively. Analysis of variance showed interaction effects between genotypes and environments in days to ripening, plant height, spike length, number of grains per spike, number of spikes per unit area, grain mass and grain yield. The grain yield showed the highest positive correlation with number of grains per spike also grain mass (91 % and 85 %, respectively. A relatively high heritability of these traits (82.1 % and 82.2 %, respectively suggests that their genetic improvement is possible. The maximum genetic gain (19.6 % was observed for grain mass, indicating this trait should be a very important indicator for durum wheat breeders, although the climatic effects should not be ignored.

  15. Genome-wide association studies establish that human intelligence is highly heritable and polygenic.

    Science.gov (United States)

    Davies, G; Tenesa, A; Payton, A; Yang, J; Harris, S E; Liewald, D; Ke, X; Le Hellard, S; Christoforou, A; Luciano, M; McGhee, K; Lopez, L; Gow, A J; Corley, J; Redmond, P; Fox, H C; Haggarty, P; Whalley, L J; McNeill, G; Goddard, M E; Espeseth, T; Lundervold, A J; Reinvang, I; Pickles, A; Steen, V M; Ollier, W; Porteous, D J; Horan, M; Starr, J M; Pendleton, N; Visscher, P M; Deary, I J

    2011-10-01

    General intelligence is an important human quantitative trait that accounts for much of the variation in diverse cognitive abilities. Individual differences in intelligence are strongly associated with many important life outcomes, including educational and occupational attainments, income, health and lifespan. Data from twin and family studies are consistent with a high heritability of intelligence, but this inference has been controversial. We conducted a genome-wide analysis of 3511 unrelated adults with data on 549,692 single nucleotide polymorphisms (SNPs) and detailed phenotypes on cognitive traits. We estimate that 40% of the variation in crystallized-type intelligence and 51% of the variation in fluid-type intelligence between individuals is accounted for by linkage disequilibrium between genotyped common SNP markers and unknown causal variants. These estimates provide lower bounds for the narrow-sense heritability of the traits. We partitioned genetic variation on individual chromosomes and found that, on average, longer chromosomes explain more variation. Finally, using just SNP data we predicted ∼1% of the variance of crystallized and fluid cognitive phenotypes in an independent sample (P=0.009 and 0.028, respectively). Our results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation, and are consistent with many genes of small effects underlying the additive genetic influences on intelligence.

  16. Personality traits below facets: The consensual validity, longitudinal stability, heritability, and utility of personality nuances.

    Science.gov (United States)

    Mõttus, René; Kandler, Christian; Bleidorn, Wiebke; Riemann, Rainer; McCrae, Robert R

    2017-03-01

    It has been argued that facets do not represent the bottom of the personality hierarchy-even more specific personality characteristics, nuances, could be useful for describing and understanding individuals and their differences. Combining 2 samples of German twins, we assessed the consensual validity (correlations across different observers), rank-order stability, and heritability of nuances. Personality nuances were operationalized as the 240 items of the Revised NEO Personality Inventory (NEO-PI-R). Their attributes were examined by analyzing item residuals, controlling for the variance of the facet the item had been assigned to and all other facets. Most nuances demonstrated significant (p personality traits, with median estimates of rank-order stability and heritability being .77 and .52, respectively. Few nuances demonstrated robust associations with age and gender, but many showed incremental, conceptually meaningful, and replicable (across methods and/or samples) predictive validity for a range of interest domains and body mass index. We argue that these narrow personality characteristics constitute a valid level of the personality hierarchy. They may be especially useful for providing a deep and contextualized description of the individual, but also for the prediction of specific outcomes. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  17. Heritability and Temporal Stability of Ambulatory Autonomic Stress Reactivity in Unstructured 24-Hour Recordings.

    Science.gov (United States)

    Neijts, Melanie; van Lien, Rene; Kupper, Nina; Boomsma, Dorret; Willemsen, Gonneke; de Geus, Eco J C

    2015-10-01

    Measurements of ambulatory autonomic reactivity can help with our understanding of the long-term health consequences of exposure to psychosocial stress in real-life settings. In this study, unstructured 24-hour ambulatory recordings of cardiac parasympathetic and sympathetic control were obtained in 1288 twins and siblings, spanning both work time and leisure time. These data were used to define two ambulatory baseline (sleep, leisure) and four stress conditions (wake, work, work_sitting, work_peak) from which six ambulatory stress reactivity measures were derived. The use of twin families allowed for estimation of heritability and testing for the amplification of existing or emergence of new genetic variance during stress compared with baseline conditions. Temporal stability of ambulatory reactivity was assessed in 62 participants and was moderate to high over a 3-year period (0.36 unstructured real-life setting shows reliable, stable, and heritable individual differences. Real-life situations uncover a new and different genetic variation compared with that seen in resting baseline conditions, including sleep.

  18. Genetic co-variance functions for live weight, feed intake, and efficiency measures in growing pigs.

    Science.gov (United States)

    Coyne, J M; Berry, D P; Matilainen, K; Sevon-Aimonen, M-L; Mantysaari, E A; Juga, J; Serenius, T; McHugh, N

    2017-09-01

    The objective of the present study was to estimate genetic co-variance parameters pertaining to live weight, feed intake, and 2 efficiency traits (i.e., residual feed intake and residual daily gain) in a population of pigs over a defined growing phase using Legendre polynomial equations. The data set used consisted of 51,893 live weight records and 903,436 feed intake, residual feed intake (defined as the difference between an animal's actual feed intake and its expected feed intake), and residual daily gain (defined as the difference between an animal's actual growth rate and its expected growth rate) records from 10,201 growing pigs. Genetic co-variance parameters for all traits were estimated using random regression Legendre polynomials. Daily heritability estimates for live weight ranged from 0.25 ± 0.04 (d 73) to 0.50 ± 0.03 (d 122). Low to moderate heritability estimates were evident for feed intake, ranging from 0.07 ± 0.03 (d 66) to 0.25 ± 0.02 (d 170). The estimated heritability for residual feed intake was generally lower than those of both live weight and feed intake and ranged from 0.04 ± 0.01 (d 96) to 0.17 ± 0.02 (d 159). The heritability for feed intake and residual feed intake increased in the early stages of the test period and subsequently sharply declined, coinciding with older ages. Heritability estimates for residual daily gain ranged from 0.26 ± 0.03 (d 188) to 0.42 ± 0.03 (d 101). Genetic correlations within trait were strongest between adjacent ages but weakened as the interval between ages increased; however, the genetic correlations within all traits tended to strengthen between the extremes of the trajectory. Moderate to strong genetic correlations were evident among live weight, feed intake, and the efficiency traits, particularly in the early stage of the trial period (d 66 to 86), but weakened with age. Results from this study could be implemented into the national genetic evaluation for pigs, providing comprehensive

  19. Componentes de (covariância e parâmetros genéticos de caracteres pós-desmama em bovinos da raça Angus (Co variance components and genetic parameters of post-weaning traits in Angus cattle

    Directory of Open Access Journals (Sweden)

    Fernando Flores Cardoso

    2004-04-01

    Full Text Available Foram determinados os componentes de (covariância para caracteres do período pós-desmama na raça Angus e de covariância com peso ao nascer (PN e caracteres do período pré-desmama por intermédio de um modelo animal. Utilizaram-se dados de 18.921 animais com registros de peso à desmama e ao sobreano, dos quais 4.452 tinham avaliações completas para escores visuais à desmama e ao sobreano. Registros de PN estavam disponíveis para 11.788 animais. As herdabilidades do ganho de peso pós-desmama (GP205 e dos escores de conformação (CS, precocidade (GS, musculatura (MS e tamanho (TS ao sobreano foram de 0,20, 0,19, 0,25, 0,26 e 0,24 respectivamente. As correlações genéticas entre os caracteres estudados foram todas positivas: entre GP205 e escores visuais variaram de 0,50 a 0,71; para os escores ao sobreano entre si, de 0,22 a 0,94; entre GP205 e PN foram de 0,14; entre GP205 e ganho pré-desmama, de 0,23; e para o mesmo escore visual observado à desmama e ao sobreano, de 0,90 a 0,99. Esses resultados indicam que é possível selecionar para GP205, sem aumento importante do PN, e que a seleção para GP205 deverá promover uma mudança genética correlacionada em escores visuais ao sobreano.(Covariance components were determined for post-weaning traits, and covariances with birth weight (BW and pre-weaning traits, in Angus cattle using an animal model. Records of weaning and yearling weights of 18,921 animals were used and from these 4,452 had complete evaluations of visual scores at weaning and post-weaning phases. Records of BW were available for 11,788 animals. Heritabilities of post-weaning gain (GP205 and visual scores for conformation (YC, precocity (YP, muscling (YM and size (YS were 0.20, 0.19, 0.25, 0.26 and 0.24, respectively. Genetic correlations among all traits considered were positive: between GP205 and visual scores the range was from 0.50 to 0.71; for yearling scores among themselves from 0.22 to 0.94; between GP205

  20. Heritability of QT interval : How much is explained by genes for resting heart rate? Heritability of QT interval: How much is explained by genes for resting heart rate?

    NARCIS (Netherlands)

    Dalageorgou, Chrysoula; Ge, Dongliang; Jamshidi, Yalda; Nolte, Ilja M.; Riese, Harriette; Savelieva, Irina; Carter, Nicholas D.; Spector, Tim D.; Snieder, Harold

    Heritability of QT Interval. Introduction: Objective of this study was to determine the optimal (most heritable) phenotype for gene finding studies of QT interval in the general population. We also studied the extent to which heritability of QT interval can be explained by genes that also influence

  1. Noise variance estimation for Kalman filter

    Science.gov (United States)

    Beniak, Ryszard; Gudzenko, Oleksandr; Pyka, Tomasz

    2017-10-01

    In this paper, we propose an algorithm that evaluates noise variance with a numerical integration method. For noise variance estimation, we use Krogh method with a variable integration step. In line with common practice, we limit our study to fourth-order method. First, we perform simulation tests for randomly generated signals, related to the transition state and steady state. Next, we formulate three methodologies (research hypotheses) of noise variance estimation, and then compare their efficiency.

  2. Influence of Family Structure on Variance Decomposition

    DEFF Research Database (Denmark)

    Edwards, Stefan McKinnon; Sarup, Pernille Merete; Sørensen, Peter

    Partitioning genetic variance by sets of randomly sampled genes for complex traits in D. melanogaster and B. taurus, has revealed that population structure can affect variance decomposition. In fruit flies, we found that a high likelihood ratio is correlated with a high proportion of explained ge...... capturing pure noise. Therefore it is necessary to use both criteria, high likelihood ratio in favor of a more complex genetic model and proportion of genetic variance explained, to identify biologically important gene groups...

  3. Spondylosis deformans in the boxer: estimates of heritability.

    Science.gov (United States)

    Langeland, M; Lingaas, F

    1995-04-01

    This study presents the estimates of heritability for spondylosis deformans in the boxer based on 353 offspring from 24 randomly selected sires, each with at least three radiographically investigated offspring. The estimated heritability (h2) for maximum degree of osteophyte development was high, both when estimated by paternal half-sib correlation (0.42) and by the regression of offspring based on the parents (0.62). The heritability for the number of affected discs estimated by paternal half-sib correlation was also high (0.47). The estimate of heritability for the number of affected discs based on regression of offspring on the parents was lower at 0.13. All heritabilities had large standard errors. A positive phenotypic correlation between spondylosis deformans and hip dysplasia was observed. Assuming a significant portion of the correlation is genetic, this fact may permit selection against spondylosis deformans without negatively influencing the incidence of hip dysplasia. Since the incidence of spondylosis deformans is high even in young dogs, it should be possible to detect a large proportion of genetically predisposed animals by radiographic examination of the spine at one year of age; at the same time that dogs are presented for a routine test for hip dysplasia.

  4. Accounting for female space sharing in St. Kilda Soay sheep (Ovis aries) results in little change in heritability estimates.

    Science.gov (United States)

    Regan, C E; Pilkington, J G; Bérénos, C; Pemberton, J M; Smiseth, P T; Wilson, A J

    2017-01-01

    When estimating heritability in free-living populations, it is common practice to account for common environment effects, because of their potential to generate phenotypic covariance among relatives thereby biasing heritability estimates. In quantitative genetic studies of natural populations, however, philopatry, which results in relatives being clustered in space, is rarely accounted for. The two studies that have been carried out so far suggest absolute declines in heritability estimates of up to 43% when accounting for space sharing by relatives. However, due to methodological limitations these estimates may not be representative. We used data from the St. Kilda Soay sheep population to estimate heritabilities with and without accounting for space sharing for five traits for which there is evidence for additive genetic variance (birthweight, birth date, lamb August weight, and female post-mortem jaw and metacarpal length). We accounted for space sharing by related females by separately incorporating spatial autocorrelation, and a home range similarity matrix. Although these terms accounted for up to 18% of the variance in these traits, heritability estimates were only reduced by up to 7%. Our results suggest that the bias caused by not accounting for space sharing may be lower than previously thought. This suggests that philopatry does not inevitably lead to a large bias if space sharing by relatives is not accounted for. We hope our work stimulates researchers to model shared space when relatives in their study population share space, as doing so will enable us to better understand when bias may be of particular concern. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  5. Heritability of racing performance in the Australian Thoroughbred racing population.

    Science.gov (United States)

    Velie, B D; Hamilton, N A; Wade, C M

    2015-02-01

    Performance data for 164,046 Thoroughbreds entered in a race or official barrier trial in Australia were provided by Racing Information Services Australia. Analyses estimating the heritability for a range of racing performance traits using a single-trait animal model were performed using ASREML-R. Log of cumulative earnings (LCE; 0.19 ± 0.01), log of earnings per race start (0.23 ± 0.02) and best race distance (0.61 ± 0.03) were all significantly heritable. Fixed effects for sex were significant (P racing industry, contemporary heritability estimates from the current population of Thoroughbreds will play a vital role in identifying which traits are better suited to selection and in the development of more accurate genomic evaluations for racing performance. © 2014 Stichting International Foundation for Animal Genetics.

  6. 40 CFR 142.41 - Variance request.

    Science.gov (United States)

    2010-07-01

    ... Section 1415(a) of the Act § 142.41 Variance request. A supplier of water may request the granting of a... enforcement responsibility by submitting a request for a variance in writing to the Administrator. Suppliers... and evidence of the best available treatment technology and techniques. (2) Economic and legal factors...

  7. Nonlinear Epigenetic Variance: Review and Simulations

    Science.gov (United States)

    Kan, Kees-Jan; Ploeger, Annemie; Raijmakers, Maartje E. J.; Dolan, Conor V.; van Der Maas, Han L. J.

    2010-01-01

    We present a review of empirical evidence that suggests that a substantial portion of phenotypic variance is due to nonlinear (epigenetic) processes during ontogenesis. The role of such processes as a source of phenotypic variance in human behaviour genetic studies is not fully appreciated. In addition to our review, we present simulation studies…

  8. Influence of Family Structure on Variance Decomposition

    DEFF Research Database (Denmark)

    Edwards, Stefan McKinnon; Sarup, Pernille Merete; Sørensen, Peter

    Partitioning genetic variance by sets of randomly sampled genes for complex traits in D. melanogaster and B. taurus, has revealed that population structure can affect variance decomposition. In fruit flies, we found that a high likelihood ratio is correlated with a high proportion of explained...

  9. Sexual dimorphism in melanin pigmentation, feather coloration and its heritability in the barn swallow (Hirundo rustica).

    Science.gov (United States)

    Saino, Nicola; Romano, Maria; Rubolini, Diego; Teplitsky, Celine; Ambrosini, Roberto; Caprioli, Manuela; Canova, Luca; Wakamatsu, Kazumasa

    2013-01-01

    Melanin is the main pigment in animal coloration and considerable variation in the concentrations of the two melanin forms (pheo- and eumlanin) in pigmented tissues exists among populations and individuals. Melanin-based coloration is receiving increasing attention particularly in socio-sexual communication contexts because the melanocortin system has been hypothesized to provide a mechanistic basis for covariation between coloration and fitness traits. However, with few notable exceptions, little detailed information is available on inter-individual and inter-population variation in melanin pigmentation and on its environmental, genetic and ontogenetic components. Here, we investigate melanin-based coloration in an Italian population of a passerine bird, the barn swallow (Hirundo rustica rustica), its sex- and age-related variation, and heritability. The concentrations of eu- and pheomelanin in the throat (brown) and belly (white-to-brownish) feathers differed between sexes but not according to age. The relative concentration of either melanin (Pheo:Eu) differed between sexes in throat but not in belly feathers, and the concentrations in males compared to females were larger in belly than in throat feathers. There were weak correlations between the concentrations of melanins within as well as among plumage regions. Coloration of belly feathers was predicted by the concentration of both melanins whereas coloration of throat feathers was only predicted by pheomelanin in females. In addition, Pheo:Eu predicted coloration of throat feathers in females and that of belly feathers in males. Finally, we found high heritability of color of throat feathers. Melanization was found to differ from that recorded in Hirundo rustica rustica from Scotland or from H. r. erythrogaster from North America. Hence, present results show that pigmentation strategies vary in a complex manner according to sex and plumage region, and also among geographical populations, potentially

  10. Sexual dimorphism in melanin pigmentation, feather coloration and its heritability in the barn swallow (Hirundo rustica.

    Directory of Open Access Journals (Sweden)

    Nicola Saino

    Full Text Available Melanin is the main pigment in animal coloration and considerable variation in the concentrations of the two melanin forms (pheo- and eumlanin in pigmented tissues exists among populations and individuals. Melanin-based coloration is receiving increasing attention particularly in socio-sexual communication contexts because the melanocortin system has been hypothesized to provide a mechanistic basis for covariation between coloration and fitness traits. However, with few notable exceptions, little detailed information is available on inter-individual and inter-population variation in melanin pigmentation and on its environmental, genetic and ontogenetic components. Here, we investigate melanin-based coloration in an Italian population of a passerine bird, the barn swallow (Hirundo rustica rustica, its sex- and age-related variation, and heritability. The concentrations of eu- and pheomelanin in the throat (brown and belly (white-to-brownish feathers differed between sexes but not according to age. The relative concentration of either melanin (Pheo:Eu differed between sexes in throat but not in belly feathers, and the concentrations in males compared to females were larger in belly than in throat feathers. There were weak correlations between the concentrations of melanins within as well as among plumage regions. Coloration of belly feathers was predicted by the concentration of both melanins whereas coloration of throat feathers was only predicted by pheomelanin in females. In addition, Pheo:Eu predicted coloration of throat feathers in females and that of belly feathers in males. Finally, we found high heritability of color of throat feathers. Melanization was found to differ from that recorded in Hirundo rustica rustica from Scotland or from H. r. erythrogaster from North America. Hence, present results show that pigmentation strategies vary in a complex manner according to sex and plumage region, and also among geographical populations

  11. Variance Risk Premia on Stocks and Bonds

    DEFF Research Database (Denmark)

    Mueller, Philippe; Sabtchevsky, Petar; Vedolin, Andrea

    : First, exposure to bond market volatility is strongly priced with a Sharpe ratio of -1.8, 20% higher than what is observed in the equity market. Second, while there is strong co-movement between equity and bond market variance risk, there are distinct periods when the bond variance risk premium...... is different from the equity variance risk premium. Third, the conditional correlation between stock and bond market variance risk premium switches sign often and ranges between -60% and +90%. We then show that these stylized facts pose a challenge to standard consumption-based asset pricing models.......Investors in fixed income markets are willing to pay a very large premium to be hedged against shocks in expected volatility and the size of this premium can be studied through variance swaps. Using thirty years of option and high-frequency data, we document the following novel stylized facts...

  12. Heritability of fear: Ukrainian experience | Filiptsova | Egyptian ...

    African Journals Online (AJOL)

    Conclusions: The conducted research demonstrated genetic component presence for nine types of fear – psychic disorder development, complications in personal life, making responsible decisions, senility, closed spaces, sexual dysfunction, suicide commission, speaking in public, and aggressive behavior possibility to ...

  13. Dominance genetic variance for traits under directional selection in Drosophila serrata.

    Science.gov (United States)

    Sztepanacz, Jacqueline L; Blows, Mark W

    2015-05-01

    In contrast to our growing understanding of patterns of additive genetic variance in single- and multi-trait combinations, the relative contribution of nonadditive genetic variance, particularly dominance variance, to multivariate phenotypes is largely unknown. While mechanisms for the evolution of dominance genetic variance have been, and to some degree remain, subject to debate, the pervasiveness of dominance is widely recognized and may play a key role in several evolutionary processes. Theoretical and empirical evidence suggests that the contribution of dominance variance to phenotypic variance may increase with the correlation between a trait and fitness; however, direct tests of this hypothesis are few. Using a multigenerational breeding design in an unmanipulated population of Drosophila serrata, we estimated additive and dominance genetic covariance matrices for multivariate wing-shape phenotypes, together with a comprehensive measure of fitness, to determine whether there is an association between directional selection and dominance variance. Fitness, a trait unequivocally under directional selection, had no detectable additive genetic variance, but significant dominance genetic variance contributing 32% of the phenotypic variance. For single and multivariate morphological traits, however, no relationship was observed between trait-fitness correlations and dominance variance. A similar proportion of additive and dominance variance was found to contribute to phenotypic variance for single traits, and double the amount of additive compared to dominance variance was found for the multivariate trait combination under directional selection. These data suggest that for many fitness components a positive association between directional selection and dominance genetic variance may not be expected. Copyright © 2015 by the Genetics Society of America.

  14. Portfolio optimization using median-variance approach

    Science.gov (United States)

    Wan Mohd, Wan Rosanisah; Mohamad, Daud; Mohamed, Zulkifli

    2013-04-01

    Optimization models have been applied in many decision-making problems particularly in portfolio selection. Since the introduction of Markowitz's theory of portfolio selection, various approaches based on mathematical programming have been introduced such as mean-variance, mean-absolute deviation, mean-variance-skewness and conditional value-at-risk (CVaR) mainly to maximize return and minimize risk. However most of the approaches assume that the distribution of data is normal and this is not generally true. As an alternative, in this paper, we employ the median-variance approach to improve the portfolio optimization. This approach has successfully catered both types of normal and non-normal distribution of data. With this actual representation, we analyze and compare the rate of return and risk between the mean-variance and the median-variance based portfolio which consist of 30 stocks from Bursa Malaysia. The results in this study show that the median-variance approach is capable to produce a lower risk for each return earning as compared to the mean-variance approach.

  15. Heritability of resting heart rate and association with mortality in middle-aged and elderly twins

    DEFF Research Database (Denmark)

    Jensen, Magnus T; Wod, Mette; Galatius, Søren

    2017-01-01

    OBJECTIVE: Resting heart rate (RHR) possibly has a hereditary component and is associated with longevity. We used the classical biometric twin study design to investigate the heritability of RHR in a population of middle-aged and elderly twins and, furthermore, studied the association between RHR...... in RHR. CONCLUSIONS: RHR is a trait with a genetic influence in middle-aged and elderly twins free of cardiovascular disease. RHR is independently associated with longevity even when familial factors are controlled for in a twin design....... and mortality. METHODS: In total, 4282 twins without cardiovascular disease were included from the Danish Twin Registry, hereof 1233 twin pairs and 1816 'single twins' (twins with a non-participating co-twin); mean age 61.7 (SD 11.1) years; 1334 (31.2%) twins died during median 16.3 (IQR 13.8-16.5) years......OBJECTIVE: Resting heart rate (RHR) possibly has a hereditary component and is associated with longevity. We used the classical biometric twin study design to investigate the heritability of RHR in a population of middle-aged and elderly twins and, furthermore, studied the association between RHR...

  16. Additive vs non-additive genetic components in lethal cadmium tolerance of Gammarus (Crustacea): Novel light on the assessment of the potential for adaptation to contamination

    Energy Technology Data Exchange (ETDEWEB)

    Chaumot, Arnaud, E-mail: arnaud.chaumot@cemagref.fr [Cemagref, UR MALY, 3 bis quai Chauveau - CP 220, F-69336 Lyon (France); Gos, Pierre; Garric, Jeanne; Geffard, Olivier [Cemagref, UR MALY, 3 bis quai Chauveau - CP 220, F-69336 Lyon (France)

    2009-10-04

    Questioning the likelihood that populations adapt to contamination is critical for ecotoxicological risk assessment. The appraisal of genetic variance in chemical sensitivities within populations is currently used to evaluate a priori this evolutionary potential. Nevertheless, conclusions from this approach are questionable since non-additive genetic components in chemical tolerance could limit the response of such complex phenotypic traits to selection. Coupling quantitative genetics with ecotoxicology, this study illustrates how the comparison between cadmium sensitivities among Gammarus siblings enabled discrimination between genetic variance components in chemical tolerance. The results revealed that, whereas genetically determined differences in lethal tolerance exist within the studied population, such differences were not significantly heritable since genetic variance mainly relied on non-additive components. Therefore the potential for genetic adaptation to acute Cd stress appeared to be weak. These outcomes are discussed in regard to previous findings for asexual daphnids, which suggest a strong potency of genetic adaptation to environmental contamination, but which contrast with compiled field observations where adaptation is not the rule. Hereafter, we formulate the reconciling hypothesis of a widespread weakness of additive components in tolerance to contaminants, which needs to be further tested to gain insight into the question of the likelihood of adaptation to contamination.

  17. Large-scale parentage analysis reveals reproductive patterns and heritability of spawn timing in a hatchery population of steelhead (Oncorhynchus mykiss).

    Science.gov (United States)

    Abadía-Cardoso, Alicia; Anderson, Eric C; Pearse, Devon E; Garza, John Carlos

    2013-09-01

    Understanding life history traits is an important first step in formulating effective conservation and management strategies. The use of artificial propagation and supplementation as such a strategy can have numerous effects on the supplemented natural populations and minimizing life history divergence is crucial in minimizing these effects. Here, we use single nucleotide polymorphism (SNP) genotypes for large-scale parentage analysis and pedigree reconstruction in a hatchery population of steelhead, the anadromous form of rainbow trout. Nearly complete sampling of the broodstock for several consecutive years in two hatchery programmes allowed inference about multiple aspects of life history. Reconstruction of cohort age distribution revealed a strong component of fish that spawn at 2 years of age, in contrast to programme goals and distinct from naturally spawning steelhead in the region, which raises a significant conservation concern. The first estimates of variance in family size for steelhead in this region can be used to calculate effective population size and probabilities of inbreeding, and estimation of iteroparity rate indicates that it is reduced by hatchery production. Finally, correlations between family members in the day of spawning revealed for the first time a strongly heritable component to this important life history trait in steelhead and demonstrated the potential for selection to alter life history traits rapidly in response to changes in environmental conditions. Taken together, these results demonstrate the extraordinary promise of SNP-based pedigree reconstruction for providing biological inference in high-fecundity organisms that is not easily achievable with traditional physical tags. © Published 2013. This article is a U.S. Government work and is in the public domain in the U.S.A.

  18. Variablity, heritability and genetic advance in quantitative traits of Tef ...

    African Journals Online (AJOL)

    Seventy nine tef populations collected from ten administrative regions and seven altitude classes were planted with two improved varieties in simple lattice design at Gute and Bako during 2007 and 2008 cropping season, respectively, to assess variability, and estimate heritability and genetic advance of quantitative traits.

  19. Genetic variability and heritability studies of some reproductive traits ...

    African Journals Online (AJOL)

    The success of most crop improvement programs largely depends upon the genetic variability and the heritability of desirable traits. The magnitude and type of genetic variability help the breeder to determine the selection criteria and breeding schemes to be used for improvement purposes. A screen house experiment was ...

  20. Childhood and Adolescent Anxiety and Depression: Beyond Heritability

    Science.gov (United States)

    Franic, Sanja; Middeldorp, Christel M.; Dolan, Conor V.; Ligthart, Lannie; Boomsma, Dorret I.

    2010-01-01

    Objective: To review the methodology of behavior genetics studies addressing research questions that go beyond simple heritability estimation and illustrate these using representative research on childhood and adolescent anxiety and depression. Method: The classic twin design and its extensions may be used to examine age and gender differences in…

  1. A Note on the Heritability of Memory Span.

    Science.gov (United States)

    Jensen, Arthur R.; Marisi, Daniel Q.

    The contribution of heredity to scores on a digit span intelligence test, Jensen's Memory for Numbers, was estimated with a standard heritability formula. The test measures level I mental ability--the capacity to store and recall, but not ability to elaborate or manipulate stimuli. Subjects were 35 monozygotic (MZ) twins and 35 same-sex dizygotic…

  2. Heritabilities of reproductive traits in a beef cattle herd using ...

    African Journals Online (AJOL)

    Unknown

    Heritabilities of reproductive traits in a beef cattle herd using multitrait analysis. R.R. van der Westhuizen. 1 ... animal, particularly in dairy cattle (Rege & Famula, 1993). However, in beef operations, ... These include lower birth weights, reduced incidence of dystocia, higher weaning and yearling weights and higher ...

  3. Heritability of carotid intima-media thickness : A twin study

    NARCIS (Netherlands)

    Zhao, Jinying; Cheema, Faiz A.; Bremner, J. Douglas; Goldberg, Jack; Su, Shaoyong; Snieder, Harold; Maisano, Carisa; Jones, Linda; Javed, Farhan; Murrah, Nancy; Le, Ngoc-Anh; Vaccarino, Viola

    Objective: To estimate the heritability of carotid intima-media thickness (IMT), a surrogate marker for atherosclerosis, independent of traditional coronary risk factors. Methods and results: We performed a classical twin study of carotid IMT using 98 middle-aged male twin pairs, 58 monozygotic (MZ)

  4. Heritability and genetic correlation of production and reproduction ...

    African Journals Online (AJOL)

    Heritability and genetic correlation of production and reproduction traits of Simmental cows. V Pantelić, L Sretenović, D Ostojić-Andrić, S Trivunović, MM Petrović, S Aleksić, D Ružić-Muslić ...

  5. Genetic variability, heritability and genetic advance of quantitative ...

    African Journals Online (AJOL)

    ONOS

    2010-05-10

    May 10, 2010 ... variability, heritability and genetic advance with significant enhancement (P 0.05 and P 0.01) in growth .... Effect of gamma rays on quantitative mean .... and genetic advance in pea. (Pisum sativum L.). Internat J. Plant Sci. 3(1): 211-212. Lush JL (1940). Intrusive collection of regression of offspring on dams.

  6. The heritability of depressive symptoms : multiple informants and multiple measures

    NARCIS (Netherlands)

    Happonen, M; Pulkkinen, L; Kaprio, J; Van der Meere, J; Viken, RJ; Rose, RJ

    Background: Earlier research suggests large rater differences in heritability estimates of children's depressive symptoms in the context of significant age and sex-limitation effects. Methods: With data from an ongoing, population-based twin-family study, we estimated genetic and environmental

  7. Heritability of psoriasis in a large twin sample

    DEFF Research Database (Denmark)

    Lønnberg, Ann Sophie; Skov, Liselotte; Skytthe, A

    2013-01-01

    AIM: To study the concordance of psoriasis in a population-based twin sample. METHODS: Data on psoriasis in 10,725 twin pairs, 20-71 years of age, from the Danish Twin Registry was collected via a questionnaire survey. The concordance and heritability of psoriasis were estimated. RESULTS: In total...

  8. Genetic Variability, Heritability and Genetic Advance for the ...

    African Journals Online (AJOL)

    Sesame (Sesamum indicum L.) is an important crop produced in Ethiopia for oilseed production and it ranks first in total production from oil crops. a study was conducted to determine the extent of genetic variability, heritability and genetic advance among 64 sesame populations from Ethiopia. The populations were grown in ...

  9. Review Genetic prediction models and heritability estimates for ...

    African Journals Online (AJOL)

    edward

    2015-05-09

    sajas.v45i2.1. Review. Genetic prediction models and heritability estimates for functional longevity in dairy cattle. V.E. Imbayarwo-Chikosi1#, K. Dzama1, T.E. Halimani3, J.B. van Wyk4,. A. Maiwashe2 & C.B. Banga2. 1 Department ...

  10. Heritability and correlates of maize yield ( Zea mays L .) under ...

    African Journals Online (AJOL)

    The study was undertaken to estimate broad-sense heritability and correlations between grain yields and other traits in maize under non-stress, intermediate stress and severe drought stress conditions. Fifty six genotypes were evaluated in a simple lattice design with two replications during the 2012/13 dry season at ...

  11. Heritability of cold tolerance in Nile tilapia, Oreochromis niloticus, juveniles

    NARCIS (Netherlands)

    Charo-Karisa, H.; Rezk, M.A.; Bovenhuis, H.; Komen, J.

    2005-01-01

    The inability of tilapia to tolerate low temperatures is of major economic concern as it reduces their growing season and leads to over winter mortality. In this study, cold tolerance of juvenile Nile tilapia, Oreochromis niloticus, was investigated and heritability estimates obtained. A total of 80

  12. narrow sense heritability and gene effects for late leaf spot

    African Journals Online (AJOL)

    ACSS

    3Department of Food Technology and Nutrition, School of Food Technology, Nutrition and Bio-systems. Engineering, Makerere ... narrow sense heritability and gene action controlling LLS resistance in Valencia groundnut materials. The materials .... of gene actions controlling LLS resistance using. Valencia groundnut ...

  13. Narrow sense heritability and gene effects for late leaf spot ...

    African Journals Online (AJOL)

    The deployment of resistant cultivars is a better option to control this disease in groundnut. A study was conducted to determine narrow sense heritability and gene action controlling LLS resistance in Valencia groundnut materials. The materials used included six generations; F1, F2, F1 backcrosses to the susceptible ...

  14. Evaluation of Some Litter Traits and Heritability Estimates of ...

    African Journals Online (AJOL)

    SH

    indigenous pigs (NIP) from the Swine Unit of Obafemi Awolowo University Teaching and Research Farm for a period of fourteen years ... Key words: Litter traits, heritability estimates, Nigerian Indigenous Pigs, Sows. Introduction. Information on the .... and endoparasites was controlled by deworming the animals using ...

  15. Heritability of flow-mediated dilation : a twin study

    NARCIS (Netherlands)

    Zhao, J.; Cheema, F. A.; Reddy, U.; Bremner, J. D.; Su, S.; Goldberg, J.; Snieder, H.; Vaccarino, V.

    2007-01-01

    Background: Endothelial dysfunction assessed by brachial artery flow-mediated dilation (FMD) is a marker for early atherosclerotic vascular disease and future cardiovascular events.Objective: To estimate the heritability of brachial artery FMD using a twin design.Methods: We estimated the

  16. Heritability of decisions and outcomes of public goods games

    Directory of Open Access Journals (Sweden)

    Kai eHiraishi

    2015-04-01

    Full Text Available Prosociality is one of the most distinctive features of human beings but there are individual differences in cooperative behavior. Employing the twin method, we examined the heritability of cooperativeness and its outcomes on public goods games using a strategy method. In two experiments (Study 1 and Study 2, twin participants were asked to indicate 1 how much they would contribute to a group when they did not know how much the other group members were contributing, and 2 how much they would contribute if they knew the contributions of others. Overall, the heritability estimates were relatively small for each type of decision, but heritability was greater when participants knew that the others had made larger contributions. Using registered decisions in Study 2, we conducted five Monte Carlo simulations to examine genetic and environmental influences on the expected game payoffs. For the simulated one-shot game, the heritability estimates were small, comparable to those of game decisions. For the simulated iterated games, we found that the genetic influences first decreased, then increased as the numbers of iterations grew. The implication for the evolution of individual differences in prosociality is discussed.

  17. Componentes de (covariância e parâmetros genéticos de características de crescimento da raça Simental no Brasil Variance components and genetic parameters estimates for growth traits of Simmental cattle in Brazil

    Directory of Open Access Journals (Sweden)

    L.F.A. Marques

    1999-08-01

    Full Text Available Informações de genealogia e produção, cedidas pela Associação Brasileira de Criadores da Raça Simental (ABCRS, relativas aos pesos desde o nascimento até um ano de idade, foram utilizadas para estimar, sob modelos alternativos, os componentes de variância e os parâmetros genéticos em animais da raça Simental no Brasil. A matriz de parentesco incluiu 25.812 animais dos quais 7587 com dados de produção. O modelo 1 contém, além do erro, o efeito genético direto. Os modelos seguintes contêm os componentes do modelo 1, mais o efeito permanente de ambiente materno (modelo 2, ou o componente genético materno (modelo 3, ambos os componentes (modelo 5, os componentes do modelo 3 mais a covariância entre os efeitos genéticos direto e materno (modelo 4 e todos os componentes citados (modelo 6. Os modelos foram comparados pelo teste de razão de verossimilhança pelo chi² (PBirth, 100-day, weaning and yearling weights of 7587 Simmental cattle, and 25,812 pedigree data were used to estimate genetic parameters using different animal models. The simplest model (model l included additive genetic and residual random effects. Models 2 and 3 were the same as model 1, but included, respectively, maternal permanent and maternal genetic effects. Model 4 did not include permanent effect. The most complete model (model 6 also included maternal additive and permanent effects, assuming covariance between them. Model 5 was the same as model 6, but did not included direct maternal covariance. Contemporary groups considered animals born in the same herd, year and season, from the same sex and raised under the same nutritional system. The models were compared using likelihood ratio tests. The (covariance components and the genetic parameters decreased from the most simple (model 1 to the most complete model (model 6. One-hundred-day weight showed no (.00±.00 maternal genetic variance but moderate maternal environmental permanent effect (.17±.07. The

  18. Realized heritability and repeatability of risk-taking behaviour in relation to avian personalities

    NARCIS (Netherlands)

    Van Oers, K.; Drent, P.J.; De Goede, P.; Van Noordwijk, A.J.

    2004-01-01

    Personalities are general properties of humans and other animals. Different personality traits are phenotypically correlated, and heritabilities of personality traits have been reported in humans and various animals. In great tits, consistent heritable differences have been found in relation to

  19. Heritability estimations for diseases, coat color, body weight and height in a birth cohort of Boxers

    NARCIS (Netherlands)

    Nielen, A.L.J.; Janss, L.L.G.; Knol, B.W.

    2001-01-01

    Objective - To obtain heritability estimates for diseases and characteristics in Boxers. Animals - Birth cohort of 2,929 purebred Boxers from 414 litters. Procedure - Heritability estimates were determined for cheiloschisis-palatoschisis, cryptorchidism, epilepsy, stifle disorders, cardiac

  20. Grammatical and lexical variance in English

    CERN Document Server

    Quirk, Randolph

    2014-01-01

    Written by one of Britain's most distinguished linguists, this book is concerned with the phenomenon of variance in English grammar and vocabulary across regional, social, stylistic and temporal space.

  1. Bias/Variance Analysis for Relational Domains

    National Research Council Canada - National Science Library

    Neville, Jennifer; Jensen, David

    2007-01-01

    .... To date, the impact of inference error on model performance has not been investigated. In this paper, we propose a new bias/variance framework that decomposes loss into errors due to both the learning and inference process...

  2. Importance Sampling Variance Reduction in GRESS ATMOSIM

    Energy Technology Data Exchange (ETDEWEB)

    Wakeford, Daniel Tyler [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-04-26

    This document is intended to introduce the importance sampling method of variance reduction to a Geant4 user for application to neutral particle Monte Carlo transport through the atmosphere, as implemented in GRESS ATMOSIM.

  3. Heritability of hypothyroidism in the Finnish Hovawart population.

    Science.gov (United States)

    Åhlgren, Johanna; Uimari, Pekka

    2016-06-07

    The Hovawart is a working and companion dog breed of German origin. A few hundred Hovawart dogs are registered annually in Finland. The most common disease with a proposed genetic background in Hovawarts is hypothyroidism. The disease is usually caused by lymphocytic thyroiditis, an autoimmune disorder which destroys the thyroid gland. Hypothyroidism can be treated medically with hormone replacement. Its overall incidence could also be reduced through selection, provided that the trait shows an adequate genetic basis. The aim of this study was to estimate the heritability of hypothyroidism in the Finnish Hovawart population. The pedigree data for the study were provided by the Finnish Kennel Club and the hypothyroidism data by the Finnish Hovawart Club. The data included 4953 dogs born between 1990 and 2010, of which 107 had hypothyroidism and 4846 were unaffected. Prior to the estimation of heritability, we studied the effects of gender, birth year, birth month, and inbreeding on susceptibility to hypothyroidism. Heritability was estimated with the probit model both via restricted maximum likelihood (REML) and Gibbs sampling, using litter and sire of the dog as random effects. None of the studied systematic effects or level of inbreeding had a significant effect on susceptibility to hypothyroidism. The estimated heritability of hypothyroidism varied from 0.47 (SE = 0.18) using REML to 0.62 (SD = 0.21) using Gibbs sampling. Based on our analysis, the heritability of hypothyroidism is moderate to high, suggesting that its prevalence could be decreased through selection. Thus, breeders should notify the breed association of any affected dogs, and their use for breeding should be avoided.

  4. Marker-Based Estimation of Heritability in Immortal Populations

    Science.gov (United States)

    Kruijer, Willem; Boer, Martin P.; Malosetti, Marcos; Flood, Pádraic J.; Engel, Bas; Kooke, Rik; Keurentjes, Joost J. B.; van Eeuwijk, Fred A.

    2015-01-01

    Heritability is a central parameter in quantitative genetics, from both an evolutionary and a breeding perspective. For plant traits heritability is traditionally estimated by comparing within- and between-genotype variability. This approach estimates broad-sense heritability and does not account for different genetic relatedness. With the availability of high-density markers there is growing interest in marker-based estimates of narrow-sense heritability, using mixed models in which genetic relatedness is estimated from genetic markers. Such estimates have received much attention in human genetics but are rarely reported for plant traits. A major obstacle is that current methodology and software assume a single phenotypic value per genotype, hence requiring genotypic means. An alternative that we propose here is to use mixed models at the individual plant or plot level. Using statistical arguments, simulations, and real data we investigate the feasibility of both approaches and how these affect genomic prediction with the best linear unbiased predictor and genome-wide association studies. Heritability estimates obtained from genotypic means had very large standard errors and were sometimes biologically unrealistic. Mixed models at the individual plant or plot level produced more realistic estimates, and for simulated traits standard errors were up to 13 times smaller. Genomic prediction was also improved by using these mixed models, with up to a 49% increase in accuracy. For genome-wide association studies on simulated traits, the use of individual plant data gave almost no increase in power. The new methodology is applicable to any complex trait where multiple replicates of individual genotypes can be scored. This includes important agronomic crops, as well as bacteria and fungi. PMID:25527288

  5. Heritability of longevity in Large White and Landrace sows using continuous time and grouped data models.

    Science.gov (United States)

    Mészáros, Gábor; Pálos, Judit; Ducrocq, Vincent; Sölkner, Johann

    2010-05-13

    Using conventional measurements of lifetime, it is not possible to differentiate between productive and non-productive days during a sow's lifetime and this can lead to estimated breeding values favoring less productive animals. By rescaling the time axis from continuous to several discrete classes, grouped survival data (discrete survival time) models can be used instead. The productive life length of 12319 Large White and 9833 Landrace sows was analyzed with continuous scale and grouped data models. Random effect of herd*year, fixed effects of interaction between parity and relative number of piglets, age at first farrowing and annual herd size change were included in the analysis. The genetic component was estimated from sire, sire-maternal grandsire, sire-dam, sire-maternal grandsire and animal models, and the heritabilities computed for each model type in both breeds. If age at first farrowing was under 43 weeks or above 60 weeks, the risk of culling sows increased. An interaction between parity and relative litter size was observed, expressed by limited culling during first parity and severe risk increase of culling sows having small litters later in life. In the Landrace breed, heritabilities ranged between 0.05 and 0.08 (s.e. 0.014-0.020) for the continuous and between 0.07 and 0.11 (s.e. 0.016-0.023) for the grouped data models, and in the Large White breed, they ranged between 0.08 and 0.14 (s.e. 0.012-0.026) for the continuous and between 0.08 and 0.13 (s.e. 0.012-0.025) for the grouped data models. Heritabilities for length of productive life were similar with continuous time and grouped data models in both breeds. Based on these results and because grouped data models better reflect the economical needs in meat animals, we conclude that grouped data models are more appropriate in pig.

  6. Heritability and Genome-Wide Association Analyses of Sleep Duration in Children: The EAGLE Consortium.

    Science.gov (United States)

    Marinelli, Marcella; Pappa, Irene; Bustamante, Mariona; Bonilla, Carolina; Suarez, Anna; Tiesler, Carla M; Vilor-Tejedor, Natalia; Zafarmand, Mohammad Hadi; Alvarez-Pedrerol, Mar; Andersson, Sture; Bakermans-Kranenburg, Marian J; Estivill, Xavier; Evans, David M; Flexeder, Claudia; Forns, Joan; Gonzalez, Juan R; Guxens, Monica; Huss, Anke; van IJzendoorn, Marinus H; Jaddoe, Vincent W V; Julvez, Jordi; Lahti, Jari; López-Vicente, Mónica; Lopez-Espinosa, Maria-Jose; Manz, Judith; Mileva-Seitz, Viara R; Perola, Markus; Pesonen, Anu-Katriina; Rivadeneira, Fernando; Salo, Perttu P; Shahand, Shayan; Schulz, Holger; Standl, Marie; Thiering, Elisabeth; Timpson, Nicholas J; Torrent, Maties; Uitterlinden, André G; Smith, George Davey; Estarlich, Marisa; Heinrich, Joachim; Räikkönen, Katri; Vrijkotte, Tanja G M; Tiemeier, Henning; Sunyer, Jordi

    2016-10-01

    Low or excessive sleep duration has been associated with multiple outcomes, but the biology behind these associations remains elusive. Specifically, genetic studies in children are scarce. In this study, we aimed to: (1) estimate the proportion of genetic variance of sleep duration in children attributed to common single nucleotide polymorphisms (SNPs), (2) identify novel SNPs associated with sleep duration in children, and (3) investigate the genetic overlap of sleep duration in children and related metabolic and psychiatric traits. We performed a population-based molecular genetic study, using data form the EArly Genetics and Life course Epidemiology (EAGLE) Consortium. 10,554 children of European ancestry were included in the discovery, and 1,250 children in the replication phase. We found evidence of significant but modest SNP heritability of sleep duration in children (SNP h(2) 0.14, 95% CI [0.05, 0.23]) using the LD score regression method. A novel region at chromosome 11q13.4 (top SNP: rs74506765, P = 2.27e-08) was associated with sleep duration in children, but this was not replicated in independent studies. Nominally significant genetic overlap was only found (rG = 0.23, P = 0.05) between sleep duration in children and type 2 diabetes in adults, supporting the hypothesis of a common pathogenic mechanism. The significant SNP heritability of sleep duration in children and the suggestive genetic overlap with type 2 diabetes support the search for genetic mechanisms linking sleep duration in children to multiple outcomes in health and disease.

  7. Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for Thirteen Cancer Types.

    Science.gov (United States)

    Sampson, Joshua N; Wheeler, William A; Yeager, Meredith; Panagiotou, Orestis; Wang, Zhaoming; Berndt, Sonja I; Lan, Qing; Abnet, Christian C; Amundadottir, Laufey T; Figueroa, Jonine D; Landi, Maria Teresa; Mirabello, Lisa; Savage, Sharon A; Taylor, Philip R; De Vivo, Immaculata; McGlynn, Katherine A; Purdue, Mark P; Rajaraman, Preetha; Adami, Hans-Olov; Ahlbom, Anders; Albanes, Demetrius; Amary, Maria Fernanda; An, She-Juan; Andersson, Ulrika; Andriole, Gerald; Andrulis, Irene L; Angelucci, Emanuele; Ansell, Stephen M; Arici, Cecilia; Armstrong, Bruce K; Arslan, Alan A; Austin, Melissa A; Baris, Dalsu; Barkauskas, Donald A; Bassig, Bryan A; Becker, Nikolaus; Benavente, Yolanda; Benhamou, Simone; Berg, Christine; Van Den Berg, David; Bernstein, Leslie; Bertrand, Kimberly A; Birmann, Brenda M; Black, Amanda; Boeing, Heiner; Boffetta, Paolo; Boutron-Ruault, Marie-Christine; Bracci, Paige M; Brinton, Louise; Brooks-Wilson, Angela R; Bueno-de-Mesquita, H Bas; Burdett, Laurie; Buring, Julie; Butler, Mary Ann; Cai, Qiuyin; Cancel-Tassin, Geraldine; Canzian, Federico; Carrato, Alfredo; Carreon, Tania; Carta, Angela; Chan, John K C; Chang, Ellen T; Chang, Gee-Chen; Chang, I-Shou; Chang, Jiang; Chang-Claude, Jenny; Chen, Chien-Jen; Chen, Chih-Yi; Chen, Chu; Chen, Chung-Hsing; Chen, Constance; Chen, Hongyan; Chen, Kexin; Chen, Kuan-Yu; Chen, Kun-Chieh; Chen, Ying; Chen, Ying-Hsiang; Chen, Yi-Song; Chen, Yuh-Min; Chien, Li-Hsin; Chirlaque, María-Dolores; Choi, Jin Eun; Choi, Yi Young; Chow, Wong-Ho; Chung, Charles C; Clavel, Jacqueline; Clavel-Chapelon, Françoise; Cocco, Pierluigi; Colt, Joanne S; Comperat, Eva; Conde, Lucia; Connors, Joseph M; Conti, David; Cortessis, Victoria K; Cotterchio, Michelle; Cozen, Wendy; Crouch, Simon; Crous-Bou, Marta; Cussenot, Olivier; Davis, Faith G; Ding, Ti; Diver, W Ryan; Dorronsoro, Miren; Dossus, Laure; Duell, Eric J; Ennas, Maria Grazia; Erickson, Ralph L; Feychting, Maria; Flanagan, Adrienne M; Foretova, Lenka; Fraumeni, Joseph F; Freedman, Neal D; Beane Freeman, Laura E; Fuchs, Charles; Gago-Dominguez, Manuela; Gallinger, Steven; Gao, Yu-Tang; Gapstur, Susan M; Garcia-Closas, Montserrat; García-Closas, Reina; Gascoyne, Randy D; Gastier-Foster, Julie; Gaudet, Mia M; Gaziano, J Michael; Giffen, Carol; Giles, Graham G; Giovannucci, Edward; Glimelius, Bengt; Goggins, Michael; Gokgoz, Nalan; Goldstein, Alisa M; Gorlick, Richard; Gross, Myron; Grubb, Robert; Gu, Jian; Guan, Peng; Gunter, Marc; Guo, Huan; Habermann, Thomas M; Haiman, Christopher A; Halai, Dina; Hallmans, Goran; Hassan, Manal; Hattinger, Claudia; He, Qincheng; He, Xingzhou; Helzlsouer, Kathy; Henderson, Brian; Henriksson, Roger; Hjalgrim, Henrik; Hoffman-Bolton, Judith; Hohensee, Chancellor; Holford, Theodore R; Holly, Elizabeth A; Hong, Yun-Chul; Hoover, Robert N; Horn-Ross, Pamela L; Hosain, G M Monawar; Hosgood, H Dean; Hsiao, Chin-Fu; Hu, Nan; Hu, Wei; Hu, Zhibin; Huang, Ming-Shyan; Huerta, Jose-Maria; Hung, Jen-Yu; Hutchinson, Amy; Inskip, Peter D; Jackson, Rebecca D; Jacobs, Eric J; Jenab, Mazda; Jeon, Hyo-Sung; Ji, Bu-Tian; Jin, Guangfu; Jin, Li; Johansen, Christoffer; Johnson, Alison; Jung, Yoo Jin; Kaaks, Rudolph; Kamineni, Aruna; Kane, Eleanor; Kang, Chang Hyun; Karagas, Margaret R; Kelly, Rachel S; Khaw, Kay-Tee; Kim, Christopher; Kim, Hee Nam; Kim, Jin Hee; Kim, Jun Suk; Kim, Yeul Hong; Kim, Young Tae; Kim, Young-Chul; Kitahara, Cari M; Klein, Alison P; Klein, Robert J; Kogevinas, Manolis; Kohno, Takashi; Kolonel, Laurence N; Kooperberg, Charles; Kricker, Anne; Krogh, Vittorio; Kunitoh, Hideo; Kurtz, Robert C; Kweon, Sun-Seog; LaCroix, Andrea; Lawrence, Charles; Lecanda, Fernando; Lee, Victor Ho Fun; Li, Donghui; Li, Haixin; Li, Jihua; Li, Yao-Jen; Li, Yuqing; Liao, Linda M; Liebow, Mark; Lightfoot, Tracy; Lim, Wei-Yen; Lin, Chien-Chung; Lin, Dongxin; Lindstrom, Sara; Linet, Martha S; Link, Brian K; Liu, Chenwei; Liu, Jianjun; Liu, Li; Ljungberg, Börje; Lloreta, Josep; Di Lollo, Simonetta; Lu, Daru; Lund, Eiluv; Malats, Nuria; Mannisto, Satu; Le Marchand, Loic; Marina, Neyssa; Masala, Giovanna; Mastrangelo, Giuseppe; Matsuo, Keitaro; Maynadie, Marc; McKay, James; McKean-Cowdin, Roberta; Melbye, Mads; Melin, Beatrice S; Michaud, Dominique S; Mitsudomi, Tetsuya; Monnereau, Alain; Montalvan, Rebecca; Moore, Lee E; Mortensen, Lotte Maxild; Nieters, Alexandra; North, Kari E; Novak, Anne J; Oberg, Ann L; Offit, Kenneth; Oh, In-Jae; Olson, Sara H; Palli, Domenico; Pao, William; Park, In Kyu; Park, Jae Yong; Park, Kyong Hwa; Patiño-Garcia, Ana; Pavanello, Sofia; Peeters, Petra H M; Perng, Reury-Perng; Peters, Ulrike; Petersen, Gloria M; Picci, Piero; Pike, Malcolm C; Porru, Stefano; Prescott, Jennifer; Prokunina-Olsson, Ludmila; Qian, Biyun; Qiao, You-Lin; Rais, Marco; Riboli, Elio; Riby, Jacques; Risch, Harvey A; Rizzato, Cosmeri; Rodabough, Rebecca; Roman, Eve; Roupret, Morgan; Ruder, Avima M; Sanjose, Silvia de; Scelo, Ghislaine; Schned, Alan; Schumacher, Fredrick; Schwartz, Kendra; Schwenn, Molly; Scotlandi, Katia; Seow, Adeline; Serra, Consol; Serra, Massimo; Sesso, Howard D; Setiawan, Veronica Wendy; Severi, Gianluca; Severson, Richard K; Shanafelt, Tait D; Shen, Hongbing; Shen, Wei; Shin, Min-Ho; Shiraishi, Kouya; Shu, Xiao-Ou; Siddiq, Afshan; Sierrasesúmaga, Luis; Sihoe, Alan Dart Loon; Skibola, Christine F; Smith, Alex; Smith, Martyn T; Southey, Melissa C; Spinelli, John J; Staines, Anthony; Stampfer, Meir; Stern, Marianna C; Stevens, Victoria L; Stolzenberg-Solomon, Rachael S; Su, Jian; Su, Wu-Chou; Sund, Malin; Sung, Jae Sook; Sung, Sook Whan; Tan, Wen; Tang, Wei; Tardón, Adonina; Thomas, David; Thompson, Carrie A; Tinker, Lesley F; Tirabosco, Roberto; Tjønneland, Anne; Travis, Ruth C; Trichopoulos, Dimitrios; Tsai, Fang-Yu; Tsai, Ying-Huang; Tucker, Margaret; Turner, Jenny; Vajdic, Claire M; Vermeulen, Roel C H; Villano, Danylo J; Vineis, Paolo; Virtamo, Jarmo; Visvanathan, Kala; Wactawski-Wende, Jean; Wang, Chaoyu; Wang, Chih-Liang; Wang, Jiu-Cun; Wang, Junwen; Wei, Fusheng; Weiderpass, Elisabete; Weiner, George J; Weinstein, Stephanie; Wentzensen, Nicolas; White, Emily; Witzig, Thomas E; Wolpin, Brian M; Wong, Maria Pik; Wu, Chen; Wu, Guoping; Wu, Junjie; Wu, Tangchun; Wu, Wei; Wu, Xifeng; Wu, Yi-Long; Wunder, Jay S; Xiang, Yong-Bing; Xu, Jun; Xu, Ping; Yang, Pan-Chyr; Yang, Tsung-Ying; Ye, Yuanqing; Yin, Zhihua; Yokota, Jun; Yoon, Ho-Il; Yu, Chong-Jen; Yu, Herbert; Yu, Kai; Yuan, Jian-Min; Zelenetz, Andrew; Zeleniuch-Jacquotte, Anne; Zhang, Xu-Chao; Zhang, Yawei; Zhao, Xueying; Zhao, Zhenhong; Zheng, Hong; Zheng, Tongzhang; Zheng, Wei; Zhou, Baosen; Zhu, Meng; Zucca, Mariagrazia; Boca, Simina M; Cerhan, James R; Ferri, Giovanni M; Hartge, Patricia; Hsiung, Chao Agnes; Magnani, Corrado; Miligi, Lucia; Morton, Lindsay M; Smedby, Karin E; Teras, Lauren R; Vijai, Joseph; Wang, Sophia S; Brennan, Paul; Caporaso, Neil E; Hunter, David J; Kraft, Peter; Rothman, Nathaniel; Silverman, Debra T; Slager, Susan L; Chanock, Stephen J; Chatterjee, Nilanjan

    2015-12-01

    Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, hl (2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (ρ = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (ρ = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (ρ = 0.51, SE =0.18), and bladder and lung (ρ = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Our results provide important insights into

  8. 78 FR 79471 - Discretionary Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2013-12-30

    ... Heritable Disorders in Newborns and Children; Notice of Meeting In accordance with section 10(a)(2) of the... following meeting: Name: Discretionary Advisory Committee on Heritable Disorders in Newborns and Children....m. Eastern Standard Time (EST). Purpose: The Discretionary Advisory Committee on Heritable Disorders...

  9. 78 FR 51195 - Discretionary Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2013-08-20

    ... Heritable Disorders in Newborns and Children; Notice of Meeting In accordance with section 10(a)(2) of the... following meeting: Name: Discretionary Advisory Committee on Heritable Disorders in Newborns and Children[email protected] . Purpose: The Discretionary Advisory Committee on Heritable Disorders in Newborns and...

  10. 75 FR 68802 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2010-11-09

    ... Administration Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting... Advisory Committee on Heritable Disorders in Newborns and Children (Advisory Committee) was established to... in newborns and children having or at risk for heritable disorders. The Advisory Committee also...

  11. 76 FR 76740 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2011-12-08

    ... Administration Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting... Committee on Heritable Disorders in Newborns and Children. Dates and Times: January 26, 2012, 8:30 a.m. to 5... Advisory Committee on Heritable Disorders in [[Page 76741

  12. Family Aggregation and Heritability of ESRD in Taiwan: A Population-Based Study.

    Science.gov (United States)

    Wu, Hsin Hsu; Kuo, Chang Fu; Li, I Jung; Weng, Cheng Hao; Lee, Cheng Chia; Tu, Kun Hua; Liu, Shou Hsuan; Chen, Yung Chang; Yang, Chih Wei; Luo, Shue Fen; See, Lai Chu; Yu, Kuang Hui; Huang, Lu Hsiang; Zhang, Weiya; Doherty, Michael; Tian, Ya Chung

    2017-11-01

    Aggregation of end-stage renal disease (ESRD) has been observed in families of European origin, as well as those of African origin. However, it is not well documented if this disease aggregates in Asian families. Furthermore, the contribution of genetic factors and shared environmental factors to family aggregation remains unclear. Population-based cross-sectional cohort study. All 23,422,955 individuals registered in the Taiwan National Health Insurance Research Database in 2013. Among these, 47.45%, 57.45%, 47.29%, and 1.51% had a known parent, child, sibling, or twin, respectively. We identified 87,849 patients who had a diagnosis of ESRD. Family history of ESRD. ESRD and heritability defined as the proportion of phenotypic variance attributable to genetic factors. Having an affected first-degree relative with ESRD was associated with an adjusted relative risk of 2.46 (95% CI, 2.32-2.62). Relative risks were 96.38 (95% CI, 48.3-192.34) for twins of patients with ESRD, 2.15 (95% CI, 2.02-2.29) for parents, 2.78 (95% CI, 2.53-3.05) for offspring, 4.96 (95% CI, 4.19-5.88) for siblings, and 1.66 (95% CI, 1.54-1.78) for spouses without genetic similarities. Heritability in this study was 31.1% to 11.4% for shared environmental factors and 57.5% for nonshared environmental factors. This was a registry database study and we did not have detailed information about clinical findings or the definite causes of ESRD. This whole population-based family study in Asia confirmed, in a Taiwanese population, that a family history of ESRD is a strong risk factor for this disease. Moderate heritability was noted and environmental factors were related to disease. Family history of ESRD is an important piece of clinical information. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Genetic variability and heritability of chlorophyll a fluorescence parameters in Scots pine (Pinus sylvestris L.).

    Science.gov (United States)

    Čepl, Jaroslav; Holá, Dana; Stejskal, Jan; Korecký, Jiří; Kočová, Marie; Lhotáková, Zuzana; Tomášková, Ivana; Palovská, Markéta; Rothová, Olga; Whetten, Ross W; Kaňák, Jan; Albrechtová, Jana; Lstibůrek, Milan

    2016-07-01

    Current knowledge of the genetic mechanisms underlying the inheritance of photosynthetic activity in forest trees is generally limited, yet it is essential both for various practical forestry purposes and for better understanding of broader evolutionary mechanisms. In this study, we investigated genetic variation underlying selected chlorophyll a fluorescence (ChlF) parameters in structured populations of Scots pine (Pinus sylvestris L.) grown on two sites under non-stress conditions. These parameters were derived from the OJIP part of the ChlF kinetics curve and characterize individual parts of primary photosynthetic processes associated, for example, with the exciton trapping by light-harvesting antennae, energy utilization in photosystem II (PSII) reaction centers (RCs) and its transfer further down the photosynthetic electron-transport chain. An additive relationship matrix was estimated based on pedigree reconstruction, utilizing a set of highly polymorphic single sequence repeat markers. Variance decomposition was conducted using the animal genetic evaluation mixed-linear model. The majority of ChlF parameters in the analyzed pine populations showed significant additive genetic variation. Statistically significant heritability estimates were obtained for most ChlF indices, with the exception of DI0/RC, φD0 and φP0 (Fv/Fm) parameters. Estimated heritabilities varied around the value of 0.15 with the maximal value of 0.23 in the ET0/RC parameter, which indicates electron-transport flux from QA to QB per PSII RC. No significant correlation was found between these indices and selected growth traits. Moreover, no genotype × environment interaction (G × E) was detected, i.e., no differences in genotypes' performance between sites. The absence of significant G × E in our study is interesting, given the relatively low heritability found for the majority of parameters analyzed. Therefore, we infer that polygenic variability of these indices is

  14. Speeding Up Microevolution: The Effects of Increasing Temperature on Selection and Genetic Variance in a Wild Bird Population

    Science.gov (United States)

    Husby, Arild; Visser, Marcel E.; Kruuk, Loeske E. B.

    2011-01-01

    The amount of genetic variance underlying a phenotypic trait and the strength of selection acting on that trait are two key parameters that determine any evolutionary response to selection. Despite substantial evidence that, in natural populations, both parameters may vary across environmental conditions, very little is known about the extent to which they may covary in response to environmental heterogeneity. Here we show that, in a wild population of great tits (Parus major), the strength of the directional selection gradients on timing of breeding increased with increasing spring temperatures, and that genotype-by-environment interactions also predicted an increase in additive genetic variance, and heritability, of timing of breeding with increasing spring temperature. Consequently, we therefore tested for an association between the annual selection gradients and levels of additive genetic variance expressed each year; this association was positive, but non-significant. However, there was a significant positive association between the annual selection differentials and the corresponding heritability. Such associations could potentially speed up the rate of micro-evolution and offer a largely ignored mechanism by which natural populations may adapt to environmental changes. PMID:21408101

  15. On the reliability of a simple method for scoring phenotypes to estimate heritability: A case study with pupal color in Heliconius erato phyllis , Fabricius 1775 (Lepidoptera, Nymphalidae

    Directory of Open Access Journals (Sweden)

    Adriano Andrejew Ferreira

    2009-01-01

    Full Text Available In this paper, two methods for assessing the degree of melanization of pupal exuviae from the butterfly Heliconius erato phyllis , Fabricius 1775 (Lepidoptera, Nymphalidae, Heliconiini are compared. In the first method, which was qualitative, the exuviae were classified by scoring the degree of melanization, whereas in the second method, which was quantitative, the exuviae were classified by optical density followed by analysis with appropriate software. The heritability (h 2 of the degree of melanization was estimated by regression and analysis of variance. The estimates of h 2 were similar with both methods, indicating that the qualitative method could be particularly suitable for field work. The low estimates obtained for heritability may have resulted from the small sample size ( n = 7-18 broods, including the parents or from the allocation-priority hypothesis in which pupal color would be a lower priority trait compared to morphological traits and adequate larval development.

  16. The heritability of shell morphometrics in the freshwater pulmonate gastropod Physa.

    Directory of Open Access Journals (Sweden)

    Robert T Dillon

    Full Text Available The cosmopolitan freshwater pulmonate snail Physa acuta hybridizes readily with Physa carolinae in the laboratory, although their F1 progeny are sterile. The two species differ qualitatively in shell shape, the former bearing a more globose shell and the latter more fusiform. We performed a hybridization experiment, measuring a set of 14 traditional (linear and landmark-based shell morphological variables on even-aged parents and their offspring from both hybrids and purebred control lines. Parent-offspring regression yielded a strikingly high heritability estimate for score on the first relative warp axis, h2 = 0.819 ± 0.073, a result that would seem to confirm the value of geometric morphometrics as a tool for retrieving evolutionary relationships from gastropod shell form. Score on the second relative warp axis was also significantly heritable (h2 = 0.312 ± 0.123, although more moderate, as were scores on second principal components extracted from traditional measurements (correlation h2 = 0.308 ± 0.069, covariance h2 = 0.314 ± 0.050. Although score on the first relative warp axis was significantly correlated with centroid size (p < 0.001, scores on none of the three second axes were so correlated. This result suggests that second axis score might prove especially useful for estimating genetic divergence among mixed-age populations of gastropods sampled from the field.

  17. Maximum Variance Hashing via Column Generation

    Directory of Open Access Journals (Sweden)

    Lei Luo

    2013-01-01

    item search. Recently, a number of data-dependent methods have been developed, reflecting the great potential of learning for hashing. Inspired by the classic nonlinear dimensionality reduction algorithm—maximum variance unfolding, we propose a novel unsupervised hashing method, named maximum variance hashing, in this work. The idea is to maximize the total variance of the hash codes while preserving the local structure of the training data. To solve the derived optimization problem, we propose a column generation algorithm, which directly learns the binary-valued hash functions. We then extend it using anchor graphs to reduce the computational cost. Experiments on large-scale image datasets demonstrate that the proposed method outperforms state-of-the-art hashing methods in many cases.

  18. Genetic and environmental heterogeneity of residual variance of weight traits in Nellore beef cattle

    Directory of Open Access Journals (Sweden)

    Neves Haroldo HR

    2012-07-01

    Full Text Available Abstract Background Many studies have provided evidence of the existence of genetic heterogeneity of environmental variance, suggesting that it could be exploited to improve robustness and uniformity of livestock by selection. However, little is known about the perspectives of such a selection strategy in beef cattle. Methods A two-step approach was applied to study the genetic heterogeneity of residual variance of weight gain from birth to weaning and long-yearling weight in a Nellore beef cattle population. First, an animal model was fitted to the data and second, the influence of additive and environmental effects on the residual variance of these traits was investigated with different models, in which the log squared estimated residuals for each phenotypic record were analyzed using the restricted maximum likelihood method. Monte Carlo simulation was performed to assess the reliability of variance component estimates from the second step and the accuracy of estimated breeding values for residual variation. Results The results suggest that both genetic and environmental factors have an effect on the residual variance of weight gain from birth to weaning and long-yearling in Nellore beef cattle and that uniformity of these traits could be improved by selecting for lower residual variance, when considering a large amount of information to predict genetic merit for this criterion. Simulations suggested that using the two-step approach would lead to biased estimates of variance components, such that more adequate methods are needed to study the genetic heterogeneity of residual variance in beef cattle.

  19. Integrating Variances into an Analytical Database

    Science.gov (United States)

    Sanchez, Carlos

    2010-01-01

    For this project, I enrolled in numerous SATERN courses that taught the basics of database programming. These include: Basic Access 2007 Forms, Introduction to Database Systems, Overview of Database Design, and others. My main job was to create an analytical database that can handle many stored forms and make it easy to interpret and organize. Additionally, I helped improve an existing database and populate it with information. These databases were designed to be used with data from Safety Variances and DCR forms. The research consisted of analyzing the database and comparing the data to find out which entries were repeated the most. If an entry happened to be repeated several times in the database, that would mean that the rule or requirement targeted by that variance has been bypassed many times already and so the requirement may not really be needed, but rather should be changed to allow the variance's conditions permanently. This project did not only restrict itself to the design and development of the database system, but also worked on exporting the data from the database to a different format (e.g. Excel or Word) so it could be analyzed in a simpler fashion. Thanks to the change in format, the data was organized in a spreadsheet that made it possible to sort the data by categories or types and helped speed up searches. Once my work with the database was done, the records of variances could be arranged so that they were displayed in numerical order, or one could search for a specific document targeted by the variances and restrict the search to only include variances that modified a specific requirement. A great part that contributed to my learning was SATERN, NASA's resource for education. Thanks to the SATERN online courses I took over the summer, I was able to learn many new things about computers and databases and also go more in depth into topics I already knew about.

  20. heterosis and heritability estimates of purine alkaloids and ...

    African Journals Online (AJOL)

    ACSS

    Besides, the heritability value in strict sense of this Cyanidin-3-galactoside was very high. ... croisement réciproque (F5 et F9) ont présenté une meilleure hétérosis par rapport au meilleur parent. L'utilisation de ces deux clones dans un .... banks of the Cameroon Cocoa Development. Corporation (SODECAO) at Mengang ...

  1. Heritability and genetics of lipid metabolism

    DEFF Research Database (Denmark)

    Fenger, Mogens

    2007-01-01

    In this article, the concept of heritability and genetic effect will be reviewed and our current knowledge of the genetics of lipid metabolism summarized. The concepts of polygenic conditions and epistasis are discussed at length, and an effort is made to put the biological processes in context...... in the search for genetic factors influencing the metabolic pathways. Particular physiological heterogeneity is addressed and procedures to handle this complex issue are suggested....

  2. Helping financial analysts communicate variance analysis.

    Science.gov (United States)

    Dove, H G; Forthman, T

    1995-04-01

    Healthcare organizations often use variance analysis to explain variation between planned and actual costs and charges. This type of analysis is becoming even more common as healthcare executives work to improve efficiency, to set priorities for organizational improvement as part of strategic planning, and to explain costs and charges to interested groups such as purchasers and payers. Variance analysis produces data that must be presented in a format useful to senior executives. An effective format would express the data in a visual summary that is simple enough to be readily understood and detailed enough to provide valuable information.

  3. Short communication: Heritability of twinning rate in Holstein cattle.

    Science.gov (United States)

    Lett, Beth M; Kirkpatrick, Brian W

    2018-02-14

    Multiple births or twinning in cattle is a naturally occurring reproductive phenomenon. For dairy cattle, twinning is considered a detrimental trait as it can be harmful to cow and calf as well as costly to the producer. The objective of this study was to examine recent US calving records for the Holstein breed to determine a current estimate of heritability for twinning rate along with effects of season and parity. Two models were used in this study: a linear sire model and a binary threshold-logit sire model. Both were mixed models considering fixed effects and random effects. Analyses were conducted using a restricted maximum likelihood method. Heritability estimates were 0.0192 ± 0.0009 and 0.1420 ± 0.0069 for the linear and threshold models, respectively. Repeatabilities from the linear and threshold-logit models were 0.0443 ± 0.0012 and 0.2310 ± 0.0072, respectively. The nonzero estimates of heritability indicate the potential to select against this trait for genetic improvement of Holstein cattle. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. Leveraging population admixture to explain missing heritability of complex traits

    Science.gov (United States)

    Zaitlen, Noah; Pasaniuc, Bogdan; Sankararaman, Sriram; Bhatia, Gaurav; Zhang, Jianqi; Gusev, Alexander; Young, Taylor; Tandon, Arti; Pollack, Samuela; Vilhjálmsson, Bjarni J.; Assimes, Themistocles L.; Berndt, Sonja I.; Blot, William J.; Chanock, Stephen; Franceschini, Nora; Goodman, Phyllis G.; He, Jing; Hennis, Anselm JM; Hsing, Ann; Ingles, Sue A.; Isaacs, William; Kittles, Rick A.; Klein, Eric A.; Lange, Leslie A.; Nemesure, Barbara; Patterson, Nick; Reich, David; Rybicki, Benjamin A.; Stanford, Janet L.; Stevens, Victoria L; Strom, Sara S.; Whitsel, Eric A; Witte, John S.; Xu, Jianfeng; Haiman, Christopher; Wilson, James G.; Kooperberg, Charles; Stram, Daniel; Reiner, Alex P.; Tang, Hua; Price, Alkes L.

    2014-01-01

    Despite recent progress on estimating the heritability explained by genotyped SNPs (hg2), a large gap between hg2 and estimates of total narrow-sense heritability (h2) remains. Explanations for this gap include rare variants, or upward bias in family-based estimates of h2 due to shared environment or epistasis. We estimate h2 from unrelated individuals in admixed populations by first estimating the heritability explained by local ancestry (hγ2). We show that hγ2 = 2FSTCθ(1−θ)h2, where FSTC measures frequency differences between populations at causal loci and θ is the genome-wide ancestry proportion. Our approach is not susceptible to biases caused by epistasis or shared environment. We examined 21,497 African Americans from three cohorts, analyzing 13 phenotypes. For height and BMI, we obtained h2 estimates of 0.55 ± 0.09 and 0.23 ± 0.06, respectively, which are larger than estimates of hg2 in these and other data, but smaller than family-based estimates of h2. PMID:25383972

  5. Familial Aggregation and Heritability of Wuchereria bancrofti Infection.

    Science.gov (United States)

    Chesnais, Cédric B; Sabbagh, Audrey; Pion, Sébastien D; Missamou, François; Garcia, André; Boussinesq, Michel

    2016-08-15

    The familial recurrence risk of lymphatic filariasis (LF) is unknown. This case study aimed to evaluate the familial susceptibility to infection with Wuchereria bancrofti and to microfilaremia in a village of the Republic of Congo. The heritability and intrafamilial correlation coefficients were assessed for both W. bancrofti infection and microfilaremia by controlling for individual risk factors, environmental influence, and household effects. Pedigree charts were constructed for 829 individuals, including 143 individuals with a diagnosis of W. bancrofti circulating filarial antigens (CFAs) and 44 who also had microfilariae (MF). There was no intrafamilial correlation regarding CFA levels. However, the presence of MF (ρ = 0.45) and microfilarial density (ρ = 0.44) were significantly correlated among parent-offspring pairs. Heritability estimates for CFA positivity and intensity were 0.23 and 0.18, respectively. Heritability estimates were high for microfilarial positivity (h(2) = 0.74) and microfilarial density traits (h(2) = 0.81). Our study suggests that the acquisition of LF is mainly driven by environmental factors and habits and that genetic factors are moderately involved in the regulation of infection. By contrast, genetic factors play a major role in both the presence and intensity of microfilaremia. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  6. Cognitive profiles and heritability estimates in the Old Order Amish.

    Science.gov (United States)

    Kuehner, Ryan M; Kochunov, Peter; Nugent, Katie L; Jurius, Deanna E; Savransky, Anya; Gaudiot, Christopher; Bruce, Heather A; Gold, James; Shuldiner, Alan R; Mitchell, Braxton D; Hong, L Elliot

    2016-08-01

    This study aimed to establish the applicability of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) in the Old Order Amish (OOA) and to assess the genetic contribution toward the RBANS total score and its cognitive domains using a large family-based sample of OOA. RBANS data were collected in 103 OOA individuals from Lancaster County, Pennsylvania, including 85 individuals without psychiatric illness and 18 individuals with current psychiatric diagnoses. The RBANS total score and all five cognitive domains of in nonpsychiatric OOA were within half a SD of the normative data of the general population. The RBANS total score was highly heritable (h=0.51, P=0.019). OOA with psychiatric diagnoses had a numerically lower RBANS total score and domain scores compared with the nonpsychiatric participants. The RBANS appears to be a suitable cognitive battery for the OOA population as measurements obtained from the OOA are comparable with normative data in the US population. The heritability estimated from the OOA is in line with heritabilities of other cognitive batteries estimated in other populations. These results support the use of RBANS in cognitive assessment, clinical care, and behavioral genetic studies of neuropsychological functioning in this population.

  7. Epidemiology and Heritability of Major Depressive Disorder, Stratified by Age of Onset, Sex, and Illness Course in Generation Scotland: Scottish Family Health Study (GS:SFHS.

    Directory of Open Access Journals (Sweden)

    Ana Maria Fernandez-Pujals

    Full Text Available The heritability of Major Depressive Disorder (MDD has been estimated at 37% based largely on twin studies that rely on contested assumptions. More recently, the heritability of MDD has been estimated on large populations from registries such as the Swedish, Finnish, and Chinese cohorts. Family-based designs utilise a number of different relationships and provide an alternative means of estimating heritability. Generation Scotland: Scottish Family Health Study (GS:SFHS is a large (n = 20,198, family-based population study designed to identify the genetic determinants of common diseases, including Major Depressive Disorder. Two thousand seven hundred and six individuals were SCID diagnosed with MDD, 13.5% of the cohort, from which we inferred a population prevalence of 12.2% (95% credible interval: 11.4% to 13.1%. Increased risk of MDD was associated with being female, unemployed due to a disability, current smokers, former drinkers, and living in areas of greater social deprivation. The heritability of MDD in GS:SFHS was between 28% and 44%, estimated from a pedigree model. The genetic correlation of MDD between sexes, age of onset, and illness course were examined and showed strong genetic correlations. The genetic correlation between males and females with MDD was 0.75 (0.43 to 0.99; between earlier (≤ age 40 and later (> age 40 onset was 0.85 (0.66 to 0.98; and between single and recurrent episodic illness course was 0.87 (0.72 to 0.98. We found that the heritability of recurrent MDD illness course was significantly greater than the heritability of single MDD illness course. The study confirms a moderate genetic contribution to depression, with a small contribution of the common family environment (variance proportion = 0.07, CI: 0.01 to 0.15, and supports the relationship of MDD with previously identified risk factors. This study did not find robust support for genetic differences in MDD due to sex, age of onset, or illness course. However

  8. 21 CFR 1010.4 - Variances.

    Science.gov (United States)

    2010-04-01

    ... PERFORMANCE STANDARDS FOR ELECTRONIC PRODUCTS: GENERAL General Provisions § 1010.4 Variances. (a) Criteria for... provisions of any performance standard under subchapter J of this chapter for an electronic product subject... purposes of Subchapter C—Electronic Product Radiation Control of the Federal Food, Drug, and Cosmetic Act...

  9. 7 CFR 205.290 - Temporary variances.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Temporary variances. 205.290 Section 205.290 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) ORGANIC FOODS PRODUCTION ACT PROVISIONS NATIONAL ORGANIC PROGRAM Organic...

  10. Expected Stock Returns and Variance Risk Premia

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Zhou, Hao

    We find that the difference between implied and realized variation, or the variance risk premium, is able to explain more than fifteen percent of the ex-post time series variation in quarterly excess returns on the market portfolio over the 1990 to 2005 sample period, with high (low) premia predi...... to daily, data. Our findings suggest that temporal variation in both risk-aversion and volatility-risk play an important role in determining stock market returns.......We find that the difference between implied and realized variation, or the variance risk premium, is able to explain more than fifteen percent of the ex-post time series variation in quarterly excess returns on the market portfolio over the 1990 to 2005 sample period, with high (low) premia...... predicting high (low) future returns. The magnitude of the return predictability of the variance risk premium easily dominates that afforded by standard predictor variables like the P/E ratio, the dividend yield, the default spread, and the consumption-wealth ratio (CAY). Moreover, combining the variance...

  11. Broadband Minimum Variance Beamforming for Ultrasound Imaging

    DEFF Research Database (Denmark)

    Holfort, Iben Kraglund; Gran, Fredrik; Jensen, Jørgen Arendt

    2009-01-01

    A minimum variance (MV) approach for near-field beamforming of broadband data is proposed. The approach is implemented in the frequency domain, and it provides a set of adapted, complex apodization weights for each frequency subband. The performance of the proposed MV beamformer is tested on simu...

  12. Variance decomposition using an IRT measurement model

    NARCIS (Netherlands)

    van den Berg, Stéphanie Martine; van den Berg, Stephanie M.; Glas, Cornelis A.W.; Boomsma, Dorret I.

    2007-01-01

    Large scale research projects in behaviour genetics and genetic epidemiology are often based on questionnaire or interview data. Typically, a number of items is presented to a number of subjects, the subjects’ sum scores on the items are computed, and the variance of sum scores is decomposed into a

  13. Estimating quadratic variation using realized variance

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    This paper looks at some recent work on estimating quadratic variation using realized variance (RV) - that is, sums of M squared returns. This econometrics has been motivated by the advent of the common availability of high-frequency financial return data. When the underlying process...

  14. Decomposition of variance for spatial Cox processes

    DEFF Research Database (Denmark)

    Jalilian, Abdollah; Guan, Yongtao; Waagepetersen, Rasmus

    2013-01-01

    Spatial Cox point processes is a natural framework for quantifying the various sources of variation governing the spatial distribution of rain forest trees. We introduce a general criterion for variance decomposition for spatial Cox processes and apply it to specific Cox process models with addit...

  15. (co)variances for growth and efficiency

    African Journals Online (AJOL)

    42, 295. CANTET, R.J.C., KRESS, D.D., ANDERSON, D.C., DOORNBOS, D.E., BURFENING, P.J. &. BLACKWELL, R.L., 1988. Direct and maternal variances and covariances and maternal phenotypic effects on preweaning growth of beef cattle. J. Anim. Sci. 66, 648. CUNNINGHAM. E.P., MOON, R.A. & GJEDREN, T., 1970.

  16. Biological Variance in Agricultural Products. Theoretical Considerations

    NARCIS (Netherlands)

    Tijskens, L.M.M.; Konopacki, P.

    2003-01-01

    The food that we eat is uniform neither in shape or appearance nor in internal composition or content. Since technology became increasingly important, the presence of biological variance in our food became more and more of a nuisance. Techniques and procedures (statistical, technical) were

  17. Analysis of heritability and shared heritability based on Genome-Wide Association Studies for 13 Cancer Types

    OpenAIRE

    Sampson, JN; Wheeler, WA; Yeager, M.; Panagiotou, O.; Wang, Z; Berndt, SI; Lan, Q; Abnet, CC; Amundadottir, LT; Figueroa, JD; Landi, Mt; Mirabello, L.; Savage, SA; TAYLOR, PR; De Vivo, I

    2015-01-01

    Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common SNPs for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49,492 cancer cases and 34,131 controls. We apply novel mixed model methodology (GCTA) to this GWAS data...

  18. The influence of heritability, neuroticism, maternal warmth and media use on disordered eating behaviors: a prospective analysis of twins.

    Science.gov (United States)

    Ferguson, Christopher J; Muñoz, Monica E; Winegard, Ben; Winegard, Bo

    2012-09-01

    The relative impact of genetic and social influences on disordered eating behaviors (DEB) including binging, purging, excessive dieting and negative self-evaluations about weight remain an issue of debate. The current study sought to examine the relative influence of genetic and social influences on DEB. A 7-year prospective analysis of 580 monozygotic (MZ) and dizygotic (DZ) twins was conducted. Estimates of heritability of DEB were obtained using the DF Analysis Model. Regression equations revealed the relative predictive value of sibling's DEB, neurotic personality, maternal warmth and television and video game exposure on DEB. Heritability estimates for DEB were 0.40 for females and 0.48 for males. Among MZ and DZ twin pairs, female sex, neurotic personality and a genetic variable component, but not maternal warmth or school related problems, predicted DEB. Contrary to the expectations of media effects theory, greater media use was associated with lower DEB among DZ twins and had no influence on MZ twins. These results indicate that DEB is highly heritable and that personality variables may play an important role in the formation of DEB. This suggests that it is important to control for genetic variables when analyzing risk factors for DEB.

  19. Statistical power to detect genetic (co)variance of complex traits using SNP data in unrelated samples.

    Science.gov (United States)

    Visscher, Peter M; Hemani, Gibran; Vinkhuyzen, Anna A E; Chen, Guo-Bo; Lee, Sang Hong; Wray, Naomi R; Goddard, Michael E; Yang, Jian

    2014-04-01

    We have recently developed analysis methods (GREML) to estimate the genetic variance of a complex trait/disease and the genetic correlation between two complex traits/diseases using genome-wide single nucleotide polymorphism (SNP) data in unrelated individuals. Here we use analytical derivations and simulations to quantify the sampling variance of the estimate of the proportion of phenotypic variance captured by all SNPs for quantitative traits and case-control studies. We also derive the approximate sampling variance of the estimate of a genetic correlation in a bivariate analysis, when two complex traits are either measured on the same or different individuals. We show that the sampling variance is inversely proportional to the number of pairwise contrasts in the analysis and to the variance in SNP-derived genetic relationships. For bivariate analysis, the sampling variance of the genetic correlation additionally depends on the harmonic mean of the proportion of variance explained by the SNPs for the two traits and the genetic correlation between the traits, and depends on the phenotypic correlation when the traits are measured on the same individuals. We provide an online tool for calculating the power of detecting genetic (co)variation using genome-wide SNP data. The new theory and online tool will be helpful to plan experimental designs to estimate the missing heritability that has not yet been fully revealed through genome-wide association studies, and to estimate the genetic overlap between complex traits (diseases) in particular when the traits (diseases) are not measured on the same samples.

  20. The quantitative genetics of incipient speciation: heritability and genetic correlations of skeletal traits in populations of diverging Favia fragum ecomorphs.

    Science.gov (United States)

    Carlon, David B; Budd, Ann F; Lippé, Catherine; Andrew, Rose L

    2011-12-01

    Recent speciation events provide potential opportunities to understand the microevolution of reproductive isolation. We used a marker-based approach and a common garden to estimate the additive genetic variation in skeletal traits in a system of two ecomorphs within the coral species Favia fragum: a Tall ecomorph that is a seagrass specialist, and a Short ecomorph that is most abundant on coral reefs. Considering both ecomorphs, we found significant narrow-sense heritability (h(2) ) in a suite of measurements that define corallite architecture, and could partition additive and nonadditive variation for some traits. We found positive genetic correlations for homologous height and length measurements among different types of vertical plates (costosepta) within corallites, but negative correlations between height and length within, as well as between costosepta. Within ecomorphs, h(2) estimates were generally lower, compared to the combined ecomorph analysis. Marker-based estimates of h(2) were comparable to broad-sense heritability (H) obtained from parent-offspring regressions in a common garden for most traits, and similar genetic co-variance matrices for common garden and wild populations may indicate relatively small G × E interactions. The patterns of additive genetic variation in this system invite hypotheses of divergent selection or genetic drift as potential evolutionary drivers of reproductive isolation. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  1. Pedigree-free estimates of heritability in the wild: promising prospects for selfing populations.

    Directory of Open Access Journals (Sweden)

    Laurene Gay

    Full Text Available Estimating the genetic variance available for traits informs us about a population's ability to evolve in response to novel selective challenges. In selfing species, theory predicts a loss of genetic diversity that could lead to an evolutionary dead-end, but empirical support remains scarce. Genetic variability in a trait is estimated by correlating the phenotypic resemblance with the proportion of the genome that two relatives share identical by descent ('realized relatedness'. The latter is traditionally predicted from pedigrees (Φ A : expected value but can also be estimated using molecular markers (average number of alleles shared. Nevertheless, evolutionary biologists, unlike animal breeders, remain cautious about using marker-based relatedness coefficients to study complex phenotypic traits in populations. In this paper, we review published results comparing five different pedigree-free methods and use simulations to test individual-based models (hereafter called animal models using marker-based relatedness coefficients, with a special focus on the influence of mating systems. Our literature review confirms that Ritland's regression method is unreliable, but suggests that animal models with marker-based estimates of relatedness and genomic selection are promising and that more testing is required. Our simulations show that using molecular markers instead of pedigrees in animal models seriously worsens the estimation of heritability in outcrossing populations, unless a very large number of loci is available. In selfing populations the results are less biased. More generally, populations with high identity disequilibrium (consanguineous or bottlenecked populations could be propitious for using marker-based animal models, but are also more likely to deviate from the standard assumptions of quantitative genetics models (non-additive variance.

  2. Results of a "GWAS plus:" general cognitive ability is substantially heritable and massively polygenic.

    Directory of Open Access Journals (Sweden)

    Robert M Kirkpatrick

    Full Text Available We carried out a genome-wide association study (GWAS for general cognitive ability (GCA plus three other analyses of GWAS data that aggregate the effects of multiple single-nucleotide polymorphisms (SNPs in various ways. Our multigenerational sample comprised 7,100 Caucasian participants, drawn from two longitudinal family studies, who had been assessed with an age-appropriate IQ test and had provided DNA samples passing quality screens. We conducted the GWAS across ∼ 2.5 million SNPs (both typed and imputed, using a generalized least-squares method appropriate for the different family structures present in our sample, and subsequently conducted gene-based association tests. We also conducted polygenic prediction analyses under five-fold cross-validation, using two different schemes of weighting SNPs. Using parametric bootstrapping, we assessed the performance of this prediction procedure under the null. Finally, we estimated the proportion of variance attributable to all genotyped SNPs as random effects with software GCTA. The study is limited chiefly by its power to detect realistic single-SNP or single-gene effects, none of which reached genome-wide significance, though some genomic inflation was evident from the GWAS. Unit SNP weights performed about as well as least-squares regression weights under cross-validation, but the performance of both increased as more SNPs were included in calculating the polygenic score. Estimates from GCTA were 35% of phenotypic variance at the recommended biological-relatedness ceiling. Taken together, our results concur with other recent studies: they support a substantial heritability of GCA, arising from a very large number of causal SNPs, each of very small effect. We place our study in the context of the literature-both contemporary and historical-and provide accessible explication of our statistical methods.

  3. Efficiency of genomic selection using Bayesian multimarker models for traits selected to reflect a wide range of heritabilities and frequencies of detected quantitative traits loci in mice

    DEFF Research Database (Denmark)

    Kapell, Dagmar NRG; Sorensen, Daniel; Su, Guosheng

    2012-01-01

    generally performed better than traditional polygenic selection, especially in the context of between family cross-validation. Reducing the number of markers considered to affect the trait did not significantly change PA for most traits, particularly in the case of within family cross...... families. Results Genomic selection showed a high predictive ability (PA) in comparison to traditional polygenic selection, especially for traits of moderate heritability and when cross-validation was between families. This occurred although the proportion of genomic variance of traits using genomic models...

  4. Heritability of brain activity related to response inhibition: A longitudinal genetic study in adolescent twins.

    Science.gov (United States)

    Anokhin, Andrey P; Golosheykin, Simon; Grant, Julia D; Heath, Andrew C

    2017-05-01

    The ability to inhibit prepotent but context- or goal-inappropriate responses is essential for adaptive self-regulation of behavior. Deficits in response inhibition, a key component of impulsivity, have been implicated as a core dysfunction in a range of neuropsychiatric disorders such as ADHD and addictions. Identification of genetically transmitted variation in the neural underpinnings of response inhibition can help to elucidate etiological pathways to these disorders and establish the links between genes, brain, and behavior. However, little is known about genetic influences on the neural mechanisms of response inhibition during adolescence, a developmental period characterized by weak self-regulation of behavior. Here we investigated heritability of ERPs elicited in a Go/No-Go task in a large sample of adolescent twins assessed longitudinally at ages 12, 14, and 16. Genetic analyses showed significant heritability of inhibition-related frontal N2 and P3 components at all three ages, with 50 to 60% of inter-individual variability being attributable to genetic factors. These genetic influences included both common genetic factors active at different ages and novel genetic influences emerging during development. Finally, individual differences in the rate of developmental changes from age 12 to age 16 were significantly influenced by genetic factors. In conclusion, the present study provides the first evidence for genetic influences on neural correlates of response inhibition during adolescence and suggests that ERPs elicited in the Go/No-Go task can serve as intermediate neurophysiological phenotypes (endophenotypes) for the study of disinhibition and impulse control disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Evaluation of genetic divergence and heritability in pea (Pisum sativum L.

    Directory of Open Access Journals (Sweden)

    Natalia Georgieva

    2016-04-01

    Full Text Available An experiment on genetic evaluation of five genotypes of forage pea (Glyans, Svit, Kamerton, Modus, Pleven 4 was conducted during 2012-2014 period. Analysis of variance showed significant differences among genotypes for the traits pod width, seeds per plant, seed weight per plant and 1000 seed weight. The estimates of genetic parameters of five varieties of Pisum sativum L. indicated a good amount of genetic variation in the experimental materials under investigation. Moderate phenotypic and genotypic coefficients of variation were observed for most of traits except pod length and pod width. For the traits studied seeds per plant, seed weight per plant and plant height were found high heritability along with high genetic gain indicating preponderance of additive effects. Therefore, selection programme based on these characters would be more effective in improving yield parameters of forage pea. The seed yield was positively and significantly correlated with 1000 seed weight and pod stem, which suggested the possibilities of improving seed yield by simultaneous improvement of these traits.

  6. An Empirical Temperature Variance Source Model in Heated Jets

    Science.gov (United States)

    Khavaran, Abbas; Bridges, James

    2012-01-01

    An acoustic analogy approach is implemented that models the sources of jet noise in heated jets. The equivalent sources of turbulent mixing noise are recognized as the differences between the fluctuating and Favre-averaged Reynolds stresses and enthalpy fluxes. While in a conventional acoustic analogy only Reynolds stress components are scrutinized for their noise generation properties, it is now accepted that a comprehensive source model should include the additional entropy source term. Following Goldstein s generalized acoustic analogy, the set of Euler equations are divided into two sets of equations that govern a non-radiating base flow plus its residual components. When the base flow is considered as a locally parallel mean flow, the residual equations may be rearranged to form an inhomogeneous third-order wave equation. A general solution is written subsequently using a Green s function method while all non-linear terms are treated as the equivalent sources of aerodynamic sound and are modeled accordingly. In a previous study, a specialized Reynolds-averaged Navier-Stokes (RANS) solver was implemented to compute the variance of thermal fluctuations that determine the enthalpy flux source strength. The main objective here is to present an empirical model capable of providing a reasonable estimate of the stagnation temperature variance in a jet. Such a model is parameterized as a function of the mean stagnation temperature gradient in the jet, and is evaluated using commonly available RANS solvers. The ensuing thermal source distribution is compared with measurements as well as computational result from a dedicated RANS solver that employs an enthalpy variance and dissipation rate model. Turbulent mixing noise predictions are presented for a wide range of jet temperature ratios from 1.0 to 3.20.

  7. Source Characterization by the Allan Variance

    Science.gov (United States)

    Gattano, C.; Lambert, S.

    2016-12-01

    Until now, the main criteria for selecting geodetic sources were based on astrometric stability and structure at 8 GHz te{Fey2015}. But with more observations and the increase of accuracy, the statistical tools used to determine this stability become inappropriate with regards to sudden motions of the radiocenter. In this work, we propose to replace these tools by the Allan Variance te{Allan1966}, first used on VLBI sources by M. Feissel-Vernier te{Feissel2003}, leading to a new classification of sources into three groups according to the shape of the Allan Variance. In parallel, we combine two catalogs, the Large Quasar Astrometric Catalogue te{Souchay2015} and the Optical Characteristics of Astrometric Radio Sources te{Malkin2013}, in order to gather most physical characteristics known about these VLBI targets. By doing so, we may reveal physical criteria that may be useful in the selection of new targets for future VLBI observations.

  8. The value of travel time variance

    OpenAIRE

    Fosgerau, Mogens; Engelson, Leonid

    2010-01-01

    This paper considers the value of travel time variability under scheduling preferences that are de�fined in terms of linearly time-varying utility rates associated with being at the origin and at the destination. The main result is a simple expression for the value of travel time variability that does not depend on the shape of the travel time distribution. The related measure of travel time variability is the variance of travel time. These conclusions apply equally to travellers ...

  9. Directional variance analysis of annual rings

    Science.gov (United States)

    Kumpulainen, P.; Marjanen, K.

    2010-07-01

    The wood quality measurement methods are of increasing importance in the wood industry. The goal is to produce more high quality products with higher marketing value than is produced today. One of the key factors for increasing the market value is to provide better measurements for increased information to support the decisions made later in the product chain. Strength and stiffness are important properties of the wood. They are related to mean annual ring width and its deviation. These indicators can be estimated from images taken from the log ends by two-dimensional power spectrum analysis. The spectrum analysis has been used successfully for images of pine. However, the annual rings in birch, for example are less distinguishable and the basic spectrum analysis method does not give reliable results. A novel method for local log end variance analysis based on Radon-transform is proposed. The directions and the positions of the annual rings can be estimated from local minimum and maximum variance estimates. Applying the spectrum analysis on the maximum local variance estimate instead of the original image produces more reliable estimate of the annual ring width. The proposed method is not limited to log end analysis only. It is usable in other two-dimensional random signal and texture analysis tasks.

  10. Discussion on variance reduction technique for shielding

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Fujio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    As the task of the engineering design activity of the international thermonuclear fusion experimental reactor (ITER), on 316 type stainless steel (SS316) and the compound system of SS316 and water, the shielding experiment using the D-T neutron source of FNS in Japan Atomic Energy Research Institute has been carried out. However, in these analyses, enormous working time and computing time were required for determining the Weight Window parameter. Limitation or complication was felt when the variance reduction by Weight Window method of MCNP code was carried out. For the purpose of avoiding this difficulty, investigation was performed on the effectiveness of the variance reduction by cell importance method. The conditions of calculation in all cases are shown. As the results, the distribution of fractional standard deviation (FSD) related to neutrons and gamma-ray flux in the direction of shield depth is reported. There is the optimal importance change, and when importance was increased at the same rate as that of the attenuation of neutron or gamma-ray flux, the optimal variance reduction can be done. (K.I.)

  11. Heritability of Biomarkers of Oxidized Lipoproteins: A Twin Pair Study

    Science.gov (United States)

    Rao, Fangwen; Schork, Andrew J.; Maihofer, Adam X.; Nievergelt, Caroline M.; Marcovina, Santica; Miller, Elizabeth R.; Witztum, Joseph L.; O'Connor, Daniel T.; Tsimikas, Sotirios

    2015-01-01

    Objective To determine if biomarkers of oxidized lipoproteins are genetically determined. Lipoprotein(a) [Lp(a)] is a heritable risk factor and carrier of oxidized phospholipids (OxPL). Approach and Results We measured OxPL-apoB, Lp(a), IgG and IgM autoantibodies to malondialdehyde-modified low density lipoprotein (MDA-LDL), copper oxidized LDL (CuOxLDL) and apoB-immune complexes (ApoB-IC) in 386 monozygotic and dizygotic twins to estimate trait heritability (h2) and determine specific genetic effects among traits. A genome wide linkage study followed by genetic association was performed. The h2 (scale:0-1) for Lp(a) was 0.91±0.01 and for OxPL-apoB 0.87±0.02, which were higher than physiologic, inflammatory, or lipid traits. h2 of IgM MDA-LDL, CuOxLDL and ApoB-IC were 0.69±0.04, 0.67±0.05, and 0.80±0.03, respectively, and for IgG MDA-LDL, CuOxLDL and apoB-IC 0.62±0.05, 0.52±0.06, and 0.53±0.06, respectively. There was an inverse correlation between the major apo(a) isoform and OxPL-apoB (R=-0.49, plipoproteins are highly heritable cardiovascular risk factors that suggest novel genetic origins of atherothrombosis. PMID:25953646

  12. Heritability and linkage analysis of personality in bipolar disorder.

    Science.gov (United States)

    Greenwood, Tiffany A; Badner, Judith A; Byerley, William; Keck, Paul E; McElroy, Susan L; Remick, Ronald A; Dessa Sadovnick, A; Kelsoe, John R

    2013-11-01

    The many attempts that have been made to identify genes for bipolar disorder (BD) have met with limited success, which may reflect an inadequacy of diagnosis as an informative and biologically relevant phenotype for genetic studies. Here we have explored aspects of personality as quantitative phenotypes for bipolar disorder through the use of the Temperament and Character Inventory (TCI), which assesses personality in seven dimensions. Four temperament dimensions are assessed: novelty seeking (NS), harm avoidance (HA), reward dependence (RD), and persistence (PS). Three character dimensions are also included: self-directedness (SD), cooperativeness (CO), and self-transcendence (ST). We compared personality scores between diagnostic groups and assessed heritability in a sample of 101 families collected for genetic studies of BD. A genome-wide SNP linkage analysis was then performed in the subset of 51 families for which genetic data was available. Significant group differences were observed between BD subjects, their first-degree relatives, and independent controls for all but RD and PS, and all but HA and RD were found to be significantly heritable in this sample. Linkage analysis of the heritable dimensions produced several suggestive linkage peaks for NS (chromosomes 7q21 and 10p15), PS (chromosomes 6q16, 12p13, and 19p13), and SD (chromosomes 4q35, 8q24, and 18q12). The relatively small size of our linkage sample likely limited our ability to reach genome-wide significance in this study. While not genome-wide significant, these results suggest that aspects of personality may prove useful in the identification of genes underlying BD susceptibility. © 2013 Elsevier B.V. All rights reserved.

  13. Heritability of eleven metabolic phenotypes in Danish and Chinese twins

    DEFF Research Database (Denmark)

    Li, Shuxia; Duan, Hongmei; Pang, Zengchang

    2013-01-01

    A twin-based comparative study on the genetic influences in metabolic endophenotypes in two populations of substantial ethnic, environmental, and cultural differences was performed. Design and Methods: Data on 11 metabolic phenotypes including anthropometric measures, blood glucose, and lipids...... similar heritability patterns in the two samples with body weight showing only a slight difference. Higher genetic influences were estimated for fasting blood glucose level in Chinese twins, whereas the Danish twins showed more genetic regulation over most lipids phenotypes. Systolic blood pressure...... was more genetically controlled in Danish than in Chinese twins. Conclusions: Metabolic endophenotypes show disparity in their genetic determinants in populations under distinct environmental conditions....

  14. HERITABILITY AND PATH ANALYSIS OF SOME ECONOMICAL CHARACTERISTICS IN LENTIL

    Directory of Open Access Journals (Sweden)

    B BIÇER

    2008-07-01

    Full Text Available Twenty-nine lentil (Lens culinaris Medik genotypes were grown from 1997/98 to 1998/2001 at Dicle University, Faculty of Agriculture in Diyarbakir The heritability for days to fl owering and maturity, plant height, height of lowest pod, number of pod per plant, 1000 seed weight and seed yield were estimated as 0.94, 0.78, 0.52, 0.72, 0.37, 0.87 and 0.53, respectively. The path analysis indicated that total biological yield and number of clusters and pods per plant had very high positive direct effect on seed yield.

  15. Shared genetic variance between obesity and white matter integrity in Mexican-americans

    Directory of Open Access Journals (Sweden)

    Elena A Spieker

    2015-02-01

    Full Text Available Obesity is a chronic metabolic disorder that may also lead to reduced white matter integrity, potentially due to shared genetic risk factors. Genetic correlation analyses were conducted in a large cohort of Mexican American families in San Antonio (N=761, 58% females, ages 18-81y; 41.3±14.5 from the Genetics of Brain Structure and Function Study. Shared genetic variance was calculated between measures of adiposity ((body mass index (BMI; kg/m2 and waist circumference (WC; in and whole-brain and regional measurements of cerebral white matter integrity (fractional anisotropy. Whole-brain average and regional fractional anisotropy values for ten major white matter tracts were calculated from high angular resolution diffusion tensor imaging data (DTI; 1.7×1.7×3 mm; 55 directions. Additive genetic factors explained intersubject variance in BMI (heritability, h2=0.58, WC (h2=0.57, and FA (h2=0.49. FA shared significant portions of genetic variance with BMI in the genu (ρG = -0.25, body (ρG = -0.30, and splenium (ρG = -0.26 of the corpus callosum, internal capsule (ρG = -0.29, and thalamic radiation (ρG = -0.31 (all p’s = .043. The strongest evidence of shared variance was between BMI/WC and FA in the superior fronto-occipital fasciculus (ρG = -0.39, p = .020; ρG = -0.39, p = .030, which highlights region-specific variation in neural correlates of obesity. This may suggest that increase in obesity and reduced white matter integrity share common genetic risk factors.

  16. Environmental stress correlates with increases in both genetic and residual variances: A meta-analysis of animal studies.

    Science.gov (United States)

    Rowiński, Piotr K; Rogell, Björn

    2017-05-01

    Adaptive evolutionary responses are determined by the strength of selection and amount of genetic variation within traits, however, both are known to vary across environmental conditions. As selection is generally expected to be strongest under stressful conditions, understanding how the expression of genetic variation changes across stressful and benign environmental conditions is crucial for predicting the rate of adaptive change. Although theory generally predicts increased genetic variation under stress, previous syntheses of the field have found limited support for this notion. These studies have focused on heritability, which is dependent on other environmentally sensitive, but nongenetic, sources of variation. Here, we aim to complement these studies with a meta-analysis in which we examine changes in coefficient of variation (CV) in maternal, genetic, and residual variances across stressful and benign conditions. Confirming previous analyses, we did not find any clear direction in how heritability changes across stressful and benign conditions. However, when analyzing CV, we found higher genetic and residual variance under highly stressful conditions in life-history traits but not in morphological traits. Our findings are of broad significance to contemporary evolution suggesting that rapid evolutionary adaptive response may be mediated by increased evolutionary potential in stressed populations. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  17. Variance decomposition for single-subject task-based fMRI activity estimates across many sessions.

    Science.gov (United States)

    Gonzalez-Castillo, Javier; Chen, Gang; Nichols, Thomas E; Bandettini, Peter A

    2017-07-01

    Here we report an exploratory within-subject variance decomposition analysis conducted on a task-based fMRI dataset with an unusually large number of repeated measures (i.e., 500 trials in each of three different subjects) distributed across 100 functional scans and 9 to 10 different sessions. Within-subject variance was segregated into four primary components: variance across-sessions, variance across-runs within a session, variance across-blocks within a run, and residual measurement/modeling error. Our results reveal inhomogeneous and distinct spatial distributions of these variance components across significantly active voxels in grey matter. Measurement error is dominant across the whole brain. Detailed evaluation of the remaining three components shows that across-session variance is the second largest contributor to total variance in occipital cortex, while across-runs variance is the second dominant source for the rest of the brain. Network-specific analysis revealed that across-block variance contributes more to total variance in higher-order cognitive networks than in somatosensory cortex. Moreover, in some higher-order cognitive networks across-block variance can exceed across-session variance. These results help us better understand the temporal (i.e., across blocks, runs and sessions) and spatial distributions (i.e., across different networks) of within-subject natural variability in estimates of task responses in fMRI. They also suggest that different brain regions will show different natural levels of test-retest reliability even in the absence of residual artifacts and sufficiently high contrast-to-noise measurements. Further confirmation with a larger sample of subjects and other tasks is necessary to ensure generality of these results. Published by Elsevier Inc.

  18. Genetic and environmental variance and covariance parameters for some reproductive traits of Holstein and Jersey cattle in Antioquia (Colombia

    Directory of Open Access Journals (Sweden)

    Juan Carlos Zambrano

    2014-03-01

    Full Text Available The objective of this study was to estimate the genetic, phenotypic and environmental parameters for calving interval (CI, days open (DO, number of services per conception (NSC and conception rate (CR in Holstein and Jersey cattle in Antioquia (Colombia. Variance and covariance component estimates were obtained by an animal model that was solved using the derivative-free restricted maximum likelihood method. The means and standard deviations for CI, DO, NSC and CR were: 430.32±77.93 days, 127.15±76.96 days, 1.58±1.03 services per conception and 79.88±28.66% in Holstein cattle, and 409.33±86.48 days, 125.62±86.09 days, 1.48±0.98 services per conception and 84.08±27.23% in Jersey cattle, respectively. The heritability estimates (standard errors were: 0.088(0.037, 0.082(0.037, 0.040(0.025 and 0.030(0.026 in Holstein cattle and 0.072(0.098, 0.090(0.104, 0.093(0.097 and 0.147(0.117 in Jersey cattle, respectively. The results show that the genetic, phenotypic and permanent environmental correlations in the two evaluated breeds were favorable for CI × DO, CI × NSC and DO × NSC, but not for CI × CR, DO × CR and NSC × CR. Genetic and permanent environmental correlations were high in most cases in Holstein cattle, whereas in Jersey cattle they were moderate. In contrast, phenotypic correlations were very low in both breeds, except for CI × DO and NSC × CR, which were high. Overall, the genetic component found was very low (<8% in both evaluated breeds and this implies that their selection would take long time and that a good practical management of the herd will be essential in order to improve the reproductive performance.

  19. Estimates of (covariance components and genetic parameters for body weights and growth efficiency traits in the New Zealand white rabbit

    Directory of Open Access Journals (Sweden)

    M. Sakthivel

    2017-12-01

    Full Text Available The genetic parameters of growth traits in the New Zealand White rabbits kept at Sheep Breeding and Research Station, Sandynallah, The Nilgiris, India were estimated by partitioning the variance and covariance components. The (covariance components of body weights at weaning (W42, post-weaning (W70 and marketing (W135 age and growth efficiency traits viz., average daily gain (ADG, relative growth rate (RGR and Kleiber ratio (KR estimated on a daily basis at different age intervals (42 to 70 d; 70 to 135 d and 42 to 135 d from weaning to marketing were estimated by restricted maximum likelihood, fitting 6 animal models with various combinations of direct and maternal effects. Data were collected over a period of 15 yr (1998 to 2012. A log-likelihood ratio test was used to select the most appropriate univariate model for each trait, which was subsequently used in bivariate analysis. Heritability estimates for W42, W70 and W135 were 0.42±0.07, 0.40±0.08 and 0.27±0.07, respectively. Heritability estimates of growth efficiency traits were moderate to high (0.18 to 0.42. Of the total phenotypic variation, maternal genetic effect contributed 14 to 32% for early body weight traits (W42 and W70 and ADG1. The contribution of maternal permanent environmental effect varied from 6 to 18% for W42 and for all the growth efficiency traits except for KR2. Maternal permanent environmental effect on most of the growth efficiency traits was a carryover effect of maternal care during weaning. Direct maternal genetic correlations, for the traits in which maternal genetic effect was significant, were moderate to high in magnitude and negative in direction. Maternal effect declined as the age of the animal increased. The estimates of total heritability and maternal across year repeatability for growth traits were moderate and an optimum rate of genetic progress seems possible in the herd by mass selection. The genetic and phenotypic correlations among body weights

  20. Heritability and complex segregation analysis of deafness in Jack Russell Terriers.

    Science.gov (United States)

    Famula, Thomas R; Cargill, Edward J; Strain, George M

    2007-11-13

    The association between patterns of pigmentation and deafness in the dog has a long-documented history, with reports dating back over one hundred years. Long suspected of having a genetic basis, the search for loci with a pronounced influence in the expression of hearing loss in the dog has yet to be successful. No studies in the dog to date have found a possible influence of a specific colour locus associated with deafness. The present study is intended to evaluate the heritability of deafness in the Jack Russell Terrier (JRT), characterize the mode of inheritance, and evaluate the existence of a sex, coat colour, or coat texture influence on the expression of sensorineural deafness. The estimation of heritability of deafness in the JRT was 0.22 when deafness was considered a binary (normal/deaf) trait and 0.31 when deafness was considered a three-category (normal/unilateral/bilateral deafness). The influence of coat colour in the incidence of JRT deafness was statistically significant, indicating that dogs with more white are more likely to be deaf. The influence of sex or coat texture was not statistically significant in the incidence of JRT deafness. Complex segregation analysis revealed a model of a single locus with a large effect on the binary measure of hearing loss is not supported. This is the first attempt, to our knowledge, to characterize a genetic component responsible for deafness in the JRT. The heritability of deafness in the JRT was found to be 0.22 and 0.31 considering deafness to be a two-category or three-category trait, respectively. There appears to be an influence of coat colour on the expression of deafness. In an attempt to characterize the mode of inheritance of deafness in the JRT, a model of a single locus with a large effect on hearing loss is not supported with this data. Further study is needed to determine if a single locus may be influencing deafness in the JRT. While the absence of a clear mode of inheritance complicates genetic

  1. Heritability and complex segregation analysis of deafness in Jack Russell Terriers

    Directory of Open Access Journals (Sweden)

    Strain George M

    2007-11-01

    Full Text Available Abstract Background The association between patterns of pigmentation and deafness in the dog has a long-documented history, with reports dating back over one hundred years. Long suspected of having a genetic basis, the search for loci with a pronounced influence in the expression of hearing loss in the dog has yet to be successful. No studies in the dog to date have found a possible influence of a specific colour locus associated with deafness. The present study is intended to evaluate the heritability of deafness in the Jack Russell Terrier (JRT, characterize the mode of inheritance, and evaluate the existence of a sex, coat colour, or coat texture influence on the expression of sensorineural deafness. Results The estimation of heritability of deafness in the JRT was 0.22 when deafness was considered a binary (normal/deaf trait and 0.31 when deafness was considered a three-category (normal/unilateral/bilateral deafness. The influence of coat colour in the incidence of JRT deafness was statistically significant, indicating that dogs with more white are more likely to be deaf. The influence of sex or coat texture was not statistically significant in the incidence of JRT deafness. Complex segregation analysis revealed a model of a single locus with a large effect on the binary measure of hearing loss is not supported. Conclusion This is the first attempt, to our knowledge, to characterize a genetic component responsible for deafness in the JRT. The heritability of deafness in the JRT was found to be 0.22 and 0.31 considering deafness to be a two-category or three-category trait, respectively. There appears to be an influence of coat colour on the expression of deafness. In an attempt to characterize the mode of inheritance of deafness in the JRT, a model of a single locus with a large effect on hearing loss is not supported with this data. Further study is needed to determine if a single locus may be influencing deafness in the JRT. While the

  2. Heritability of Tpeak-Tend Interval and T-wave Amplitude: A Twin Study

    DEFF Research Database (Denmark)

    Haarmark, Christian; Kyvik, Kirsten O; Vedel-Larsen, Esben

    2011-01-01

    BACKGROUND: -Tpeak-Tend interval (TpTe) and T-wave amplitude (Tamp) carry diagnostic and prognostic information regarding cardiac morbidity and mortality. Heart rate and QT interval are known to be heritable traits. The heritability of T-wave morphology parameters such as TpTe and Tamp is unknown...... interval, QTpeak and QTend interval) were measured and averaged over three consecutive beats in lead V5. TpTe was calculated as the QTend and QTpeak interval difference. Heritability was assessed using structural equation models adjusting for age, gender and BMI. All models were reducible to a model...... are heritable ECG parameters....

  3. Are range-size distributions consistent with species-level heritability?

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Gotelli, Nicholas; Rahbek, Carsten

    2012-01-01

    The concept of species-level heritability is widely contested. Because it is most likely to apply to emergent, species-level traits, one of the central discussions has focused on the potential heritability of geographic range size. However, a central argument against range-size heritability has...... been that it is not compatible with the observed shape of present-day species range-size distributions (SRDs), a claim that has never been tested. To assess this claim, we used forward simulation of range-size evolution in clades with varying degrees of range-size heritability, and compared the output...

  4. Herdabilidade de características de produção e postura em matrizes de codornas de corte Heritability of production and laying traits in meat-type quails

    Directory of Open Access Journals (Sweden)

    Bruno Bastos Teixeira

    2013-02-01

    period 2006 to 2009, being accompanied by five generations, totaling 2136 arrays. Quail were weighed at birth, 7, 14, 21, 28, 35, 42, 77, 112 and 147 days of age. We evaluated each quail eggs were collected for three consecutive days, during four periods of 35 days and measured the width and length of eggs, yolk weight, albumen and shell. We evaluated the specific gravity of eggs and measured the rate of overall posture and age at first egg. Univariate analyzes were performed to estimate the variance components, using the method of restricted maximum likelihood using the program and calculated the MTDFREML hedabilidades. For the quality of eggs heritability values were moderate to high (0.13 to 0.55, high values for growth (0.64 to 0.68 and moderate to high for egg shape (0.10 to 0.57. Heritability estimates for egg quality found indicate a high genetic variability for both genetic groups. As for the weights indicated that selection within the population could result in increases in weight by selection based on individual information. For the characteristics of an egg shape, the heritability values suggest the possibility of genetic groups that meet a standard shape.

  5. Interaction of Prions Causes Heritable Traits in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Anton A Nizhnikov

    2016-12-01

    Full Text Available The concept of "protein-based inheritance" defines prions as epigenetic determinants that cause several heritable traits in eukaryotic microorganisms, such as Saccharomyces cerevisiae and Podospora anserina. Previously, we discovered a non-chromosomal factor, [NSI+], which possesses the main features of yeast prions, including cytoplasmic infectivity, reversible curability, dominance, and non-Mendelian inheritance in meiosis. This factor causes omnipotent suppression of nonsense mutations in strains of S. cerevisiae bearing a deleted or modified Sup35 N-terminal domain. In this work, we identified protein determinants of [NSI+] using an original method of proteomic screening for prions. The suppression of nonsense mutations in [NSI+] strains is determined by the interaction between [SWI+] and [PIN+] prions. Using genetic and biochemical methods, we showed that [SWI+] is the key determinant of this nonsense suppression, whereas [PIN+] does not cause nonsense suppression by itself but strongly enhances the effect of [SWI+]. We demonstrated that interaction of [SWI+] and [PIN+] causes inactivation of SUP45 gene that leads to nonsense suppression. Our data show that prion interactions may cause heritable traits in Saccharomyces cerevisiae.

  6. Heritability of dollar spot resistance in creeping bentgrass.

    Science.gov (United States)

    Bonos, Stacy A

    2006-08-01

    ABSTRACT The dollar spot disease incited by Sclerotinia homoeocarpa is an important disease of creeping bentgrass (Agrostis stolonifera). Genetic resistance is an important control strategy and could reduce fungicide use. Despite recent research, the genetic mechanism of dollar spot resistance in turfgrasses is still not fully understood. The objectives of this study were to (i) determine narrow-sense heritability and predicted gain from selection for dollar spot resistance in creeping bentgrass and (ii) evaluate inheritance characteristics of dollar spot disease resistance. Inheritance characteristics such as the detection of major genes, heterosis, maternal effects, and combining ability were determined by evaluating the disease severity of progeny from crosses between resistant and susceptible bent-grass clones. Parental clones and progenies from crosses were established in a field trial in a randomized complete block design and inoculated with one isolate of S. homoeocarpa applied at a rate of 0.25 g m(-2) of prepared inoculum. Differences in progeny means between crosses were observed over both years. Progeny from resistant x resistant crosses had significantly less disease severity than resistant x susceptible and susceptible x susceptible crosses. High narrow-sense heritability estimates (0.79 [2002], 0.79 [2003]) and large mean squares for general combining ability support the idea that additive gene action plays a significant role in disease resistance and support previous research that dollar spot resistance is most likely quantitatively inherited.

  7. Dark matter: are mice the solution to missing heritability?

    Directory of Open Access Journals (Sweden)

    Clarissa Carlin Parker

    2011-06-01

    Full Text Available Genome-wide association studies (GWAS in humans have identified hundreds of single nucleotide polymorphisms associated with complex traits, yet for most traits studied, the sum total of all these identified variants fail to explain a significant portion of the heritable variation. Reasons for this missing heritability are thought to include the existence of rare causative variants not captured by current genotyping arrays, structural variants that go undetected by existing technology, insufficient power to identify multi-gene interactions, small sample sizes, and the influence of environmental and epigenetic effects. As genotyping technologies have evolved it has become inexpensive and relatively straightforward to perform GWAS in mice. Mice offer a powerful tool for elucidating the genetic architecture of behavioral and physiological traits, and are complementary to human studies. Unlike F2 crosses of inbred strains, advanced intercross lines, heterogeneous stocks, outbred, and wild-caught mice have more rapid breakdown of linkage disequilibrium which allow for increasingly high resolution mapping. Because some of these populations are created using a small number of founder chromosomes they are not expected to harbor rare alleles. We discuss the differences between these mouse populations and examine their potential to overcome some of the pitfalls that have plagued human GWAS studies.

  8. Visual SLAM Using Variance Grid Maps

    Science.gov (United States)

    Howard, Andrew B.; Marks, Tim K.

    2011-01-01

    An algorithm denoted Gamma-SLAM performs further processing, in real time, of preprocessed digitized images acquired by a stereoscopic pair of electronic cameras aboard an off-road robotic ground vehicle to build accurate maps of the terrain and determine the location of the vehicle with respect to the maps. Part of the name of the algorithm reflects the fact that the process of building the maps and determining the location with respect to them is denoted simultaneous localization and mapping (SLAM). Most prior real-time SLAM algorithms have been limited in applicability to (1) systems equipped with scanning laser range finders as the primary sensors in (2) indoor environments (or relatively simply structured outdoor environments). The few prior vision-based SLAM algorithms have been feature-based and not suitable for real-time applications and, hence, not suitable for autonomous navigation on irregularly structured terrain. The Gamma-SLAM algorithm incorporates two key innovations: Visual odometry (in contradistinction to wheel odometry) is used to estimate the motion of the vehicle. An elevation variance map (in contradistinction to an occupancy or an elevation map) is used to represent the terrain. The Gamma-SLAM algorithm makes use of a Rao-Blackwellized particle filter (RBPF) from Bayesian estimation theory for maintaining a distribution over poses and maps. The core idea of the RBPF approach is that the SLAM problem can be factored into two parts: (1) finding the distribution over robot trajectories, and (2) finding the map conditioned on any given trajectory. The factorization involves the use of a particle filter in which each particle encodes both a possible trajectory and a map conditioned on that trajectory. The base estimate of the trajectory is derived from visual odometry, and the map conditioned on that trajectory is a Cartesian grid of elevation variances. In comparison with traditional occupancy or elevation grid maps, the grid elevation variance

  9. Realized Variance and Market Microstructure Noise

    DEFF Research Database (Denmark)

    Hansen, Peter R.; Lunde, Asger

    2006-01-01

    estimation based on high-frequency data. Finally, we apply cointegration techniques to decompose transaction prices and bid-ask quotes into an estimate of the efficient price and noise. This framework enables us to study the dynamic effects on transaction prices and quotes caused by changes in the efficient......We study market microstructure noise in high-frequency data and analyze its implications for the realized variance (RV) under a general specification for the noise. We show that kernel-based estimators can unearth important characteristics of market microstructure noise and that a simple kernel...

  10. Genetic heterogeneity of within-family variance of body weight in Atlantic salmon (Salmo salar).

    Science.gov (United States)

    Sonesson, Anna K; Odegård, Jørgen; Rönnegård, Lars

    2013-10-17

    Canalization is defined as the stability of a genotype against minor variations in both environment and genetics. Genetic variation in degree of canalization causes heterogeneity of within-family variance. The aims of this study are twofold: (1) quantify genetic heterogeneity of (within-family) residual variance in Atlantic salmon and (2) test whether the observed heterogeneity of (within-family) residual variance can be explained by simple scaling effects. Analysis of body weight in Atlantic salmon using a double hierarchical generalized linear model (DHGLM) revealed substantial heterogeneity of within-family variance. The 95% prediction interval for within-family variance ranged from ~0.4 to 1.2 kg2, implying that the within-family variance of the most extreme high families is expected to be approximately three times larger than the extreme low families. For cross-sectional data, DHGLM with an animal mean sub-model resulted in severe bias, while a corresponding sire-dam model was appropriate. Heterogeneity of variance was not sensitive to Box-Cox transformations of phenotypes, which implies that heterogeneity of variance exists beyond what would be expected from simple scaling effects. Substantial heterogeneity of within-family variance was found for body weight in Atlantic salmon. A tendency towards higher variance with higher means (scaling effects) was observed, but heterogeneity of within-family variance existed beyond what could be explained by simple scaling effects. For cross-sectional data, using the animal mean sub-model in the DHGLM resulted in biased estimates of variance components, which differed substantially both from a standard linear mean animal model and a sire-dam DHGLM model. Although genetic differences in canalization were observed, selection for increased canalization is difficult, because there is limited individual information for the variance sub-model, especially when based on cross-sectional data. Furthermore, potential macro

  11. Individual differences in personality traits reflect structural variance in specific brain regions.

    Science.gov (United States)

    Gardini, Simona; Cloninger, C Robert; Venneri, Annalena

    2009-06-30

    Personality dimensions such as novelty seeking (NS), harm avoidance (HA), reward dependence (RD) and persistence (PER) are said to be heritable, stable across time and dependent on genetic and neurobiological factors. Recently a better understanding of the relationship between personality traits and brain structures/systems has become possible due to advances in neuroimaging techniques. This Magnetic Resonance Imaging (MRI) study investigated if individual differences in these personality traits reflected structural variance in specific brain regions. A large sample of eighty five young adult participants completed the Three-dimensional Personality Questionnaire (TPQ) and had their brain imaged with MRI. A voxel-based correlation analysis was carried out between individuals' personality trait scores and grey matter volume values extracted from 3D brain scans. NS correlated positively with grey matter volume in frontal and posterior cingulate regions. HA showed a negative correlation with grey matter volume in orbito-frontal, occipital and parietal structures. RD was negatively correlated with grey matter volume in the caudate nucleus and in the rectal frontal gyrus. PER showed a positive correlation with grey matter volume in the precuneus, paracentral lobule and parahippocampal gyrus. These results indicate that individual differences in the main personality dimensions of NS, HA, RD and PER, may reflect structural variance in specific brain areas.

  12. Increasing genetic variance of body mass index during the Swedish obesity epidemic.

    Directory of Open Access Journals (Sweden)

    Benjamin Rokholm

    Full Text Available BACKGROUND AND OBJECTIVES: There is no doubt that the dramatic worldwide increase in obesity prevalence is due to changes in environmental factors. However, twin and family studies suggest that genetic differences are responsible for the major part of the variation in adiposity within populations. Recent studies show that the genetic effects on body mass index (BMI may be stronger when combined with presumed risk factors for obesity. We tested the hypothesis that the genetic variance of BMI has increased during the obesity epidemic. METHODS: The data comprised height and weight measurements of 1,474,065 Swedish conscripts at age 18-19 y born between 1951 and 1983. The data were linked to the Swedish Multi-Generation Register and the Swedish Twin Register from which 264,796 full-brother pairs, 1,736 monozygotic (MZ and 1,961 dizygotic (DZ twin pairs were identified. The twin pairs were analysed to identify the most parsimonious model for the genetic and environmental contribution to BMI variance. The full-brother pairs were subsequently divided into subgroups by year of birth to investigate trends in the genetic variance of BMI. RESULTS: The twin analysis showed that BMI variation could be explained by additive genetic and environmental factors not shared by co-twins. On the basis of the analyses of the full-siblings, the additive genetic variance of BMI increased from 4.3 [95% CI 4.04-4.53] to 7.9 [95% CI 7.28-8.54] within the study period, as did the unique environmental variance, which increased from 1.4 [95% CI 1.32-1.48] to 2.0 [95% CI 1.89-2.22]. The BMI heritability increased from 75% to 78.8%. CONCLUSION: The results confirm the hypothesis that the additive genetic variance of BMI has increased strongly during the obesity epidemic. This suggests that the obesogenic environment has enhanced the influence of adiposity related genes.

  13. Variance-based Salt Body Reconstruction

    KAUST Repository

    Ovcharenko, Oleg

    2017-05-26

    Seismic inversions of salt bodies are challenging when updating velocity models based on Born approximation- inspired gradient methods. We propose a variance-based method for velocity model reconstruction in regions complicated by massive salt bodies. The novel idea lies in retrieving useful information from simultaneous updates corresponding to different single frequencies. Instead of the commonly used averaging of single-iteration monofrequency gradients, our algorithm iteratively reconstructs salt bodies in an outer loop based on updates from a set of multiple frequencies after a few iterations of full-waveform inversion. The variance among these updates is used to identify areas where considerable cycle-skipping occurs. In such areas, we update velocities by interpolating maximum velocities within a certain region. The result of several recursive interpolations is later used as a new starting model to improve results of conventional full-waveform inversion. An application on part of the BP 2004 model highlights the evolution of the proposed approach and demonstrates its effectiveness.

  14. Analysis of a genetically structured variance heterogeneity model using the Box-Cox transformation.

    Science.gov (United States)

    Yang, Ye; Christensen, Ole F; Sorensen, Daniel

    2011-02-01

    Over recent years, statistical support for the presence of genetic factors operating at the level of the environmental variance has come from fitting a genetically structured heterogeneous variance model to field or experimental data in various species. Misleading results may arise due to skewness of the marginal distribution of the data. To investigate how the scale of measurement affects inferences, the genetically structured heterogeneous variance model is extended to accommodate the family of Box-Cox transformations. Litter size data in rabbits and pigs that had previously been analysed in the untransformed scale were reanalysed in a scale equal to the mode of the marginal posterior distribution of the Box-Cox parameter. In the rabbit data, the statistical evidence for a genetic component at the level of the environmental variance is considerably weaker than that resulting from an analysis in the original metric. In the pig data, the statistical evidence is stronger, but the coefficient of correlation between additive genetic effects affecting mean and variance changes sign, compared to the results in the untransformed scale. The study confirms that inferences on variances can be strongly affected by the presence of asymmetry in the distribution of data. We recommend that to avoid one important source of spurious inferences, future work seeking support for a genetic component acting on environmental variation using a parametric approach based on normality assumptions confirms that these are met.

  15. Heritability of Biomarkers of Oxidized Lipoproteins: Twin Pair Study.

    Science.gov (United States)

    Rao, Fangwen; Schork, Andrew J; Maihofer, Adam X; Nievergelt, Caroline M; Marcovina, Santica M; Miller, Elizabeth R; Witztum, Joseph L; O'Connor, Daniel T; Tsimikas, Sotirios

    2015-07-01

    To determine whether biomarkers of oxidized lipoproteins are genetically determined. Lipoprotein(a) (Lp[a]) is a heritable risk factor and carrier of oxidized phospholipids (OxPL). We measured oxidized phospholipids on apolipoprotein B-containing lipoproteins (OxPL-apoB), Lp(a), IgG, and IgM autoantibodies to malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes in 386 monozygotic and dizygotic twins to estimate trait heritability (h(2)) and determine specific genetic effects among traits. A genome-wide linkage study followed by genetic association was performed. The h(2) (scale: 0-1) for Lp(a) was 0.91±0.01 and for OxPL-apoB 0.87±0.02, which were higher than physiological, inflammatory, or lipid traits. h(2) of IgM malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes were 0.69±0.04, 0.67±0.05, and 0.80±0.03, respectively, and for IgG malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes 0.62±0.05, 0.52±0.06, and 0.53±0.06, respectively. There was an inverse correlation between the major apo(a) isoform and OxPL-apoB (R=-0.49; Plipoprotein and copper oxidized low-density lipoprotein, and apoB-immune complexes. Sib-pair genetic linkage of the Lp(a) trait revealed that single nucleotide polymorphism rs10455872 was significantly associated with OxPL-apoB after adjusting for Lp(a). OxPL-apoB and other biomarkers of oxidized lipoproteins are highly heritable cardiovascular risk factors that suggest novel genetic origins of atherothrombosis. © 2015 American Heart Association, Inc.

  16. Diallel and prediction (REML/BLUP) for yield components in intervarietal maize hybrids.

    Science.gov (United States)

    Carvalho, I R; de Pelegrin, A J; Szareski, V J; Ferrari, M; da Rosa, T C; Martins, T S; Dos Santos, N L; Nardino, M; de Souza, V Q; de Oliveira, A C; da Maia, L C

    2017-08-31

    Genetic improvement is essential to achieve increments in maize (Zea mays L.) grain yield components. It may be obtained through crosses, which enable to exploit the effects of intervarietal heterosis, allelic complementarity, as well as gene actions and effects. This study estimated the components of variance and genetic parameters (REML/BLUP) of an intervarietal diallel to select and predict the best genotypes for maize yield components. The experimental design was randomized blocks containing 60 intervarietal maize hybrids arranged in three repetitions. They were obtained through intervarietal crosses and evaluated in a diallel scheme, where 14 open-pollinated varieties were designated as parentals. Thus, 10 crosses were performed for each hybrid combination to obtain the number of seeds necessary for the competition test. The measured traits were: grain volume relative index, the mass of one hundred grains, and grain yield. The male parents and the additive genetic fraction were determinants for grain volume relative index. Mass of one hundred grains and grain yield were defined by the specific combining ability, and female parents revealed low narrow sense heritability. The female parent Taquarão and male parent Argentino Amarelo presented the best general combining abilities for the measured traits. The specific combining abilities were expressed for crosses AL 25 x Dente de Ouro Roxo, AL 25 x BRS Pampeano, and Taquarão x Argentino Branco. Genetic estimates and predictions were consistent and applicable to breeding programs and could be applied in future quantitative genetic studies of maize.

  17. Variance Owing to Observer, Repeat Imaging, and Fundus Camera Type on Cup-to-disc Ratio Estimates by Stereo Planimetry

    NARCIS (Netherlands)

    Kwon, Young H.; Adix, Michael; Zimmerman, M. Bridget; Piette, Scott; Greenlee, Emily C.; Alward, Wallace L. M.; Abramoff, M.D.

    2009-01-01

    Objective: To determine and compare variance components in linear cup-to-disc ratio (LCDR) estimates by computer-assisted planimetry by human experts, and automated machine algorithm (digital automated planimetry). Design: Prospective case series for evaluation of planimetry.

  18. No evidence for heritability of male mating latency or copulation duration across social environments in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Michelle L Taylor

    Full Text Available A key assumption underpinning major models of sexual selection is the expectation that male sexual attractiveness is heritable. Surprisingly, however, empirical tests of this assumption are relatively scarce. Here we use a paternal full-sib/half-sib breeding design to examine genetic and environmental variation in male mating latency (a proxy for sexual attractiveness and copulation duration in a natural population of Drosophila melanogaster. As our experimental design also involved the manipulation of the social environment within each full-sibling family, we were able to further test for the presence of genotype-by-environment interactions (GEIs in these traits, which have the potential to compromise mate choice for genetic benefits. Our experimental manipulation of the social environment revealed plastic expression of both traits; males exposed to a rival male during the sensitive period of adult sexual maturation exhibited shorter mating latencies and longer copulation durations than those who matured in isolation. However, we found no evidence for GEIs, and no significant additive genetic variation underlying these traits in either environment. These results undermine the notion that the evolution of female choice rests on covariance between female preference and male displays, an expectation that underpins indirect benefit models such as the good genes and sexy sons hypotheses. However, our results may also indicate depletion of genetic variance in these traits in the natural population studied, thus supporting the expectation that traits closely aligned with reproductive fitness can exhibit low levels of additive genetic variance.

  19. Heritability of Verbal and Performance Intelligence in a Pediatric Longitudinal Sample

    NARCIS (Netherlands)

    van Soelen, I.L.C.; Brouwer, R.M.; van Leeuwen, M.; Kahn, R.S.; Hulshoff Pol, H.E.; Boomsma, D.I.

    2011-01-01

    The longitudinal stability of IQ is well-documented as is its increasing heritability with age. In a longitudinal twin study, we addressed the question to what extent heritability and stability differ for full scale (FSIQ), verbal (VIQ), and performance IQ (PIQ) in childhood (age 9-11 years), and

  20. Heritability of telomere length in a study of long-lived families

    DEFF Research Database (Denmark)

    Honig, Lawrence S; Kang, Min Suk; Cheng, Rong

    2015-01-01

    in a given age group, it has been hypothesized to be a marker of biological aging. However, the principal basis for the variation of human LTL has not been established, although various studies have reported heritability. Here, we use a family-based study of longevity to study heritability of LTL in 3037...

  1. The estimate of genetic correlation and heritability of various traits in ...

    African Journals Online (AJOL)

    This study was done on three strains of East African goats namely, Dodoma. Kigoma and Mtwara with the aim of estimating heritability for pre-weaning (4 months), post-weaning (8 months) and yearling (12 months) growth rates. Other heritability parameters measured were for weight at birth, 4, 8, and 12 months of age and ...

  2. 77 FR 22791 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2012-04-17

    ... Disorders in Newborns and Children; Notice of Meeting In accordance with section 10(a)(2) of the Federal... following meeting: Name: Secretary's Advisory Committee on Heritable Disorders in Newborns and Children... mortality in newborns and children having (or at risk for) heritable disorders. The Advisory Committee's...

  3. 75 FR 17929 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2010-04-08

    ... Disorders in Newborns and Children; Notice of Meeting In accordance with section 10(a)(2) of the Federal... Advisory Committee on Heritable Disorders in Newborns and Children. Dates and Times: May 13, 2010, 8:30 a.m... . Purpose: The Secretary's Advisory Committee on Heritable Disorders in Newborns and Children (Advisory...

  4. 77 FR 35698 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children

    Science.gov (United States)

    2012-06-14

    ... Disorders in Newborns and Children AGENCY: Health Resources and Services Administration (HRSA), Department...'s Advisory Committee on Heritable Disorders in Newborns and Children (SACHDNC) members to serve as... specialty services for newborns and children at risk for heritable disorders. Organizations will also be...

  5. 76 FR 17140 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2011-03-28

    ... Disorders in Newborns and Children; Notice of Meeting In accordance with section 10(a)(2) of the Federal... Advisory Committee on Heritable Disorders in Newborns and Children. Dates and Times: May 5, 2011, 9:30 a.m....org . Purpose: The Secretary's Advisory Committee on Heritable Disorders in Newborns and Children...

  6. 75 FR 46947 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2010-08-04

    ... Disorders in Newborns and Children; Notice of Meeting In accordance with section 10(a)(2) of the Federal...: Secretary's Advisory Committee on Heritable Disorders in Newborns and Children. Dates and Times: September....org . Purpose: The Secretary's Advisory Committee on Heritable Disorders in Newborns and Children...

  7. 78 FR 16514 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children; Notice of Meeting

    Science.gov (United States)

    2013-03-15

    ... Disorders in Newborns and Children; Notice of Meeting In accordance with section 10(a)(2) of the Federal... following meeting: Name: Secretary's Advisory Committee on Heritable Disorders in Newborns and Children.../heritabledisorders . Purpose: The Secretary's Advisory Committee on Heritable Disorders in Newborns and Children...

  8. The biological roots of complex thinking: are heritable attitudes more complex?

    Science.gov (United States)

    Conway, Lucian Gideon; Dodds, Daniel P; Towgood, Kirsten Hands; McClure, Stacey; Olson, James M

    2011-02-01

    Are highly heritable attitudes more or less complex than less heritable attitudes? Over 2,000 participant responses on topics varying in heritability were coded for overall integrative complexity and its 2 subcomponents (dialectical complexity and elaborative complexity). Across different heritability sets drawn from 2 separate prior twin research programs, the present results yielded a consistent pattern: Heritability was always significantly positively correlated with integrative complexity. Further analyses of the subcomponents suggested that the manner in which complexity was expressed differed by topic type: For societal topics, heritable attitudes were more likely to be expressed in dialectically complex terms, whereas for personally involving topics, heritable attitudes were more likely to be expressed in elaboratively complex terms. Most of these relationships remained significant even when controlling for measurements of attitude strength. The authors discuss the genetic roots of complex versus simple attitudes, implications for understanding attitude development more broadly, and the contribution of these results to previous work on both heritability and complexity. © 2011 The Authors. Journal of Personality © 2011, Wiley Periodicals, Inc.

  9. 40 CFR 798.5955 - Heritable translocation test in drosophila melanogaster.

    Science.gov (United States)

    2010-07-01

    ... drosophila melanogaster. 798.5955 Section 798.5955 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY....5955 Heritable translocation test in drosophila melanogaster. (a) Purpose. The heritable translocation test in Drosophila measures the induction of chromosomal translocations in germ cells of insects...

  10. Heritability of Facial Characteristics between Parents and Offsprings: A Photographic Study

    Directory of Open Access Journals (Sweden)

    Seema Kapil Lahoti

    2013-01-01

    Conclusion: The evidence of significant genetic contribution was there for linear and proportional parameters. Sons showed stronger heritability to their mothers than to their fathers while daughter showed heritability from both the parents. Thus, the soft tissue form of offspring can be predicted from parental data and the information from the siblings can also be used.

  11. Heritability of selective attention and working memory in preschoolers.

    Science.gov (United States)

    Stins, J F; de Sonneville, Leo M J; Groot, Alexia S; Polderman, Tinca C; van Baal, Caroline G C M; Boomsma, Dorret I

    2005-07-01

    In this study aspects of selective attention and working memory were tested in a large sample of nearly 6-year old monozygotic and dizygotic twin pairs, using a computerized test battery (Amsterdam Neuropsychological tasks). In the selective attention task the presence of a foil signal (target signal at an irrelevant location) resulted in more false alarms than a non-target signal. In the working memory task an increase in memory load lead to an increase in response times and errors. We analyzed variations in absolute performance parameters (overall speed and accuracy) and relative performance parameters (increase in errors and/or reaction time). The results showed clear familial resemblances on performance. It proved difficult to ascribe these effects to shared genes or to shared environment. An exception was memory search rate, which was clearly heritable.

  12. Pectus excavatum and heritable disorders of the connective tissue

    Directory of Open Access Journals (Sweden)

    Francesca Tocchioni

    2013-09-01

    Full Text Available Pectus excavatum, the most frequent congenital chest wall deformity, may be rarely observed as a sole deformity or as a sign of an underlying connective tissue disorder. To date, only few studies have described correlations between this deformity and heritable connective tissue disorders such as Marfan, Ehlers-Danlos, Poland, MASS (Mitral valve prolapse, not progressive Aortic enlargement, Skeletal and Skin alterations phenotype among others. When concurring with connective tissue disorder, cardiopulmonary and vascular involvement may be associated to the thoracic defect. Ruling out the concomitance of pectus excavatum and connective tissue disorders, therefore, may have a direct implication both on surgical outcome and long term prognosis. In this review we focused on biological bases of connective tissue disorders which may be relevant to the pathogenesis of pectus excavatum, portraying surgical and clinical implication of their concurrence.

  13. Pectus excavatum and heritable disorders of the connective tissue.

    Science.gov (United States)

    Tocchioni, Francesca; Ghionzoli, Marco; Messineo, Antonio; Romagnoli, Paolo

    2013-09-24

    Pectus excavatum, the most frequent congenital chest wall deformity, may be rarely observed as a sole deformity or as a sign of an underlying connective tissue disorder. To date, only few studies have described correlations between this deformity and heritable connective tissue disorders such as Marfan, Ehlers-Danlos, Poland, MASS (Mitral valve prolapse, not progressive Aortic enlargement, Skeletal and Skin alterations) phenotype among others. When concurring with connective tissue disorder, cardiopulmonary and vascular involvement may be associated to the thoracic defect. Ruling out the concomitance of pectus excavatum and connective tissue disorders, therefore, may have a direct implication both on surgical outcome and long term prognosis. In this review we focused on biological bases of connective tissue disorders which may be relevant to the pathogenesis of pectus excavatum, portraying surgical and clinical implication of their concurrence.

  14. Small RNAs and heritable epigenetic variation in plants.

    Science.gov (United States)

    Bond, Donna M; Baulcombe, David C

    2014-02-01

    Recent studies suggest that inheritance of phenotypes in plants is more likely to involve epigenetics than in mammals. There are two reasons for this difference. First, there is a RNA-based system in plants involving small (s)RNAs that influences de novo establishment and maintenance of DNA methylation at many sites in plant genomes. These regions of methylated DNA are epigenetic marks with the potential to affect gene expression that are transmitted between dividing cells of the same generation. Second, unlike mammals, DNA methyltransferases in plants are active during gametogenesis and embryogenesis so that patterns of DNA methylation can persist from parent to progeny and do not need to be reset. We discuss how the effects of stress and genome interactions in hybrid plants are two systems that illustrate how RNA-based mechanisms can influence heritable phenotypes in plants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Heritability of syringomyelia in Cavalier King Charles spaniels.

    Science.gov (United States)

    Lewis, Tom; Rusbridge, Clare; Knowler, Penny; Blott, Sarah; Woolliams, John A

    2010-03-01

    Mixed model analysis of 384 Cavalier King Charles spaniels (CKCS), with a magnetic resonance imaging diagnosis for the presence or absence of a syrinx, in conjunction with the Kennel Club pedigree records of all dogs registered from the mid 1980s to September 2007, revealed a moderately high estimate of heritability of syringomyelia (h(2)=0.37+/-0.15 standard error) when analysed as a binary trait. Inspection of cases where the disease segregated within families pointed to genes at more than one locus influencing syringomyelia. The availability of estimated breeding values for Kennel Club registered CKCS is a significant step in being able to select against syringomyelia, particularly given the difficulty of ascertaining the disease phenotype. 2009 Elsevier Ltd. All rights reserved.

  16. Power Estimation in Multivariate Analysis of Variance

    Directory of Open Access Journals (Sweden)

    Jean François Allaire

    2007-09-01

    Full Text Available Power is often overlooked in designing multivariate studies for the simple reason that it is believed to be too complicated. In this paper, it is shown that power estimation in multivariate analysis of variance (MANOVA can be approximated using a F distribution for the three popular statistics (Hotelling-Lawley trace, Pillai-Bartlett trace, Wilk`s likelihood ratio. Consequently, the same procedure, as in any statistical test, can be used: computation of the critical F value, computation of the noncentral parameter (as a function of the effect size and finally estimation of power using a noncentral F distribution. Various numerical examples are provided which help to understand and to apply the method. Problems related to post hoc power estimation are discussed.

  17. Variance in faking across noncognitive measures.

    Science.gov (United States)

    McFarland, L A; Ryan, A M

    2000-10-01

    There are discrepant findings in the literature regarding the effects of applicant faking on the validity of noncognitive measures. One explanation for these mixed results may be the failure of some studies to consider individual differences in faking. This study demonstrates that there is considerable variance across individuals in the extent of faking 3 types of noncognitive measures (i.e., personality test, biodata inventory, and integrity test). Participants completed measures honestly and with instructions to fake. Results indicated some measures were more difficult to fake than others. The authors found that integrity, conscientiousness, and neuroticism were related to faking. In addition, individuals faked fairly consistently across the measures. Implications of these results and a model of faking that includes factors that may influence faking behavior are provided.

  18. Dynamics of Variance Risk Premia, Investors' Sentiment and Return Predictability

    DEFF Research Database (Denmark)

    Rombouts, Jerome V.K.; Stentoft, Lars; Violante, Francesco

    We develop a joint framework linking the physical variance and its risk neutral expectation implying variance risk premia that are persistent, appropriately reacting to changes in level and variability of the variance and naturally satisfying the sign constraint. Using option market data and real......We develop a joint framework linking the physical variance and its risk neutral expectation implying variance risk premia that are persistent, appropriately reacting to changes in level and variability of the variance and naturally satisfying the sign constraint. Using option market data...

  19. A Monte Carlo Study of Seven Homogeneity of Variance Tests

    OpenAIRE

    Howard B. Lee; Gary S. Katz; Alberto F. Restori

    2010-01-01

    Problem statement: The decision by SPSS (now PASW) to use the unmodified Levene test to test homogeneity of variance was questioned. It was compared to six other tests. In total, seven homogeneity of variance tests used in Analysis Of Variance (ANOVA) were compared on robustness and power using Monte Carlo studies. The homogeneity of variance tests were (1) Levene, (2) modified Levene, (3) Z-variance, (4) Overall-Woodward Modified Z-variance, (5) OBrien, (6) Samiuddin Cube Root and (7) F-Max....

  20. Prevalence and heritability of distichiasis in the English Cocker spaniel.

    Science.gov (United States)

    Petersen, Tanja; Proschowsky, Helle Friis; Hardon, Tommy; Rasch, Søren Nyhuus; Fredholm, Merete

    2015-01-01

    Canine distichiasis is a well-known cause of ocular irritation and excessive lacrimation (secretion of tears) in the dog. The term distichiasis originates from the Greek words di and stichos meaning two and rows, respectively, and as the name implies, the condition is characterized by an additional row of cilia, which erupts on the eyelid margin. Many purebred dogs are known to be predisposed to the condition, with many affected individuals within the populations. Even though the problem is widespread, the exact mode of inheritance and the heredity has not been studied extensively. However, some degree of genetic influence has been assumed, due to the high incidences within specific breeds. In the present study we have examined a cohort of English Cocker spaniels in Denmark to determine the prevalence and heritability of the disease. Data from English Cocker spaniels with an ECVO eye examination registered between 2004-2013 were included in the study. The number of dogs examined during this period was 799, and the prevalence of distichiasis within this cohort was estimated at 49.31 % with a gender predisposition that females are more likely to get distichiasis than males. The correlation between the distichiasis status of the parents and their offspring revealed a significant association between the breeding combination of the parents and the occurrence of distichiasis in the offspring (p spaniels from Denmark, examined in 2004-2013 was shown to be extremely high. The relative risk of developing the disease was 1.3 and 1.8 for offspring of one or two affected parents respectively. This together with the moderate to high heritability of the condition indicates that selective breeding could be used to reduce the incidence of distichiasis.

  1. ATHENA: the analysis tool for heritable and environmental network associations.

    Science.gov (United States)

    Holzinger, Emily R; Dudek, Scott M; Frase, Alex T; Pendergrass, Sarah A; Ritchie, Marylyn D

    2014-03-01

    Advancements in high-throughput technology have allowed researchers to examine the genetic etiology of complex human traits in a robust fashion. Although genome-wide association studies have identified many novel variants associated with hundreds of traits, a large proportion of the estimated trait heritability remains unexplained. One hypothesis is that the commonly used statistical techniques and study designs are not robust to the complex etiology that may underlie these human traits. This etiology could include non-linear gene × gene or gene × environment interactions. Additionally, other levels of biological regulation may play a large role in trait variability. To address the need for computational tools that can explore enormous datasets to detect complex susceptibility models, we have developed a software package called the Analysis Tool for Heritable and Environmental Network Associations (ATHENA). ATHENA combines various variable filtering methods with machine learning techniques to analyze high-throughput categorical (i.e. single nucleotide polymorphisms) and quantitative (i.e. gene expression levels) predictor variables to generate multivariable models that predict either a categorical (i.e. disease status) or quantitative (i.e. cholesterol levels) outcomes. The goal of this article is to demonstrate the utility of ATHENA using simulated and biological datasets that consist of both single nucleotide polymorphisms and gene expression variables to identify complex prediction models. Importantly, this method is flexible and can be expanded to include other types of high-throughput data (i.e. RNA-seq data and biomarker measurements). ATHENA is freely available for download. The software, user manual and tutorial can be downloaded from http://ritchielab.psu.edu/ritchielab/software.

  2. Using variance structure to quantify responses to perturbation in fish catches

    Science.gov (United States)

    Vidal, Tiffany E.; Irwin, Brian J.; Wagner, Tyler; Rudstam, Lars G.; Jackson, James R.; Bence, James R.

    2017-01-01

    We present a case study evaluation of gill-net catches of Walleye Sander vitreus to assess potential effects of large-scale changes in Oneida Lake, New York, including the disruption of trophic interactions by double-crested cormorants Phalacrocorax auritus and invasive dreissenid mussels. We used the empirical long-term gill-net time series and a negative binomial linear mixed model to partition the variability in catches into spatial and coherent temporal variance components, hypothesizing that variance partitioning can help quantify spatiotemporal variability and determine whether variance structure differs before and after large-scale perturbations. We found that the mean catch and the total variability of catches decreased following perturbation but that not all sampling locations responded in a consistent manner. There was also evidence of some spatial homogenization concurrent with a restructuring of the relative productivity of individual sites. Specifically, offshore sites generally became more productive following the estimated break point in the gill-net time series. These results provide support for the idea that variance structure is responsive to large-scale perturbations; therefore, variance components have potential utility as statistical indicators of response to a changing environment more broadly. The modeling approach described herein is flexible and would be transferable to other systems and metrics. For example, variance partitioning could be used to examine responses to alternative management regimes, to compare variability across physiographic regions, and to describe differences among climate zones. Understanding how individual variance components respond to perturbation may yield finer-scale insights into ecological shifts than focusing on patterns in the mean responses or total variability alone.

  3. The Parabolic Variance (PVAR): A Wavelet Variance Based on the Least-Square Fit.

    Science.gov (United States)

    Vernotte, Francois; Lenczner, Michel; Bourgeois, Pierre-Yves; Rubiola, Enrico

    2016-04-01

    This paper introduces the parabolic variance (PVAR), a wavelet variance similar to the Allan variance (AVAR), based on the linear regression (LR) of phase data. The companion article arXiv:1506.05009 [physics.ins-det] details the Ω frequency counter, which implements the LR estimate. The PVAR combines the advantages of AVAR and modified AVAR (MVAR). PVAR is good for long-term analysis because the wavelet spans over 2τ, the same as the AVAR wavelet, and good for short-term analysis because the response to white and flicker PM is 1/τ(3) and 1/τ(2), the same as the MVAR. After setting the theoretical framework, we study the degrees of freedom and the confidence interval for the most common noise types. Then, we focus on the detection of a weak noise process at the transition-or corner-where a faster process rolls off. This new perspective raises the question of which variance detects the weak process with the shortest data record. Our simulations show that PVAR is a fortunate tradeoff. PVAR is superior to MVAR in all cases, exhibits the best ability to divide between fast noise phenomena (up to flicker FM), and is almost as good as AVAR for the detection of random walk and drift.

  4. Heritability and gene effects for yield related quantitative traits in eggplant

    Directory of Open Access Journals (Sweden)

    Chintan Mistry

    2016-12-01

    Full Text Available Knowledge of gene actions and their relative contribution in expression of characters is of great importance. Therefore, four crosses were made among the six parents viz., Doli-5 × GBL-1 (cross 1, Doli-5 × KS-331 (cross 2, Pusa Uttam × KS-331 (cross 3 and AB 07-02 × GOB 1 (cross 4 to study gene actions responsible for inheritance of twelve fruit yield traits. The generation mean analysis in six populations revealed significant digenic interactions for all the characters in majority of the crosses studied. Character-cross combination revealed the adequacy of simple additive dominance model for plant height (in cross 1, primary branches per plant (in cross 2, secondary branches per plant (in cross 3, fruit length (in cross 2, fruit girth (in cross 3 and pedicel length (in cross 3 indicating the absence of non-allelic interactions. Most of the crosses for all the yield traits showed low magnitude of dominance and environmental variances, revealing higher heritabilities. Duplicate epistasis effects controlled all traits in different cross-combinations suggesting the mild selection intensity in the earlier generations while intense in later generations. However, in few cases average dominance ratio was more than unity indicated the importance of dominance gene effects. These results indicated that for eggplant improvement, additive variation is of great importance and makes it possible to successfully select better individuals in segregating populations, since the selective gains will depend only on gametic variation. For this reason, backcross, pedigree, single-seed descent or gametic selection methods are recommended for advancing the segregating populations.

  5. Variation, correlation and heritability of interest characters for ...

    African Journals Online (AJOL)

    High phenotypic and genotypic coefficients of variation were observed for fruit diameter, number of seeds per fruit, fruit weight, leaf blade length and width, and height at flowering. In addition, genetic and phenotypic variances were high for the number of seed, fruit weight, plant height at flowering and days to 50% flowering.

  6. Heritability of Resting State EEG Functional Connectivity Patterns

    NARCIS (Netherlands)

    Schutte, N.M.; Hansell, N.K.; de Geus, E.J.C.; Martin, N.G.; Wright, M.J.; Smit, D.J.A.

    2013-01-01

    We examined the genetic architecture of functional brain connectivity measures in resting state electroencephalographic (EEG) recordings. Previous studies in Dutch twins have suggested that genetic factors are a main source of variance in functional brain connectivity derived from EEG recordings. In

  7. Heritability of sperm length in the bumblebee Bombus terrestris

    DEFF Research Database (Denmark)

    Baer, Boris; de Jong, Gerdien; Schmid-Hempel, Regula

    2006-01-01

    Sperm length is highly variable, both between and within species, but the evolutionary significance of this variation is poorly understood. Sexual selection on sperm length requires a significant additive genetic variance, but few studies have actually measured this. Here we present the first est...

  8. Repeatability, heritability, and age-dependence of seasonal plasticity in aggressiveness in a wild passerine bird.

    Science.gov (United States)

    Araya-Ajoy, Yimen G; Dingemanse, Niels J

    2017-03-01

    Labile characters allow individuals to flexibly adjust their phenotype to changes in environmental conditions. There is growing evidence that individuals can differ both in average expression and level of plasticity in this type of character. Both of these aspects are studied in conjunction within a reaction norm framework. Theoreticians have investigated the factors promoting variation in reaction norm intercepts (average phenotype) and slopes (level of plasticity) of a key labile character: behaviour. A general prediction from their work is that selection will favour the evolution of repeatable individual variation in level of plasticity only under certain ecological conditions. While factors promoting individual repeatability of plasticity have thus been identified, empirical estimates of this phenomenon are largely lacking for wild populations. We assayed aggressiveness of individual male great tits (Parus major) twice during their egg-laying stage and twice during their egg-incubation stage to quantify each male's level of seasonal plasticity. This procedure was applied during six consecutive years; all males breeding in our plots during those years were assayed, resulting in repeated measures of individual reaction norms for any individual breeding in multiple years. We quantified among- and within-individual variation in reaction norm components, allowing us to estimate repeatability of seasonal plasticity. Using social pedigree information, we further partitioned reaction norm components into their additive genetic and permanent environmental counterparts. Cross-year individual repeatability for the intercepts (average aggressiveness) and slopes (level of seasonal plasticity) of the aggressiveness reaction norms were 0·574 and 0·516 respectively. The mean of the posterior distributions suggested modest heritabilities (h(2)  = 0·260 for intercepts; h(2)  = 0·266 for slopes), but these estimates were relatively uncertain. Males behaved more

  9. PCOM: A Microcomputer Program that Performs a Principal Components Analysis.

    Science.gov (United States)

    Powers, Stephen

    1984-01-01

    This paper describes a microcomputer program that extracts principal components from a correlation matrix and rotates them to a varimax solution. Eigenvalues, variances associated with each component, unrotated component loadings, and varimax rotated loadings are output by the program. (Author)

  10. Adjustment for heterogeneous variances due to days in milk and ...

    African Journals Online (AJOL)

    ARC-IRENE

    models for national genetic evaluation of dairy cattle in South Africa ... Test-Day Model (FRTDM), which assumes equal variances of the response variable at different .... adjusted for heterogeneous variances, BLUEs are the best linear unbiased .... This makes sense as part of the residual variance has already been taken ...

  11. Hidden Item Variance in Multiple Mini-Interview Scores

    Science.gov (United States)

    Zaidi, Nikki L.; Swoboda, Christopher M.; Kelcey, Benjamin M.; Manuel, R. Stephen

    2017-01-01

    The extant literature has largely ignored a potentially significant source of variance in multiple mini-interview (MMI) scores by "hiding" the variance attributable to the sample of attributes used on an evaluation form. This potential source of hidden variance can be defined as rating items, which typically comprise an MMI evaluation…

  12. A New Nonparametric Levene Test for Equal Variances

    Science.gov (United States)

    Nordstokke, David W.; Zumbo, Bruno D.

    2010-01-01

    Tests of the equality of variances are sometimes used on their own to compare variability across groups of experimental or non-experimental conditions but they are most often used alongside other methods to support assumptions made about variances. A new nonparametric test of equality of variances is described and compared to current "gold…

  13. Indirect genetic effects contribute substantially to heritable variation in aggression-related traits in group-housed mink (Neovison vison).

    Science.gov (United States)

    Alemu, Setegn Worku; Bijma, Piter; Møller, Steen Henrik; Janss, Luc; Berg, Peer

    2014-05-07

    Since the recommendations on group housing of mink (Neovison vison) were adopted by the Council of Europe in 1999, it has become common in mink production in Europe. Group housing is advantageous from a production perspective, but can lead to aggression between animals and thus raises a welfare issue. Bite marks on the animals are an indicator of this aggressive behaviour and thus selection against frequency of bite marks should reduce aggression and improve animal welfare. Bite marks on one individual reflect the aggression of its group members, which means that the number of bite marks carried by one individual depends on the behaviour of other individuals and that it may have a genetic basis. Thus, for a successful breeding strategy it could be crucial to consider both direct (DGE) and indirect (IGE) genetic effects on this trait. However, to date no study has investigated the genetic basis of bite marks in mink. A model that included DGE and IGE fitted the data significantly better than a model with DGE only, and IGE contributed a substantial proportion of the heritable variation available for response to selection. In the model with IGE, the total heritable variation expressed as the proportion of phenotypic variance (T2) was six times greater than classical heritability (h2). For instance, for total bite marks, T2 was equal to 0.61, while h2 was equal to 0.10. The genetic correlation between direct and indirect effects ranged from 0.55 for neck bite marks to 0.99 for tail bite marks. This positive correlation suggests that mink have a tendency to fight in a reciprocal way (giving and receiving bites) and thus, a genotype that confers a tendency to bite other individuals can also cause its bearer to receive more bites. Both direct and indirect genetic effects contribute to variation in number of bite marks in group-housed mink. Thus, a genetic selection design that includes both direct genetic and indirect genetic effects could reduce the frequency of bite

  14. Physical appearance perfectionism explains variance in eating disorder symptoms above general perfectionism

    OpenAIRE

    Stoeber, Joachim; Yang, Hongfei

    2015-01-01

    Physical appearance perfectionism is a domain-specific form of perfectionism comprising two components: hope for perfection and worry about imperfection (Yang & Stoeber, 2012). Previous studies found that physical appearance perfectionism is related to eating disorder symptoms, particularly the worry about imperfection component, but did not address the question of whether physical appearance perfectionism explains variance in eating disorder symptoms above general perfectionism. The present ...

  15. Partitioning Phenotypic Variance Due to Parent-of-Origin Effects Using Genomic Relatedness Matrices.

    Science.gov (United States)

    Laurin, Charles; Cuellar-Partida, Gabriel; Hemani, Gibran; Smith, George Davey; Yang, Jian; Evans, David M

    2018-01-01

    We propose a new method, G-REMLadp, to estimate the phenotypic variance explained by parent-of-origin effects (POEs) across the genome. Our method uses restricted maximum likelihood analysis of genome-wide genetic relatedness matrices based on individuals' phased genotypes. Genome-wide SNP data from parent child duos or trios is required to obtain relatedness matrices indexing the parental origin of offspring alleles, as well as offspring phenotype data to partition the trait variation into variance components. To calibrate the power of G-REMLadp to detect non-null POEs when they are present, we provide an analytic approximation derived from Haseman-Elston regression. We also used simulated data to quantify the power and Type I Error rates of G-REMLadp, as well as the sensitivity of its variance component estimates to violations of underlying assumptions. We subsequently applied G-REMLadp to 36 phenotypes in a sample of individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC). We found that the method does not seem to be inherently biased in estimating variance due to POEs, and that substantial correlation between parental genotypes is necessary to generate biased estimates. Our empirical results, power calculations and simulations indicate that sample sizes over 10000 unrelated parent-offspring duos will be necessary to detect POEs explaining POEs tagged by our genetic relationship matrices are unlikely to explain large proportions of the phenotypic variance (i.e. > 15%) for the 36 traits that we have examined.

  16. Use of a genealogical database demonstrates heritability of pulmonary fibrosis.

    Science.gov (United States)

    Scholand, Mary Beth; Coon, Hilary; Wolff, Roger; Cannon-Albright, Lisa

    2013-10-01

    Pulmonary fibrosis (PF) is a progressive fatal disease of unknown etiology. Identification of risk genes and pathways will enhance our understanding of this disease. Analysis of Utah genealogical resources has shown previously strong evidence for a genetic contribution to other disease, such as cancer. This approach has led to gene discovery in diseases, such as breast cancer and colon cancer and is used here for PF to quantify the heritability. We hypothesize that there is a heritable contribution to death from PF and use existing genealogic and death certificate data to examine patterns of relatedness amongst individuals who have died of PF. We analyzed familial clustering of individuals who died from PF using the Utah Population Database, a unique population-based genealogical resource that has been linked to death certificates dating from 1904. We identified 1,000 individuals with at least three generations of genealogy data and a cause of death documented as PF (cases). We estimated the relative risk (RR) of death from PF among the first-, second-, and third-degree relatives of cases. We also tested the hypothesis of excess relatedness among the cases by comparing the average pairwise relatedness of all cases to the average pair-wise relatedness of 1,000 sets of matched controls. We observed significantly increased risk for death from PF among the first- (RR = 4.69), second- (RR = 1.92), and third-degree relatives (RR = 1.14) of cases. The average relatedness of the 1,000 cases was significantly higher than the expected average relatedness of matched control sets (p < 0.001). When close (first- and second-degree) relationships were ignored, significantly increased relatedness remained (p = 0.002). Our results demonstrate significant clustering among both close and distant relatives, providing strong support for genetic contributions to death from PF. High-risk pedigrees derived from this unique resource may help identify new risk genes and gene

  17. Resistance to infectious diseases is a heritable trait in rabbits.

    Science.gov (United States)

    Gunia, M; David, I; Hurtaud, J; Maupin, M; Gilbert, H; Garreau, H

    2015-12-01

    Selection for disease resistance is a powerful way to improve the health status of herds and to reduce the use of antibiotics. The objectives of this study were to estimate 1) the genetic parameters for simple visually assessed disease syndromes and for a composite trait of resistance to infectious disease including all syndromes and 2) their genetic correlations with production traits in a rabbit population. Disease symptoms were recorded in the selection herds of 2 commercial paternal rabbit lines during weighing at the end of the test (63 and 70 d of age, respectively). Causes of mortality occurring before these dates were also recorded. Seven disease traits were analyzed: 3 elementary traits visually assessed by technicians on farm (diarrhea, various digestive syndromes, and respiratory syndromes), 2 composite traits (all digestive syndromes and all infectious syndromes), and 2 mortality traits (digestive mortality and infectious mortality). Each animal was assigned only 1 disease trait, corresponding to the main syndrome ( = 153,400). Four production traits were also recorded: live weight the day before the end of test on most animals ( = 137,860) and cold carcass weight, carcass yield, and perirenal fat percentage of the carcass on a subset of slaughtered animals ( = 13,765). Records on both lines were analyzed simultaneously using bivariate linear animal models after validation of consistency with threshold models applied to logit-transformed traits. The heritabilities were low for disease traits, from 0.01 ± 0.002 for various digestive syndromes to 0.04 ± 0.004 for infectious mortality, and moderate to high for production traits. The genetic correlations between digestive syndromes were high and positive, whereas digestive and respiratory syndromes were slightly negatively correlated. The genetic correlations between the composite infectious disease trait and digestive or respiratory syndromes were moderate. Genetic correlations between disease and

  18. Fast Minimum Variance Beamforming Based on Legendre Polynomials.

    Science.gov (United States)

    Bae, MooHo; Park, Sung Bae; Kwon, Sung Jae

    2016-09-01

    Currently, minimum variance beamforming (MV) is actively investigated as a method that can improve the performance of an ultrasound beamformer, in terms of the lateral and contrast resolution. However, this method has the disadvantage of excessive computational complexity since the inverse spatial covariance matrix must be calculated. Some noteworthy methods among various attempts to solve this problem include beam space adaptive beamforming methods and the fast MV method based on principal component analysis, which are similar in that the original signal in the element space is transformed to another domain using an orthonormal basis matrix and the dimension of the covariance matrix is reduced by approximating the matrix only with important components of the matrix, hence making the inversion of the matrix very simple. Recently, we proposed a new method with further reduced computational demand that uses Legendre polynomials as the basis matrix for such a transformation. In this paper, we verify the efficacy of the proposed method through Field II simulations as well as in vitro and in vivo experiments. The results show that the approximation error of this method is less than or similar to those of the above-mentioned methods and that the lateral response of point targets and the contrast-to-speckle noise in anechoic cysts are also better than or similar to those methods when the dimensionality of the covariance matrices is reduced to the same dimension.

  19. Meta-analysis of SNPs involved in variance heterogeneity using Levene's test for equal variances

    OpenAIRE

    Deng, Wei Q; Asma, Senay; Paré, Guillaume

    2013-01-01

    Meta-analysis is a commonly used approach to increase the sample size for genome-wide association searches when individual studies are otherwise underpowered. Here, we present a meta-analysis procedure to estimate the heterogeneity of the quantitative trait variance attributable to genetic variants using Levene's test without needing to exchange individual-level data. The meta-analysis of Levene's test offers the opportunity to combine the considerable sample size of a genome-wide meta-analys...

  20. Genetic variances, heritabilities and maternal effects on body weight, breast meat yield, meat quality traits and the shape of the growth curve in turkey birds

    National Research Council Canada - National Science Library

    Aslam, M.L; Bastiaansen, J.W.M; Crooijmans, R.P.M.A; Ducro, B.J; Vereijken, A; Groenen, M.A.M

    2011-01-01

    .... This rapidly increasing importance of turkeys was a reason to design this study for the estimation of genetic parameters that control body weight, body composition, meat quality traits and parameters...

  1. Genetic variances, heritabilities and maternal effects on body weight, breast meat yield, meat quality traits and the shape of the growth curve in turkey birds

    OpenAIRE

    Aslam, M.L.; Bastiaansen, J W M; Crooijmans, R.P.M.A.; Ducro, B.J.; Vereijken, A.; Groenen, M A M

    2011-01-01

    Background Turkey is an important agricultural species and is largely used as a meat bird. In 2004, turkey represented 6.5% of the world poultry meat production. The world-wide turkey population has rapidly grown due to increased commercial farming. Due to the high demand for turkey meat from both consumers and industry global turkey stocks increased from 100 million in 1970 to over 276 million in 2004. This rapidly increasing importance of turkeys was a reason to design this study for the es...

  2. Genetic variances, heritabilities and maternal effects on body weight, breast meat yield, meat quality traits and the shape of the growth curve in turkey birds

    OpenAIRE

    Ducro Bart J; Crooijmans Richard PMA; Bastiaansen John WM; Aslam Muhammad L; Vereijken Addie; Groenen Martien AM

    2011-01-01

    Abstract Background Turkey is an important agricultural species and is largely used as a meat bird. In 2004, turkey represented 6.5% of the world poultry meat production. The world-wide turkey population has rapidly grown due to increased commercial farming. Due to the high demand for turkey meat from both consumers and industry global turkey stocks increased from 100 million in 1970 to over 276 million in 2004. This rapidly increasing importance of turkeys was a reason to design this study f...

  3. Genetic variances, heritabilities and maternal effects on body weight, breast meat yield, meat quality traits and the shape of the growth curve in turkey birds

    NARCIS (Netherlands)

    Aslam, M.L.; Bastiaansen, J.W.M.; Crooijmans, R.P.M.A.; Ducro, B.J.; Vereijken, A.; Groenen, M.A.M.

    2011-01-01

    Background Turkey is an important agricultural species and is largely used as a meat bird. In 2004, turkey represented 6.5% of the world poultry meat production. The world-wide turkey population has rapidly grown due to increased commercial farming. Due to the high demand for turkey meat from both

  4. Handedness, heritability, neurocognition and brain asymmetry in schizophrenia

    Science.gov (United States)

    Deep-Soboslay, Amy; Hyde, Thomas M.; Callicott, Joseph P.; Lener, Marc S.; Verchinski, Beth A.; Apud, José A.; Weinberger, Daniel R.

    2010-01-01

    Higher rates of non-right-handedness (i.e. left- and mixed-handedness) have been reported in schizophrenia and have been a centrepiece for theories of anomalous lateralization in this disorder. We investigated whether non-right-handedness is (i) more prevalent in patients as compared with unaffected siblings and healthy unrelated control participants; (ii) familial; (iii) associated with disproportionately poorer neurocognition; and (iv) associated with grey matter volume asymmetries. We examined 1445 participants (375 patients with schizophrenia, 502 unaffected siblings and 568 unrelated controls) using the Edinburgh Handedness Inventory, a battery of neuropsychological tasks and structural magnetic resonance imaging data. Patients displayed a leftward shift in Edinburgh Handedness Inventory laterality quotient scores as compared with both their unaffected siblings and unrelated controls, but this finding disappeared when sex was added to the model. Moreover, there was no evidence of increased familial risk for non-right-handedness. Non-right-handedness was not associated with disproportionate neurocognitive disadvantage or with grey matter volume asymmetries in the frontal pole, lateral occipital pole or temporal pole. Non-right-handedness was associated with a significant reduction in left asymmetry in the superior temporal gyrus in both patients and controls. Our data neither provide strong support for ‘atypical’ handedness as a schizophrenia risk-associated heritable phenotype nor that it is associated with poorer neurocognition or anomalous cerebral asymmetries. PMID:20639549

  5. Handedness, heritability, neurocognition and brain asymmetry in schizophrenia.

    Science.gov (United States)

    Deep-Soboslay, Amy; Hyde, Thomas M; Callicott, Joseph P; Lener, Marc S; Verchinski, Beth A; Apud, José A; Weinberger, Daniel R; Elvevåg, Brita

    2010-10-01

    Higher rates of non-right-handedness (i.e. left- and mixed-handedness) have been reported in schizophrenia and have been a centrepiece for theories of anomalous lateralization in this disorder. We investigated whether non-right-handedness is (i) more prevalent in patients as compared with unaffected siblings and healthy unrelated control participants; (ii) familial; (iii) associated with disproportionately poorer neurocognition; and (iv) associated with grey matter volume asymmetries. We examined 1445 participants (375 patients with schizophrenia, 502 unaffected siblings and 568 unrelated controls) using the Edinburgh Handedness Inventory, a battery of neuropsychological tasks and structural magnetic resonance imaging data. Patients displayed a leftward shift in Edinburgh Handedness Inventory laterality quotient scores as compared with both their unaffected siblings and unrelated controls, but this finding disappeared when sex was added to the model. Moreover, there was no evidence of increased familial risk for non-right-handedness. Non-right-handedness was not associated with disproportionate neurocognitive disadvantage or with grey matter volume asymmetries in the frontal pole, lateral occipital pole or temporal pole. Non-right-handedness was associated with a significant reduction in left asymmetry in the superior temporal gyrus in both patients and controls. Our data neither provide strong support for 'atypical' handedness as a schizophrenia risk-associated heritable phenotype nor that it is associated with poorer neurocognition or anomalous cerebral asymmetries.

  6. Analysis of a genetically structured variance heterogeneity model using the Box-Cox transformation

    DEFF Research Database (Denmark)

    Yang, Ye; Christensen, Ole Fredslund; Sorensen, Daniel

    2011-01-01

    of the marginal distribution of the data. To investigate how the scale of measurement affects inferences, the genetically structured heterogeneous variance model is extended to accommodate the family of Box–Cox transformations. Litter size data in rabbits and pigs that had previously been analysed...... in the untransformed scale were reanalysed in a scale equal to the mode of the marginal posterior distribution of the Box–Cox parameter. In the rabbit data, the statistical evidence for a genetic component at the level of the environmental variance is considerably weaker than that resulting from an analysis...

  7. Heritability of thromboxane A2 and prostaglandin E2 biosynthetic machinery in a Spanish population.

    Science.gov (United States)

    Vila, Luis; Martinez-Perez, Angel; Camacho, Mercedes; Buil, Alfonso; Alcolea, Sonia; Pujol-Moix, Nuria; Soler, Marta; Antón, Rosa; Souto, Juan-Carlos; Fontcuberta, Jordi; Soria, José-Manuel

    2010-01-01

    Prostanoids play a critical role in clinical areas such as inflammation, thrombosis, immune response, and cancer. Although some studies suggest that there are genes that determine variability of some prostanoid-related phenotypes, the genetic influence on these traits has not been evaluated. The relative contributions of genetic and environmental influences to the prostanoid biosynthetic pathway-related phenotypes, cyclooxygenase isoenzymes, microsomal-PGE-synthase-1 and TxA-synthase expression, and thromboxane-A(2) and prostaglandin-E(2) production by stimulated whole blood, were assessed in a sample of 308 individuals in 15 extended families. The effects of measured covariates (such as sex, age, and smoking), genes, and environmental variables shared by members of a household were quantified. Heritabilities ranging from 0.406 to 0.634 for enzyme expression and from 0.283 to 0. 751 for prostanoid production were found. These results demonstrate clearly the importance of genetic factors in determining variation in phenotypes that are components of the prostanoid biosynthetic pathways. The presence of such strong genetic effects suggest that it will be possible to localize previously unknown genes that influence quantitative variation in these phenotypes, some of which affect multiple aspects of cell biology, with important clinical implications.

  8. Broadband minimum variance beamforming for ultrasound imaging.

    Science.gov (United States)

    Holfort, Iben Kraglund; Gran, Fredrik; Jensen, Jørgen Arendt

    2009-02-01

    A minimum variance (MV) approach for near-field beamforming of broadband data is proposed. The approach is implemented in the frequency domain, and it provides a set of adapted, complex apodization weights for each frequency subband. The performance of the proposed MV beamformer is tested on simulated data obtained using Field II. The method is validated using synthetic aperture data and data obtained from a plane wave emission. Data for 13 point targets and a circular cyst with a radius of 5 mm are simulated. The performance of the MV beamformer is compared with delay-and-sum (DS) using boxcar weights and Hanning weights and is quantified by the full width at half maximum (FWHM) and the peak-side-lobe level (PSL). Single emission {DS boxcar, DS Hanning, MV} provide a PSL of {-16, -36, -49} dB and a FWHM of {0.79, 1.33, 0.08} mm. Using all 128 emissions, {DS boxcar, DS Hanning, MV} provides a PSL of {-32, -49, -65} dB, and a FWHM of {0.63, 0.97, 0.08} mm. The contrast of the beamformed single emission responses of the circular cyst was calculated as {-18, -37, -40} dB. The simulations have shown that the frequency subband MV beamformer provides a significant increase in lateral resolution compared with DS, even when using considerably fewer emissions. An increase in resolution is seen when using only one single emission. Furthermore, the effect of steering vector errors is investigated. The steering vector errors are investigated by applying an error of the sound speed estimate to the ultrasound data. As the error increases, it is seen that the MV beamformer is not as robust compared with the DS beamformer with boxcar and Hanning weights. Nevertheless, it is noted that the DS does not outperform the MV beamformer. For errors of 2% and 4% of the correct value, the FWHM are {0.81, 1.25, 0.34} mm and {0.89, 1.44, 0.46} mm, respectively.

  9. ANOVA and the variance homogeneity assumption: Exploring a better gatekeeper.

    Science.gov (United States)

    Kim, Yoosun Jamie; Cribbie, Robert A

    2018-02-01

    Valid use of the traditional independent samples ANOVA procedure requires that the population variances are equal. Previous research has investigated whether variance homogeneity tests, such as Levene's test, are satisfactory as gatekeepers for identifying when to use or not to use the ANOVA procedure. This research focuses on a novel homogeneity of variance test that incorporates an equivalence testing approach. Instead of testing the null hypothesis that the variances are equal against an alternative hypothesis that the variances are not equal, the equivalence-based test evaluates the null hypothesis that the difference in the variances falls outside or on the border of a predetermined interval against an alternative hypothesis that the difference in the variances falls within the predetermined interval. Thus, with the equivalence-based procedure, the alternative hypothesis is aligned with the research hypothesis (variance equality). A simulation study demonstrated that the equivalence-based test of population variance homogeneity is a better gatekeeper for the ANOVA than traditional homogeneity of variance tests. © 2017 The British Psychological Society.

  10. 75 FR 21645 - Secretary's Advisory Committee on Heritable Disorders in Newborns and Children

    Science.gov (United States)

    2010-04-26

    ... risk for heritable disorders. The changing dynamics of emerging technology and the complexity of... identifies rare genetic, congenital and functional disorders, ensures early management and endeavors to... Standards Institute (CLSI). Blood collection on filter paper for newborn screening programs; approved...

  11. Childhood intelligence is heritable, highly polygenic and associated with FNBP1L

    NARCIS (Netherlands)

    Benyamin, B.; Pourcain, B.; Davis, O.S.; Davies, G.; Hansell, N.K.; Brion, M.J.; Kirkpatrick, R.M.; Cents, R.A.; Franić, S.; Miller, M.B.; Haworth, C.M.; Meaburn, E.; Price, T.S.; Evans, D.M.; Timpson, N.; Kemp, J.; Ring, S.; McArdle, W.; Medland, S.E.; Yang, J.; Harris, S.E.; Liewald, D.C.; Scheet, P.; Xiao, X.; Hudziak, J.J.; de Geus, E.J.C.; Jaddoe, V.W.; Star, J.M.; Verhulst, F.C.; Pennell, C.; Tiemeier, H.; Iacono, W.G.; Palmer, L.J.; Montgomery, G.W.; Martin, N.G.; Boomsma, D.I.; Posthuma, D.; McGue, M.; Wright, M.J.; Davey Smith, G.; Deary, I.J.; Plomin, R.; Visscher, P.M.

    2014-01-01

    Intelligence in childhood, as measured by psychometric cognitive tests, is a strong predictor of many important life outcomes, including educational attainment, income, health and lifespan. Results from twin, family and adoption studies are consistent with general intelligence being highly heritable

  12. Heritability of performance test traits in Chianina, Marchigiana and Romagnola breeds

    National Research Council Canada - National Science Library

    Sbarra, Fiorella; Mantovani, Roberto; Bittante, Giovanni

    2010-01-01

    .... Data of 2422 young bulls (735 Marchigiana, 863 Chianina and 824 Romagnola) were used to update estimates of heritability for performance test traits of aforementioned Italian beef cattle breeds...

  13. HERITABLE VARIATION FOR AGGRESSION AS A REFLECTION OF INDIVIDUAL COPING STRATEGIES

    NARCIS (Netherlands)

    BENUS, RF; BOHUS, B; KOOLHAAS, JM; VANOORTMERSSEN, GA

    1991-01-01

    Evidence is presented in rodents, that individual differences in aggression reflect heritable, fundamentally different, but equally valuable alternative strategies to cope with environmental demands. Generally, aggressive individuals show an active response to aversive situations. In a social

  14. Herdabilidade da habilidade de permanência no rebanho em fêmeas de bovinos da raça Canchim Heritability for stayability in Canchim beef cattle breed

    Directory of Open Access Journals (Sweden)

    Leonardo Martin Nieto

    2007-10-01

    . The analises were perfomed with a single-trait sire and maternal grandsire model. Gibbs sampling was used to estimate variance components and heritabilities. The estimated heritability was 0.07 for the binary trait and 0.08 for the trait with the four categories. The results indicate small diferences in the estimated heritability for the binary and four-category models. They also suggest that the stayability in Canchim breed presents low potential for response to selection.

  15. Heritability of pulmonary function estimated from genome-wide SNPs in healthy Japanese adults.

    Science.gov (United States)

    Yamada, Hideyasu; Yatagai, Yohei; Masuko, Hironori; Sakamoto, Tohru; Iijima, Hiroaki; Naito, Takashi; Noguchi, Emiko; Hirota, Tomomitsu; Tamari, Mayumi; Hizawa, Nobuyuki

    2015-03-01

    Pulmonary function is a heritable trait, and recent genome-wide association studies (GWASs) have identified a number of loci influencing the trait. Genome-wide Complex Trait Analysis (GCTA) is a novel method provided by a software package that estimates the total additive genetic influence caused by common single nucleotide polymorphisms (SNPs) on whole-genome arrays. We conducted a GWAS and assessed the heritability of pulmonary function in an adult Japanese population using this approach. We initially conducted a GWAS on %forced vital capacity (FVC), %forced expiratory volume (FEV1) and FEV1/FVC in healthy Japanese adults (N=967). We then examined the heritability of these traits using GCTA with a total of 480,026 SNPs. We also estimated the genetic impact of the 24 genes identified as susceptibility genes to FEV1/FVC in six previous GWASs on the heritability of FEV1/FVC in the Japanese population. The heritabilities for %FVC, %FEV1, and FEV1/FVC were 71.2%, 51.9% and 41.6%, respectively. These results corresponded to previous heritability estimates for pulmonary function obtained by GCTA or by twin studies. The 24 previously reported pulmonary function genes accounted for 4.3-12.0% of the entire estimated heritability of FEV1/FVC. This study demonstrated that the heritability of pulmonary function traits can be explained by the additive effects of multiple common SNPs in healthy Japanese adults. The pulmonary function genes reported in previous GWASs of non-Japanese populations showed a definite impact of the genes on FEV1/FVC, thus indicating the presence of common pathways related to this trait beyond ethnicity. Copyright © 2014 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

  16. Genetic (co)variance of rainbow trout (Oncorhynchus mykiss) body weight and its uniformity across production environments.

    Science.gov (United States)

    Sae-Lim, Panya; Kause, Antti; Janhunen, Matti; Vehviläinen, Harri; Koskinen, Heikki; Gjerde, Bjarne; Lillehammer, Marie; Mulder, Han A

    2015-05-19

    When rainbow trout from a single breeding program are introduced into various production environments, genotype-by-environment (GxE) interaction may occur. Although growth and its uniformity are two of the most important traits for trout producers worldwide, GxE interaction on uniformity of growth has not been studied. Our objectives were to quantify the genetic variance in body weight (BW) and its uniformity and the genetic correlation (rg) between these traits, and to investigate the degree of GxE interaction on uniformity of BW in breeding (BE) and production (PE) environments using double hierarchical generalized linear models. Log-transformed data were also used to investigate whether the genetic variance in uniformity of BW, GxE interaction on uniformity of BW, and rg between BW and its uniformity were influenced by a scale effect. Although heritability estimates for uniformity of BW were low and of similar magnitude in BE (0.014) and PE (0.012), the corresponding coefficients of genetic variation reached 19 and 21%, which indicated a high potential for response to selection. The genetic re-ranking for uniformity of BW (rg = 0.56) between BE and PE was moderate but greater after log-transformation, as expressed by the low rg (-0.08) between uniformity in BE and PE, which indicated independent genetic rankings for uniformity in the two environments when the scale effect was accounted for. The rg between BW and its uniformity were 0.30 for BE and 0.79 for PE but with log-transformed BW, these values switched to -0.83 and -0.62, respectively. Genetic variance exists for uniformity of BW in both environments but its low heritability implies that a large number of relatives are needed to reach even moderate accuracy of selection. GxE interaction on uniformity is present for both environments and sib-testing in PE is recommended when the aim is to improve uniformity across environments. Positive and negative rg between BW and its uniformity estimated with original

  17. What role does heritability play in transgenerational phenotypic responses to captivity? Implications for managing captive populations.

    Science.gov (United States)

    Courtney Jones, Stephanie K; Byrne, Phillip G

    2017-12-01

    Animals maintained in captivity exhibit rapid changes in phenotypic traits, which may be maladaptive for natural environments. The phenotype can shift away from the wild phenotype via transgenerational effects, with the environment experienced by parents influencing the phenotype and fitness of offspring. There is emerging evidence that controlling transgenerational effects could help mitigate the effects of captivity, improving the success of captively bred animals post release. However, controlling transgenerational effects requires knowledge of the mechanisms driving transgenerational changes. To better understand the genetic mechanisms that contribute to transgenerational effects in captivity we investigated the heritability of behavioral phenotypes using mid parent- and single parent-offspring regressions in a population of captive-reared house mouse (Mus musculus) that we had previously shown exhibit transgenerational changes in boldness and activity behavioral types. Slopes for boldness and activity were all positive, indicating a low to moderate degree of heritability. Though, none of the heritability estimates were statistically significant due to the large surrounding errors. However, the large error surrounding the heritability estimates may also indicate that there is variability in heritability between behavioral traits within the boldness and activity behavioral types. The implication of this finding is that the potential for heritable genetic changes in captivity varies considerably between traits. We conclude that continued investigation of the potential for traits to evolve in captivity is needed to better inform captive breeding and reintroduction programs. © 2017 Wiley Periodicals, Inc.

  18. The contribution of additive genetic variation to personality variation: heritability of personality.

    Science.gov (United States)

    Dochtermann, Ned A; Schwab, Tori; Sih, Andrew

    2015-01-07

    Individual animals frequently exhibit repeatable differences from other members of their population, differences now commonly referred to as 'animal personality'. Personality differences can arise, for example, from differences in permanent environmental effects--including parental and epigenetic contributors--and the effect of additive genetic variation. Although several studies have evaluated the heritability of behaviour, less is known about general patterns of heritability and additive genetic variation in animal personality. As overall variation in behaviour includes both the among-individual differences that reflect different personalities and temporary environmental effects, it is possible for personality to be largely genetically influenced even when heritability of behaviour per se is quite low. The relative contribution of additive genetic variation to personality variation can be estimated whenever both repeatability and heritability are estimated for the same data. Using published estimates to address this issue, we found that approximately 52% of animal personality variation was attributable to additive genetic variation. Thus, while the heritability of behaviour is often moderate or low, the heritability of personality is much higher. Our results therefore (i) demonstrate that genetic differences are likely to be a major contributor to variation in animal personality and (ii) support the phenotypic gambit: that evolutionary inferences drawn from repeatability estimates may often be justified. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  19. On the reconciliation of missing heritability for genome-wide association studies

    Science.gov (United States)

    Chen, Guo-Bo

    2016-01-01

    The definition of heritability has been unique and clear, but its estimation and estimates vary across studies. Linear mixed model (LMM) and Haseman–Elston (HE) regression analyses are commonly used for estimating heritability from genome-wide association data. This study provides an analytical resolution that can be used to reconcile the differences between LMM and HE in the estimation of heritability given the genetic architecture, which is responsible for these differences. The genetic architecture was classified into three forms via thought experiments: (i) coupling genetic architecture that the quantitative trait loci (QTLs) in the linkage disequilibrium (LD) had a positive covariance; (ii) repulsion genetic architecture that the QTLs in the LD had a negative covariance; (iii) and neutral genetic architecture that the QTLs in the LD had a covariance with a summation of zero. The neutral genetic architecture is so far most embraced, whereas the coupling and the repulsion genetic architecture have not been well investigated. For a quantitative trait under the coupling genetic architecture, HE overestimated the heritability and LMM underestimated the heritability; under the repulsion genetic architecture, HE underestimated but LMM overestimated the heritability for a quantitative trait. These two methods gave identical results under the neutral genetic architecture. A general analytical result for the statistic estimated under HE is given regardless of genetic architecture. In contrast, the performance of LMM remained elusive, such as further depended on the ratio between the sample size and the number of markers, but LMM converged to HE with increased sample size. PMID:27436266

  20. Individual Variation in Social Behaviours of Male Lab-reared Prairie voles (Microtus ochrogaster) is Non-heritable and Weakly Associated with V1aR Density.

    Science.gov (United States)

    Vogel, Andrea R; Patisaul, Heather B; Arambula, Sheryl E; Tiezzi, Francesco; McGraw, Lisa A

    2018-01-23

    The genetic and environmental factors that contribute to pair bonding behaviour remain poorly understood. Prairie voles (Microtus ochrogaster) often, but not always, form stable pair bonds and present an ideal model species for investigating the genetic and environmental factors that influence monogamy. Here, we assessed variation in partner preference, a measure of pair bonding, and related social behaviours in a population of laboratory-reared prairie voles under controlled environmental conditions. We evaluated to what extent variation in these behaviours correlate with vasopressin 1a receptor (V1aR) expression in the ventral pallidum (VP) and retrosplenial cortex (RSC), and estimated the heritability of these behaviours and V1aR expression. We found substantial variation in partner preference and measures of aggression, paternal care, and anxiety-like behaviours, but no correlation between these traits. We also found variation in V1aR density in the VP and RSC can account for behavioural components of paternal care and aggression, but not in partner preference. Heritability estimates of variation in partner preference were low, yet heritability estimates for V1aR expression were high, indicating that the extensive variation in partner preference observed within this population is due largely to environmental plasticity.