Silbiger, Vivian N; Hirata, Mario H; Luchessi, Andre D; Genvigir, Fabiana D V; Cerda, Alvaro; Rodrigues, Alice C; Willrich, Maria A V; Arazi, Simone S; Dorea, Egidio L; Bernik, Marcia M S; Faludi, Andre A; Bertolami, Marcelo C; Santos, Carla; Carracedo, Angel; Salas, Antonio; Freire, Ana; Lareu, Maria Victoria; Phillips, Christopher; Porras-Hurtado, Liliana; Fondevila, Manuel; Hirata, Rosario D C
Balancing the subject composition of case and control groups to create homogenous ancestries between each group is essential for medical association studies. We explored the applicability of single-tube 34-plex ancestry informative markers (AIM) single nucleotide polymorphisms (SNPs) to estimate the African Component of Ancestry (ACA) to design a future case-control association study of a Brazilian urban sample. One hundred eighty individuals (107 case group; 73 control group) self-described as white, brown-intermediate or black were selected. The proportions of the relative contribution of a variable number of ancestral population components were similar between case and control groups. Moreover, the case and control groups demonstrated similar distributions for ACA 0.50 categories. Notably a high number of outlier values (23 samples) were observed among individuals with ACA population. This can be achieved using a straight forward multiplexed AIM-SNPs assay of highly discriminatory ancestry markers.
Franasiak, Jason M; Olcha, Meir; Shastri, Shefali; Molinaro, Thomas A; Congdon, Haley; Treff, Nathan R; Scott, Richard T
Is embryonic aneuploidy, as determined by comprehensive chromosome screening (CCS), related to genetic ancestry, as determined by ancestry informative markers (AIMs)? In this study, when determining continental ancestry utilizing AIMs, genetic ancestry does not have an impact on embryonic aneuploidy. Aneuploidy is one of the best-characterized barriers to ART success and little information exists regarding ethnicity and whole chromosome aneuploidy in IVF. Classifying continental ancestry utilizing genetic profiles from a selected group of single nucleotide polymorphisms, termed AIMs, can determine ancestral origin with more accuracy than self-reported data. This is a retrospective cohort study of patients undergoing their first cycle of IVF with CCS at a single center from 2008 to 2014. There were 2328 patients identified whom had undergone IVF/CCS and AIM genotyping. All patients underwent IVF/ICSI and CCS after trophectoderm biopsy. Patients' serum was genotyped using 32 custom AIMs to identify continental origin. Admixture proportions were determined using Bayesian clustering algorithms. Patients were assigned to the population (European, African, East Asian or Central/South Asian) corresponding to their greatest admixture proportion. The mean number of embryos tested was 5.3 (range = 1-40) and the mode was 1. Patients' ethnic classifications revealed European (n = 1698), African (n = 103), East Asian (n = 206) or Central/South Asian (n = 321). When controlling for age and BMI, aneuploidy rate did not differ by genetic ancestry (P = 0.28). The study type (retrospective) and the ability to classify patients by continental rather than sub-continental origin as well as the predominantly European patient mix may impact generalizability. Post hoc power calculation revealed power to detect a 16.8% difference in embryonic aneuploidy between the two smallest sample size groups. These data do not support differences in embryonic aneuploidy among various genetic
Stefflova, Klara; Dulik, Matthew C; Barnholtz-Sloan, Jill S; Pai, Athma A; Walker, Amy H; Rebbeck, Timothy R
The ancestry of African-descended Americans is known to be drawn from three distinct populations: African, European, and Native American. While many studies consider this continental admixture, few account for the genetically distinct sources of ancestry within Africa--the continent with the highest genetic variation. Here, we dissect the within-Africa genetic ancestry of various populations of the Americas self-identified as having primarily African ancestry using uniparentally inherited mitochondrial DNA. We first confirmed that our results obtained using uniparentally-derived group admixture estimates are correlated with the average autosomal-derived individual admixture estimates (hence are relevant to genomic ancestry) by assessing continental admixture using both types of markers (mtDNA and Y-chromosome vs. ancestry informative markers). We then focused on the within-Africa maternal ancestry, mining our comprehensive database of published mtDNA variation (∼5800 individuals from 143 African populations) that helped us thoroughly dissect the African mtDNA pool. Using this well-defined African mtDNA variation, we quantified the relative contributions of maternal genetic ancestry from multiple W/WC/SW/SE (West to South East) African populations to the different pools of today's African-descended Americans of North and South America and the Caribbean. Our analysis revealed that both continental admixture and within-Africa admixture may be critical to achieving an adequate understanding of the ancestry of African-descended Americans. While continental ancestry reflects gender-specific admixture processes influenced by different socio-historical practices in the Americas, the within-Africa maternal ancestry reflects the diverse colonial histories of the slave trade. We have confirmed that there is a genetic thread connecting Africa and the Americas, where each colonial system supplied their colonies in the Americas with slaves from African colonies they controlled
Nannini, Drew; Torres, Mina; Chen, Yii-Der I; Taylor, Kent D; Rotter, Jerome I; Varma, Rohit; Gao, Xiaoyi
Intraocular pressure (IOP) is a major risk factor, as well as the only modifiable risk factor, for glaucoma. Racial differences have been observed in IOP measurements with individuals of African descent experiencing the highest IOP when compared with other ethnic groups. The purpose of this study was to examine the relationship between genetic ancestry and IOP in Latinos. Population-based genetic association study. A total of 3541 participants recruited from the Los Angeles Latino Eye Study. Study participants were genotyped using the Illumina OmniExpress BeadChip (∼730K markers). We used STRUCTURE to estimate individual genetic ancestry. Simple and multiple linear regression, as well as quantile regression, analyses were performed to investigate the relationship between genetic ancestry and IOP. The relationship between genetic ancestry and IOP in Latinos. African ancestry was significantly associated with higher IOP in Latinos in our simple linear regression analysis (P = 0.002). After adjusting for age, gender, body mass index, systolic blood pressure, central corneal thickness, and type 2 diabetes, this association remained significant (P = 0.0005). The main association was modified by a significant interaction between African ancestry and hypertension (P = 0.037), with hypertensive individuals experiencing a greater increase in IOP with increasing African ancestry. To our knowledge, we demonstrate for the first time that African ancestry and its interaction with hypertension are associated with higher IOP in Latinos. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.
Yoneyama, S; Yao, J; Guo, X; Fernandez-Rhodes, L; Lim, U; Boston, J; Buzková, P; Carlson, C S; Cheng, I; Cochran, B; Cooper, R; Ehret, G; Fornage, M; Gong, J; Gross, M; Gu, C C; Haessler, J; Haiman, C A; Henderson, B; Hindorff, L A; Houston, D; Irvin, M R; Jackson, R; Kuller, L; Leppert, M; Lewis, C E; Li, R; Le Marchand, L; Matise, T C; Nguyen, K-Dh; Chakravarti, A; Pankow, J S; Pankratz, N; Pooler, L; Ritchie, M D; Bien, S A; Wassel, C L; Chen, Y-D I; Taylor, K D; Allison, M; Rotter, J I; Schreiner, P J; Schumacher, F; Wilkens, L; Boerwinkle, E; Kooperberg, C; Peters, U; Buyske, S; Graff, M; North, K E
Central adiposity measures such as waist circumference (WC) and waist-to-hip ratio (WHR) are associated with cardiometabolic disorders independently of body mass index (BMI) and are gaining clinically utility. Several studies report genetic variants associated with central adiposity, but most utilize only European ancestry populations. Understanding whether the genetic associations discovered among mainly European descendants are shared with African ancestry populations will help elucidate the biological underpinnings of abdominal fat deposition. To identify the underlying functional genetic determinants of body fat distribution, we conducted an array-wide association meta-analysis among persons of African ancestry across seven studies/consortia participating in the Population Architecture using Genomics and Epidemiology (PAGE) consortium. We used the Metabochip array, designed for fine-mapping cardiovascular-associated loci, to explore novel array-wide associations with WC and WHR among 15 945 African descendants using all and sex-stratified groups. We further interrogated 17 known WHR regions for African ancestry-specific variants. Of the 17 WHR loci, eight single-nucleotide polymorphisms (SNPs) located in four loci were replicated in the sex-combined or sex-stratified meta-analyses. Two of these eight independently associated with WHR after conditioning on the known variant in European descendants (rs12096179 in TBX15-WARS2 and rs2059092 in ADAMTS9). In the fine-mapping assessment, the putative functional region was reduced across all four loci but to varying degrees (average 40% drop in number of putative SNPs and 20% drop in genomic region). Similar to previous studies, the significant SNPs in the female-stratified analysis were stronger than the significant SNPs from the sex-combined analysis. No novel associations were detected in the array-wide analyses. Of 17 previously identified loci, four loci replicated in the African ancestry populations of this
Yoneyama, Sachiko; Yao, Jie; Guo, Xiuqing; Fernandez-Rhodes, Lindsay; Lim, Unhee; Boston, Jonathan; Buzková, Petra; Carlson, Christopher S.; Cheng, Iona; Cochran, Barbara; Cooper, Richard; Ehret, Georg; Fornage, Myriam; Gong, Jian; Gross, Myron; Gu, C. Charles; Haessler, Jeff; Haiman, Christopher A.; Henderson, Brian; Hindorff, Lucia A.; Houston, Denise; Irvin, Marguerite R.; Jackson, Rebecca; Kuller, Lew; Leppert, Mark; Lewis, Cora E.; Li, Rongling; Le Marchand, Loic; Matise, Tara C.; Nguyen, Khanh-Dung H.; Chakravarti, Aravinda; Pankow, James S.; Pankratz, Nathan; Pooler, Loreall; Ritchie, Marylyn D.; Bien, Stephanie A.; Wassel, Christina L.; Chen, Yii-Der I.; Taylor, Kent D.; Allison, Matthew; Rotter, Jerome I.; Schreiner, Pamela J.; Schumacher, Fredrick; Wilkens, Lynne; Boerwinkle, Eric; Kooperberg, Charles; Peters, Ulrike; Buyske, Steven; Graff, Mariaelisa; North, Kari E.
Background/Objectives Central adiposity measures such as waist circumference (WC) and waist-to-hip ratio (WHR) are associated with cardiometabolic disorders independently of BMI and are gaining clinically utility. Several studies report genetic variants associated with central adiposity, but most utilize only European ancestry populations. Understanding whether the genetic associations discovered among mainly European descendants are shared with African ancestry populations will help elucidate the biological underpinnings of abdominal fat deposition. Subjects/Methods To identify the underlying functional genetic determinants of body fat distribution, we conducted an array-wide association meta-analysis among persons of African ancestry across seven studies/consortia participating in the Population Architecture using Genomics and Epidemiology (PAGE) consortium. We used the Metabochip array, designed for fine mapping cardiovascular associated loci, to explore novel array-wide associations with WC and WHR among 15 945 African descendants using all and sex-stratified groups. We further interrogated 17 known WHR regions for African ancestry-specific variants. Results Of the 17 WHR loci, eight SNPs located in four loci were replicated in the sex-combined or sex-stratified meta-analyses. Two of these eight independently associated with WHR after conditioning on the known variant in European descendants (rs12096179 in TBX15-WARS2 and rs2059092 in ADAMTS9). In the fine mapping assessment, the putative functional region was reduced across all four loci but to varying degrees (average 40% drop in number of putative SNPs and 20% drop in genomic region). Similar to previous studies, the significant SNPs in the female stratified analysis were stronger than the significant SNPs from the sex-combined analysis. No novel associations were detected in the array-wide analyses. Conclusions Of 17 previously identified loci, four loci replicated in the African ancestry populations of
Background Population stratification is a systematic difference in allele frequencies between subpopulations. This can lead to spurious association findings in the case–control genome wide association studies (GWASs) used to identify single nucleotide polymorphisms (SNPs) associated with disease-linked phenotypes. Methods such as self-declared ancestry, ancestry informative markers, genomic control, structured association, and principal component analysis are used to assess and correct population stratification but each has limitations. We provide an alternative technique to address population stratification. Results We propose a novel machine learning method, ETHNOPRED, which uses the genotype and ethnicity data from the HapMap project to learn ensembles of disjoint decision trees, capable of accurately predicting an individual’s continental and sub-continental ancestry. To predict an individual’s continental ancestry, ETHNOPRED produced an ensemble of 3 decision trees involving a total of 10 SNPs, with 10-fold cross validation accuracy of 100% using HapMap II dataset. We extended this model to involve 29 disjoint decision trees over 149 SNPs, and showed that this ensemble has an accuracy of ≥ 99.9%, even if some of those 149 SNP values were missing. On an independent dataset, predominantly of Caucasian origin, our continental classifier showed 96.8% accuracy and improved genomic control’s λ from 1.22 to 1.11. We next used the HapMap III dataset to learn classifiers to distinguish European subpopulations (North-Western vs. Southern), East Asian subpopulations (Chinese vs. Japanese), African subpopulations (Eastern vs. Western), North American subpopulations (European vs. Chinese vs. African vs. Mexican vs. Indian), and Kenyan subpopulations (Luhya vs. Maasai). In these cases, ETHNOPRED produced ensembles of 3, 39, 21, 11, and 25 disjoint decision trees, respectively involving 31, 502, 526, 242 and 271 SNPs, with 10-fold cross validation accuracy of
Shriner, Daniel; Bentley, Amy R; Doumatey, Ayo P; Chen, Guanjie; Zhou, Jie; Adeyemo, Adebowale; Rotimi, Charles N
We surveyed 26 quantitative traits and disease outcomes to understand the proportion of phenotypic variance explained by local ancestry in admixed African Americans. After inferring local ancestry as the number of African-ancestry chromosomes at hundreds of thousands of genotyped loci across all autosomes, we used a linear mixed effects model to estimate the variance explained by local ancestry in two large independent samples of unrelated African Americans. We found that local ancestry at major and polygenic effect genes can explain up to 20 and 8% of phenotypic variance, respectively. These findings provide evidence that most but not all additive genetic variance is explained by genetic markers undifferentiated by ancestry. These results also inform the proportion of health disparities due to genetic risk factors and the magnitude of error in association studies not controlling for local ancestry.
Garwood, Candice L; Clemente, Jennifer L; Ibe, George N; Kandula, Vijay A; Curtis, Kristy D; Whittaker, Peter
Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed. Our chart review examined 170 patients of African ancestry and 49 patients of European ancestry cared for in our anticoagulation clinic. We calculated the average weekly dose required for each stable, anticoagulated patient to maintain an international normalized ratio of 2.0 to 3.0, determined dose averages for groups 80 years of age and plotted dose as a function of age. The maintenance dose in patients of African ancestry decreased with age (PAfrican ancestry required higher average weekly doses than patients of European ancestry: 33% higher in the 70- to 79-year-old group (38.2+/-1.9 vs. 28.8+/-1.7 mg; P=0.006) and 52% in the >80-year-old group (33.2+/-1.7 vs. 21.8+/-3.8 mg; P=0.011). Therefore, 43% of older patients of African ancestry required daily doses >5mg and hence would have been under-dosed using current starting-dose guidelines. The dose frequency distribution was wider for older patients of African ancestry compared to those of European ancestry (PAfrican ancestry indicate that strategies for initiating warfarin therapy based on studies of patients of European ancestry could result in insufficient anticoagulation and thereby potentially increase their thromboembolism risk. Copyright 2010 Elsevier Inc. All rights reserved.
Schlesinger, D; Grinberg, L T; Alba, J G; Naslavsky, M S; Licinio, L; Farfel, J M; Suemoto, C K; de Lucena Ferretti, R E; Leite, R E P; de Andrade, M P; dos Santos, A C F; Brentani, H; Pasqualucci, C A; Nitrini, R; Jacob-Filho, W; Zatz, M
Previous studies in dementia epidemiology have reported higher Alzheimer's disease rates in African-Americans when compared with White Americans. To determine whether genetically determined African ancestry is associated with neuropathological changes commonly associated with dementia, we analyzed a population-based brain bank in the highly admixed city of São Paulo, Brazil. African ancestry was estimated through the use of previously described ancestry-informative markers. Risk of presence of neuritic plaques, neurofibrillary tangles, small vessel disease, brain infarcts and Lewy bodies in subjects with significant African ancestry versus those without was determined. Results were adjusted for multiple environmental risk factors, demographic variables and apolipoprotein E genotype. African ancestry was inversely correlated with neuritic plaques (P=0.03). Subjects with significant African ancestry (n=112, 55.4%) showed lower prevalence of neuritic plaques in the univariate analysis (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.55-0.95, P=0.01) and when adjusted for age, sex, APOE genotype and environmental risk factors (OR 0.43, 95% CI 0.21-0.89, P=0.02). There were no significant differences for the presence of other neuropathological alterations. We show for the first time, using genetically determined ancestry, that African ancestry may be highly protective of Alzheimer's disease neuropathology, functioning through either genetic variants or unknown environmental factors. Epidemiological studies correlating African-American race/ethnicity with increased Alzheimer's disease rates should not be interpreted as surrogates of genetic ancestry or considered to represent African-derived populations from the developing nations such as Brazil.
Emery, Leslie S.; Magnaye, Kevin M.; Bigham, Abigail W.; Akey, Joshua M.; Bamshad, Michael J.
The association between a geographical region and an mtDNA haplogroup(s) has provided the basis for using mtDNA haplogroups to infer an individual’s place of origin and genetic ancestry. Although it is well known that ancestry inferences using mtDNA haplogroups and those using genome-wide markers are frequently discrepant, little empirical information exists on the magnitude and scope of such discrepancies between multiple mtDNA haplogroups and worldwide populations. We compared genetic-ancestry inferences made by mtDNA-haplogroup membership to those made by autosomal SNPs in ∼940 samples of the Human Genome Diversity Panel and recently admixed populations from the 1000 Genomes Project. Continental-ancestry proportions often varied widely among individuals sharing the same mtDNA haplogroup. For only half of mtDNA haplogroups did the highest average continental-ancestry proportion match the highest continental-ancestry proportion of a majority of individuals with that haplogroup. Prediction of an individual’s mtDNA haplogroup from his or her continental-ancestry proportions was often incorrect. Collectively, these results indicate that for most individuals in the worldwide populations sampled, mtDNA-haplogroup membership provides limited information about either continental ancestry or continental region of origin. PMID:25620206
Gregersen Peter K
Full Text Available Abstract Background Case-control genetic studies of complex human diseases can be confounded by population stratification. This issue can be addressed using panels of ancestry informative markers (AIMs that can provide substantial population substructure information. Previously, we described a panel of 128 SNP AIMs that were designed as a tool for ascertaining the origins of subjects from Europe, Sub-Saharan Africa, Americas, and East Asia. Results In this study, genotypes from Human Genome Diversity Panel populations were used to further evaluate a 93 SNP AIM panel, a subset of the 128 AIMS set, for distinguishing continental origins. Using both model-based and relatively model-independent methods, we here confirm the ability of this AIM set to distinguish diverse population groups that were not previously evaluated. This study included multiple population groups from Oceana, South Asia, East Asia, Sub-Saharan Africa, North and South America, and Europe. In addition, the 93 AIM set provides population substructure information that can, for example, distinguish Arab and Ashkenazi from Northern European population groups and Pygmy from other Sub-Saharan African population groups. Conclusion These data provide additional support for using the 93 AIM set to efficiently identify continental subject groups for genetic studies, to identify study population outliers, and to control for admixture in association studies.
Gutiérrez, Orlando M; Parsa, Afshin; Isakova, Tamara; Scialla, Julia J; Chen, Jing; Flack, John M; Nessel, Lisa C; Gupta, Jayanta; Bellovich, Keith A; Steigerwalt, Susan; Sondheimer, James H; Wright, Jackson T; Feldman, Harold I; Kusek, John W; Lash, James P; Wolf, Myles
Disorders of mineral metabolism are more common in African Americans with CKD than in European Americans with CKD. Previous studies have focused on the differences in mineral metabolism by self-reported race, making it difficult to delineate the importance of environmental compared with biologic factors. In a cross-sectional analysis of 3013 participants of the Chronic Renal Insufficiency Cohort study with complete data, we compared markers of mineral metabolism (phosphorus, calcium, alkaline phosphatase, parathyroid hormone, fibroblast growth factor 23, and urine calcium and phosphorus excretion) in European Americans versus African Americans and separately, across quartiles of genetic African ancestry in African Americans (n=1490). Compared with European Americans, African Americans had higher blood concentrations of phosphorus, alkaline phosphatase, fibroblast growth factor 23, and parathyroid hormone, lower 24-hour urinary excretion of calcium and phosphorus, and lower urinary fractional excretion of calcium and phosphorus at baseline (PAfrican Americans, a higher percentage of African ancestry was associated with lower 24-hour urinary excretion of phosphorus (PtrendAfrican ancestry was significantly associated with lower 24-hour urinary phosphorus excretion (each 10% higher African ancestry was associated with 39.6 mg lower 24-hour urinary phosphorus, PAfrican ancestry was associated with an absolute 1.1% lower fractional excretion of phosphorus, P=0.01). A higher percentage of African ancestry was independently associated with lower 24-hour urinary phosphorus excretion and lower fractional excretion of phosphorus among African Americans with CKD. These findings suggest that genetic variability might contribute to racial differences in urinary phosphorus excretion in CKD. Copyright © 2016 by the American Society of Nephrology.
Bryc, Katarzyna; Durand, Eric Y.; Macpherson, J. Michael; Reich, David; Mountain, Joanna L.
Over the past 500 years, North America has been the site of ongoing mixing of Native Americans, European settlers, and Africans (brought largely by the trans-Atlantic slave trade), shaping the early history of what became the United States. We studied the genetic ancestry of 5,269 self-described African Americans, 8,663 Latinos, and 148,789 European Americans who are 23andMe customers and show that the legacy of these historical interactions is visible in the genetic ancestry of present-day Americans. We document pervasive mixed ancestry and asymmetrical male and female ancestry contributions in all groups studied. We show that regional ancestry differences reflect historical events, such as early Spanish colonization, waves of immigration from many regions of Europe, and forced relocation of Native Americans within the US. This study sheds light on the fine-scale differences in ancestry within and across the United States and informs our understanding of the relationship between racial and ethnic identities and genetic ancestry. PMID:25529636
Pierron, Denis; Heiske, Margit; Razafindrazaka, Harilanto; Pereda-Loth, Veronica; Sanchez, Jazmin; Alva, Omar; Arachiche, Amal; Boland, Anne; Olaso, Robert; Deleuze, Jean-Francois; Ricaut, Francois-Xavier; Rakotoarisoa, Jean-Aimé; Radimilahy, Chantal; Stoneking, Mark; Letellier, Thierry
While admixed populations offer a unique opportunity to detect selection, the admixture in most of the studied populations occurred too recently to produce conclusive signals. By contrast, Malagasy populations originate from admixture between Asian and African populations that occurred ~27 generations ago, providing power to detect selection. We analyze local ancestry across the genomes of 700 Malagasy and identify a strong signal of recent positive selection, with an estimated selection coefficient >0.2. The selection is for African ancestry and affects 25% of chromosome 1, including the Duffy blood group gene. The null allele at this gene provides resistance to Plasmodium vivax malaria, and previous studies have suggested positive selection for this allele in the Malagasy population. This selection event also influences numerous other genes implicated in immunity, cardiovascular diseases, and asthma and decreases the Asian ancestry genome-wide by 10%, illustrating the role played by selection in recent human history.
Newman, Lisa A
Recognition of breast cancer disparities between African-American and White American women has generated exciting research opportunities investigating the biologic and hereditary factors that contribute to the observed outcome differences, leading to international studies of breast cancer in Africa. The study of breast cancer in women with African ancestry has opened the door to unique investigations regarding breast cancer subtypes and the genetics of this disease. International research efforts can advance our understanding of race/ethnicity-associated breast cancer disparities within the USA; the pathogenesis of triple negative breast cancer; and hereditary susceptibility for breast cancer. © 2015 Wiley Periodicals, Inc.
In light of this realization, this article discusses the contributions of the African Diaspora towards continental African liberation from European colonial domination, with a view to theorizing the implications of this history on the criticism of African Renaissance literature. Focusing on Diasporan African agency in organizing ...
D'Elia, Maria Paula Barbieri; Brandão, Marcela Calixto; de Andrade Ramos, Bruna Ribeiro; da Silva, Márcia Guimarães; Miot, Luciane Donida Bartoli; Dos Santos, Sidney Emanuel Batista; Miot, Hélio Amante
Melasma is a chronic acquired focal hypermelanosis affecting photoexposed areas, especially for women during fertile age. Several factors contribute to its development: sun exposure, sex steroids, medicines, and family history. Melanic pigmentation pathway discloses several SNPs in different populations. Here, we evaluated the association between genetic ancestry and facial melasma. A cross-sectional study involving women with melasma and an age-matched control group from outpatients at FMB-Unesp, Botucatu-SP, Brazil was performed. DNA was extracted from oral mucosa swabs and ancestry determined by studying 61 INDELs. The genetic ancestry components were adjusted by other known risk factors by multiple logistic regression. We evaluated 119 women with facial melasma and 119 controls. Mean age was 39 ± 9 years. Mean age at beginning of disease was 27 ± 8 years. Pregnancy (40%), sun exposure (37%), and hormonal oral contraception (22%) were the most frequently reported melasma triggers. All subjects presented admixed ancestry, African and European genetic contributions were significantly different between cases and controls (respectively 10% vs 6%; 77% vs 82%; p ancestry (OR = 1.04; 95% CI 1.01 to 1.07), first generation family history (OR = 3.04; 95% CI 1.56 to 5.94), low education level (OR = 4.04; 95% CI 1.56 to 5.94), and use of antidepressants by individuals with affected family members (OR = 6.15; 95% CI 1.13 to 33.37) were associated with melasma, independently of other known risk factors. Facial melasma was independently associated with African ancestry in a highly admixed population.
Conley, Andrew B; Rishishwar, Lavanya; Norris, Emily T; Valderrama-Aguirre, Augusto; Mariño-Ramírez, Leonardo; Medina-Rivas, Miguel A; Jordan, I King
At least 20% of Colombians identify as having African ancestry, yielding the second largest population of Afro-descendants in Latin America. To date, there have been relatively few studies focused on the genetic ancestry of Afro-Latino populations. We report a comparative analysis of the genetic ancestry of Chocó, a state located on Colombia's Pacific coast with a population that is >80% Afro-Colombian. We compared genome-wide patterns of genetic ancestry and admixture for Chocó to six other admixed American populations, with an emphasis on a Mestizo population from the nearby Colombian city of Medellín. One hundred sample donors from Chocó were genotyped across 610,545 genomic sites and compared with 94 publicly available whole genome sequences from Medellín. At the continental level, Chocó shows mostly African genetic ancestry (76%) with a nearly even split between European (13%) and Native American (11%) fractions, whereas Medellín has primarily European ancestry (75%), followed by Native American (18%) and African (7%). Sample donors from Chocó self-identify as having more African ancestry, and conversely less European and Native American ancestry, than can be genetically inferred, as opposed to what we previously found for Medellín, where individuals tend to overestimate levels of European ancestry. We developed a novel approach for subcontinental ancestry assignment, which allowed us to characterize subcontinental source populations for each of the three distinct continental ancestry fractions separately. Despite the clear differences between Chocó and Medellín at the level of continental ancestry, the two populations show overall patterns of subcontinental ancestry that are highly similar. Their African subcontinental ancestries are only slightly different, with Chocó showing more exclusive shared ancestry with the modern Yoruba (Nigerian) population, and Medellín having relatively more shared ancestry with West African populations in Sierra
Melinda C Aldrich
Full Text Available BACKGROUND: Smoking tobacco reduces lung function. African Americans have both lower lung function and decreased metabolism of tobacco smoke compared to European Americans. African ancestry is also associated with lower pulmonary function in African Americans. We aimed to determine whether African ancestry modifies the association between smoking and lung function and its rate of decline in African Americans. METHODOLOGY/PRINCIPAL FINDINGS: We evaluated a prospective ongoing cohort of 1,281 African Americans participating in the Health, Aging, and Body Composition (Health ABC Study initiated in 1997. We also examined an ongoing prospective cohort initiated in 1985 of 1,223 African Americans in the Coronary Artery Disease in Young Adults (CARDIA Study. Pulmonary function and tobacco smoking exposure were measured at baseline and repeatedly over the follow-up period. Individual genetic ancestry proportions were estimated using ancestry informative markers selected to distinguish European and West African ancestry. African Americans with a high proportion of African ancestry had lower baseline forced expiratory volume in one second (FEV₁ per pack-year of smoking (-5.7 ml FEV₁/ smoking pack-year compared with smokers with lower African ancestry (-4.6 ml in FEV₁/ smoking pack-year (interaction P value = 0.17. Longitudinal analyses revealed a suggestive interaction between smoking, and African ancestry on the rate of FEV(1 decline in Health ABC and independently replicated in CARDIA. CONCLUSIONS/SIGNIFICANCE: African American individuals with a high proportion of African ancestry are at greater risk for losing lung function while smoking.
Full Text Available Adult height is a classic polygenic trait of high heritability (h(2 approximately 0.8. More than 180 single nucleotide polymorphisms (SNPs, identified mostly in populations of European descent, are associated with height. These variants convey modest effects and explain approximately10% of the variance in height. Discovery efforts in other populations, while limited, have revealed loci for height not previously implicated in individuals of European ancestry. Here, we performed a meta-analysis of genome-wide association (GWA results for adult height in 20,427 individuals of African ancestry with replication in up to 16,436 African Americans. We found two novel height loci (Xp22-rs12393627, P = 3.4×10(-12 and 2p14-rs4315565, P = 1.2×10(-8. As a group, height associations discovered in European-ancestry samples replicate in individuals of African ancestry (P = 1.7×10(-4 for overall replication. Fine-mapping of the European height loci in African-ancestry individuals showed an enrichment of SNPs that are associated with expression of nearby genes when compared to the index European height SNPs (P<0.01. Our results highlight the utility of genetic studies in non-European populations to understand the etiology of complex human diseases and traits.
do Rego Borges, Andrea; Sá, Jamile; Hoshi, Ryuichi; Viena, Camila Sane; Mariano, Lorena C; de Castro Veiga, Patricia; Medrado, Alena Peixoto; Machado, Renato Assis; de Aquino, Sibele Nascimento; Messetti, Ana Camila; Spritz, Richard A; Coletta, Ricardo D; Reis, Silvia R A
Nonsyndromic cleft lip with or without cleft palate (NSCL ± P) is the most common orofacial birth defect, exhibiting variable prevalence around the world, often attributed to ethnic and environmental differences. Linkage analyses and genome-wide association studies have identified several genomic susceptibility regions for NSCL ± P, mostly in European-derived or Asian populations. Genetic predisposition to NSCL ± P is ethnicity-dependent, and the genetic basis of susceptibility to NSCL ± P likely varies among populations. The population of Brazil is highly admixed, with highly variable ancestry; thus, the genetic determinants of NSCL ± P susceptibility may be quite different. This study tested association of 8 single-nucleotide polymorphisms (SNPs), previously identified by genome-wide studies in other populations, with NSCL ± P in a Brazilian population with high African ancestry. SNPs rs560426, rs642961, rs1530300, rs987525, rs3758249, rs7078160, rs17085106, and rs13041247 were genotyped in 293 Brazilian patients with NSCL ± P and 352 unaffected Brazilian controls. Each sample was also genotyped for 40 biallelic short insertion/deletion polymorphic markers to characterize genetic ancestry. The average African ancestry background was 31.1% for the NSCL ± P group and 36.7% for the control group. After adjustment for ancestry and multiple testing, the minor alleles of rs3758249 (OR: 1.58, 95% CI: 1.25-2.01, P = 0.0001) and rs7078160 (OR: 1.59, 95% CI: 1.21-2.07, P = 0.0002) were significantly associated with risk of NSCL ± P. Polymorphisms located in IRF6 (rs642961) and 8q24 (rs1530300 and rs987525) showed marginal associations in this Brazilian population with high African ancestry. These results indicate that rs3758249 at 9q22 and rs7078160 at 10q25.3 represent risk loci for NSCL ± P in the Brazilian population with high African ancestry. © 2015 Wiley Periodicals, Inc.
Nadkarni, Girish N.; Belbin, Gillian; Lotay, Vaneet; Wyatt, Christina; Gottesman, Omri; Bottinger, Erwin P.; Kenny, Eimear E.; Peter, Inga
Self-reported ancestry, genetically determined ancestry, and APOL1 polymorphisms are associated with variation in kidney function and related disease risk, but the relative importance of these factors remains unclear. We estimated the global proportion of African ancestry for 9048 individuals at Mount Sinai Medical Center in Manhattan (3189 African Americans, 1721 European Americans, and 4138 Hispanic/Latino Americans by self-report) using genome-wide genotype data. CKD-EPI eGFR and genotypes of three APOL1 coding variants were available. In admixed African Americans and Hispanic/Latino Americans, serum creatinine values increased as African ancestry increased (per 10% increase in African ancestry, creatinine values increased 1% in African Americans and 0.9% in Hispanic/Latino Americans; P≤1x10−7). eGFR was likewise significantly associated with African genetic ancestry in both populations. In contrast, APOL1 risk haplotypes were significantly associated with CKD, eGFRblack on the basis of ≥50% African ancestry resulted in higher eGFR for 14.7% of Hispanic/Latino Americans and lower eGFR for 4.1% of African Americans, affecting CKD staging in 4.3% and 1% of participants, respectively. Reclassified individuals had electrolyte values consistent with their newly assigned CKD stage. In summary, proportion of African ancestry was significantly associated with normal-range creatinine and eGFR, whereas APOL1 risk haplotypes drove the associations with CKD. Recalculation of eGFR on the basis of genetic ancestry affected CKD staging and warrants additional investigation. PMID:25349204
Santangelo, Roberta; González-Andrade, Fabricio; Børsting, Claus; Torroni, Antonio; Pereira, Vania; Morling, Niels
Ancestry inference is traditionally done using autosomal SNPs that present great allele frequency differences among populations from different geographic regions. These ancestry informative markers (AIMs) are useful for determining the most likely biogeographic ancestry or population of origin of an individual. Due to the growing interest in AIMs and their applicability in different fields, commercial companies have started to develop AIM multiplexes targeted for Massive Parallel Sequencing platforms. This project focused on the study of three main ethnic groups from Ecuador (Kichwa, Mestizo, and Afro-Ecuadorian) using the Precision ID Ancestry panel (Thermo Fisher Scientific). In total, 162 Ecuadorian individuals were investigated. The Afro-Ecuadorian and Mestizo showed higher average genetic diversities compared to the Kichwa. These results are consistent with the highly admixed nature of the first two groups. The Kichwa showed the highest proportion of Native Amerindian (NAM) ancestry relative to the other two groups. The Mestizo had an admixed ancestry of NAM and European with a larger European component, whereas the Afro-Ecuadorian were highly admixed presenting proportions of African, Native Amerindian, and European ancestries. The comparison of our results with previous studies based on uniparental markers (i.e. Y chromosome and mtDNA) highlighted the sex-biased admixture process in the Ecuadorian Mestizo. Overall, the data generated in this work represent one important step to assess the application of ancestry inference in admixed populations in a forensic context. Copyright © 2017 Elsevier B.V. All rights reserved.
Ng, Maggie C Y; Graff, Mariaelisa; Lu, Yingchang; Justice, Anne E; Mudgal, Poorva; Liu, Ching-Ti; Young, Kristin; Yanek, Lisa R; Feitosa, Mary F; Wojczynski, Mary K; Rand, Kristin; Brody, Jennifer A; Cade, Brian E; Dimitrov, Latchezar; Duan, Qing; Guo, Xiuqing; Lange, Leslie A; Nalls, Michael A; Okut, Hayrettin; Tajuddin, Salman M; Tayo, Bamidele O; Vedantam, Sailaja; Bradfield, Jonathan P; Chen, Guanjie; Chen, Wei-Min; Chesi, Alessandra; Irvin, Marguerite R; Padhukasahasram, Badri; Smith, Jennifer A; Zheng, Wei; Allison, Matthew A; Ambrosone, Christine B; Bandera, Elisa V; Bartz, Traci M; Berndt, Sonja I; Bernstein, Leslie; Blot, William J; Bottinger, Erwin P; Carpten, John; Chanock, Stephen J; Chen, Yii-Der Ida; Conti, David V; Cooper, Richard S; Fornage, Myriam; Freedman, Barry I; Garcia, Melissa; Goodman, Phyllis J; Hsu, Yu-Han H; Hu, Jennifer; Huff, Chad D; Ingles, Sue A; John, Esther M; Kittles, Rick; Klein, Eric; Li, Jin; McKnight, Barbara; Nayak, Uma; Nemesure, Barbara; Ogunniyi, Adesola; Olshan, Andrew; Press, Michael F; Rohde, Rebecca; Rybicki, Benjamin A; Salako, Babatunde; Sanderson, Maureen; Shao, Yaming; Siscovick, David S; Stanford, Janet L; Stevens, Victoria L; Stram, Alex; Strom, Sara S; Vaidya, Dhananjay; Witte, John S; Yao, Jie; Zhu, Xiaofeng; Ziegler, Regina G; Zonderman, Alan B; Adeyemo, Adebowale; Ambs, Stefan; Cushman, Mary; Faul, Jessica D; Hakonarson, Hakon; Levin, Albert M; Nathanson, Katherine L; Ware, Erin B; Weir, David R; Zhao, Wei; Zhi, Degui; Arnett, Donna K; Grant, Struan F A; Kardia, Sharon L R; Oloapde, Olufunmilayo I; Rao, D C; Rotimi, Charles N; Sale, Michele M; Williams, L Keoki; Zemel, Babette S; Becker, Diane M; Borecki, Ingrid B; Evans, Michele K; Harris, Tamara B; Hirschhorn, Joel N; Li, Yun; Patel, Sanjay R; Psaty, Bruce M; Rotter, Jerome I; Wilson, James G; Bowden, Donald W; Cupples, L Adrienne; Haiman, Christopher A; Loos, Ruth J F; North, Kari E
Genome-wide association studies (GWAS) have identified >300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHRadjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHRadjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified one novel locus (TCF7L2/HABP2) for WHRadjBMI and eight previously established loci at P African ancestry individuals. An additional novel locus (SPRYD7/DLEU2) was identified for WHRadjBMI when combined with European GWAS. In the sex-stratified analyses, we identified three novel loci for BMI (INTS10/LPL and MLC1 in men, IRX4/IRX2 in women) and four for WHRadjBMI (SSX2IP, CASC8, PDE3B and ZDHHC1/HSD11B2 in women) in individuals of African ancestry or both African and European ancestry. For four of the novel variants, the minor allele frequency was low (African ancestry sex-combined and sex-stratified analyses, 26 BMI loci and 17 WHRadjBMI loci contained ≤ 20 variants in the credible sets that jointly account for 99% posterior probability of driving the associations. The lead variants in 13 of these loci had a high probability of being causal. As compared to our previous HapMap imputed GWAS for BMI and WHRadjBMI including up to 71,412 and 27,350 African ancestry individuals, respectively, our results suggest that 1000 Genomes imputation showed modest improvement in identifying GWAS loci including low frequency variants. Trans-ethnic meta-analyses further improved fine mapping of putative causal variants in loci shared between the African and European ancestry populations.
Daya, Michelle; van der Merwe, Lize; Galal, Ushma; Möller, Marlo; Salie, Muneeb; Chimusa, Emile R.; Galanter, Joshua M.; van Helden, Paul D.; Henn, Brenna M.; Gignoux, Chris R.; Hoal, Eileen
Admixture is a well known confounder in genetic association studies. If genome-wide data is not available, as would be the case for candidate gene studies, ancestry informative markers (AIMs) are required in order to adjust for admixture. The predominant population group in the Western Cape, South Africa, is the admixed group known as the South African Coloured (SAC). A small set of AIMs that is optimized to distinguish between the five source populations of this population (African San, African non-San, European, South Asian, and East Asian) will enable researchers to cost-effectively reduce false-positive findings resulting from ignoring admixture in genetic association studies of the population. Using genome-wide data to find SNPs with large allele frequency differences between the source populations of the SAC, as quantified by Rosenberg et. al's -statistic, we developed a panel of AIMs by experimenting with various selection strategies. Subsets of different sizes were evaluated by measuring the correlation between ancestry proportions estimated by each AIM subset with ancestry proportions estimated using genome-wide data. We show that a panel of 96 AIMs can be used to assess ancestry proportions and to adjust for the confounding effect of the complex five-way admixture that occurred in the South African Coloured population. PMID:24376522
Full Text Available Background. Fanconi anaemia (FA is a rare genetic disorder of impaired DNA repair that results in physical and haematological consequences in affected individuals. In South Africa (SA, individuals with Afrikaner ancestry are at an increased risk of inheriting disease-causing FA mutations, owing to the three common FANCA (FA, complementation group A founder mutations present in this population subgroup. Objectives. To describe the physical phenotype of SA patients with FANCA mutations for the purpose of recommending appropriate care for affected individuals. Methods. A structured clinical examination and file-based review were used to evaluate the physical phenotype of 7 patients with compound heterozygous and homozygous FANCA founder mutations, and 1 patient with confirmed FANCA complementation analysis. Descriptive statistical analysis was used to determine the frequency of physical anomalies in Afrikaner patients and to compare the described phenotype to other FA cohorts, including a previously clinically characterised black SA FA cohort. Results. An earlier age of diagnosis of FA in Afrikaner patients, a high frequency of somatic anomalies and a higher-than-expected incidence of the VACTERL/H phenotype were noted. Conclusions. Based on our findings, recommendations for the care of FA patients with Afrikaner ancestry are made, including renal ultrasound evaluation at diagnosis and hearing screening
Seedat, Yackoob K; Brewster, Lizzy M
This article is a summary of the response of the four commonly used antihypertensive agents in African ancestry patients. They are thiazide like diuretics or indapamide, calcium channel blockers (CCB), angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers, and β-adrenergic blockers (ARB). Response was superior in African ancestry patients on a thiazide like diuretic or indapamide and CCB, while the response to β-adrenergic blockers and ACEI are attenuated. Available data are very limited but self-defined ancestry seems to be the best predictor of individual responses to antihypertensive drugs. Knowledge of the factors like economic and social consideration affect the lower rate of detection, treatment and control of hypertension in the African ancestry population of the USA. For regions in which health care resources are particularly scarce, investment in population-based primary prevention strategies may yield the largest benefit.
Full Text Available Paraoxonase 1 (PON1 activity is markedly influenced by coding polymorphisms, Q/R at position 192 and M/L at position 55 of the PON1 gene. We investigated the frequencies of these polymorphisms and their effects on PON1 and antioxidant activities in 844 South African mixed ancestry individuals. Genotyping was done using allele-specific TaqMan technology, PON1 activities were measured using paraoxon and phenylacetate, oxidative status was determined by measuring the antioxidant activities of ferric reducing antioxidant power and trolox equivalent antioxidant capacity, and lipid peroxidation markers included malondialdehyde and oxidized LDL. The frequencies of Q192R and L55M were 47.6% and 28.8%, respectively, and the most common corresponding alleles were 192R (60.4% and 55M (82.6%. The Q192 was significantly associated with 5.8 units’ increase in PON1 concentration and 15.4 units’ decrease in PONase activity after adjustment for age, sex, BMI, and diabetes, with suggestion of differential effects by diabetes status. The PON1 L55 variant was associated with none of the measured indices. In conclusion, we have shown that the Q192R polymorphism is a determinant of both PON1 concentration and activity and this association appeared to be enhanced in subjects with diabetes.
Haddad, Stephen A; Ruiz-Narváez, Edward A; Cozier, Yvette C; Gerlovin, Hanna; Rosenberg, Lynn; Palmer, Julie R
Circulating levels of vitamin D are generally lower in African Americans compared to U.S. whites, and one prior analysis in a small number of African Americans suggested that, within this population, vitamin D levels may be related to the degree of genetic admixture. We assessed the association of percent European ancestry with serum vitamin D levels in 2183 African American women from the Black Women's Health Study in 2013-2015, whose DNA had been genotyped for ancestry informative markers. ADMIXMAP software was used to estimate percent European versus African ancestry in each individual. In linear regression analyses with adjustment for genotype batch, age, body mass index, supplemental vitamin D use, UVB flux in state of residence, and season of blood draw, each 10% increase in European ancestry was associated with a 0.672 ng/mL increase in serum vitamin D concentration (95% confidence interval 0.173, 1.170). The association was statistically significant only among women who were not taking vitamin D supplements (beta coefficient for 10% increase in European ancestry 0.855, 95% confidence interval 0.139, 1.571). Among African Americans, use of vitamin D supplementation may help to reduce vitamin D deficiency due to genetic ancestry. © The Author(s) 2018. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: email@example.com.
L'Abbé, E N; Van Rooyen, C; Nawrocki, S P; Becker, P J
Establishing ancestry from a skeleton for forensic purposes has been shown to be difficult. The purpose of this paper is to address the application of thirteen non-metric traits to estimate ancestry in three South African groups, namely White, Black and "Coloured". In doing so, the frequency distribution of thirteen non-metric traits among South Africans are presented; the relationship of these non-metric traits with ancestry, sex, age at death are evaluated; and Kappa statistics are utilized to assess the inter and intra-rater reliability. Crania of 520 known individuals were obtained from four skeletal samples in South Africa: the Pretoria Bone Collection, the Raymond A. Dart Collection, the Kirsten Collection and the Student Bone Collection from the University of the Free State. Average age at death was 51, with an age range between 18 and 90. Thirteen commonly used non-metric traits from the face and jaw were scored; definition and illustrations were taken from Hefner, Bass and Hauser and De Stephano. Frequency distributions, ordinal regression and Cohen's Kappa statistics were performed as a means to assess population variation and repeatability. Frequency distributions were highly variable among South Africans. Twelve of the 13 variables had a statistically significant relationship with ancestry. Sex significantly affected only one variable, inter-orbital breadth, and age at death affected two (anterior nasal spine and alveolar prognathism). The interaction of ancestry and sex independently affected three variables (nasal bone contour, nasal breadth, and interorbital breadth). Seven traits had moderate to excellent repeatability, while poor scoring consistency was noted for six variables. Difficulties in repeating several of the trait scores may require either a need for refinement of the definitions, or these character states may not adequately describe the observable morphology in the population. The application of the traditional experience-based approach
Full Text Available Ethnic groups can display differential genetic susceptibility to infectious diseases. The arthropod-born viral dengue disease is one such disease, with empirical and limited genetic evidence showing that African ancestry may be protective against the haemorrhagic phenotype. Global ancestry analysis based on high-throughput genotyping in admixed populations can be used to test this hypothesis, while admixture mapping can map candidate protective genes. A Cuban dengue fever cohort was genotyped using a 2.5 million SNP chip. Global ancestry was ascertained through ADMIXTURE and used in a fine-matched corrected association study, while local ancestry was inferred by the RFMix algorithm. The expression of candidate genes was evaluated by RT-PCR in a Cuban dengue patient cohort and gene set enrichment analysis was performed in a Thai dengue transcriptome. OSBPL10 and RXRA candidate genes were identified, with most significant SNPs placed in inferred weak enhancers, promoters and lncRNAs. OSBPL10 had significantly lower expression in Africans than Europeans, while for RXRA several SNPs may differentially regulate its transcription between Africans and Europeans. Their expression was confirmed to change through dengue disease progression in Cuban patients and to vary with disease severity in a Thai transcriptome dataset. These genes interact in the LXR/RXR activation pathway that integrates lipid metabolism and immune functions, being a key player in dengue virus entrance into cells, its replication therein and in cytokine production. Knockdown of OSBPL10 expression in THP-1 cells by two shRNAs followed by DENV2 infection tests led to a significant reduction in DENV replication, being a direct functional proof that the lower OSBPL10 expression profile in Africans protects this ancestry against dengue disease.
Egan, Kieren J; Campos Santos, Hadassa; Beijamini, Felipe; Duarte, Núbia E; Horimoto, Andréa R V R; Taporoski, Tâmara P; Vallada, Homero; Negrão, André B; Krieger, José E; Pedrazzoli, Mário; Knutson, Kristen L; Pereira, Alexandre C; von Schantz, Malcolm
Significant questions remain unanswered regarding the genetic versus environmental contributions to racial/ethnic differences in sleep and circadian rhythms. We addressed this question by investigating the association between diurnal preference, using the morningness-eveningness questionnaire (MEQ), and genetic ancestry within the Baependi Heart Study cohort, a highly admixed Brazilian population based in a rural town. Analysis was performed using measures of ancestry, using the Admixture program, and MEQ from 1,453 individuals. We found an association between the degree of Amerindian (but not European of African) ancestry and morningness, equating to 0.16 units for each additional percent of Amerindian ancestry, after adjustment for age, sex, education, and residential zone. To our knowledge, this is the first published report identifying an association between genetic ancestry and MEQ, and above all, the first one based on ancestral contributions within individuals living in the same community. This previously unknown ancestral dimension of diurnal preference suggests a stratification between racial/ethnic groups in an as yet unknown number of genetic polymorphisms.
Gravel, Simon; Wang, Wei; Brisbin, Abra; Byrnes, Jake K.; Fadhlaoui-Zid, Karima; Zalloua, Pierre A.; Moreno-Estrada, Andres; Bertranpetit, Jaume; Bustamante, Carlos D.; Comas, David
North African populations are distinct from sub-Saharan Africans based on cultural, linguistic, and phenotypic attributes; however, the time and the extent of genetic divergence between populations north and south of the Sahara remain poorly understood. Here, we interrogate the multilayered history of North Africa by characterizing the effect of hypothesized migrations from the Near East, Europe, and sub-Saharan Africa on current genetic diversity. We present dense, genome-wide SNP genotyping array data (730,000 sites) from seven North African populations, spanning from Egypt to Morocco, and one Spanish population. We identify a gradient of likely autochthonous Maghrebi ancestry that increases from east to west across northern Africa; this ancestry is likely derived from “back-to-Africa” gene flow more than 12,000 years ago (ya), prior to the Holocene. The indigenous North African ancestry is more frequent in populations with historical Berber ethnicity. In most North African populations we also see substantial shared ancestry with the Near East, and to a lesser extent sub-Saharan Africa and Europe. To estimate the time of migration from sub-Saharan populations into North Africa, we implement a maximum likelihood dating method based on the distribution of migrant tracts. In order to first identify migrant tracts, we assign local ancestry to haplotypes using a novel, principal component-based analysis of three ancestral populations. We estimate that a migration of western African origin into Morocco began about 40 generations ago (approximately 1,200 ya); a migration of individuals with Nilotic ancestry into Egypt occurred about 25 generations ago (approximately 750 ya). Our genomic data reveal an extraordinarily complex history of migrations, involving at least five ancestral populations, into North Africa. PMID:22253600
Brenna M Henn
Full Text Available North African populations are distinct from sub-Saharan Africans based on cultural, linguistic, and phenotypic attributes; however, the time and the extent of genetic divergence between populations north and south of the Sahara remain poorly understood. Here, we interrogate the multilayered history of North Africa by characterizing the effect of hypothesized migrations from the Near East, Europe, and sub-Saharan Africa on current genetic diversity. We present dense, genome-wide SNP genotyping array data (730,000 sites from seven North African populations, spanning from Egypt to Morocco, and one Spanish population. We identify a gradient of likely autochthonous Maghrebi ancestry that increases from east to west across northern Africa; this ancestry is likely derived from "back-to-Africa" gene flow more than 12,000 years ago (ya, prior to the Holocene. The indigenous North African ancestry is more frequent in populations with historical Berber ethnicity. In most North African populations we also see substantial shared ancestry with the Near East, and to a lesser extent sub-Saharan Africa and Europe. To estimate the time of migration from sub-Saharan populations into North Africa, we implement a maximum likelihood dating method based on the distribution of migrant tracts. In order to first identify migrant tracts, we assign local ancestry to haplotypes using a novel, principal component-based analysis of three ancestral populations. We estimate that a migration of western African origin into Morocco began about 40 generations ago (approximately 1,200 ya; a migration of individuals with Nilotic ancestry into Egypt occurred about 25 generations ago (approximately 750 ya. Our genomic data reveal an extraordinarily complex history of migrations, involving at least five ancestral populations, into North Africa.
Bernardez-Pereira, Sabrina; Gioli-Pereira, Luciana; Marcondes-Braga, Fabiana G; Santos, Paulo Caleb Junior Lima; Spina, Joceli Mabel Rocha; Horimoto, Andréa Roseli Vançan Russo; Santos, Hadassa Campos; Bacal, Fernando; Fernandes, Fábio; Mansur, Alfredo Jose; Pietrobon, Ricardo; Krieger, José Eduardo; Mesquita, Evandro Tinoco; Pereira, Alexandre Costa
The aim of this study is to assess the association between genetic ancestry, self-declared race and haemodynamic parameters in patients with chronic heart failure (HF). Observational, cross-sectional study. Eligible participants were aged between 18 and 80 years; ejection fraction was ≤50%. Patients underwent genetic analysis of ancestry informative markers, echocardiography and impedance cardiography (ICG). Race was determined by self-classification into two groups: white and non-white. Genomic ancestry was estimated using a panel of 101 348 polymorphic markers and three continental reference populations (European, African and Native American). Our study included 362 patients with HF between August 2012 and August 2014. 123 patients with HF declared themselves as white and 234 patients declared themselves as non-white. No statistically significant differences were found regarding the ICG parameters according to self-declared race. The Amerindian ancestry was positively correlated with systolic time ratio (r=0.109, pancestry. In multiple linear regression, African ancestry remained associated with the E/e' ratio, even after adjustment to risk factors. The African genetic ancestry was associated with worse parameters of diastolic function; the Amerindian ancestry correlated with a worse pattern of ventricular contractility, while self-declared colour was not helpful to infer haemodynamic profiles in HF. NTC02043431.
Background. Fanconi anaemia (FA) is a rare genetic disorder of impaired DNA repair that results in physical and haematological consequences in affected individuals. In South Africa (SA), individuals with Afrikaner ancestry are at an increased risk of inheriting disease-causing FA mutations, owing to the three common ...
Seedat, Yackoob K.; Brewster, Lizzy M.
This article is a summary of the response of the four commonly used antihypertensive agents in African ancestry patients. They are thiazide like diuretics or indapamide, calcium channel blockers (CCB), angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers, and β-adrenergic
Rand, Kristin A; Song, Chi; Dean, Eric; Serie, Daniel J; Curtin, Karen; Sheng, Xin; Hu, Donglei; Huff, Carol Ann; Bernal-Mizrachi, Leon; Tomasson, Michael H; Ailawadhi, Sikander; Singhal, Seema; Pawlish, Karen; Peters, Edward S; Bock, Cathryn H; Stram, Alex; Van Den Berg, David J; Edlund, Christopher K; Conti, David V; Zimmerman, Todd; Hwang, Amie E; Huntsman, Scott; Graff, John; Nooka, Ajay; Kong, Yinfei; Pregja, Silvana L; Berndt, Sonja I; Blot, William J; Carpten, John; Casey, Graham; Chu, Lisa; Diver, W Ryan; Stevens, Victoria L; Lieber, Michael R; Goodman, Phyllis J; Hennis, Anselm J M; Hsing, Ann W; Mehta, Jayesh; Kittles, Rick A; Kolb, Suzanne; Klein, Eric A; Leske, Cristina; Murphy, Adam B; Nemesure, Barbara; Neslund-Dudas, Christine; Strom, Sara S; Vij, Ravi; Rybicki, Benjamin A; Stanford, Janet L; Signorello, Lisa B; Witte, John S; Ambrosone, Christine B; Bhatti, Parveen; John, Esther M; Bernstein, Leslie; Zheng, Wei; Olshan, Andrew F; Hu, Jennifer J; Ziegler, Regina G; Nyante, Sarah J; Bandera, Elisa V; Birmann, Brenda M; Ingles, Sue A; Press, Michael F; Atanackovic, Djordje; Glenn, Martha J; Cannon-Albright, Lisa A; Jones, Brandt; Tricot, Guido; Martin, Thomas G; Kumar, Shaji K; Wolf, Jeffrey L; Deming Halverson, Sandra L; Rothman, Nathaniel; Brooks-Wilson, Angela R; Rajkumar, S Vincent; Kolonel, Laurence N; Chanock, Stephen J; Slager, Susan L; Severson, Richard K; Janakiraman, Nalini; Terebelo, Howard R; Brown, Elizabeth E; De Roos, Anneclaire J; Mohrbacher, Ann F; Colditz, Graham A; Giles, Graham G; Spinelli, John J; Chiu, Brian C; Munshi, Nikhil C; Anderson, Kenneth C; Levy, Joan; Zonder, Jeffrey A; Orlowski, Robert Z; Lonial, Sagar; Camp, Nicola J; Vachon, Celine M; Ziv, Elad; Stram, Daniel O; Hazelett, Dennis J; Haiman, Christopher A; Cozen, Wendy
Genome-wide association studies (GWAS) in European populations have identified genetic risk variants associated with multiple myeloma. We performed association testing of common variation in eight regions in 1,318 patients with multiple myeloma and 1,480 controls of European ancestry and 1,305 patients with multiple myeloma and 7,078 controls of African ancestry and conducted a meta-analysis to localize the signals, with epigenetic annotation used to predict functionality. We found that variants in 7p15.3, 17p11.2, 22q13.1 were statistically significantly (P ancestry and persons of European ancestry, and the variant in 3p22.1 was associated in European ancestry only. In a combined African ancestry-European ancestry meta-analysis, variation in five regions (2p23.3, 3p22.1, 7p15.3, 17p11.2, 22q13.1) was statistically significantly associated with multiple myeloma risk. In 3p22.1, the correlated variants clustered within the gene body of ULK4 Correlated variants in 7p15.3 clustered around an enhancer at the 3' end of the CDCA7L transcription termination site. A missense variant at 17p11.2 (rs34562254, Pro251Leu, OR, 1.32; P = 2.93 × 10 -7 ) in TNFRSF13B encodes a lymphocyte-specific protein in the TNF receptor family that interacts with the NF-κB pathway. SNPs correlated with the index signal in 22q13.1 cluster around the promoter and enhancer regions of CBX7 CONCLUSIONS: We found that reported multiple myeloma susceptibility regions contain risk variants important across populations, supporting the use of multiple racial/ethnic groups with different underlying genetic architecture to enhance the localization and identification of putatively functional alleles. A subset of reported risk loci for multiple myeloma has consistent effects across populations and is likely to be functional. Cancer Epidemiol Biomarkers Prev; 25(12); 1609-18. ©2016 AACR. ©2016 American Association for Cancer Research.
Lara E Sucheston
Full Text Available Family history and African-American race are important risk factors for both prostate cancer (CaP incidence and aggressiveness. When studying complex diseases such as CaP that have a heritable component, chances of finding true disease susceptibility alleles can be increased by accounting for genetic ancestry within the population investigated. Race, ethnicity and ancestry were studied in a geographically diverse cohort of men with newly diagnosed CaP.Individual ancestry (IA was estimated in the population-based North Carolina and Louisiana Prostate Cancer Project (PCaP, a cohort of 2,106 incident CaP cases (2063 with complete ethnicity information comprising roughly equal numbers of research subjects reporting as Black/African American (AA or European American/Caucasian/Caucasian American/White (EA from North Carolina or Louisiana. Mean genome wide individual ancestry estimates of percent African, European and Asian were obtained and tested for differences by state and ethnicity (Cajun and/or Creole and Hispanic/Latino using multivariate analysis of variance models. Principal components (PC were compared to assess differences in genetic composition by self-reported race and ethnicity between and within states.Mean individual ancestries differed by state for self-reporting AA (p = 0.03 and EA (p = 0.001. This geographic difference attenuated for AAs who answered "no" to all ethnicity membership questions (non-ethnic research subjects; p = 0.78 but not EA research subjects, p = 0.002. Mean ancestry estimates of self-identified AA Louisiana research subjects for each ethnic group; Cajun only, Creole only and both Cajun and Creole differed significantly from self-identified non-ethnic AA Louisiana research subjects. These ethnicity differences were not seen in those who self-identified as EA.Mean IA differed by race between states, elucidating a potential contributing factor to these differences in AA research participants: self-reported ethnicity
Gichohi-Wainaina, Wanjiku N; Tanaka, Toshiko; Towers, G Wayne; Verhoef, Hans; Veenemans, Jacobien; Talsma, Elise F; Harryvan, Jan; Boekschoten, Mark V; Feskens, Edith J; Melse-Boonstra, Alida
Large genome-wide association (GWA) studies of European ancestry individuals have identified multiple genetic variants influencing iron status. Studies on the generalizability of these associations to African ancestry populations have been limited. These studies are important given interethnic differences in iron status and the disproportionate burden of iron deficiency among African ancestry populations. We tested the associations of 20 previously identified iron status-associated single nucleotide polymorphisms (SNPs) in 628 Kenyans, 609 Tanzanians, 608 South Africans and 228 African Americans. In each study, we examined the associations present between 20 SNPs with ferritin and haemoglobin, adjusting for age, sex and CRP levels. In the meta analysis including all 4 African ancestry cohorts, we replicated previously reported associations with lowered haemoglobin concentrations for rs2413450 (β = -0.19, P = 0.02) and rs4820268 (β = -0.16, P = 0.04) in TMPRSS6. An association with increased ferritin concentrations was also confirmed for rs1867504 in TF (β = 1.04, P = ancestry individuals. While there is now evidence for the associations of a number of genetic variants with iron status in both European and African ancestry populations, the considerable lack of concordance highlights the importance of continued ancestry-specific studies to elucidate the genetic underpinnings of iron status in ethnically diverse populations.
Dlova, N C; Hamed, S H; Tsoka-Gwegweni, J; Grobler, A
Cutaneous adverse sequelae of skin lightening creams present with myriad skin complications and affect dermatology practice, particularly in sub-Saharan Africa where such products are widely used, with a prevalence of 25-67%. To examine the skin lightening practices of both African and Indian women living in South Africa. A cross-sectional survey was undertaken in the general outpatient departments of two regional university hospitals in Durban, South Africa. All consenting African and Indian women aged 18-70 years were recruited and asked to complete a questionnaire. Six hundred women completed the questionnaire, of whom 32·7% reported using skin lightening products. The main reasons cited were treatment of skin problems (66·7%) and skin lightening (33·3%). Products were purchased from a variety of sources. Twenty-five percent reported using sunscreen. The use of skin lightening cosmetics is common among darkly pigmented South African women, including those of both African and Indian ancestries. Despite more than 20 years of governmental regulations aimed at prohibiting both the sale of cosmetics containing mercury, hydroquinone and corticosteroids, and the advertising of any kind of skin lightener, they are far from having disappeared. The main motivations for using these products are the desire to treat skin disorders and to achieve a lighter skin colour. Television and magazine advertisements seem to influence women's choice of these products and, thus, would be efficient channels for raising public awareness about the dangers of using uncontrolled skin lighteners. © 2015 The Authors BJD © 2015 British Association of Dermatologists.
Cheruvu, Vinay K.; Igo, Robert P.; Jurevic, Richard J.; Serre, David; Zimmerman, Peter A.; Rodriguez, Benigno; Mehlotra, Rajeev K.
Introduction In a North American, HIV-positive, highly active antiretroviral therapy (HAART)-treated, adherent cohort of self-identified white and black patients, we previously observed that chemokine (C-C motif) receptor 5 (CCR5) –2459G>A genotype had a strong association with time to achieve virologic success (TVLS) in black but not in white patients. Methods Using 128 genome-wide ancestry informative markers, we performed a quantitative assessment of ancestry in these patients (n = 310) to determine (1) whether CCR5 –2459G>A genotype is still associated with TVLS of HAART when ancestry, not self-identified race, is considered and (2) whether this association is influenced by varying African ancestry. Results We found that the interaction between CCR5 –2459G>A genotype and African ancestry (≤0.125 vs. ≥0.425 and A genotype and TVLS was stronger in patients with African ancestry ≥0.71 than in patients with African ancestry ≥0.452, in both Kaplan-Meier (log-rank P = 0.039 and 0.057, respectively, for AA, GA, and GG) and Cox proportional hazards regression (relative hazard for GG compared with AA 2.59 [95% CI, 1.27–5.22; P = 0.01] and 2.26 [95% CI, 1.18–4.32; P = 0.01], respectively) analyses. Conclusions We observed that the association between CCR5 –2459G>A genotype and TVLS of HAART increased with stronger African ancestry. Understanding the genomic mechanisms by which African ancestry influences this association is critical, and requires further studies. PMID:24714069
Ossa, Humberto; Aquino, Juliana; Pereira, Rui; Ibarra, Adriana; Ossa, Rafael H; Pérez, Luz Adriana; Granda, Juan David; Lattig, Maria Claudia; Groot, Helena; Fagundes de Carvalho, Elizeu; Gusmão, Leonor
The ancestry of the Colombian population comprises a large number of well differentiated Native communities belonging to diverse linguistic groups. In the late fifteenth century, a process of admixture was initiated with the arrival of the Europeans, and several years later, Africans also became part of the Colombian population. Therefore, the genepool of the current Colombian population results from the admixture of Native Americans, Europeans and Africans. This admixture occurred differently in each region of the country, producing a clearly stratified population. Considering the importance of population substructure in both clinical and forensic genetics, we sought to investigate and compare patterns of genetic ancestry in Colombia by studying samples from Native and non-Native populations living in its 5 continental regions: the Andes, Caribe, Amazonia, Orinoquía, and Pacific regions. For this purpose, 46 AIM-Indels were genotyped in 761 non-related individuals from current populations. Previously published genotype data from 214 Colombian Natives from five communities were used for population comparisons. Significant differences were observed between Native and non-Native populations, among non-Native populations from different regions and among Native populations from different ethnic groups. The Pacific was the region with the highest African ancestry, Amazonia harboured the highest Native ancestry and the Andean and Orinoquían regions showed the highest proportion of European ancestry. The Andean region was further sub-divided into 6 sub-regions: North East, Central West, Central East, West, South West and South East. Among these regions, the South West region showed a significantly lower European admixture than the other regions. Hardy-Weinberg equilibrium and variance values of ancestry among individuals within populations showed a potential stratification of the Pacific population.
Giri, Ayush; Edwards, Todd L; Hartmann, Katherine E; Torstenson, Eric S; Wellons, Melissa; Schreiner, Pamela J; Velez Edwards, Digna R
Race, specifically African ancestry, and obesity are important risk factors for uterine fibroids, and likely interact to provide the right conditions for fibroid growth. However, existing studies largely focus on the main-effects rather than their interaction. Here, we firstly provide evidence for interaction between categories of body mass index (BMI) and reported-race in relation to uterine fibroids. We then investigate whether the association between inferred local European ancestry and fibroid risk is modified by BMI in African American (AA) women in the Vanderbilt University Medical Center bio-repository (BioVU) (539 cases and 794 controls) and the Coronary Artery Risk Development in Young Adults study (CARDIA, 264 cases and 173 controls). We used multiple logistic regression to evaluate interactions between local European ancestry and BMI in relation to fibroid risk, then performed fixed effects meta-analysis. Statistical significance threshold for local-ancestry and BMI interactions was empirically estimated with 10,000 permutations (p-value = 1.18x10-4). Admixture mapping detected an association between European ancestry and fibroid risk which was modified by BMI (continuous-interaction p-value = 3.75x10-5) around ADTRP (chromosome 6p24); the strongest association was found in the obese category (ancestry odds ratio (AOR) = 0.51, p-value = 2.23x10-5). Evaluation of interaction between genotyped/imputed variants and BMI in this targeted region suggested race-specific interaction, present in AAs only; strongest evidence was found for insertion/deletion variant (6:11946435), again in the obese category (OR = 1.66, p-value = 1.72x10-6). We found nominal evidence for interaction between local ancestry and BMI at a previously reported region in chromosome 2q31-32, which includes COL5A2, and TFPI, an immediate downstream target of ADTRP. Interactions between BMI and SNPs (single nucleotide polymorphisms) found in this region in AA women were also detected in an
Full Text Available CYP19A1 facilitates the bioconversion of estrogens from androgens. CYP19A1 intron single nucleotide polymorphisms (SNPs may alter mRNA splicing, resulting in altered CYP19A1 activity, and potentially influencing disease susceptibility. Genetic studies of CYP19A1 SNPs have been well documented in populations of European ancestry; however, studies in populations of African ancestry are limited. In the present study, ten 'candidate' intronic SNPs in CYP19A1 from 125 African Americans (AA and 277 European Americans (EA were genotyped and their frequencies compared. Allele frequencies were also compared with HapMap and ASW 1000 Genomes populations. We observed significant differences in the minor allele frequencies between AA and EA in six of the ten SNPs including rs10459592 (p<0.0001, rs12908960 (p<0.0001, rs1902584 (p = 0.016, rs2470144 (p<0.0001, rs1961177 (p<0.0001, and rs6493497 (p = 0.003. While there were no significant differences in allele frequencies between EA and CEU in the HapMap population, a 1.2- to 19-fold difference in allele frequency for rs10459592 (p = 0.004, rs12908960 (p = 0.0006, rs1902584 (p<0.0001, rs2470144 (p = 0.0006, rs1961177 (p<0.0001, and rs6493497 (p = 0.0092 was observed between AA and the Yoruba (YRI population. Linkage disequilibrium (LD blocks and haplotype clusters that is unique to the EA population but not AA was also observed. In summary, we demonstrate that differences in the allele frequencies of CYP19A1 intron SNPs are not consistent between populations of African and European ancestry. Thus, investigations into whether CYP19A1 intron SNPs contribute to variations in cancer incidence, outcomes and pharmacological response seen in populations of different ancestry may prove beneficial.
This paper considers the extent to which the geneticization of 'race' and ethnicity is the prevailing outcome of genetic testing for genealogical purposes. The decoding of the human genome precipitated a change of paradigms in genetics research, from an emphasis on genetic similarity to a focus on molecular-level differences among individuals and groups. This shift from lumping to splitting spurred ongoing disagreements among scholars about the significance of 'race' and ethnicity in the genetics era. I characterize these divergent perspectives as 'pragmatism' and 'naturalism'. Drawing upon ethnographic fieldwork and interviews, I argue that neither position fully accounts for how understandings of 'race' and ethnicity are being transformed with genetic genealogy testing. While there is some acquiescence to genetic thinking about ancestry, and by implication, 'race', among African-American and black British consumers of genetic genealogy testing, test-takers also adjudicate between sources of genealogical information and from these construct meaningful biographical narratives. Consumers engage in highly situated 'objective' and 'affiliative' self-fashioning, interpreting genetic test results in the context of their 'genealogical aspirations'. I conclude that issues of site, scale, and subjectification must be attended to if scholars are to understand whether and to what extent social identities are being transformed by recent developments in genetic science.
Joseph P Jarvis
Full Text Available African Pygmy groups show a distinctive pattern of phenotypic variation, including short stature, which is thought to reflect past adaptation to a tropical environment. Here, we analyze Illumina 1M SNP array data in three Western Pygmy populations from Cameroon and three neighboring Bantu-speaking agricultural populations with whom they have admixed. We infer genome-wide ancestry, scan for signals of positive selection, and perform targeted genetic association with measured height variation. We identify multiple regions throughout the genome that may have played a role in adaptive evolution, many of which contain loci with roles in growth hormone, insulin, and insulin-like growth factor signaling pathways, as well as immunity and neuroendocrine signaling involved in reproduction and metabolism. The most striking results are found on chromosome 3, which harbors a cluster of selection and association signals between approximately 45 and 60 Mb. This region also includes the positional candidate genes DOCK3, which is known to be associated with height variation in Europeans, and CISH, a negative regulator of cytokine signaling known to inhibit growth hormone-stimulated STAT5 signaling. Finally, pathway analysis for genes near the strongest signals of association with height indicates enrichment for loci involved in insulin and insulin-like growth factor signaling.
Rosas-Salazar, Christian; Han, Yueh-Ying; Brehm, John M; Forno, Erick; Acosta-Pérez, Edna; Cloutier, Michelle M; Alvarez, María; Colón-Semidey, Angel; Canino, Glorisa; Celedón, Juan C
Exposure to gun violence and African ancestry have been separately associated with increased risk of asthma in Puerto Rican children. The objective of this study was to examine whether African ancestry and gun violence interact on asthma and total IgE in school-aged Puerto Rican children. This is a case-control study of 747 Puerto Rican children aged 9 to 14 years living in San Juan, Puerto Rico (n = 472), and Hartford, Connecticut (n = 275). Exposure to gun violence was defined as the child's report of hearing gunshots more than once, and the percentage of African ancestry was estimated using genome-wide genotypic data. Asthma was defined as parental report of physician-diagnosed asthma and wheeze in the previous year. Serum total IgE (IU/mL) was measured in study participants. Multivariate logistic and linear regressions were used for the analysis of asthma and total IgE, respectively. In multivariate analyses, there was a significant interaction between exposure to gun violence and African ancestry on asthma (P = .001) and serum total IgE (P = .04). Among children exposed to gun violence, each quartile increase in the percentage of African ancestry was associated with approximately 45% higher odds of asthma (95% CI, 1.15-1.84; P = .002) and an approximately 19% increment in total IgE (95% , 0.60-40.65, P = .04). In contrast, there was no significant association between African ancestry and asthma or total IgE in children not exposed to gun violence. Our results suggest that exposure to gun violence modifies the estimated effect of African ancestry on asthma and atopy in Puerto Rican children. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.
Traylor, Matthew; Curtis, Charles; Patel, Hamel; Breen, Gerome; Hyuck Lee, Sang; Xu, Xiaohui; Newhouse, Stephen; Dobson, Richard; Steer, Sophia; Cope, Andrew P; Markus, Hugh S; Lewis, Cathryn M; Scott, Ian C
To evaluate whether genetic and environmental factors associated with RA in European and Asian ancestry populations are also associated with RA in African ancestry individuals. A case-control study was undertaken in 197 RA cases and 868 controls of African ancestry (Black African, Black Caribbean or Black British ethnicity) from South London. Smoking and alcohol consumption data at RA diagnosis was captured. Genotyping was undertaken (Multi-Ethnic Genotyping Array) and human leukocyte antigen (HLA) alleles imputed. The following European/Asian RA susceptibility factors were tested: 99 genome-wide loci combined into a genetic risk score; HLA region [20 haplotypes; shared epitope (SE)]; smoking; and alcohol consumption. The SE was tested for its association with radiological erosions. Logistic regression models were used, including ancestry-informative principal components, to control for admixture. European/Asian susceptibility loci were associated with RA in African ancestry individuals. The genetic risk score provided an odds ratio (OR) for RA of 1.53 (95% CI: 1.31, 1.79; P = 1.3 × 10 - 7 ). HLA haplotype ORs in European and African ancestry individuals were highly correlated ( r = 0.83, 95% CI: 0.56, 0.94; P = 1.1 × 10 - 4 ). Ever-smoking increased (OR = 2.36, 95% CI: 1.46, 3.82; P = 4.6 × 10 - 4 ) and drinking alcohol reduced (OR = 0.34, 95% CI: 0.20, 0.56; P = 2.7 × 10 - 5 ) RA risk in African ancestry individuals. The SE was associated with erosions (OR = 2.61, 95% CI: 1.36, 5.01; P = 3.9 × 10 - 3 ). Gene-environment RA risk factors identified in European/Asian ancestry populations are relevant in African ancestry individuals. As modern statistical methods facilitate analysing ancestrally diverse populations, future genetic studies should incorporate African ancestry individuals to ensure their implications for precision medicine are universally applicable. © The Author 2017. Published by Oxford University Press on behalf of the British Society for
Magoha, G A O
To carry out an overview of prostate cancer in indigenous back Africans in sub-Saharan Africa and blacks of African ancestry in diaspora. Review of all published literature on prostate cancer on indigenous black Africans and Africans in diaspora was carried out through medline and index medicus searches. Published data of prostate cancer in indigenous black Africans and black men in diaspora from 1935-2007 were included in the review. Abstracts of articles identified were assessed, read and analysed to determine their possible suitability and relevance to the title under review. After establishing relevance from the abstract, the entire paper was read, and the significant points included in the review. Prostate cancer incidence and magnitude in black Africans was grossly misunderstood and underestimated in the past. Prostate cancer incidence is on the increase and currently is perhaps the most common urological malignancy affecting black Africans. Its incidence and clinical characteristics is similar to that of the Africans in diaspora but different from all other races. There currently exists significant evidence which suggests a common enhancing genetic predisposition in black men to prostate cancer. There is very urgent need for further investigation of this phenomenon through randomised controlled multicentre studies involving indigenous black Africans and black men in diaspora.
Lima-Costa, M Fernanda; Macinko, James; Mambrini, Juliana Vaz de Mello; Peixoto, Sérgio Viana; Pereira, Alexandre Costa; Tarazona-Santos, Eduardo; Ribeiro, Antonio Luiz Pinho
The influence of genetic ancestry on Trypanosoma cruzi infection and Chagas disease outcomes is unknown. We used 370,539 Single Nucleotide Polymorphisms (SNPs) to examine the association between individual proportions of African, European and Native American genomic ancestry with T. cruzi infection and related outcomes in 1,341 participants (aged ≥ 60 years) of the Bambui (Brazil) population-based cohort study of aging. Potential confounding variables included sociodemographic characteristics and an array of health measures. The prevalence of T. cruzi infection was 37.5% and 56.3% of those infected had a major ECG abnormality. Baseline T. cruzi infection was correlated with higher levels of African and Native American ancestry, which in turn were strongly associated with poor socioeconomic circumstances. Cardiomyopathy in infected persons was not significantly associated with African or Native American ancestry levels. Infected persons with a major ECG abnormality were at increased risk of 15-year mortality relative to their counterparts with no such abnormalities (adjusted hazard ratio = 1.80; 95% 1.41, 2.32). African and Native American ancestry levels had no significant effect modifying this association. Our findings indicate that African and Native American ancestry have no influence on the presence of major ECG abnormalities and had no influence on the ability of an ECG abnormality to predict mortality in older people infected with T. cruzi. In contrast, our results revealed a strong and independent association between prevalent T. cruzi infection and higher levels of African and Native American ancestry. Whether this association is a consequence of genetic background or differential exposure to infection remains to be determined.
Zheng, Yonglan; Ogundiran, Temidayo O; Falusi, Adeyinka G; Nathanson, Katherine L; John, Esther M; Hennis, Anselm J M; Ambs, Stefan; Domchek, Susan M; Rebbeck, Timothy R; Simon, Michael S; Nemesure, Barbara; Wu, Suh-Yuh; Leske, Maria Cristina; Odetunde, Abayomi; Niu, Qun; Zhang, Jing; Afolabi, Chibuzor; Gamazon, Eric R; Cox, Nancy J; Olopade, Christopher O; Olopade, Olufunmilayo I; Huo, Dezheng
Numerous single nucleotide polymorphisms (SNPs) associated with breast cancer susceptibility have been identified by genome-wide association studies (GWAS). However, these SNPs were primarily discovered and validated in women of European and Asian ancestry. Because linkage disequilibrium is ancestry-dependent and heterogeneous among racial/ethnic populations, we evaluated common genetic variants at 22 GWAS-identified breast cancer susceptibility loci in a pooled sample of 1502 breast cancer cases and 1378 controls of African ancestry. None of the 22 GWAS index SNPs could be validated, challenging the direct generalizability of breast cancer risk variants identified in Caucasians or Asians to other populations. Novel breast cancer risk variants for women of African ancestry were identified in regions including 5p12 (odds ratio [OR] = 1.40, 95% confidence interval [CI] = 1.11-1.76; P = 0.004), 5q11.2 (OR = 1.22, 95% CI = 1.09-1.36; P = 0.00053) and 10p15.1 (OR = 1.22, 95% CI = 1.08-1.38; P = 0.0015). We also found positive association signals in three regions (6q25.1, 10q26.13 and 16q12.1-q12.2) previously confirmed by fine mapping in women of African ancestry. In addition, polygenic model indicated that eight best markers in this study, compared with 22 GWAS-identified SNPs, could better predict breast cancer risk in women of African ancestry (per-allele OR = 1.21, 95% CI = 1.16-1.27; P = 9.7 × 10(-16)). Our results demonstrate that fine mapping is a powerful approach to better characterize the breast cancer risk alleles in diverse populations. Future studies and new GWAS in women of African ancestry hold promise to discover additional variants for breast cancer susceptibility with clinical implications throughout the African diaspora.
Klimentidis, Yann C; Arora, Amit; Zhou, Jin; Kittles, Rick; Allison, David B
Over 80% of African-American (AA) women are overweight or obese. A large racial disparity between AA and European-Americans (EA) in obesity rates exists among women, but curiously not among men. Although socio-economic and/or cultural factors may partly account for this race-by-sex interaction, the potential involvement of genetic factors has not yet been investigated. Among 2814 self-identified AA in the Atherosclerosis Risk in Communities study, we estimated each individual's degree of West-African genetic ancestry using 3437 ancestry informative markers. We then tested whether sex modifies the association between West-African genetic ancestry and body mass index (BMI), waist-circumference (WC), and waist-to-hip ratio (WHR), adjusting for income and education levels, and examined associations of ancestry with the phenotypes separately in males and females. We replicated our findings in the Multi-Ethnic Study of Atherosclerosis (n = 1611 AA). In both studies, we find that West-African ancestry is negatively associated with obesity, especially central obesity, among AA men, but not among AA women (pinteraction = 4.14 × 10(-5) in pooled analysis of WHR). In conclusion, our results suggest that the combination of male gender and West-African genetic ancestry is associated with protection against central adiposity, and suggest that the large racial disparity that exists among women, but not men, may be at least partly attributed to genetic factors.
Zhao, Qian; Zmuda, Joseph M; Kuipers, Allison L; Bunker, Clareann H; Patrick, Alan L; Youk, Ada O; Miljkovic, Iva
Increased ectopic adipose tissue infiltration in skeletal muscle is associated with insulin resistance and diabetes mellitus. We evaluated whether change in skeletal muscle adiposity predicts subsequent development of hypertension in men of African ancestry, a population sample understudied in previous studies. In the Tobago Health Study, a prospective longitudinal study among men of African ancestry (age range 40-91 years), calf intermuscular adipose tissue, and skeletal muscle attenuation were measured with computed tomography. Hypertension was defined as a systolic blood pressure ≥140 mm Hg, or a diastolic blood pressure ≥90 mm Hg, or receiving antihypertensive medications. Logistic regression was performed with adjustment for age, insulin resistance, baseline and 6-year change in body mass index, baseline and 6-year change in waist circumference, and other potential confounding factors. Among 746 normotensive men at baseline, 321 (43%) developed hypertension during the mean 6.2 years of follow-up. Decreased skeletal muscle attenuation was associated with newly developed hypertension after adjustment for baseline and 6-year change of body mass index (odds ratio [95% confidence interval] per SD, 1.3 [1.0-1.6]) or baseline and 6-year change of waist circumference (odds ratio [95% confidence interval] per SD, 1.3 [1.0-1.6]). No association was observed between increased intermuscular adipose tissue and hypertension. Our novel findings show that decreased muscle attenuation is associated with newly developed hypertension among men of African ancestry, independent of general and central adiposity and insulin resistance. Further studies are needed to adjust for inflammation, visceral and other ectopic adipose tissue depots, and to confirm our findings in other population samples. © 2017 American Heart Association, Inc.
Fortes-Lima, Cesar; Gessain, Antoine; Ruiz-Linares, Andres; Bortolini, Maria-Cátira; Migot-Nabias, Florence; Bellis, Gil; Moreno-Mayar, J Víctor; Restrepo, Berta Nelly; Rojas, Winston; Avendaño-Tamayo, Efren; Bedoya, Gabriel; Orlando, Ludovic; Salas, Antonio; Helgason, Agnar; Gilbert, M Thomas P; Sikora, Martin; Schroeder, Hannes; Dugoujon, Jean-Michel
The transatlantic slave trade was the largest forced migration in world history. However, the origins of the enslaved Africans and their admixture dynamics remain unclear. To investigate the demographic history of African-descendant Marron populations, we generated genome-wide data (4.3 million markers) from 107 individuals from three African-descendant populations in South America, as well as 124 individuals from six west African populations. Throughout the Americas, thousands of enslaved Africans managed to escape captivity and establish lasting communities, such as the Noir Marron. We find that this population has the highest proportion of African ancestry (∼98%) of any African-descendant population analyzed to date, presumably because of centuries of genetic isolation. By contrast, African-descendant populations in Brazil and Colombia harbor substantially more European and Native American ancestry as a result of their complex admixture histories. Using ancestry tract-length analysis, we detect different dates for the European admixture events in the African-Colombian (1749 CE; confidence interval [CI]: 1737-1764) and African-Brazilian (1796 CE; CI: 1789-1804) populations in our dataset, consistent with the historically attested earlier influx of Africans into Colombia. Furthermore, we find evidence for sex-specific admixture patterns, resulting from predominantly European paternal gene flow. Finally, we detect strong genetic links between the African-descendant populations and specific source populations in Africa on the basis of haplotype sharing patterns. Although the Noir Marron and African-Colombians show stronger affinities with African populations from the Bight of Benin and the Gold Coast, the African-Brazilian population from Rio de Janeiro has greater genetic affinity with Bantu-speaking populations from the Bight of Biafra and west central Africa. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.
... What is genetic ancestry testing? What is genetic ancestry testing? Genetic ancestry testing, or genetic genealogy, is ... with other groups. For more information about genetic ancestry testing: The University of Utah provides video tutorials ...
Wang, Shengfeng; Qian, Frank; Zheng, Yonglan; Ogundiran, Temidayo; Ojengbede, Oladosu; Zheng, Wei; Blot, William; Nathanson, Katherine L; Hennis, Anselm; Nemesure, Barbara; Ambs, Stefan; Olopade, Olufunmilayo I; Huo, Dezheng
Few studies have evaluated the performance of existing breast cancer risk prediction models among women of African ancestry. In replication studies of genetic variants, a change in direction of the risk association is a common phenomenon. Termed flip-flop, it means that a variant is risk factor in one population but protective in another, affecting the performance of risk prediction models. We used data from the genome-wide association study (GWAS) of breast cancer in the African diaspora (The Root consortium), which included 3686 participants of African ancestry from Nigeria, USA, and Barbados. Polygenic risk scores (PRSs) were constructed from the published odds ratios (ORs) of four sets of susceptibility loci for breast cancer. Discrimination capacity was measured using the area under the receiver operating characteristic curve (AUC). Flip-flop phenomenon was observed among 30~40% of variants across studies. Using the 34 variants with consistent directionality among previous studies, we constructed a PRS with AUC of 0.531 (95% confidence interval [CI]: 0.512-0.550), which is similar to the PRS using 93 variants and ORs from European ancestry populations (AUC = 0.525, 95% CI: 0.506-0.544). Additionally, we found the 34-variant PRS has good discriminative accuracy in women with family history of breast cancer (AUC = 0.586, 95% CI: 0.532-0.640). We found that PRS based on variants identified from prior GWASs conducted in women of European and Asian ancestries did not provide a comparable degree of risk stratification for women of African ancestry. Further large-scale fine-mapping studies in African ancestry populations are desirable to discover population-specific genetic risk variants.
Loubser, Shayne; Paximadis, Maria; Tiemessen, Caroline T
South Africa has a large (∼53million), ethnically diverse population (black African, Caucasian, Indian/Asian and Mixed ancestry) and a high disease burden (particularly HIV-1 and Mycobacterium tuberculosis). The Mixed ancestry population constitutes ∼9% of the total population and was established ∼365years ago in the Western Cape region through interracial mixing of black Africans, Europeans and Asians. Admixed populations present unique opportunities to identify genetic factors involved in disease susceptibility. Since HLA genes are important mediators of host immunity, we investigated HLA-A, -B and -C allele and haplotype diversity in 50 healthy, unrelated individuals recruited from the Mixed ancestry population. Copyright © 2017. Published by Elsevier Inc.
Galanter, Joshua M; Gignoux, Christopher R; Oh, Sam S; Torgerson, Dara; Pino-Yanes, Maria; Thakur, Neeta; Eng, Celeste; Hu, Donglei; Huntsman, Scott; Farber, Harold J; Avila, Pedro C; Brigino-Buenaventura, Emerita; LeNoir, Michael A; Meade, Kelly; Serebrisky, Denise; Rodríguez-Cintrón, William; Kumar, Rajesh; Rodríguez-Santana, Jose R; Seibold, Max A; Borrell, Luisa N; Burchard, Esteban G; Zaitlen, Noah
Populations are often divided categorically into distinct racial/ethnic groups based on social rather than biological constructs. Genetic ancestry has been suggested as an alternative to this categorization. Herein, we typed over 450,000 CpG sites in whole blood of 573 individuals of diverse Hispanic origin who also had high-density genotype data. We found that both self-identified ethnicity and genetically determined ancestry were each significantly associated with methylation levels at 916 and 194 CpGs, respectively, and that shared genomic ancestry accounted for a median of 75.7% (IQR 45.8% to 92%) of the variance in methylation associated with ethnicity. There was a significant enrichment (p=4.2×10-64) of ethnicity-associated sites amongst loci previously associated environmental exposures, particularly maternal smoking during pregnancy. We conclude that differential methylation between ethnic groups is partially explained by the shared genetic ancestry but that environmental factors not captured by ancestry significantly contribute to variation in methylation. DOI: http://dx.doi.org/10.7554/eLife.20532.001 PMID:28044981
Nandakumar, Priyanka; Lee, Dongwon; Richard, Melissa A; Tekola-Ayele, Fasil; Tayo, Bamidele O; Ware, Erin; Sung, Yun J; Salako, Babatunde; Ogunniyi, Adesola; Gu, C Charles; Grove, Megan L; Fornage, Myriam; Kardia, Sharon; Rotimi, Charles; Cooper, Richard S; Morrison, Alanna C; Ehret, Georg; Chakravarti, Aravinda
Hypertension is a major risk factor for all cardiovascular diseases, especially among African Americans. This study focuses on identifying specific blood pressure (BP) genes using 15 914 individuals of African ancestry from eight cohorts (Africa America Diabetes Mellitus, Atherosclerosis Risk in Communities Study, Coronary Artery Risk Development in young Adults, Genetics Network, Genetic Epidemiology Network of Arteriopathy, Howard University Family Study, Hypertension Genetic Epidemiology Network, and Loyola University Chicago Cohort) to further genetic findings in this population which has generally been underrepresented in BP studies. We genotyped and performed various single variant and gene-based exome-wide analyses on 15 914 individuals on the Illumina HumanExome Beadchip v1.0 or v1.1 to test association with SBP and DBP long-term average residuals that were adjusted for age, age-squared, sex, and BMI. We identified rare variants affecting SBP and DBP in 10 genes: AFF1, GAPDHS, SLC28A3, COL6A1, CRYBA2, KRBA1, SEL1L3, YOD1, CCDC13, and QSOX1. Prior experimental evidence for six of these 10 candidate genes supports their involvement in cardiovascular mechanisms, corroborating their potential roles in BP regulation. Although our results require replication or validation due to their low numbers of carriers, and an ethnicity-specific genotyping array may be more informative, this study, which has identified several candidate genes in this population most susceptible to hypertension, presents one of the largest African-ancestry BP studies to date and the largest including analysis of rare variants.
Monda, Keri L.; Chen, Gary K.; Taylor, Kira C.; Palmer, Cameron; Edwards, Todd L.; Lange, Leslie A.; Ng, Maggie C.Y.; Adeyemo, Adebowale A.; Allison, Matthew A.; Bielak, Lawrence F.; Chen, Guanji; Graff, Mariaelisa; Irvin, Marguerite R.; Rhie, Suhn K.; Li, Guo; Liu, Yongmei; Liu, Youfang; Lu, Yingchang; Nalls, Michael A.; Sun, Yan V.; Wojczynski, Mary K.; Yanek, Lisa R.; Aldrich, Melinda C.; Ademola, Adeyinka; Amos, Christopher I.; Bandera, Elisa V.; Bock, Cathryn H.; Britton, Angela; Broeckel, Ulrich; Cai, Quiyin; Caporaso, Neil E.; Carlson, Chris; Carpten, John; Casey, Graham; Chen, Wei-Min; Chen, Fang; Chen, Yii-Der I.; Chiang, Charleston W.K.; Coetzee, Gerhard A.; Demerath, Ellen; Deming-Halverson, Sandra L.; Driver, Ryan W.; Dubbert, Patricia; Feitosa, Mary F.; Freedman, Barry I.; Gillanders, Elizabeth M.; Gottesman, Omri; Guo, Xiuqing; Haritunians, Talin; Harris, Tamara; Harris, Curtis C.; Hennis, Anselm JM; Hernandez, Dena G.; McNeill, Lorna H.; Howard, Timothy D.; Howard, Barbara V.; Howard, Virginia J.; Johnson, Karen C.; Kang, Sun J.; Keating, Brendan J.; Kolb, Suzanne; Kuller, Lewis H.; Kutlar, Abdullah; Langefeld, Carl D.; Lettre, Guillaume; Lohman, Kurt; Lotay, Vaneet; Lyon, Helen; Manson, JoAnn E.; Maixner, William; Meng, Yan A.; Monroe, Kristine R.; Morhason-Bello, Imran; Murphy, Adam B.; Mychaleckyj, Josyf C.; Nadukuru, Rajiv; Nathanson, Katherine L.; Nayak, Uma; N’Diaye, Amidou; Nemesure, Barbara; Wu, Suh-Yuh; Leske, M. Cristina; Neslund-Dudas, Christine; Neuhouser, Marian; Nyante, Sarah; Ochs-Balcom, Heather; Ogunniyi, Adesola; Ogundiran, Temidayo O.; Ojengbede, Oladosu; Olopade, Olufunmilayo I.; Palmer, Julie R.; Ruiz-Narvaez, Edward A.; Palmer, Nicholette D.; Press, Michael F.; Rampersaud, Evandine; Rasmussen-Torvik, Laura J.; Rodriguez-Gil, Jorge L.; Salako, Babatunde; Schadt, Eric E.; Schwartz, Ann G.; Shriner, Daniel A.; Siscovick, David; Smith, Shad B.; Wassertheil-Smoller, Sylvia; Speliotes, Elizabeth K.; Spitz, Margaret R.; Sucheston, Lara; Taylor, Herman; Tayo, Bamidele O.; Tucker, Margaret A.; Van Den Berg, David J.; Velez Edwards, Digna R.; Wang, Zhaoming; Wiencke, John K.; Winkler, Thomas W.; Witte, John S.; Wrensch, Margaret; Wu, Xifeng; Yang, James J.; Levin, Albert M.; Young, Taylor R.; Zakai, Neil A.; Cushman, Mary; Zanetti, Krista A.; Zhao, Jing Hua; Zhao, Wei; Zheng, Yonglan; Zhou, Jie; Ziegler, Regina G.; Zmuda, Joseph M.; Fernandes, Jyotika K.; Gilkeson, Gary S.; Kamen, Diane L.; Hunt, Kelly J.; Spruill, Ida J.; Ambrosone, Christine B.; Ambs, Stefan; Arnett, Donna K.; Atwood, Larry; Becker, Diane M.; Berndt, Sonja I.; Bernstein, Leslie; Blot, William J.; Borecki, Ingrid B.; Bottinger, Erwin P.; Bowden, Donald W.; Burke, Gregory; Chanock, Stephen J.; Cooper, Richard S.; Ding, Jingzhong; Duggan, David; Evans, Michele K.; Fox, Caroline; Garvey, W. Timothy; Bradfield, Jonathan P.; Hakonarson, Hakon; Grant, Struan F.A.; Hsing, Ann; Chu, Lisa; Hu, Jennifer J.; Huo, Dezheng; Ingles, Sue A.; John, Esther M.; Jordan, Joanne M.; Kabagambe, Edmond K.; Kardia, Sharon L.R.; Kittles, Rick A.; Goodman, Phyllis J.; Klein, Eric A.; Kolonel, Laurence N.; Le Marchand, Loic; Liu, Simin; McKnight, Barbara; Millikan, Robert C.; Mosley, Thomas H.; Padhukasahasram, Badri; Williams, L. Keoki; Patel, Sanjay R.; Peters, Ulrike; Pettaway, Curtis A.; Peyser, Patricia A.; Psaty, Bruce M.; Redline, Susan; Rotimi, Charles N.; Rybicki, Benjamin A.; Sale, Michèle M.; Schreiner, Pamela J.; Signorello, Lisa B.; Singleton, Andrew B.; Stanford, Janet L.; Strom, Sara S.; Thun, Michael J.; Vitolins, Mara; Zheng, Wei; Moore, Jason H.; Williams, Scott M.; Zhu, Xiaofeng; Zonderman, Alan B.; Kooperberg, Charles; Papanicolaou, George; Henderson, Brian E.; Reiner, Alex P.; Hirschhorn, Joel N.; Loos, Ruth JF; North, Kari E.; Haiman, Christopher A.
Genome-wide association studies (GWAS) have identified 36 loci associated with body mass index (BMI), predominantly in populations of European ancestry. We conducted a meta-analysis to examine the association of >3.2 million SNPs with BMI in 39,144 men and women of African ancestry, and followed up the most significant associations in an additional 32,268 individuals of African ancestry. We identified one novel locus at 5q33 (GALNT10, rs7708584, p=3.4×10−11) and another at 7p15 when combined with data from the Giant consortium (MIR148A/NFE2L3, rs10261878, p=1.2×10−10). We also found suggestive evidence of an association at a third locus at 6q16 in the African ancestry sample (KLHL32, rs974417, p=6.9×10−8). Thirty-two of the 36 previously established BMI variants displayed directionally consistent effect estimates in our GWAS (binomial p=9.7×10−7), of which five reached genome-wide significance. These findings provide strong support for shared BMI loci across populations as well as for the utility of studying ancestrally diverse populations. PMID:23583978
Susan E Steck
Full Text Available African Americans (AAs have lower circulating 25-hydroxyvitamin D3 [25(OHD3] concentrations and higher prostate cancer (CaP aggressiveness than other racial/ethnic groups. The purpose of the current study was to examine the relationship between plasma 25(OHD3, African ancestry and CaP aggressiveness among AAs and European Americans (EAs.Plasma 25(OHD3 was measured using LC-MS/MS (Liquid Chromatography Tandem Mass Spectrometry in 537 AA and 663 EA newly-diagnosed CaP patients from the North Carolina-Louisiana Prostate Cancer Project (PCaP classified as having either 'high' or 'low' aggressive disease based on clinical stage, Gleason grade and prostate specific antigen at diagnosis. Mean plasma 25(OHD3 concentrations were compared by proportion of African ancestry. Logistic regression was used to calculate multivariable adjusted odds ratios (OR and 95% confidence intervals (95%CI for high aggressive CaP by tertile of plasma 25(OHD3.AAs with highest percent African ancestry (>95% had the lowest mean plasma 25(OHD3 concentrations. Overall, plasma 25(OHD3 was associated positively with aggressiveness among AA men, an association that was modified by calcium intake (ORT 3vs.T1: 2.23, 95%CI: 1.26-3.95 among men with low calcium intake, and ORT 3vs.T1: 0.19, 95%CI: 0.05-0.70 among men with high calcium intake. Among EAs, the point estimates of the ORs were <1.0 for the upper tertiles with CIs that included the null.Among AAs, plasma 25(OHD3 was associated positively with CaP aggressiveness among men with low calcium intake and inversely among men with high calcium intake. The clinical significance of circulating concentrations of 25(OHD3 and interactions with calcium intake in the AA population warrants further study.
Moreno, Diana J; Pino, Sebastián; Ríos, Ángela; Lopera, Francisco; Ostos, Henry; Via, Marc; Bedoya, Gabriel
Differences in the prevalence of dementia among populations and in the effect of apolipoprotein E (APOE) on the emergence of Alzheimer disease (AD), which is the main type of dementia, have been reported. This study estimated the ancestry of a group of individuals with late-onset Alzheimer disease (LOAD) (N=280) and established whether there were any differences when compared with a control group (N=357) in a sample of the Colombian population. When the analyses were adjusted for known risk factors such as age, sex, presence of APOE[Latin Small Letter Open E]4, socioeconomic status, educational attainment, and place of birth, African ancestry was associated with an increased LOAD risk (odds ratio: 1.55; 95% confidence interval, 1.09-2.03; P=0.029), whereas Native American ancestry was associated with lower risk (odds ratio: 0.75; 95% confidence interval, 0.61-0.98; P=0.046), for every 10% increase in ancestry. In addition, there were significant differences in the proportion of Native American ancestry between carriers and noncarriers of the APOE[Latin Small Letter Open E]4 allele (Mann-Whitney U test, P=0.047), with noncarriers having higher mean Native American ancestry when compared with carriers. Our results are consistent with the presence of variants of African origin in the genome of the Colombian population and different from APOE[Latin Small Letter Open E]4 that represents a risk factor for the development of LOAD, whereas variants of Native American origin may be conferring protection. However, unknown environmental factors or epigenetic differences among continental groups could also explain the observed associations.
Narang, Ankita; Jha, Pankaj; Kumar, Dhirendra; Kutum, Rintu; Mondal, Anupam Kumar; Dash, Debasis; Mukerji, Mitali
Admixture mapping has been enormously resourceful in identifying genetic variations linked to phenotypes, adaptation, and diseases. In this study through analysis of copy number variable regions (CNVRs), we report extensive restructuring in the genomes of the recently admixed African-Indian population (OG-W-IP) that inhabits a highly saline environment in Western India. The study included subjects from OG-W-IP (OG), five different Indian and three HapMap populations that were genotyped using Affymetrix version 6.0 arrays. Copy number variations (CNVs) detected using Birdsuite were used to define CNVRs. Population structure with respect to CNVRs was delineated using random forest approach. OG genomes have a surprising excess of CNVs in comparison to other studied populations. Individual ancestry proportions computed using STRUCTURE also reveals a unique genetic component in OGs. Population structure analysis with CNV genotypes indicates OG to be distant from both the African and Indian ancestral populations. Interestingly, it shows genetic proximity with respect to CNVs to only one Indian population IE-W-LP4, which also happens to reside in the same geographical region. We also observe a significant enrichment of molecular processes related to ion binding and receptor activity in genes encompassing OG-specific CNVRs. Our results suggest that retention of CNVRs from ancestral natives and de novo acquisition of CNVRs could accelerate the process of adaptation especially in an extreme environment. Additionally, this population would be enormously useful for dissecting genes and delineating the involvement of CNVs in salt adaptation. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
Krause, A; Mitchell, CL; Essop, F; Tager, S; Temlett, J; Stevanin, G; Ross, CA; Rudnicki, DD; Margolis, RL
Huntington disease (HD) is a progressive autosomal dominant neurodegenerative disorder, characterized by abnormal movements, cognitive decline and psychiatric symptoms, caused by a CAG repeat expansion in the huntingtin (HTT) gene on chromosome 4p. A CAG/CTG repeat expansion in the junctophilin-3 (JPH3) gene on chromosome 16q24.2 causes a Huntington disease-like phenotype (HDL2). All patients to date with HDL2 have some African ancestry. The present study aimed to characterize the genetic basis of the Huntington disease phenotype in South Africans and to investigate the possible origin of the JPH3 mutation. In a sample of unrelated South African individuals referred for diagnostic HD testing, 62% (106/171) of white patients compared to only 36% (47/130) of black patients had an expansion in HTT. However, 15% (20/130) of black South African patients and no white patients (0/171) had an expansion in JPH3, confirming the diagnosis of Huntington disease like 2 (HDL2). Individuals with HDL2 share many clinical features with individuals with HD and are clinically indistinguishable in many cases, although the average age of onset and diagnosis in HDL2 is 5 years later than HD and individual clinical features may be more prominent. HDL2 mutations contribute significantly to the HD phenotype in South Africans with African ancestry. JPH3 haplotype studies in 31 families, mainly from South Africa and North America, provide evidence for a founder mutation and support a common African origin for all HDL2 patients. Molecular testing in individuals with an HD phenotype and African ancestry should include testing routinely for JPH3 mutations. PMID:26079385
Full Text Available Central obesity, measured by waist circumference (WC or waist-hip ratio (WHR, is a marker of body fat distribution. Although obesity disproportionately affects minority populations, few studies have conducted genome-wide association study (GWAS of fat distribution among those of predominantly African ancestry (AA. We performed GWAS of WC and WHR, adjusted and unadjusted for BMI, in up to 33,591 and 27,350 AA individuals, respectively. We identified loci associated with fat distribution in AA individuals using meta-analyses of GWA results for WC and WHR (stage 1. Overall, 25 SNPs with single genomic control (GC-corrected p-values<5.0 × 10(-6 were followed-up (stage 2 in AA with WC and with WHR. Additionally, we interrogated genomic regions of previously identified European ancestry (EA WHR loci among AA. In joint analysis of association results including both Stage 1 and 2 cohorts, 2 SNPs demonstrated association, rs2075064 at LHX2, p = 2.24×10(-8 for WC-adjusted-for-BMI, and rs6931262 at RREB1, p = 2.48×10(-8 for WHR-adjusted-for-BMI. However, neither signal was genome-wide significant after double GC-correction (LHX2: p = 6.5 × 10(-8; RREB1: p = 5.7 × 10(-8. Six of fourteen previously reported loci for waist in EA populations were significant (p<0.05 divided by the number of independent SNPs within the region in AA studied here (TBX15-WARS2, GRB14, ADAMTS9, LY86, RSPO3, ITPR2-SSPN. Further, we observed associations with metabolic traits: rs13389219 at GRB14 associated with HDL-cholesterol, triglycerides, and fasting insulin, and rs13060013 at ADAMTS9 with HDL-cholesterol and fasting insulin. Finally, we observed nominal evidence for sexual dimorphism, with stronger results in AA women at the GRB14 locus (p for interaction = 0.02. In conclusion, we identified two suggestive loci associated with fat distribution in AA populations in addition to confirming 6 loci previously identified in populations of EA. These findings reinforce the concept
Full Text Available The risk of type 2 diabetes is approximately 2-fold higher in African Americans than in European Americans even after adjusting for known environmental risk factors, including socioeconomic status (SES, suggesting that genetic factors may explain some of this population difference in disease risk. However, relatively few genetic studies have examined this hypothesis in a large sample of African Americans with and without diabetes. Therefore, we performed an admixture analysis using 2,189 ancestry-informative markers in 7,021 African Americans (2,373 with type 2 diabetes and 4,648 without from the Atherosclerosis Risk in Communities Study, the Jackson Heart Study, and the Multiethnic Cohort to 1 determine the association of type 2 diabetes and its related quantitative traits with African ancestry controlling for measures of SES and 2 identify genetic loci for type 2 diabetes through a genome-wide admixture mapping scan. The median percentage of African ancestry of diabetic participants was slightly greater than that of non-diabetic participants (study-adjusted difference = 1.6%, P<0.001. The odds ratio for diabetes comparing participants in the highest vs. lowest tertile of African ancestry was 1.33 (95% confidence interval 1.13-1.55, after adjustment for age, sex, study, body mass index (BMI, and SES. Admixture scans identified two potential loci for diabetes at 12p13.31 (LOD = 4.0 and 13q14.3 (Z score = 4.5, P = 6.6 × 10(-6. In conclusion, genetic ancestry has a significant association with type 2 diabetes above and beyond its association with non-genetic risk factors for type 2 diabetes in African Americans, but no single gene with a major effect is sufficient to explain a large portion of the observed population difference in risk of diabetes. There undoubtedly is a complex interplay among specific genetic loci and non-genetic factors, which may both be associated with overall admixture, leading to the observed ethnic differences in diabetes
Santangelo, Roberta; González-Andrade, Fabricio; Børsting, Claus
Ancestry inference is traditionally done using autosomal SNPs that present great allele frequency differences among populations from different geographic regions. These ancestry informative markers (AIMs) are useful for determining the most likely biogeographic ancestry or population of origin...... of an individual. Due to the growing interest in AIMs and their applicability in different fields, commercial companies have started to develop AIM multiplexes targeted for Massive Parallel Sequencing platforms. This project focused on the study of three main ethnic groups from Ecuador (Kichwa, Mestizo, and Afro...
Kosk, Dominique; Kramer, Holly; Luke, Amy; Camacho, Pauline; Bovet, Pascal; Rhule, Jacob Plange; Forrester, Terrence; Wolf, Myles; Sempos, Chris; Melamed, Michal L; Dugas, Lara R; Cooper, Richard; Durazo-Arvizu, Ramon
Fibroblast growth factor-23 (FGF23), a phosphaturic hormone secreted mainly by osteocytes, maintains serum phosphate levels within a tight range by promoting phosphaturia. Previous studies have mainly focused on the link between FGF23 levels and dietary intake of phosphate, but other dietary factors may also influence FGF23 levels. This cross-sectional study pooled three populations of young adults with African ancestry (452 in Chicago, IL, USA; 477 in Victoria, Seychelles; and 482 in Kumasi, Ghana) with estimated glomerular filtration rate >80 ml/min/1.73 m 2 to examine the association of dietary factors based on two 24-h recalls with FGF23 levels measured using a C-terminal assay. Linear regression was used to examine the association between log-transformed FGF23 levels and quartiles of calorie-adjusted dietary factors with adjustment for covariates. In the pooled sample of 1411 study participants, the mean age was 35.2 (6.2) years and 45.3% were male. Median plasma C-terminal FGF23 values in relative units (RU)/ml were 59.5 [interquartile range (IQR) 44.1, 85.3] in the USA, 43.2 (IQR 33.1, 57.9) in Seychelles, and 34.0 (IQR 25.2, 50.4) in Ghana. With adjustment for covariates, increasing quartiles of calcium and animal protein and decreasing quartiles of vegetable protein, fiber, and magnesium intake were associated with significantly higher FGF23 levels compared to the lowest quartile. After further adjustment for dietary factors, significant trends in FGF23 levels were noted only for quartiles of calcium, fiber, and magnesium intake (P young adults.
Wang, Shengfeng; Huo, Dezheng; Ogundiran, Temidayo O; Ojengbede, Oladosu; Zheng, Wei; Nathanson, Katherine L; Nemesure, Barbara; Ambs, Stefan; Olopade, Olufunmilayo I; Zheng, Yonglan
Functional studies have elucidated the role of the mammalian target of rapamycin (mTOR) pathway in breast carcinogenesis, but to date, there is a paucity of data on its contribution to breast cancer risk in women of African ancestry. We examined 47628 SNPs in 61 mTOR pathway genes in the genome wide association study of breast cancer in the African Diaspora study (The Root consortium), which included 3686 participants (1657 cases). Pathway- and gene-level analyses were conducted using the adaptive rank truncated product (ARTP) test for 10994 SNPs that were not highly correlated (r2 studies of breast cancer in the African Diaspora. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Heather E Wheeler
Full Text Available Chemotherapeutic agents are used in the treatment of many cancers, yet variable resistance and toxicities among individuals limit successful outcomes. Several studies have indicated outcome differences associated with ancestry among patients with various cancer types. Using both traditional SNP-based and newly developed gene-based genome-wide approaches, we investigated the genetics of chemotherapeutic susceptibility in lymphoblastoid cell lines derived from 83 African Americans, a population for which there is a disparity in the number of genome-wide studies performed. To account for population structure in this admixed population, we incorporated local ancestry information into our association model. We tested over 2 million SNPs and identified 325, 176, 240, and 190 SNPs that were suggestively associated with cytarabine-, 5'-deoxyfluorouridine (5'-DFUR-, carboplatin-, and cisplatin-induced cytotoxicity, respectively (p≤10(-4. Importantly, some of these variants are found only in populations of African descent. We also show that cisplatin-susceptibility SNPs are enriched for carboplatin-susceptibility SNPs. Using a gene-based genome-wide association approach, we identified 26, 11, 20, and 41 suggestive candidate genes for association with cytarabine-, 5'-DFUR-, carboplatin-, and cisplatin-induced cytotoxicity, respectively (p≤10(-3. Fourteen of these genes showed evidence of association with their respective chemotherapeutic phenotypes in the Yoruba from Ibadan, Nigeria (p<0.05, including TP53I11, COPS5 and GAS8, which are known to be involved in tumorigenesis. Although our results require further study, we have identified variants and genes associated with chemotherapeutic susceptibility in African Americans by using an approach that incorporates local ancestry information.
Background Clinicians are encouraged to take an individualized approach when treating hypertension in patients of African ancestry, but little is known about why the individual patient may respond well to calcium blockers and diuretics, but generally has an attenuated response to drugs inhibiting the renin-angiotensin system and to β-adrenergic blockers. Therefore, we systematically reviewed the factors associated with the differential drug response of patients of African ancestry to antihypertensive drug therapy. Methods Using the methodology of the systematic reviews narrative synthesis approach, we sought for published or unpublished studies that could explain the differential clinical efficacy of antihypertensive drugs in patients of African ancestry. PUBMED, EMBASE, LILACS, African Index Medicus and the Food and Drug Administration and European Medicines Agency databases were searched without language restriction from their inception through June 2012. Results We retrieved 3,763 papers, and included 72 reports that mainly considered the 4 major classes of antihypertensive drugs, calcium blockers, diuretics, drugs that interfere with the renin-angiotensin system and β-adrenergic blockers. Pharmacokinetics, plasma renin and genetic polymorphisms did not well predict the response of patients of African ancestry to antihypertensive drugs. An emerging view that low nitric oxide and high creatine kinase may explain individual responses to antihypertensive drugs unites previous observations, but currently clinical data are very limited. Conclusion Available data are inconclusive regarding why patients of African ancestry display the typical response to antihypertensive drugs. In lieu of biochemical or pharmacogenomic parameters, self-defined African ancestry seems the best available predictor of individual responses to antihypertensive drugs. PMID:23721258
Steck, Susan E.; Arab, Lenore; Zhang, Hongmei; Bensen, Jeannette T.; Fontham, Elizabeth T. H.; Johnson, Candace S.; Mohler, James L.; Smith, Gary J.; Su, Joseph L.; Trump, Donald L.; Woloszynska-Read, Anna
Background African Americans (AAs) have lower circulating 25-hydroxyvitamin D3 [25(OH)D3] concentrations and higher prostate cancer (CaP) aggressiveness than other racial/ethnic groups. The purpose of the current study was to examine the relationship between plasma 25(OH)D3, African ancestry and CaP aggressiveness among AAs and European Americans (EAs). Methods Plasma 25(OH)D3 was measured using LC-MS/MS (Liquid Chromatography Tandem Mass Spectrometry) in 537 AA and 663 EA newly-diagnosed CaP patients from the North Carolina-Louisiana Prostate Cancer Project (PCaP) classified as having either ‘high’ or ‘low’ aggressive disease based on clinical stage, Gleason grade and prostate specific antigen at diagnosis. Mean plasma 25(OH)D3 concentrations were compared by proportion of African ancestry. Logistic regression was used to calculate multivariable adjusted odds ratios (OR) and 95% confidence intervals (95%CI) for high aggressive CaP by tertile of plasma 25(OH)D3. Results AAs with highest percent African ancestry (>95%) had the lowest mean plasma 25(OH)D3 concentrations. Overall, plasma 25(OH)D3 was associated positively with aggressiveness among AA men, an association that was modified by calcium intake (ORT3vs.T1: 2.23, 95%CI: 1.26–3.95 among men with low calcium intake, and ORT3vs.T1: 0.19, 95%CI: 0.05–0.70 among men with high calcium intake). Among EAs, the point estimates of the ORs were <1.0 for the upper tertiles with CIs that included the null. Conclusions Among AAs, plasma 25(OH)D3 was associated positively with CaP aggressiveness among men with low calcium intake and inversely among men with high calcium intake. The clinical significance of circulating concentrations of 25(OH)D3 and interactions with calcium intake in the AA population warrants further study. PMID:25919866
Luzum, Jasmine A; Peterson, Edward; Li, Jia; She, Ruicong; Gui, Hongsheng; Liu, Bin; Spertus, John A; Pinto, Yigal M; Williams, L Keoki; Sabbah, Hani N; Lanfear, David E
It remains unclear whether beta-blockade is similarly effective in black patients with heart failure and reduced ejection fraction as in white patients, but self-reported race is a complex social construct with both biological and environmental components. The objective of this study was to compare the reduction in mortality associated with beta-blocker exposure in heart failure and reduced ejection fraction patients by both self-reported race and by proportion African genetic ancestry. Insured patients with heart failure and reduced ejection fraction (n=1122) were included in a prospective registry at Henry Ford Health System. This included 575 self-reported blacks (129 deaths, 22%) and 547 self-reported whites (126 deaths, 23%) followed for a median 3.0 years. Beta-blocker exposure (BBexp) was calculated from pharmacy claims, and the proportion of African genetic ancestry was determined from genome-wide array data. Time-dependent Cox proportional hazards regression was used to separately test the association of BBexp with all-cause mortality by self-reported race or by proportion of African genetic ancestry. Both sets of models were evaluated unadjusted and then adjusted for baseline risk factors and beta-blocker propensity score. BBexp effect estimates were protective and of similar magnitude both by self-reported race and by African genetic ancestry (adjusted hazard ratio=0.56 in blacks and adjusted hazard ratio=0.48 in whites). The tests for interactions with BBexp for both self-reported race and for African genetic ancestry were not statistically significant in any model ( P >0.1 for all). Among black and white patients with heart failure and reduced ejection fraction, reduction in all-cause mortality associated with BBexp was similar, regardless of self-reported race or proportion African genetic ancestry. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.
Full Text Available Terrestrial tortoises are the most endangered group of vertebrates but they are still largely ignored for defining global conservation priorities. In this paper, we explored within a hierarchical framework the potential contribution of prioritization studies at the continental scale to the planning of local initiatives for the conservation of African tortoises at the regional level. First, we modeled the distribution of all the African tortoise species, we calculated three indicators of conservation priority (i.e., species richness, conservation value, and complementarity, and we carried out a gap analysis at continental scale. Second, we focused on the most important region for tortoise conservation and performed the same analyses at higher resolution. Finally, we compared the results from the two scales for understanding the degree to which they are complementary. Southern Africa emerged from the continental analysis as the most important region for tortoises. Within this area, the high-resolution analysis pointed out specific core sites for conservation. The relative degree of species protection was assessed similarly at the two different resolutions. Two species appeared particularly vulnerable at both scales. Priority indices calculated at high resolution were correlated to the values calculated for the corresponding cells at low resolution but the congruence was stronger for species richness. Our results suggest to integrate the calculation of conservation value and complementarity into a hierarchical framework driven by species richness. The advantages of large scale planning include its broad perspective on complementarity and the capability to identify regions with greatest conservation potential. In this light, continental analyses allow targeting fine scale studies toward regions with maximum priority. The regional analyses at fine scale allow planning conservation measure at a resolution similar to that required for the practical
Bandera, Elisa V; Chandran, Urmila; Zirpoli, Gary; Gong, Zhihong; McCann, Susan E; Hong, Chi-Chen; Ciupak, Gregory; Pawlish, Karen; Ambrosone, Christine B
Obesity has been shown to be inversely associated with breast cancer risk in premenopausal women, while increasing risk in postmenopausal women. However, the current evidence is largely based on studies in Caucasian populations. Associations in women of African ancestry (AA), who have a higher prevalence of obesity, have been evaluated in few studies and results suggest different effects. We evaluated the impact of body size, body fat distribution, and body composition on breast cancer risk among AA women (978 cases and 958 controls) participating in the Women’s Circle of Health Study, a multi-site case–control study in New York City (NYC) and New Jersey (NJ). Cases were newly diagnosed with histologically confirmed ductal carcinoma in situ or invasive breast cancer, age 20–75 yrs. In NYC, cases were recruited through hospitals with the largest referral patterns for AA women and controls through random digit dialing (RDD). In NJ, cases were identified in seven counties in NJ thorough the NJ State Cancer Registry, and controls through RDD and community-based recruitment. During in-person interviews, questionnaires were administered and detailed anthropometric measurements were obtained. Body composition was assessed by bioelectrical impedance analysis. BMI did not have a major impact on pre- or post-menopausal breast cancer, but was significantly associated with reduced risk of ER-/PR- tumors among postmenopausal women (OR: 0.37; 95% CI: 0.15-0.96 for BMI > 30 vs. BMI < 25). Furthermore, increased premenopausal breast cancer risk was found for higher waist and hip circumferences after adjusting for BMI, with ORs of 2.25 (95% CI: 1.07-4.74) and 2.91 (95% CI: 1.39-6.10), respectively, comparing the highest vs. lowest quartile. While ORs for higher fat mass and percent body fat among postmenopausal women were above one, confidence intervals included the null value. Our study suggests that in AA women BMI is generally unrelated to breast cancer. However, higher
Williams, Robert C; Elston, Robert C; Kumar, Pankaj; Knowler, William C; Abboud, Hanna E; Adler, Sharon; Bowden, Donald W; Divers, Jasmin; Freedman, Barry I; Igo, Robert P; Ipp, Eli; Iyengar, Sudha K; Kimmel, Paul L; Klag, Michael J; Kohn, Orly; Langefeld, Carl D; Leehey, David J; Nelson, Robert G; Nicholas, Susanne B; Pahl, Madeleine V; Parekh, Rulan S; Rotter, Jerome I; Schelling, Jeffrey R; Sedor, John R; Shah, Vallabh O; Smith, Michael W; Taylor, Kent D; Thameem, Farook; Thornley-Brown, Denyse; Winkler, Cheryl A; Guo, Xiuqing; Zager, Phillip; Hanson, Robert L
The presence of population structure in a sample may confound the search for important genetic loci associated with disease. Our four samples in the Family Investigation of Nephropathy and Diabetes (FIND), European Americans, Mexican Americans, African Americans, and American Indians are part of a genome- wide association study in which population structure might be particularly important. We therefore decided to study in detail one component of this, individual genetic ancestry (IGA). From SNPs present on the Affymetrix 6.0 Human SNP array, we identified 3 sets of ancestry informative markers (AIMs), each maximized for the information in one the three contrasts among ancestral populations: Europeans (HAPMAP, CEU), Africans (HAPMAP, YRI and LWK), and Native Americans (full heritage Pima Indians). We estimate IGA and present an algorithm for their standard errors, compare IGA to principal components, emphasize the importance of balancing information in the ancestry informative markers (AIMs), and test the association of IGA with diabetic nephropathy in the combined sample. A fixed parental allele maximum likelihood algorithm was applied to the FIND to estimate IGA in four samples: 869 American Indians; 1385 African Americans; 1451 Mexican Americans; and 826 European Americans. When the information in the AIMs is unbalanced, the estimates are incorrect with large error. Individual genetic admixture is highly correlated with principle components for capturing population structure. It takes ~700 SNPs to reduce the average standard error of individual admixture below 0.01. When the samples are combined, the resulting population structure creates associations between IGA and diabetic nephropathy. The identified set of AIMs, which include American Indian parental allele frequencies, may be particularly useful for estimating genetic admixture in populations from the Americas. Failure to balance information in maximum likelihood, poly-ancestry models creates biased
Kuipers, Allison L; Zmuda, Joseph M; Carr, J Jeffrey; Terry, James G; Nair, Sangeeta; Cvejkus, Ryan; Bunker, Clareann H; Patrick, Alan L; Wassel, Christina L; Miljkovic, Iva
There is strong evidence that fat accumulating in non-adipose sites, "ectopic fat", is associated with cardiovascular disease (CVD), including vascular calcification. Most previous studies of this association have assessed only a single ectopic fat depot. Therefore, our aim was to assess the association of total, regional, and ectopic fat with abdominal aorto-illiac calcification (AAC) and coronary artery calcification (CAC) in 798 African ancestry men. Participants (mean age 62) were from the Tobago Bone Health Study cohort. Adiposity was assessed via clinical examination, dual x-ray absorptiometry, and computed tomography (CT). Ectopic fat depots included: abdominal visceral adipose tissue (VAT), liver attenuation, and calf intermuscular adipose tissue (IMAT). Vascular calcification was assessed by CT and quantified as present versus absent. Associations were tested using multiple logistic regression adjusted for traditional cardiovascular risk factors. Models of ectopic fat were additionally adjusted for total body fat and standing height. All adiposity measures, except VAT, were associated with AAC. Lower liver attenuation or greater calf IMAT was associated with 1.2-1.3-fold increased odds of AAC (p fat measure was associated with CAC. Greater adiposity in the skeletal muscle and liver, but not in the visceral compartment, was associated with increased odds of AAC in African ancestry men. These results highlight the potential importance of both quantity and location of adiposity accumulation throughout the body. Copyright © 2017 Elsevier B.V. All rights reserved.
Brewster, Lizzy M.; Seedat, Yackoob K.
Clinicians are encouraged to take an individualized approach when treating hypertension in patients of African ancestry, but little is known about why the individual patient may respond well to calcium blockers and diuretics, but generally has an attenuated response to drugs inhibiting the
Liang, Jingjing; Le, Thu H.; Edwards, Digna R. Velez; Tayo, Bamidele O.; Gaulton, Kyle J.; Smith, Jennifer A.; Lu, Yingchang; Jensen, Richard A.; Chen, Guanjie; Yanek, Lisa R.; Schwander, Karen; Tajuddin, Salman M.; Sofer, Tamar; Kim, Wonji; Kayima, James
© 2017 Public Library of Science. All Rights Reserved. Hypertension is a leading cause of global disease, mortality, and disability. While individuals of African descent suffer a disproportionate burden of hypertension and its complications, they have been underrepresented in genetic studies. To identify novel susceptibility loci for blood pressure and hypertension in people of African ancestry, we performed both single and multiple-trait genome-wide association analyses. We analyzed 21 genom...
The anticipated establishment of an African Standby Force (ASF) in 2015 and the interim African Capacity for Immediate Response to Crises (ACIRC), in the midst of new and continuing conflicts, have sparked renewed interest in the underpinnings of, and prospects for, the African Peace and Security Architecture.
Maples, Brian K.; Gravel, Simon; Kenny, Eimear E.; Bustamante, Carlos D.
Local-ancestry inference is an important step in the genetic analysis of fully sequenced human genomes. Current methods can only detect continental-level ancestry (i.e., European versus African versus Asian) accurately even when using millions of markers. Here, we present RFMix, a powerful discriminative modeling approach that is faster (∼30×) and more accurate than existing methods. We accomplish this by using a conditional random field parameterized by random forests trained on reference panels. RFMix is capable of learning from the admixed samples themselves to boost performance and autocorrect phasing errors. RFMix shows high sensitivity and specificity in simulated Hispanics/Latinos and African Americans and admixed Europeans, Africans, and Asians. Finally, we demonstrate that African Americans in HapMap contain modest (but nonzero) levels of Native American ancestry (∼0.4%). PMID:23910464
Rishishwar, Lavanya; Conley, Andrew B; Vidakovic, Brani; Jordan, I King
Uniparental genetic markers, mitochondrial DNA (mtDNA) and Y chromosomal DNA, are widely used for the inference of human ancestry. However, the resolution of ancestral origins based on mtDNA haplotypes is limited by the fact that such haplotypes are often found to be distributed across wide geographical regions. We have addressed this issue here by combining two sources of ancestry information that have typically been considered separately: historical records regarding population origins and genetic information on mtDNA haplotypes. To combine these distinct data sources, we applied a Bayesian approach that considers historical records, in the form of prior probabilities, together with data on the geographical distribution of mtDNA haplotypes, formulated as likelihoods, to yield ancestry assignments from posterior probabilities. This combined evidence Bayesian approach to ancestry assignment was evaluated for its ability to accurately assign sub-continental African ancestral origins to Afro-Colombians based on their mtDNA haplotypes. We demonstrate that the incorporation of historical prior probabilities via this analytical framework can provide for substantially increased resolution in sub-continental African ancestry assignment for members of this population. In addition, a personalized approach to ancestry assignment that involves the tuning of priors to individual mtDNA haplotypes yields even greater resolution for individual ancestry assignment. Despite the fact that Colombia has a large population of Afro-descendants, the ancestry of this community has been understudied relative to populations with primarily European and Native American ancestry. Thus, the application of the kind of combined evidence approach developed here to the study of ancestry in the Afro-Colombian population has the potential to be impactful. The formal Bayesian analytical framework we propose for combining historical and genetic information also has the potential to be widely applied
Cappuccio, F P
Mortality from coronary heart disease (CHD), stroke and end-stage renal failure are high in South Asian migrants in the UK. This is associated with high prevalence of diabetes and hypertension. These seem to be manifestations of a metabolic syndrome with insulin resistance (hyperinsulinaemia) and central obesity (based on high waist-to-hip ratio rather than on conventional measures of body mass index). This is associated with sedentary lifestyle, high serum triglycerides and low HDL-cholesterol. Mortality from stroke and end-stage renal failure are high in black migrants to the UK (both Caribbeans and West Africans). However, CHD mortality is low in this group. This pattern of mortality is associated with high prevalence of hypertension and diabetes. This group tends to be obese (particularly women) according to conventional measures of body mass index and to have hyperinsulinaemia, low serum triglycerides and high HDL-cholesterol. Conventional risk factors such as cigarette smoking and hypercholesterolaemia are less prevalent in ethnic minority populations in the United Kingdom and unlikely to explain the differences seen between groups, although each risk factor is likely to contribute to the variation in vascular disease within each group. There is difficulty in reconciling the results of migration studies (eg, from rural to urban environments) pointing to major environmental influences on the changes in cardiovascular risk factors with the consistent pattern of disease of ethnic groups across the world and in subsequent generations, suggesting a certain degree of genetic susceptibility. Important environment-gene interplays might be underlying some of these processes. The detection and management of hypertension and diabetes are still unsatisfactory in inner city areas and show variations by ethnic origin. Strategies for the control of CHD and stroke adopted in European countries directed mostly to white populations may be inappropriate for ethnic minority
Full Text Available Hypertension is a leading cause of global disease, mortality, and disability. While individuals of African descent suffer a disproportionate burden of hypertension and its complications, they have been underrepresented in genetic studies. To identify novel susceptibility loci for blood pressure and hypertension in people of African ancestry, we performed both single and multiple-trait genome-wide association analyses. We analyzed 21 genome-wide association studies comprised of 31,968 individuals of African ancestry, and validated our results with additional 54,395 individuals from multi-ethnic studies. These analyses identified nine loci with eleven independent variants which reached genome-wide significance (P < 1.25×10-8 for either systolic and diastolic blood pressure, hypertension, or for combined traits. Single-trait analyses identified two loci (TARID/TCF21 and LLPH/TMBIM4 and multiple-trait analyses identified one novel locus (FRMD3 for blood pressure. At these three loci, as well as at GRP20/CDH17, associated variants had alleles common only in African-ancestry populations. Functional annotation showed enrichment for genes expressed in immune and kidney cells, as well as in heart and vascular cells/tissues. Experiments driven by these findings and using angiotensin-II induced hypertension in mice showed altered kidney mRNA expression of six genes, suggesting their potential role in hypertension. Our study provides new evidence for genes related to hypertension susceptibility, and the need to study African-ancestry populations in order to identify biologic factors contributing to hypertension.
Schroeder, Hannes; Avila-Arcos, Maria C.; Malaspinas, Anna-Sapfo
Between 1500 and 1850, more than 12 million enslaved Africans were transported to the New World. The vast majority were shipped from West and West-Central Africa, but their precise origins are largely unknown. We used genome-wide ancient DNA analyses to investigate the genetic origins of three en...
Jennifer A. Smith
Full Text Available Inter-individual variability in blood pressure (BP is influenced by both genetic and non-genetic factors including socioeconomic and psychosocial stressors. A deeper understanding of the gene-by-socioeconomic/psychosocial factor interactions on BP may help to identify individuals that are genetically susceptible to high BP in specific social contexts. In this study, we used a genomic region-based method for longitudinal analysis, Longitudinal Gene-Environment-Wide Interaction Studies (LGEWIS, to evaluate the effects of interactions between known socioeconomic/psychosocial and genetic risk factors on systolic and diastolic BP in four large epidemiologic cohorts of European and/or African ancestry. After correction for multiple testing, two interactions were significantly associated with diastolic BP. In European ancestry participants, outward/trait anger score had a significant interaction with the C10orf107 genomic region (p = 0.0019. In African ancestry participants, depressive symptom score had a significant interaction with the HFE genomic region (p = 0.0048. This study provides a foundation for using genomic region-based longitudinal analysis to identify subgroups of the population that may be at greater risk of elevated BP due to the combined influence of genetic and socioeconomic/psychosocial risk factors.
Zainabadi, Kayvan; Jain, Anuja V.; Donovan, Frank X.; Elashoff, David; Rao, Nagesh P.; Murty, Vundavalli V.; Chandrasekharappa, Settara C.; Srivatsan, Eri S.
Cloning and sequencing of 5.5kb deletion at chromosome 11q13.1 from the HeLa cells, tumorigenic hybrids and two fibroblast cell lines has revealed homologous recombination between AluSx and AluY resulting in the deletion of intervening sequences. Long-range PCR of the 5.5kb sequence in 494 normal lymphocyte samples showed heterozygous deletion in 28.3% of African- American ancestry samples but only in 4.8% of Caucasian samples (pdeletion occurs in 27% of YRI (Yoruba – West African) population but none in non-African populations. The HapMap analysis further identified strong linkage disequilibrium between 5 single nucleotide polymorphisms and the 5.5kb deletion in the people of African ancestry. Computational analysis of 175kb sequence surrounding the deletion site revealed enhanced flexibility, low thermodynamic stability, high repetitiveness, and stable stem-loop/hairpin secondary structures that are hallmarks of common fragile sites. PMID:24412158
Joshua Mark Galanter
Full Text Available Most individuals throughout the Americas are admixed descendants of Native American, European, and African ancestors. Complex historical factors have resulted in varying proportions of ancestral contributions between individuals within and among ethnic groups. We developed a panel of 446 ancestry informative markers (AIMs optimized to estimate ancestral proportions in individuals and populations throughout Latin America. We used genome-wide data from 953 individuals from diverse African, European, and Native American populations to select AIMs optimized for each of the three main continental populations that form the basis of modern Latin American populations. We selected markers on the basis of locus-specific branch length to be informative, well distributed throughout the genome, capable of being genotyped on widely available commercial platforms, and applicable throughout the Americas by minimizing within-continent heterogeneity. We then validated the panel in samples from four admixed populations by comparing ancestry estimates based on the AIMs panel to estimates based on genome-wide association study (GWAS data. The panel provided balanced discriminatory power among the three ancestral populations and accurate estimates of individual ancestry proportions (R² > 0.9 for ancestral components with significant between-subject variance. Finally, we genotyped samples from 18 populations from Latin America using the AIMs panel and estimated variability in ancestry within and between these populations. This panel and its reference genotype information will be useful resources to explore population history of admixture in Latin America and to correct for the potential effects of population stratification in admixed samples in the region.
Shriner, Daniel; Tekola-Ayele, Fasil; Adeyemo, Adebowale; Rotimi, Charles N
The Hadza and Sandawe populations in present-day Tanzania speak languages containing click sounds and therefore thought to be distantly related to southern African Khoisan languages. We analyzed genome-wide genotype data for individuals sampled from the Hadza and Sandawe populations in the context of a global data set of 3,528 individuals from 163 ethno-linguistic groups. We found that Hadza and Sandawe individuals share ancestry distinct from and most closely related to Omotic ancestry; share Khoisan ancestry with populations such as ≠Khomani, Karretjie, and Ju/'hoansi in southern Africa; share Niger-Congo ancestry with populations such as Yoruba from Nigeria and Luhya from Kenya, consistent with migration associated with the Bantu Expansion; and share Cushitic ancestry with Somali, multiple Ethiopian populations, the Maasai population in Kenya, and the Nama population in Namibia. We detected evidence for low levels of Arabian, Nilo-Saharan, and Pygmy ancestries in a minority of individuals. Our results indicate that west Eurasian ancestry in eastern Africa is more precisely the Arabian parent of Cushitic ancestry. Relative to the Out-of-Africa migrations, Hadza ancestry emerged early whereas Sandawe ancestry emerged late.
The combined risks of reduced or increased function variants in cell death pathway genes differentially influence cervical cancer risk and herpes simplex virus type 2 infection among black Africans and the Mixed Ancestry population of South Africa
Chattopadhyay, Koushik; Williamson, Anna-Lise; Hazra, Annapurna; Dandara, Collet
Cervical cancer is one of the most important cancers worldwide with a high incident and mortality rate and is caused by the human papilloma virus (HPV). Among sexually active women who get infected with human papillomavirus (HPV), a small fraction progresses to cervical cancer disease pointing to possible roles of additional risk factors in development of the disease which include host genetic factors and other infections such as HSV-2. Since cellular apoptosis plays a role in controlling the spread of virus-infections in cells, gene variants altering the function of proteins involved in cell death pathways might be associated with the clearing of virus infections. Activity altering polymorphisms in FasR (−1377G > A and -670A > G), FasL (−844 T > C) and CASP8 (−652 6 N ins/del) genes have been shown to alter the mechanism of apoptosis by modifying the level of expression of their correspondent proteins. In the present study, we set out to investigate the combined risks of CASP8, FasR, and FasL polymorphisms in cervical cancer, pre-cancerous lesions, HPV infection and HSV-2 infection. Participants were 442 South African women of black African and mixed-ancestry origin with invasive cervical cancer and 278 control women matched by age, ethnicity and domicile status. FasR and FasL polymorphisms were genotyped by TaqMan and CASP8 polymorphism by PCR-RFLP. The results were analysed with R using haplo.stats software version 1.5.2. CASP8 -652 6 N del + FasR-670A was associated with a reduced risk (P = 0.019, Combined Polymorphism Score (CPS) = −2.34) and CASP8 -652 6 N ins + FasR-1377G was associated with a marginal increased risk (P = 0.047, CPS = 1.99) of cervical cancer among black Africans. When compared within the control group, CASP8 -652 6 N ins + FasR-1377A showed a reduced risk (P = 0.023, CPS = −2.28) of HSV-2 infection in both black African and mixed-ancestry population. Our results show that the combined risks of variants in cell death pathway genes
The combined risks of reduced or increased function variants in cell death pathway genes differentially influence cervical cancer risk and herpes simplex virus type 2 infection among black Africans and the Mixed Ancestry population of South Africa.
Chattopadhyay, Koushik; Williamson, Anna-Lise; Hazra, Annapurna; Dandara, Collet
Cervical cancer is one of the most important cancers worldwide with a high incident and mortality rate and is caused by the human papilloma virus (HPV). Among sexually active women who get infected with human papillomavirus (HPV), a small fraction progresses to cervical cancer disease pointing to possible roles of additional risk factors in development of the disease which include host genetic factors and other infections such as HSV-2. Since cellular apoptosis plays a role in controlling the spread of virus-infections in cells, gene variants altering the function of proteins involved in cell death pathways might be associated with the clearing of virus infections. Activity altering polymorphisms in FasR (-1377G > A and -670A > G), FasL (-844 T > C) and CASP8 (-652 6 N ins/del) genes have been shown to alter the mechanism of apoptosis by modifying the level of expression of their correspondent proteins. In the present study, we set out to investigate the combined risks of CASP8, FasR, and FasL polymorphisms in cervical cancer, pre-cancerous lesions, HPV infection and HSV-2 infection. Participants were 442 South African women of black African and mixed-ancestry origin with invasive cervical cancer and 278 control women matched by age, ethnicity and domicile status. FasR and FasL polymorphisms were genotyped by TaqMan and CASP8 polymorphism by PCR-RFLP. The results were analysed with R using haplo.stats software version 1.5.2. CASP8 -652 6 N del + FasR-670A was associated with a reduced risk (P = 0.019, Combined Polymorphism Score (CPS) = -2.34) and CASP8 -652 6 N ins + FasR-1377G was associated with a marginal increased risk (P = 0.047, CPS = 1.99) of cervical cancer among black Africans. When compared within the control group, CASP8 -652 6 N ins + FasR-1377A showed a reduced risk (P = 0.023, CPS = -2.28) of HSV-2 infection in both black African and mixed-ancestry population. Our results show that the combined risks of
Santos, Hadassa C; Horimoto, Andréa V R; Tarazona-Santos, Eduardo; Rodrigues-Soares, Fernanda; Barreto, Mauricio L; Horta, Bernardo L; Lima-Costa, Maria F; Gouveia, Mateus H; Machado, Moara; Silva, Thiago M; Sanches, José M; Esteban, Nubia; Magalhaes, Wagner C S; Rodrigues, Maíra R; Kehdy, Fernanda S G; Pereira, Alexandre C
The Brazilian population is considered to be highly admixed. The main contributing ancestral populations were European and African, with Amerindians contributing to a lesser extent. The aims of this study were to provide a resource for determining and quantifying individual continental ancestry using the smallest number of SNPs possible, thus allowing for a cost- and time-efficient strategy for genomic ancestry determination. We identified and validated a minimum set of 192 ancestry informative markers (AIMs) for the genetic ancestry determination of Brazilian populations. These markers were selected on the basis of their distribution throughout the human genome, and their capacity of being genotyped on widely available commercial platforms. We analyzed genotyping data from 6487 individuals belonging to three Brazilian cohorts. Estimates of individual admixture using this 192 AIM panels were highly correlated with estimates using ~370 000 genome-wide SNPs: 91%, 92%, and 74% of, respectively, African, European, and Native American ancestry components. Besides that, 192 AIMs are well distributed among populations from these ancestral continents, allowing greater freedom in future studies with this panel regarding the choice of reference populations. We also observed that genetic ancestry inferred by AIMs provides similar association results to the one obtained using ancestry inferred by genomic data (370 K SNPs) in a simple regression model with rs1426654, related to skin pigmentation, genotypes as dependent variable. In conclusion, these markers can be used to identify and accurately quantify ancestry of Latin Americans or US Hispanics/Latino individuals, in particular in the context of fine-mapping strategies that require the quantification of continental ancestry in thousands of individuals.
Rahul C Deo
Full Text Available Lipoprotein(a (Lp(a is an important causal cardiovascular risk factor, with serum Lp(a levels predicting atherosclerotic heart disease and genetic determinants of Lp(a levels showing association with myocardial infarction. Lp(a levels vary widely between populations, with African-derived populations having nearly 2-fold higher Lp(a levels than European Americans. We investigated the genetic basis of this difference in 4464 African Americans from the Jackson Heart Study (JHS using a panel of up to 1447 ancestry informative markers, allowing us to accurately estimate the African ancestry proportion of each individual at each position in the genome. In an unbiased genome-wide admixture scan for frequency-differentiated genetic determinants of Lp(a level, we found a convincing peak (LOD = 13.6 at 6q25.3, which spans the LPA locus. Dense fine-mapping of the LPA locus identified a number of strongly associated, common biallelic SNPs, a subset of which can account for up to 7% of the variation in Lp(a level, as well as >70% of the African-European population differences in Lp(a level. We replicated the association of the most strongly associated SNP, rs9457951 (p = 6 × 10(-22, 27% change in Lp(a per allele, ∼5% of Lp(a variance explained in JHS, in 1,726 African Americans from the Dallas Heart Study and found an even stronger association after adjustment for the kringle(IV repeat copy number. Despite the strong association with Lp(a levels, we find no association of any LPA SNP with incident coronary heart disease in 3,225 African Americans from the Atherosclerosis Risk in Communities Study.
Dia, A.; Allegre, C.J.; Erlank, A.J.
Nd isotopic compositions and 147 Sm/ 144 Nd ratios were measured in fifty-eight South African shales and greywackes with depositional ages ranging from 0.2 to 3.3 b.y. Elements such as the rare earths, which are poorly soluble in water and not fractionated during exogeneous processes, preserve the signature of the original crustal source. The 147 Sm/ 144 Nd ratios appear to be approximately constant throughout the time interval sampled. We calculated Nd model ages of crustal differentiation. Knowing that the shales represent a true blend of different continental areas we consider these model ages representative of the mean ages of their primitive continental sources. Then, using the inverse technique developed by Allegre and Rousseau in 1984, we computed a growth curve for the continental crust in South Africa. Two periods of important crustal genesis (Archaean and around 1.5 b.y.) can be compared with the observed geology and with other continental crust growth curves obtained in previous studies in southern Africa and in Australia. The observation of large variations in the MgO content and Ni, Cr, U and Th concentrations between Archaean South African shales and post-Archaean samples compared to the constancy of the 147 Sm/ 144 Nd ratios leads us to propose that the Archaean crust was composed of both granite (70.5%) and a mafic component (29.5%) which could have been komatiite. The small dispersion of 147 Sm/ 144 Nd ratios suggests that erosion and sedimentation processes yielded homogeneous Archaean shales. The present-day continental crust is much more heterogeneous, because it has undergone several episodes of recycling. Thus recent shales are characterized by more variable 147 Sm/ 144 Nd ratios. (orig.)
Romanini, Carola; Romero, Magdalena; Salado Puerto, Mercedes; Catelli, Laura; Phillips, Christopher; Pereira, Rui; Gusmão, Leonor; Vullo, Carlos
Ancestry informative markers (AIMs) can be useful to infer ancestry proportions of the donors of forensic evidence. The probability of success typing degraded samples, such as human skeletal remains, is strongly influenced by the DNA fragment lengths that can be amplified and the presence of PCR inhibitors. Several AIM panels are available amongst the many forensic marker sets developed for genotyping degraded DNA. Using a 46 AIM Insertion Deletion (Indel) multiplex, we analyzed human skeletal remains of post mortem time ranging from 35 to 60 years from four different continents (Sub-Saharan Africa, South and Central America, East Asia and Europe) to ascertain the genetic ancestry components. Samples belonging to non-admixed individuals could be assigned to their corresponding continental group. For the remaining samples with admixed ancestry, it was possible to estimate the proportion of co-ancestry components from the four reference population groups. The 46 AIM Indel set was informative enough to efficiently estimate the proportion of ancestry even in samples yielding partial profiles, a frequent occurrence when analyzing inhibited and/or degraded DNA extracts. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Deng, Lian; Ruiz-Linares, Andrés; Xu, Shuhua; Wang, Sijia
Latin American populations stem from the admixture of Europeans, Africans and Native Americans, which started over 400 years ago and had lasted for several centuries. Extreme deviation over the genome-wide average in ancestry estimations at certain genomic locations could reflect recent natural selection. We evaluated the distribution of ancestry estimations using 678 genome-wide microsatellite markers in 249 individuals from 13 admixed populations across Latin America. We found significant deviations in ancestry estimations including three locations with more than 3.5 times standard deviations from the genome-wide average: an excess of European ancestry at 1p36 and 14q32, and an excess of African ancestry at 6p22. Using simulations, we could show that at least the deviation at 6p22 was unlikely to result from genetic drift alone. By applying different linguistic groups as well as the most likely ancestral Native American populations as the ancestry, we showed that the choice of Native American ancestry could affect the local ancestry estimation. However, the signal at 6p22 consistently appeared in most of the analyses using various ancestral groups. This study provided important insights for recent natural selection in the context of the unique history of the New World and implications for disease mapping.
Kidd, Jeffrey M; Gravel, Simon; Byrnes, Jake; Moreno-Estrada, Andres; Musharoff, Shaila; Bryc, Katarzyna; Degenhardt, Jeremiah D; Brisbin, Abra; Sheth, Vrunda; Chen, Rong; McLaughlin, Stephen F; Peckham, Heather E; Omberg, Larsson; Bormann Chung, Christina A; Stanley, Sarah; Pearlstein, Kevin; Levandowsky, Elizabeth; Acevedo-Acevedo, Suehelay; Auton, Adam; Keinan, Alon; Acuña-Alonzo, Victor; Barquera-Lozano, Rodrigo; Canizales-Quinteros, Samuel; Eng, Celeste; Burchard, Esteban G; Russell, Archie; Reynolds, Andy; Clark, Andrew G; Reese, Martin G; Lincoln, Stephen E; Butte, Atul J; De La Vega, Francisco M; Bustamante, Carlos D
Full sequencing of individual human genomes has greatly expanded our understanding of human genetic variation and population history. Here, we present a systematic analysis of 50 human genomes from 11 diverse global populations sequenced at high coverage. Our sample includes 12 individuals who have admixed ancestry and who have varying degrees of recent (within the last 500 years) African, Native American, and European ancestry. We found over 21 million single-nucleotide variants that contribute to a 1.75-fold range in nucleotide heterozygosity across diverse human genomes. This heterozygosity ranged from a high of one heterozygous site per kilobase in west African genomes to a low of 0.57 heterozygous sites per kilobase in segments inferred to have diploid Native American ancestry from the genomes of Mexican and Puerto Rican individuals. We show evidence of all three continental ancestries in the genomes of Mexican, Puerto Rican, and African American populations, and the genome-wide statistics are highly consistent across individuals from a population once ancestry proportions have been accounted for. Using a generalized linear model, we identified subtle variations across populations in the proportion of neutral versus deleterious variation and found that genome-wide statistics vary in admixed populations even once ancestry proportions have been factored in. We further infer that multiple periods of gene flow shaped the diversity of admixed populations in the Americas-70% of the European ancestry in today's African Americans dates back to European gene flow happening only 7-8 generations ago. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.
were measured by ELISA and did not differ between groups (Appendix A, Figure 2E). Interestingly, DBP levels correlated with vitamin D metabolite...to affect the fraction available for conversion to 1,25(OH)2D (35). DBP was measured in serum using a polyclonal antibody ELISA , which has been...vitamin D binding protein (DBP) quantified by polyclonal antibody ELISA and correlation with 25(OH) D levels in the (F) serum and (G) prostate tissue (EA
Urlaub, M.; Krastel, S.; Geersen, J.; Schwenk, T.
Numerous studies invoke weak layers to explain the occurrence of large submarine landslides (>100 km³), in particular those on very gentle slopes (translational, such that failure takes place along bedding-parallel surfaces at different stratigraphic depths. This suggests that failure occurs along weak layers, which are deposited repeatedly over time. Using high resolution seismic reflection data we trace several failure surfaces of the Cap Blanc Slide complex offshore Northwest Africa to ODP-Site 658. Core-seismic integration shows that the failure surfaces coincide with diatom oozes that are topped by clay. Along Northwest Africa diatom-rich sediments are typically deposited at the end of glacial periods. In the seismic data these oozes show up as distinct high amplitude reflectors due to their characteristic low densities. Similar high-amplitude reflectors embedded into low-reflective seismic units are commonly observed in shallow sediments (<100 m below seafloor) along the entire Northwest African continental slope. The failure surfaces of at least three large landslides coincide with such reflectors. As the most recent Pleistocene glacial periods likely influenced sediment deposition along the entire Northwest African margin in a similar manner we hypothesize that diatom oozes play a critical role for the generation of submarine landslides off Northwest Africa as well as globally within subtropical regions. An initiative to drill the Northwest African continental slope with IODP is ongoing, within which this hypothesis shall be tested.
Oliveira, J S; Ferreira, R S; Santos, L M; Marin, L J; Corrêa, R X; Luizon, M R; Simões, A L; Gadelha, S R; Sousa, S M B
Some studies of polymorphisms in prostate cancer (PCa) analyze individuals in a uniform manner, regardless of genetic ancestry. However, PCa aggressiveness differs between subjects of African descent and those of European extraction. Thus, genetic ancestry analysis may be used to detect population stratification in case-control association studies. We genotyped 11 ancestry informative markers to estimate the contributions of African, European, and Amerindian ancestries in a case-control sample of 213 individuals from Bahia State, Northeast Brazil, including 104 PCa patients. We compared this data with self-reported ancestry and the stratification of cases by PCa aggressiveness according to Gleason score. A larger African genetic contribution (44%) was detected among cases, and a greater European contribution (61%) among controls. Self-declaration data revealed that 74% of PCa patients considered themselves non-white (black and brown), and 41.3% of controls viewed themselves as white. Our data showed a higher degree of European ancestry among fast-growing cancer cases than those of intermediate and slow development. This differs from many previous studies, in which the prevalence of African ancestry has been reported for all grades. Differences were observed between degrees of PCa aggressiveness in terms of genetic ancestry. In particular, the greater European contribution among patients with high-grade PCa indicates that a population's genetic structure can influence case-control studies. This investigation contributes to our understanding of the genetic basis of tumor aggressiveness among groups of different genetic ancestries, especially admixed populations, and has significant implications for the assessment of inter-population heterogeneity in drug treatment effects.
As the COP22 is about to take place in an African country (Morocco), the author discusses how African countries deal with the fact that they belong to different negotiation groups, and which are the strategies adopted until now by the group of African negotiators to cope with the delicate combination of national requests and continental vision. Thus, the author recalls and comments the positions adopted since COP1 by the five groups of negotiators and their relationships with different international bodies. She discuses the posture and strategies of African countries, and how to gather them about topics of common interest such as adaptation, financing and transfer of capacities and technologies. She also comments the emergence of a new strategy regarding financing mechanisms
Dhamo, Brunilda; Kragt, Lea; Grgic, Olja; Vucic, Strahinja; Medina-Gomez, Carolina; Rivadeneira, Fernando; Jaddoe, Vincent W V; Wolvius, Eppo B; Ongkosuwito, Edwin M
In this study, we investigated the influence of ancestry on dental development in the Generation R Study. Information on geographic ancestry was available in 3,600 children (1,810 boys and 1,790 girls, mean age 9.81 ± 0.35 years) and information about genetic ancestry was available in 2,786 children (1,387 boys and 1,399 girls, mean age 9.82 ± 0.34 years). Dental development was assessed in all children using the Demirjian method. The associations of geographic ancestry (Cape Verdean, Moroccan, Turkish, Dutch Antillean, Surinamese Creole and Surinamese Hindustani vs Dutch as the reference group) and genetic content of ancestry (European, African or Asian) with dental development was analyzed using linear regression models. In a geographic perspective of ancestry, Moroccan (β = 0.18; 95% CI: 0.07, 0.28), Turkish (β = 0.22; 95% CI: 0.12, 0.32), Dutch Antillean (β = 0.27; 95% CI: 0.12, 0.41), and Surinamese Creole (β = 0.16; 95% CI: 0.03, 0.30) preceded Dutch children in dental development. Moreover, in a genetic perspective of ancestry, a higher proportion of European ancestry was associated with decelerated dental development (β = -0.32; 95% CI: -.44, -.20). In contrast, a higher proportion of African ancestry (β = 0.29; 95% CI: 0.16, 0.43) and a higher proportion of Asian ancestry (β = 0.28; 95% CI: 0.09, 0.48) were associated with accelerated dental development. When investigating only European children, these effect estimates increased to twice as large in absolute value. Based on a geographic and genetic perspective, differences in dental development exist in a population of heterogeneous ancestry and should be considered when describing the physiological growth in children. © 2017 The Authors American Journal of Physical Anthropology Published by Wiley Periodicals, Inc.
Huo, Dezheng; Feng, Ye; Haddad, Stephen; Zheng, Yonglan; Yao, Song; Han, Yoo-Jeong; Ogundiran, Temidayo O; Adebamowo, Clement; Ojengbede, Oladosu; Falusi, Adeyinka G; Zheng, Wei; Blot, William; Cai, Qiuyin; Signorello, Lisa; John, Esther M; Bernstein, Leslie; Hu, Jennifer J; Ziegler, Regina G; Nyante, Sarah; Bandera, Elisa V; Ingles, Sue A; Press, Michael F; Deming, Sandra L; Rodriguez-Gil, Jorge L; Nathanson, Katherine L; Domchek, Susan M; Rebbeck, Timothy R; Ruiz-Narváez, Edward A; Sucheston-Campbell, Lara E; Bensen, Jeannette T; Simon, Michael S; Hennis, Anselm; Nemesure, Barbara; Leske, M Cristina; Ambs, Stefan; Chen, Lin S; Qian, Frank; Gamazon, Eric R; Lunetta, Kathryn L; Cox, Nancy J; Chanock, Stephen J; Kolonel, Laurence N; Olshan, Andrew F; Ambrosone, Christine B; Olopade, Olufunmilayo I; Palmer, Julie R; Haiman, Christopher A
Multiple breast cancer loci have been identified in previous genome-wide association studies, but they were mainly conducted in populations of European ancestry. Women of African ancestry are more likely to have young-onset and oestrogen receptor (ER) negative breast cancer for reasons that are unknown and understudied. To identify genetic risk factors for breast cancer in women of African descent, we conducted a meta-analysis of two genome-wide association studies of breast cancer; one study consists of 1,657 cases and 2,029 controls genotyped with Illumina’s HumanOmni2.5 BeadChip and the other study included 3,016 cases and 2,745 controls genotyped using Illumina Human1M-Duo BeadChip. The top 18,376 single nucleotide polymorphisms (SNP) from the meta-analysis were replicated in the third study that consists of 1,984 African Americans cases and 2,939 controls. We found that SNP rs13074711, 26.5 Kb upstream of TNFSF10 at 3q26.21, was significantly associated with risk of oestrogen receptor (ER)-negative breast cancer (odds ratio [OR]=1.29, 95% CI: 1.18-1.40; P = 1.8 × 10 − 8). Functional annotations suggest that the TNFSF10 gene may be involved in breast cancer aetiology, but further functional experiments are needed. In addition, we confirmed SNP rs10069690 was the best indicator for ER-negative breast cancer at 5p15.33 (OR = 1.30; P = 2.4 × 10 − 10) and identified rs12998806 as the best indicator for ER-positive breast cancer at 2q35 (OR = 1.34; P = 2.2 × 10 − 8) for women of African ancestry. These findings demonstrated additional susceptibility alleles for breast cancer can be revealed in diverse populations and have important public health implications in building race/ethnicity-specific risk prediction model for breast cancer.
Serrano-Gómez, Silvia J; Sanabria-Salas, María Carolina; Garay, Jone; Baddoo, Melody C; Hernández-Suarez, Gustavo; Mejía, Juan Carlos; García, Oscar; Miele, Lucio; Fejerman, Laura; Zabaleta, Jovanny
Hispanic/Latino populations are a genetically admixed and heterogeneous group, with variable fractions of European, Indigenous American and African ancestries. The molecular profile of breast cancer has been widely described in non-Hispanic Whites but equivalent knowledge is lacking in Hispanic/Latinas. We have previously reported that the most prevalent breast cancer intrinsic subtype in Colombian women was Luminal B as defined by St. Gallen 2013 criteria. In this study we explored ancestry-associated differences in molecular profiles of Luminal B tumors among these highly admixed women. We performed whole-transcriptome RNA-seq analysis in 42 Luminal tumors (21 Luminal A and 21 Luminal B) from Colombian women. Genetic ancestry was estimated from a panel of 80 ancestry-informative markers (AIM). We categorized patients according to Luminal subtype and to the proportion of European and Indigenous American ancestry and performed differential expression analysis comparing Luminal B against Luminal A tumors according to the assigned ancestry groups. We found 5 genes potentially modulated by genetic ancestry: ERBB2 (log2FC = 2.367, padjancestry (p = 0.02, B = 3.11). This association was not biased by the distribution of HER2+ tumors among the groups analyzed. Our results suggest that genetic ancestry in Hispanic/Latina women might modify ERBB2 gene expression in Luminal tumors. Further analyses are needed to confirm these findings and explore their prognostic value.
Tian, Chao; Kosoy, Roman; Nassir, Rami; Lee, Annette; Villoslada, Pablo; Klareskog, Lars; Hammarström, Lennart; Garchon, Henri-Jean; Pulver, Ann E.; Ransom, Michael; Gregersen, Peter K.; Seldin, Michael F.
The definition of European population genetic substructure and its application to understanding complex phenotypes is becoming increasingly important. In the current study using over 4000 subjects genotyped for 300 thousand SNPs we provide further insight into relationships among European population groups and identify sets of SNP ancestry informative markers (AIMs) for application in genetic studies. In general, the graphical description of these principal components analyses (PCA) of diverse European subjects showed a strong correspondence to the geographical relationships of specific countries or regions of origin. Clearer separation of different ethnic and regional populations was observed when northern and southern European groups were considered separately and the PCA results were influenced by the inclusion or exclusion of different self-identified population groups including Ashkenazi Jewish, Sardinian and Orcadian ethnic groups. SNP AIM sets were identified that could distinguish the regional and ethnic population groups. Moreover, the studies demonstrated that most allele frequency differences between different European groups could be effectively controlled in analyses using these AIM sets. The European substructure AIMs should be widely applicable to ongoing studies to confirm and delineate specific disease susceptibility candidate regions without the necessity to perform additional genome-wide SNP studies in additional subject sets. PMID:19707526
Lynch, Elizabeth B.; Holmes, Shane
Objective: Describe lay food group categories of low-income African American women and assess the overlap of lay food groups and MyPyramid food groups. Design: A convenience sample of African American mothers from a low-income Chicago neighborhood performed a card-sorting task in which they grouped familiar food items into food groups. Setting:…
Li, Cai-Xia; Pakstis, Andrew J; Jiang, Li; Wei, Yi-Liang; Sun, Qi-Fan; Wu, Hong; Bulbul, Ozlem; Wang, Ping; Kang, Long-Li; Kidd, Judith R; Kidd, Kenneth K
Many ancestry informative SNP (AISNP) panels have been published. Ancestry resolution in them varies from three to eight continental clusters of populations depending on the panel used. However, none of these panels differentiates well among East Asian populations. To meet this need, we have developed a 74 AISNP panel after analyzing a much larger number of SNPs for Fst and allele frequency differences between two geographically close population groups within East Asia. The 74 AISNP panel can now distinguish at least 10 biogeographic groups of populations globally: Sub-Saharan Africa, North Africa, Europe, Southwest Asia, South Asia, North Asia, East Asia, Southeast Asia, Pacific and Americas. Compared with our previous 55-AISNP panel, Southeast Asia and North Asia are two newly assignable clusters. For individual ancestry assignment, the likelihood ratio and ancestry components were analyzed on a different set of 500 test individuals from 11 populations. All individuals from five of the test populations - Yoruba (YRI), European (CEU), Han Chinese in Henan (CHNH), Rondonian Surui (SUR) and Ticuna (TIC) - were assigned to their appropriate geographical regions unambiguously. For the other test populations, most of the individuals were assigned to their self-identified geographical regions with a certain degree of overlap with adjacent populations. These alternative ancestry components for each individual thus help give a clearer picture of the possible group origins of the individual. We have demonstrated that the new AISNP panel can achieve a deeper resolution of global ancestry. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Schuenemann, Verena J.; Peltzer, Alexander; Welte, Beatrix; van Pelt, W. Paul; Molak, Martyna; Wang, Chuan-Chao; Furtwängler, Anja; Urban, Christian; Reiter, Ella; Nieselt, Kay; Teßmann, Barbara; Francken, Michael; Harvati, Katerina; Haak, Wolfgang; Schiffels, Stephan; Krause, Johannes
Egypt, located on the isthmus of Africa, is an ideal region to study historical population dynamics due to its geographic location and documented interactions with ancient civilizations in Africa, Asia and Europe. Particularly, in the first millennium BCE Egypt endured foreign domination leading to growing numbers of foreigners living within its borders possibly contributing genetically to the local population. Here we present 90 mitochondrial genomes as well as genome-wide data sets from three individuals obtained from Egyptian mummies. The samples recovered from Middle Egypt span around 1,300 years of ancient Egyptian history from the New Kingdom to the Roman Period. Our analyses reveal that ancient Egyptians shared more ancestry with Near Easterners than present-day Egyptians, who received additional sub-Saharan admixture in more recent times. This analysis establishes ancient Egyptian mummies as a genetic source to study ancient human history and offers the perspective of deciphering Egypt's past at a genome-wide level. PMID:28556824
Johnston, Henry Richard; Hu, Yi-Juan; Gao, Jingjing; O'Connor, Timothy D; Abecasis, Gonçalo R; Wojcik, Genevieve L; Gignoux, Christopher R; Gourraud, Pierre-Antoine; Lizee, Antoine; Hansen, Mark; Genuario, Rob; Bullis, Dave; Lawley, Cindy; Kenny, Eimear E; Bustamante, Carlos; Beaty, Terri H; Mathias, Rasika A; Barnes, Kathleen C; Qin, Zhaohui S
A primary goal of The Consortium on Asthma among African-ancestry Populations in the Americas (CAAPA) is to develop an 'African Diaspora Power Chip' (ADPC), a genotyping array consisting of tagging SNPs, useful in comprehensively identifying African specific genetic variation. This array is designed based on the novel variation identified in 642 CAAPA samples of African ancestry with high coverage whole genome sequence data (~30× depth). This novel variation extends the pattern of variation catalogued in the 1000 Genomes and Exome Sequencing Projects to a spectrum of populations representing the wide range of West African genomic diversity. These individuals from CAAPA also comprise a large swath of the African Diaspora population and incorporate historical genetic diversity covering nearly the entire Atlantic coast of the Americas. Here we show the results of designing and producing such a microchip array. This novel array covers African specific variation far better than other commercially available arrays, and will enable better GWAS analyses for researchers with individuals of African descent in their study populations. A recent study cataloging variation in continental African populations suggests this type of African-specific genotyping array is both necessary and valuable for facilitating large-scale GWAS in populations of African ancestry.
Meghan E Healy
Full Text Available We examined the relationship between continental-level genetic ancestry and racial and ethnic identity in an admixed population in New Mexico with the goal of increasing our understanding of how racial and ethnic identity influence genetic substructure in admixed populations. Our sample consists of 98 New Mexicans who self-identified as Hispanic or Latino (NM-HL and who further categorized themselves by race and ethnic subgroup membership. The genetic data consist of 270 newly-published autosomal microsatellites from the NM-HL sample and previously published data from 57 globally distributed populations, including 13 admixed samples from Central and South America. For these data, we 1 summarized the major axes of genetic variation using principal component analyses, 2 performed tests of Hardy Weinberg equilibrium, 3 compared empirical genetic ancestry distributions to those predicted under a model of admixture that lacked substructure, 4 tested the hypotheses that individuals in each sample had 100%, 0%, and the sample-mean percentage of African, European, and Native American ancestry. We found that most NM-HL identify themselves and their parents as belonging to one of two groups, conforming to a region-specific narrative that distinguishes recent immigrants from Mexico from individuals whose families have resided in New Mexico for generations and who emphasize their Spanish heritage. The "Spanish" group had significantly lower Native American ancestry and higher European ancestry than the "Mexican" group. Positive FIS values, PCA plots, and heterogeneous ancestry distributions suggest that most Central and South America admixed samples also contain substructure, and that this substructure may be related to variation in social identity. Genetic substructure appears to be common in admixed populations in the Americas and may confound attempts to identify disease-causing genes and to understand the social causes of variation in health outcomes
Browning, Sharon R; Grinde, Kelsey; Plantinga, Anna; Gogarten, Stephanie M; Stilp, Adrienne M; Kaplan, Robert C; Avilés-Santa, M Larissa; Browning, Brian L; Laurie, Cathy C
We estimated local ancestry on the autosomes and X chromosome in a large US-based study of 12,793 Hispanic/Latino individuals using the RFMix method, and we compared different reference panels and approaches to local ancestry estimation on the X chromosome by means of Mendelian inconsistency rates as a proxy for accuracy. We developed a novel and straightforward approach to performing ancestry-specific PCA after finding artifactual behavior in the results from an existing approach. Using the ancestry-specific PCA, we found significant population structure within African, European, and Amerindian ancestries in the Hispanic/Latino individuals in our study. In the African ancestral component of the admixed individuals, individuals whose grandparents were from Central America clustered separately from individuals whose grandparents were from the Caribbean, and also from reference Yoruba and Mandenka West African individuals. In the European component, individuals whose grandparents were from Puerto Rico diverged partially from other background groups. In the Amerindian ancestral component, individuals clustered into multiple different groups depending on the grandparental country of origin. Therefore, local ancestry estimation provides further insight into the complex genetic structure of US Hispanic/Latino populations, which must be properly accounted for in genotype-phenotype association studies. It also provides a basis for admixture mapping and ancestry-specific allele frequency estimation, which are useful in the identification of risk factors for disease. Copyright © 2016 Browning et al.
Full Text Available We evaluated the association of indices of paraoxonase (PON1 and oxidative status with subclinical cardiovascular disease (CVD in mixed-ancestry South Africans. Participants were 491 adults (126 men who were stratified by diabetes status and body mass index (BMI. Carotid intima-media thickness (CIMT was used as a measure of subclinical CVD. Indices of PON1 and oxidative status were determined by measuring levels and activities (paraoxonase and arylesterase of PON1, antioxidant activity (ferric reducing antioxidant power and trolox equivalent antioxidant capacity, and lipid peroxidation markers (malondialdehyde and oxidized LDL. Diabetic subjects (28.9% displayed a significant decrease in PON1 status and antioxidant activity as well as increase in oxidized LDL and malondialdehyde. A similar profile was apparent across increasing BMI categories. CIMT was higher in diabetic than nondiabetic subjects (P<0.0001 but showed no variation across BMI categories. Overall, CIMT correlated negatively with indices of antioxidant activity and positively with measures of lipid oxidation. Sex, age, BMI, and diabetes altogether explained 29.2% of CIMT, with no further improvement from adding PON1 and/or antioxidant status indices. Though indices of PON1 and oxidative status correlate with CIMT, their measurements may not be useful for identifying subjects at high CVD risk in this population.
Wang, Shengfeng; Huo, Dezheng; Kupfer, Sonia; Alleyne, Dereck; Ogundiran, Temidayo O; Ojengbede, Oladosu; Zheng, Wei; Nathanson, Katherine L; Nemesure, Barbara; Ambs, Stefan; Olopade, Olufunmilayo I; Zheng, Yonglan
The vitamin D related pathway has been evaluated in carcinogenesis but its genetic contribution remains poorly understood. We examined single-nucleotide polymorphisms (SNPs) in the vitamin D related pathway genes using data from a genome-wide association study (GWAS) of breast cancer in the African Diaspora that included 3,686 participants (1,657 cases). Pathway- and gene-level analyses were conducted using the adaptive rank truncated product test. Odds ratios (OR) and 95% confidence intervals (CI) were estimated at SNP-level. After stringent Bonferroni corrections, we observed no significant association between variants in the vitamin D pathway and breast cancer risk at the pathway-, gene-, or SNP-level. In addition, no association was found for either the reported signals from GWASs of vitamin D related traits, or the SNPs within vitamin D receptor (VDR) binding regions. Furthermore, a decrease in genetically predicted 25(OH)D levels by Mendelian randomization was not associated with breast cancer (p = 0.23). However, an association for breast cancer with the pigment synthesis/metabolism pathway almost approached significance (pathway-level p = 0.08), driven primarily by a nonsense SNP rs41302073 in TYRP1, with an OR of 1.54 (95% CI = 1.24-1.91, p adj = 0.007). In conclusion, we found no evidence to support an association between vitamin D status and breast cancer risk in women of African ancestry, suggesting that vitamin D is unlikely to have significant effect on breast carcinogenesis. Interestingly, TYRP1 might be related to breast cancer through a non-vitamin D relevant mechanism but further studies are needed. © 2017 UICC.
Migrations have played an important role in shaping the genetic diversity of human populations. Understanding genomic data thus requires careful modeling of historical gene flow. Here we consider the effect of relatively recent population structure and gene flow and interpret genomes of individuals that have ancestry from multiple source populations as mosaics of segments originating from each population. This article describes general and tractable models for local ancestry patterns with a focus on the length distribution of continuous ancestry tracts and the variance in total ancestry proportions among individuals. The models offer improved agreement with Wright-Fisher simulation data when compared to the state-of-the art and can be used to infer time-dependent migration rates from multiple populations. Considering HapMap African-American (ASW) data, we find that a model with two distinct phases of "European" gene flow significantly improves the modeling of both tract lengths and ancestry variances.
The African Network Operators Group (AfNOG) is a forum for technical cooperation and coordination between African network operators and engineers from the region's universities, research institutions and industry. This year, AfNOG's training workshops and meetings will be held in Rabat, Morocco, between 24 May and 6 ...
Full Text Available There is extensive variation in DNA methylation between individuals and ethnic groups. These differences arise from a combination of genetic and non-genetic influences and potential modifiers include nutritional cues, early life experience, and social and physical environments. Here we compare genome-wide DNA methylation in neonatal cord blood from African American (AA; N = 112 and European American (EA; N = 91 participants of the CANDLE Study (Conditions Affecting Neurocognitive Development and Learning in Early Childhood. Our goal is to determine if there are replicable ancestry-specific methylation patterns that may implicate risk factors for diseases that have differential prevalence between populations. To identify the most robust ancestry-specific CpG sites, we replicate our results in lymphoblastoid cell lines from Yoruba African and CEPH European panels of HapMap. We also evaluate the influence of maternal nutrition--specifically, plasma levels of vitamin D and folate during pregnancy--on methylation in newborns. We define stable ancestry-dependent methylation of genes that include tumor suppressors and cell cycle regulators (e.g., APC, BRCA1, MCC. Overall, there is lower global methylation in African ancestral groups. Plasma levels of 25-hydroxy vitamin D are also considerably lower among AA mothers and about 60% of AA and 40% of EA mothers have concentrations below 20 ng/ml. Using a weighted correlation analysis, we define a network of CpG sites that is jointly modulated by ancestry and maternal vitamin D. Our results show that differences in DNA methylation patterns are remarkably stable and maternal micronutrients can exert an influence on the child epigenome.
Jia, Jing; Wei, Yi-Liang; Qin, Cui-Jiao; Hu, Lan; Wan, Li-Hua; Li, Cai-Xia
Inferring the ancestral origin of DNA samples can be helpful in correcting population stratification in disease association studies or guiding crime investigations. Populations throughout the world vary in appearance features and biological characteristics. Based on this idea, we performed a genome-wide scan for SNPs within genes that are related to physical and biological traits. Using the HapMap database, we screened 52 genes and their flanking regions. Thirty-five SNPs that displayed highly contrasting allele frequencies (F(st)>0.3, linkage disequilibrium r(2)0.001) among Africans, Europeans, and East Asians were selected and validated. A multiplexed assay was developed to genotype these 35 SNPs in 357 individuals from 10 populations worldwide. This panel provided accurate estimates of individual ancestry proportions with balanced discriminatory power among the three continental ancestries: Africans, Europeans, and East Asians. It also proved very effective in evaluating admixed populations living in joint regions of continents (e.g., Uyghurs and Indians) and discriminating some subpopulations within each of the three continents. Structure analysis was performed to establish and evaluate the panel of ancestry-informative markers, and the components of each population were also described to indicate the structural composition. The 21 population structures in our study are consistent with geographic patterns, and individuals were properly assigned to their original ancestral populations with proportion analyses and random match probability calculations. Thus, the panel and its population information will be useful resources to minimize the effects of population stratification in association analyses and to assign the most likely origin of an unknown DNA contributor in forensic investigations. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
Bulbul, O; Filoglu, G; Zorlu, T; Altuncul, H; Freire-Aradas, A; Söchtig, J; Ruiz, Y; Klintschar, M; Triki-Fendri, S; Rebai, A; Phillips, C; Lareu, M V; Carracedo, Á; Schneider, P M
The inference of biogeographical ancestry (BGA) can provide useful information for forensic investigators when there are no suspects to be compared with DNA collected at the crime scene or when no DNA database matches exist. Although public databases are increasing in size and population scope, there is a lack of information regarding genetic variation in Eurasian populations, especially in central regions such as the Middle East. Inhabitants of these regions show a high degree of genetic admixture, characterized by an allele frequency cline running from NW Europe to East Asia. Although a proper differentiation has been established between the cline extremes of western Europe and South Asia, populations geographically located in between, i.e, Middle East and Mediterranean populations, require more detailed study in order to characterize their genetic background as well as to further understand their demographic histories. To initiate these studies, three ancestry informative SNP (AI-SNP) multiplex panels: the SNPforID 34-plex, Eurasiaplex and a novel 33-plex assay were used to describe the ancestry patterns of a total of 24 populations ranging across the longitudinal axis from NW Europe to East Asia. Different ancestry inference approaches, including STRUCTURE, PCA, DAPC and Snipper Bayes analysis, were applied to determine relationships among populations. The structure results show differentiation between continental groups and a NW to SE allele frequency cline running across Eurasian populations. This study adds useful population data that could be used as reference genotypes for future ancestry investigations in forensic cases. The 33-plex assay also includes pigmentation predictive SNPs, but this study primarily focused on Eurasian population differentiation using 33-plex and its combination with the other two AI-SNP sets.
Ducci, Francesca; Roy, Alec; Shen, Pei-Hong; Yuan, Qiaoping; Yuan, Nicole P; Hodgkinson, Colin A; Goldman, Lynn R; Goldman, David
Genetic variation influences differential vulnerability to addiction within populations. However, it remains unclear whether differences in frequencies of vulnerability alleles contribute to disparities between populations and to what extent ancestry correlates with differential exposure to environmental risk factors, including poverty and trauma. The authors used 186 ancestry-informative markers to measure African ancestry in 407 addicts and 457 comparison subjects self-identified as African Americans. The reference group was 1,051 individuals from the Human Genome Diversity Cell Line Panel, which includes 51 diverse populations representing most worldwide genetic diversity. African Americans varied in degrees of African, European, Middle Eastern, and Central Asian genetic heritage. The overall level of African ancestry was actually smaller among cocaine, opiate, and alcohol addicts (proportion=0.76-0.78) than nonaddicted African American comparison subjects (proportion=0.81). African ancestry was associated with living in impoverished neighborhoods, a factor previously associated with risk. There was no association between African ancestry and exposure to childhood abuse or neglect, a factor that strongly predicted all types of addictions. These results suggest that African genetic heritage does not increase the likelihood of genetic risk for addictions. They highlight the complex interrelation between genetic ancestry and social, economic, and environmental conditions and the strong relation of those factors to addiction. Studies of epidemiological samples characterized for genetic ancestry and social, psychological, demographic, economic, cultural, and historical factors are needed to better disentangle the effects of genetic and environmental factors underlying interpopulation differences in vulnerability to addiction and other health disparities.
Cavalcante, Lourianne Nascimento; Stefano, Jose Tadeu; Machado, Mariana V; Mazo, Daniel F; Rabelo, Fabiola; Sandes, Kiyoko Abe; Carrilho, Flair José; Cortez-Pinto, Helena; Lyra, Andre Castro; de Oliveira, Claudia P
To study the association between genetic ancestry, non-alcoholic fatty liver disease (NAFLD) metabolic characteristics in two cohorts of patients, from Brazil and Portugal. We included 131 subjects from Brazil [(n = 45 with simple steatosis (S. Steatosis) and n = 86 with nonalcoholic steatohepatitis (NASH)] and 90 patients from Portugal (n = 66, S. Steatosis; n = 24, NASH). All patients had biopsy-proven NAFLD. In histologic evaluation NAFLD activity score was used to assess histology and more than 5 points defined NASH in this study. Patients were divided into two groups according to histology diagnosis: simple steatosis or non-alcoholic statohepatitis. Genetic ancestry was assessed using real-time polymerase chain reaction. Seven ancestry informative markers (AT3-I/D, LPL, Sb19.3, APO, FY-Null, PV92, and CKMM) with the greatest ethnic-geographical differential frequencies (≥ 48%) were used to define genetic ancestry. Data were analyzed using R PROJECTS software. Ancestry allele frequencies between groups were analyzed by GENEPOP online and the estimation of genetic ancestry contribution was evaluated by ADMIX-95 software. The 5% alpha-error was considered as significant (P 2.5 [NASH 5.3 (70.8%) vs S. Steatosis 4.6 (29.2%) P = 0.04]. In the Portuguese study population, dyslipidemia was present in all patients with NASH (P = 0.03) and hypertension was present in a larger percentage of subjects in the S. Steatosis group (P = 0.003, respectively). The genetic ancestry contribution among Brazilian and Portuguese individuals with NASH was similar to those with S. Steatosis from each cohort (Brazilian cohort: P = 0.75; Portuguese cohort: P = 0.97). Nonetheless, the genetic ancestry contribution of the Brazilian and Portuguese population were different, and a greater European and Amerindian ancestry contribution was detected in the Portuguese population while a higher African genetic ancestry contribution was observed in Brazilian population of both NASH and S
Cavalcante, Lourianne Nascimento; Stefano, Jose Tadeu; Machado, Mariana V; Mazo, Daniel F; Rabelo, Fabiola; Sandes, Kiyoko Abe; Carrilho, Flair José; Cortez-Pinto, Helena; Lyra, Andre Castro; de Oliveira, Claudia P
AIM: To study the association between genetic ancestry, non-alcoholic fatty liver disease (NAFLD) metabolic characteristics in two cohorts of patients, from Brazil and Portugal. METHODS: We included 131 subjects from Brazil [(n = 45 with simple steatosis (S. Steatosis) and n = 86 with nonalcoholic steatohepatitis (NASH)] and 90 patients from Portugal (n = 66, S. Steatosis; n = 24, NASH). All patients had biopsy-proven NAFLD. In histologic evaluation NAFLD activity score was used to assess histology and more than 5 points defined NASH in this study. Patients were divided into two groups according to histology diagnosis: simple steatosis or non-alcoholic statohepatitis. Genetic ancestry was assessed using real-time polymerase chain reaction. Seven ancestry informative markers (AT3-I/D, LPL, Sb19.3, APO, FY-Null, PV92, and CKMM) with the greatest ethnic-geographical differential frequencies (≥ 48%) were used to define genetic ancestry. Data were analyzed using R PROJECTS software. Ancestry allele frequencies between groups were analyzed by GENEPOP online and the estimation of genetic ancestry contribution was evaluated by ADMIX-95 software. The 5% alpha-error was considered as significant (P 2.5 [NASH 5.3 (70.8%) vs S. Steatosis 4.6 (29.2%) P = 0.04]. In the Portuguese study population, dyslipidemia was present in all patients with NASH (P = 0.03) and hypertension was present in a larger percentage of subjects in the S. Steatosis group (P = 0.003, respectively). The genetic ancestry contribution among Brazilian and Portuguese individuals with NASH was similar to those with S. Steatosis from each cohort (Brazilian cohort: P = 0.75; Portuguese cohort: P = 0.97). Nonetheless, the genetic ancestry contribution of the Brazilian and Portuguese population were different, and a greater European and Amerindian ancestry contribution was detected in the Portuguese population while a higher African genetic ancestry contribution was observed in Brazilian population of both NASH
Tashiro, Cathy J
People of mixed ancestry promise to be a significant percentage of the population of the United States in the 21st century. This article describes a qualitative study of 20 older mixed-race adults of African-American-white and Asian-American-white ancestries and focuses on how the participants construct identity. Using grounded theory methodology, racial identity did not emerge as a singular, distinct entity in this study, and five dimensions of racial identity were observed. Significant differences in patterns of identity dimensions were noted for the two mixed groups. Implications for nursing practice are discussed.
This article describes a group counseling intervention promoting academic achievement and ethnic identity development for twenty fifth grade African American elementary students. The Multigroup Ethnic Identity Measure (MEIM) scores of students participating in the treatment group improved significantly over those in the control group. Implications…
Struan F A Grant
Full Text Available Recently an association was demonstrated between the single nucleotide polymorphism (SNP, rs9939609, within the FTO locus and obesity as a consequence of a genome wide association (GWA study of type 2 diabetes in adults. We examined the effects of two perfect surrogates for this SNP plus 11 other SNPs at this locus with respect to our childhood obesity cohort, consisting of both Caucasians and African Americans (AA. Utilizing data from our ongoing GWA study in our cohort of 418 Caucasian obese children (BMI>or=95th percentile, 2,270 Caucasian controls (BMI<95th percentile, 578 AA obese children and 1,424 AA controls, we investigated the association of the previously reported variation at the FTO locus with the childhood form of this disease in both ethnicities. The minor allele frequencies (MAF of rs8050136 and rs3751812 (perfect surrogates for rs9939609 i.e. both r(2 = 1 in the Caucasian cases were 0.448 and 0.443 respectively while they were 0.391 and 0.386 in Caucasian controls respectively, yielding for both an odds ratio (OR of 1.27 (95% CI 1.08-1.47; P = 0.0022. Furthermore, the MAFs of rs8050136 and rs3751812 in the AA cases were 0.449 and 0.115 respectively while they were 0.436 and 0.090 in AA controls respectively, yielding an OR of 1.05 (95% CI 0.91-1.21; P = 0.49 and of 1.31 (95% CI 1.050-1.643; P = 0.017 respectively. Investigating all 13 SNPs present on the Illumina HumanHap550 BeadChip in this region of linkage disequilibrium, rs3751812 was the only SNP conferring significant risk in AA. We have therefore replicated and refined the association in an AA cohort and distilled a tag-SNP, rs3751812, which captures the ancestral origin of the actual mutation. As such, variants in the FTO gene confer a similar magnitude of risk of obesity to children as to their adult counterparts and appear to have a global impact.
Lutz, Sharon M; Cho, Michael H; Young, Kendra; Hersh, Craig P; Castaldi, Peter J; McDonald, Merry-Lynn; Regan, Elizabeth; Mattheisen, Manuel; DeMeo, Dawn L; Parker, Margaret; Foreman, Marilyn; Make, Barry J; Jensen, Robert L; Casaburi, Richard; Lomas, David A; Bhatt, Surya P; Bakke, Per; Gulsvik, Amund; Crapo, James D; Beaty, Terri H; Laird, Nan M; Lange, Christoph; Hokanson, John E; Silverman, Edwin K
Pulmonary function decline is a major contributor to morbidity and mortality among smokers. Post bronchodilator FEV1 and FEV1/FVC ratio are considered the standard assessment of airflow obstruction. We performed a genome-wide association study (GWAS) in 9919 current and former smokers in the COPDGene study (6659 non-Hispanic Whites [NHW] and 3260 African Americans [AA]) to identify associations with spirometric measures (post-bronchodilator FEV1 and FEV1/FVC). We also conducted meta-analysis of FEV1 and FEV1/FVC GWAS in the COPDGene, ECLIPSE, and GenKOLS cohorts (total n = 13,532). Among NHW in the COPDGene cohort, both measures of pulmonary function were significantly associated with SNPs at the 15q25 locus [containing CHRNA3/5, AGPHD1, IREB2, CHRNB4] (lowest p-value = 2.17 × 10(-11)), and FEV1/FVC was associated with a genomic region on chromosome 4 [upstream of HHIP] (lowest p-value = 5.94 × 10(-10)); both regions have been previously associated with COPD. For the meta-analysis, in addition to confirming associations to the regions near CHRNA3/5 and HHIP, genome-wide significant associations were identified for FEV1 on chromosome 1 [TGFB2] (p-value = 8.99 × 10(-9)), 9 [DBH] (p-value = 9.69 × 10(-9)) and 19 [CYP2A6/7] (p-value = 3.49 × 10(-8)) and for FEV1/FVC on chromosome 1 [TGFB2] (p-value = 8.99 × 10(-9)), 4 [FAM13A] (p-value = 3.88 × 10(-12)), 11 [MMP3/12] (p-value = 3.29 × 10(-10)) and 14 [RIN3] (p-value = 5.64 × 10(-9)). In a large genome-wide association study of lung function in smokers, we found genome-wide significant associations at several previously described loci with lung function or COPD. We additionally identified a novel genome-wide significant locus with FEV1 on chromosome 9 [DBH] in a meta-analysis of three study populations.
Fish, Alexandra E; Crawford, Dana C; Capra, John A; Bush, William S
Genomic maps of local ancestry identify ancestry transitions - points on a chromosome where recent recombination events in admixed individuals have joined two different ancestral haplotypes. These events bring together alleles that evolved within separate continential populations, providing a unique opportunity to evaluate the joint effect of these alleles on health outcomes. In this work, we evaluate the impact of genetic variants in the context of nearby local ancestry transitions within a sample of nearly 10,000 adults of African ancestry with traits derived from electronic health records. Genetic data was located using the Metabochip, and used to derive local ancestry. We develop a model that captures the effect of both single variants and local ancestry, and use it to identify examples where local ancestry transitions significantly interact with nearby variants to influence metabolic traits. In our most compelling example, we find that the minor allele of rs16890640 occuring on a European background with a downstream local ancestry transition to African ancestry results in significantly lower mean corpuscular hemoglobin and volume. This finding represents a new way of discovering genetic interactions, and is supported by molecular data that suggest changes to local ancestry may impact local chromatin looping.
McCormack, Shana E; Chesi, Alessandra; Mitchell, Jonathan A; Roy, Sani M; Cousminer, Diana L; Kalkwarf, Heidi J; Lappe, Joan M; Gilsanz, Vicente; Oberfield, Sharon E; Shepherd, John A; Mahboubi, Soroosh; Winer, Karen K; Kelly, Andrea; Grant, Struan Fa; Zemel, Babette S
More rapid skeletal maturation in African-American (AA) children is recognized and generally attributed to an increased prevalence of obesity. The objective of the present study was to evaluate the effects of population ancestry on relative skeletal maturation in healthy, non-obese children and adolescents, accounting for body composition and sexual maturation. To do this, we leveraged a multiethnic, mixed-longitudinal study with annual assessments for up to 7 years (The Bone Mineral Density in Childhood Study and its ancillary cohort) conducted at five US clinical centers. Participants included 1592 children, skeletally immature (45% females, 19% AA) who were aged 5 to 17 years at study entry. The primary outcome measure was relative skeletal maturation as assessed by hand-wrist radiograph. Additional covariates measured included anthropometrics, body composition by dual-energy X-ray absorptiometry (DXA), and Tanner stage of sexual maturation. Using mixed effects longitudinal models, without covariates, advancement in relative skeletal maturation was noted in self-reported AA girls (∼0.33 years, p ancestry groups showed independent positive associations of height, lean mass, fat mass, and puberty with relative skeletal maturation. The effect of ancestry was attenuated but persistent after accounting for covariates: for girls, 0.19 years (ancestry by self-report, p = 0.02) or 0.29 years (ancestry by admixture, p = 0.004); and for boys, 0.20 years (ancestry by self-report, p = 0.004), or 0.29 years (ancestry by admixture, p = 0.004). In summary, we conclude that advancement in relative skeletal maturation was associated with AA ancestry in healthy, non-obese children, independent of growth, body composition, and puberty. Further research into the mechanisms underlying this observation may provide insights into the regulation of skeletal maturation. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and
Full Text Available Gastric cancer is one of the most lethal types of cancer and its incidence varies worldwide, with the Andean region of South America showing high incidence rates. We evaluated the genetic structure of the population from Lima (Peru and performed a case-control genetic association study to test the contribution of African, European, or Native American ancestry to risk for gastric cancer, controlling for the effect of non-genetic factors. A wide set of socioeconomic, dietary, and clinic information was collected for each participant in the study and ancestry was estimated based on 103 ancestry informative markers. Although the urban population from Lima is usually considered as mestizo (i.e., admixed from Africans, Europeans, and Native Americans, we observed a high fraction of Native American ancestry (78.4% for the cases and 74.6% for the controls and a very low African ancestry (<5%. We determined that higher Native American individual ancestry is associated with gastric cancer, but socioeconomic factors associated both with gastric cancer and Native American ethnicity account for this association. Therefore, the high incidence of gastric cancer in Peru does not seem to be related to susceptibility alleles common in this population. Instead, our result suggests a predominant role for ethnic-associated socioeconomic factors and disparities in access to health services. Since Native Americans are a neglected group in genomic studies, we suggest that the population from Lima and other large cities from Western South America with high Native American ancestry background may be convenient targets for epidemiological studies focused on this ethnic group.
The African Union High-Level Audit Panel, appointed in 2007 to audit African Union (AU) organs, was designed to inform decisions on the proposed Union Government, but it assumed a much more significant role than the technical process implied. Using a subaltern perspective in the form of Afrocentricity, the article links ...
Hui, Daniel; Fang, Zhou; Lin, Jerome; Duan, Qing; Li, Yun; Hu, Ming; Chen, Wei
Inferring local ancestry in individuals of mixed ancestry has many applications, most notably in identifying disease-susceptible loci that vary among different ethnic groups. Many software packages are available for inferring local ancestry in admixed individuals. However, most of these existing software packages require specific formatted input files and generate output files in various types, yielding practical inconvenience. We developed a tool set, Local Ancestry Inference Toolkit (LAIT), which can convert standardized files into software-specific input file formats as well as standardize and summarize inference results for four popular local ancestry inference software: HAPMIX, LAMP, LAMP-LD, and ELAI. We tested LAIT using both simulated and real data sets and demonstrated that LAIT provides convenience to run multiple local ancestry inference software. In addition, we evaluated the performance of local ancestry software among different supported software packages, mainly focusing on inference accuracy and computational resources used. We provided a toolkit to facilitate the use of local ancestry inference software, especially for users with limited bioinformatics background.
Doralina Guimarães Brum
Full Text Available BACKGROUND: Neuromyelitis optica (NMO is considered relatively more common in non-Whites, whereas multiple sclerosis (MS presents a high prevalence rate, particularly in Whites from Western countries populations. However, no study has used ancestry informative markers (AIMs to estimate the genetic ancestry contribution to NMO patients. METHODS: Twelve AIMs were selected based on the large allele frequency differences among European, African, and Amerindian populations, in order to investigate the genetic contribution of each ancestral group in 236 patients with MS and NMO, diagnosed using the McDonald and Wingerchuck criteria, respectively. All 128 MS patients were recruited at the Faculty of Medicine of Ribeirão Preto (MS-RP, Southeastern Brazil, as well as 108 healthy bone marrow donors considered as healthy controls. A total of 108 NMO patients were recruited from five Neurology centers from different Brazilian regions, including Ribeirão Preto (NMO-RP. PRINCIPAL FINDINGS: European ancestry contribution was higher in MS-RP than in NMO-RP (78.5% vs. 68.7% patients. In contrast, African ancestry estimates were higher in NMO-RP than in MS-RP (20.5% vs. 12.5% patients. Moreover, principal component analyses showed that groups of NMO patients from different Brazilian regions were clustered close to the European ancestral population. CONCLUSIONS: Our findings demonstrate that European genetic contribution predominates in NMO and MS patients from Brazil.
Santiago-Torres, M; De Dieu Tapsoba, J; Kratz, M; Lampe, J W; Breymeyer, K L; Levy, L; Song, X; Villaseñor, A; Wang, C-Y; Fejerman, L; Neuhouser, M L; Carlson, C S
Certain populations with a large proportion of indigenous American (IA) genetic ancestry may be evolutionarily adapted to traditional diets high in legumes and complex carbohydrates, and may have a detrimental metabolic response to US diets high in refined carbohydrates and added sugars. We tested whether IA ancestry modified the metabolic response to a US versus traditional Mexican diet in a controlled dietary intervention. First and second generation Mexican immigrant women (n=53) completed a randomized crossover feeding trial testing the effects of a US versus traditional Mexican diet. The metabolic response to the diets was measured by fasting serum concentrations of glucose, insulin, insulin-like growth factor-1 (IGF-1), IGF-binding protein-3 (IGFBP-3), adiponectin, C-reactive protein, interleukin-6 and computed homeostasis model assessment for insulin resistance (HOMA IR ). Blood collected at baseline was used for genotyping, and estimation of African, European and IA ancestries with the use of 214 ancestry informative markers. The genetic ancestral background was 56% IA, 38% European and 6% African. Women in the highest IA ancestry tertile (>62%) were shorter in height, less educated and less acculturated to the US lifestyle, and tended to have higher waist-to-hip ratio compared with women in the middle and lowest IA ancestry tertiles, respectively. Compared with the US diet, the traditional Mexican diet tended to reduce glucose, insulin, IGF-1, IGFBP-3 and HOMA IR among women in the middle IA ancestry group (IA ancestry ⩽45-62%), whereas having no effect on biomarkers related to inflammation. We observed modest interactions between IA ancestry and the metabolic response to a US versus traditional Mexican diet among Mexican immigrant women.
Ion microprobe zircon ages, a Nd model age and Rb-Sr whole-rock dates are reported from the high-grade gneiss terrain at Sabaloka on the River Nile north of Khartoum, formally considered to be part of the Archaean/early Proterozoic Nile craton. The granulites, which are of both sedimentary and igneous derivation, occur as remnants in migmatites. Detrital zircon ages range from ≅ 1000 to ≅ 2650 Ma and prove the existence of Archaean to late Proterozoic continental crust in the sedimentary source region. The Nd model age for one sedimentary granulite is between 1.26 (T CHUR ) and 1.70 (T DM ) Ga and provides a mean crustal residence age for the sedimentary precursor. Igneous zircons in enderbitic gneiss crystallized at 719±81 Ma ago, an age that also corresponds to severe Pb loss in the detrital zircons and whic probably reflects the granulite event at Sabaloka. The Rb-Sr data indicate isotropic homogenization at about 700 Ma ago in the granulites and severe post-granulite disturbance at ≅ 570 Ma in the migmatites. We associate this disturbance with hydration, retrograde metamorphism and anatexis that produced undeformed granites ≅ 540 Ma ago. The ≅ 700 Ma granulite event at Sabaloka suggests that this part of the Sudan belongs to the Pan-African Mozambique belt while the ancient Nile craton lay farther west. The gneisses studied here may represent the infrastructure of the ancient African continental margin onto which the juvenile arc assemblage of the Arabian-Nubian shield was accreted during intense horizontal shortening and crustal interstacking of a major collision event. (orig.)
Decker, Jared E.; McKay, Stephanie D.; Rolf, Megan M.; Kim, JaeWoo; Molina Alcalá, Antonio; Sonstegard, Tad S.; Hanotte, Olivier; Götherström, Anders; Seabury, Christopher M.; Praharani, Lisa; Babar, Masroor Ellahi; Correia de Almeida Regitano, Luciana; Yildiz, Mehmet Ali; Heaton, Michael P.; Liu, Wan-Sheng; Lei, Chu-Zhao; Reecy, James M.; Saif-Ur-Rehman, Muhammad; Schnabel, Robert D.; Taylor, Jeremy F.
The domestication and development of cattle has considerably impacted human societies, but the histories of cattle breeds and populations have been poorly understood especially for African, Asian, and American breeds. Using genotypes from 43,043 autosomal single nucleotide polymorphism markers scored in 1,543 animals, we evaluate the population structure of 134 domesticated bovid breeds. Regardless of the analytical method or sample subset, the three major groups of Asian indicine, Eurasian taurine, and African taurine were consistently observed. Patterns of geographic dispersal resulting from co-migration with humans and exportation are recognizable in phylogenetic networks. All analytical methods reveal patterns of hybridization which occurred after divergence. Using 19 breeds, we map the cline of indicine introgression into Africa. We infer that African taurine possess a large portion of wild African auroch ancestry, causing their divergence from Eurasian taurine. We detect exportation patterns in Asia and identify a cline of Eurasian taurine/indicine hybridization in Asia. We also identify the influence of species other than Bos taurus taurus and B. t. indicus in the formation of Asian breeds. We detect the pronounced influence of Shorthorn cattle in the formation of European breeds. Iberian and Italian cattle possess introgression from African taurine. American Criollo cattle originate from Iberia, and not directly from Africa with African ancestry inherited via Iberian ancestors. Indicine introgression into American cattle occurred in the Americas, and not Europe. We argue that cattle migration, movement and trading followed by admixture have been important forces in shaping modern bovine genomic variation. PMID:24675901
Clark, Melissa A; Guatelli-Steinberg, Debbie; Hubbe, Mark; Stout, Sam
Previous studies suggest that palate shape is a useful indicator of biological ancestry in human remains. This study evaluates interobserver error in ancestry estimation using palate shape and explores palate shape variation in Gullah (descendants of West Africans) and Seminole (Indigenous American) population samples using geometric morphometric analysis. Ten participants were asked to ascribe biological ancestry and shape to 28 dental casts based on a classification scheme employed in previous studies. The mean correct classification was 42.0%, indicating that the likelihood of assigning the correct ancestry is very poor and not significantly different from random assignment (p = 0.12). The accuracy analysis based on categorical classification of the casts was complemented by geometric morphometric analysis of nine 3D landmarks reflecting palate shape of 158 casts. Principal component analysis results show no difference between populations regarding palate shape, and cross-validated discriminant function analysis correctly classified only 62.0% of the specimens. Combined, these results show that previous methods to estimate ancestry are inaccurate and that this inaccuracy is probably due to a lack of palate shape differences between groups, rather than limitation of the analytical method per se. Therefore, we recommend caution should be used when choosing to apply the analysis of palate shape in forensically relevant contexts. © 2015 American Academy of Forensic Sciences.
Jacob B Hall
Full Text Available Recently, the development of biobanks linked to electronic medical records has presented new opportunities for genetic and epidemiological research. Studies based on these resources, however, present unique challenges, including the accurate assignment of individual-level population ancestry. In this work we examine the accuracy of administratively-assigned race in diverse populations by comparing assigned races to genetically-defined ancestry estimates. Using 220 ancestry informative markers, we generated principal components for patients in our dataset, which were used to cluster patients into groups based on genetic ancestry. Consistent with other studies, we find a strong overall agreement (Kappa = 0.872 between genetic ancestry and assigned race, with higher rates of agreement for African-descent and European-descent assignments, and reduced agreement for Hispanic, East Asian-descent, and South Asian-descent assignments. These results suggest caution when selecting study samples of non-African and non-European backgrounds when administratively-assigned race from biobanks is used.
Groen, T.A.; Langevelde, van F.; Vijver, van de C.A.D.M.; Raad, de A.L.; Leeuw, de J.; Prins, H.H.T.
This study analyses possible relationships between natural processes taking place in savannas and the tree patterns found in savannas. This can lead to new hypotheses about which processes are driving savanna physiognomy. To do so tree patterns were quantified for African savannas from historical
Corti, G.; van Wijk, J.W.; Cloetingh, S.A.P.L.; Morley, C.
The western branch of the East African Rift is composed of an arcuate succession of elongate asymmetric basins, which differ in terms of interaction geometry, fault architecture and kinematics, and patterns of uplift/subsidence and erosion/sedimentation. The basins are located within Proterozoic
Koptev, Alexander; Burov, Evgueni; Calais, Eric; Leroy, Sylvie; Gerya, Taras; Guillou-Frottier, Laurent; Cloetingh, Sierd
The East African Rift system (EARS) provides a unique system with the juxtaposition of two contrasting yet simultaneously formed rift branches, the eastern, magma-rich, and the western, magma-poor, on either sides of the old thick Tanzanian craton embedded in a younger lithosphere. Data on the
Thomas E. Guensburg
Full Text Available At present, a debate in the paleontologic literature focuses on whether or not the immediate ancestry of the Crinoidea lies in an unidentified member of the Blastozoa, which includes eocrinoids and an assemblage known variously as the “cystoids”. Those proposing to derive crinoids from within the blastozoans have recently argued for homologies in the construction of the oral region of certain derived taxa from both groups. An opposing viewpoint, outlined here, finds evidence that aside from plesiomorphies, proposed similarities are superficial and homoplastic. We suggest these superficialities represent convergent adaptive strategies. Earliest crinoids express ambulacral traits unlike any blastozoan but that are expressed in the only other pentaradial echinoderms with a known record early enough to be considered in the context of crinoid origins, edrioasteroids and edrioasteroid-like stem echinoderms.
Duan, Qing; Xu, Zheng; Raffield, Laura M; Chang, Suhua; Wu, Di; Lange, Ethan M; Reiner, Alex P; Li, Yun
Genetic association studies in admixed populations allow us to gain deeper understanding of the genetic architecture of human diseases and traits. However, population stratification, complicated linkage disequilibrium (LD) patterns, and the complex interplay of allelic and ancestry effects on phenotypic traits pose challenges in such analyses. These issues may lead to detecting spurious associations and/or result in reduced statistical power. Fortunately, if handled appropriately, these same challenges provide unique opportunities for gene mapping. To address these challenges and to take these opportunities, we propose a robust and powerful two-step testing procedure Local Ancestry Adjusted Allelic (LAAA) association. In the first step, LAAA robustly captures associations due to allelic effect, ancestry effect, and interaction effect, allowing detection of effect heterogeneity across ancestral populations. In the second step, LAAA identifies the source of association, namely allelic, ancestry, or the combination. By jointly modeling allele, local ancestry, and ancestry-specific allelic effects, LAAA is highly powerful in capturing the presence of interaction between ancestry and allele effect. We evaluated the validity and statistical power of LAAA through simulations over a broad spectrum of scenarios. We further illustrated its usefulness by application to the Candidate Gene Association Resource (CARe) African American participants for association with hemoglobin levels. We were able to replicate independent groups' previously identified loci that would have been missed in CARe without joint testing. Moreover, the loci, for which LAAA detected potential effect heterogeneity, were replicated among African Americans from the Women's Health Initiative study. LAAA is freely available at https://yunliweb.its.unc.edu/LAAA. © 2017 WILEY PERIODICALS, INC.
Lima-Costa, M Fernanda; Macinko, James; Mambrini, Juliana Vaz de Melo; Cesar, Cibele C; Peixoto, Sérgio V; Magalhães, Wagner C S; Horta, Bernardo L; Barreto, Mauricio; Castro-Costa, Erico; Firmo, Josélia O A; Proietti, Fernando A; Leal, Thiago Peixoto; Rodrigues, Maira R; Pereira, Alexandre; Tarazona-Santos, Eduardo
Self-rated health (SRH) has strong predictive value for mortality in different contexts and cultures, but there is inconsistent evidence on ethnoracial disparities in SRH in Latin America, possibly due to the complexity surrounding ethnoracial self-classification. We used 370,539 Single Nucleotide Polymorphisms (SNPs) to examine the association between individual genomic proportions of African, European and Native American ancestry, and ethnoracial self-classification, with baseline and 10-year SRH trajectories in 1,311 community dwelling older Brazilians. We also examined whether genomic ancestry and ethnoracial self-classification affect the predictive value of SRH for subsequent mortality. European ancestry predominated among participants, followed by African and Native American (median = 84.0%, 9.6% and 5.3%, respectively); the prevalence of Non-White (Mixed and Black) was 39.8%. Persons at higher levels of African and Native American genomic ancestry, and those self-identified as Non-White, were more likely to report poor health than other groups, even after controlling for socioeconomic conditions and an array of self-reported and objective physical health measures. Increased risks for mortality associated with worse SRH trajectories were strong and remarkably similar (hazard ratio ~3) across all genomic ancestry and ethno-racial groups. Our results demonstrated for the first time that higher levels of African and Native American genomic ancestry--and the inverse for European ancestry--were strongly correlated with worse SRH in a Latin American admixed population. Both genomic ancestry and ethnoracial self-classification did not modify the strong association between baseline SRH or SRH trajectory, and subsequent mortality.
mass atrocities, the members of ECOWAS were effectively forced to shift their security stance from conflict management to conflict prevention. 8 In...tack with regards to their role in conflict management across the continent. Following the formation of the AU in the early 2000’s, the AU’s new...Washington, DC: GPO, June 2012). 2 Ibid., 2. 3 Williams, Paul D, “The African Union’s Conflict Management Capabilities,” Council on Foreign
Full Text Available The incidence of chronic kidney disease varies by ethnic group in the USA, with African Americans displaying a two-fold higher rate than European Americans. One of the two defining variables underlying staging of chronic kidney disease is the glomerular filtration rate. Meta-analysis in individuals of European ancestry has identified 23 genetic loci associated with the estimated glomerular filtration rate (eGFR. We conducted a follow-up study of these 23 genetic loci using a population-based sample of 1,018 unrelated admixed African Americans. We included in our follow-up study two variants in APOL1 associated with end-stage kidney disease discovered by admixture mapping in admixed African Americans. To address confounding due to admixture, we estimated local ancestry at each marker and global ancestry. We performed regression analysis stratified by local ancestry and combined the resulting regression estimates across ancestry strata using an inverse variance-weighted fixed effects model. We found that 11 of the 24 loci were significantly associated with eGFR in our sample. The effect size estimates were not significantly different between the subgroups of individuals with two copies of African ancestry vs. two copies of European ancestry for any of the 11 loci. In contrast, allele frequencies were significantly different at 10 of the 11 loci. Collectively, the 11 loci, including four secondary signals revealed by conditional analyses, explained 14.2% of the phenotypic variance in eGFR, in contrast to the 1.4% explained by the 24 loci in individuals of European ancestry. Our findings provide insight into the genetic basis of variation in renal function among admixed African Americans.
Briers, N; Briers, T M; Becker, P J; Steyn, M
In children, craniofacial changes due to facial growth complicate facial approximations and require specific knowledge of soft tissue thicknesses (STT). The lack of South African juvenile STT standards of particular age groups, sex and ancestry is problematic. According to forensic artists in the South African Police Service the use of African-American values to reconstruct faces of Black South African children yields poor results. In order to perform a facial approximation that presents a true reflection of the child in question, information regarding differences in facial soft tissue at different ages, sexes and ancestry groups is needed. The aims of this study were to provide data on STT of South African Black and Coloured children and to assess differences in STT with respect to age, sex and ancestry. STT was measured using cephalograms of South African children (n=388), aged 6-13 years. After digitizing the images, STT measurements were taken at ten mid-facial landmarks from each image using the iTEM measuring program. STT comparisons between groups per age, sex and ancestry were statistically analyzed. The results showed that STT differences at lower face landmarks are more pronounced in age groups per ancestry as opposed to differences per age and sex. Generally, an increase in STT was seen between 6-10 year old groups and 11-13 year old groups, regardless of ancestry and sex, at the midphiltrum, labiale inferius, pogonion, and beneath chin landmarks. This research created a reference dataset for STT of South African children of Black and Coloured ancestry per age and sex that will be useful for facial reconstruction/approximation of juvenile remains. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Santos, Carla; Phillips, Christopher; Fondevila, Manuel; Daniel, Runa; van Oorschot, Roland A H; Burchard, Esteban G; Schanfield, Moses S; Souto, Luis; Uacyisrael, Jolame; Via, Marc; Carracedo, Ángel; Lareu, Maria V
The analysis of human population variation is an area of considerable interest in the forensic, medical genetics and anthropological fields. Several forensic single nucleotide polymorphism (SNP) assays provide ancestry-informative genotypes in sensitive tests designed to work with limited DNA samples, including a 34-SNP multiplex differentiating African, European and East Asian ancestries. Although assays capable of differentiating Oceanian ancestry at a global scale have become available, this study describes markers compiled specifically for differentiation of Oceanian populations. A sensitive multiplex assay, termed Pacifiplex, was developed and optimized in a small-scale test applicable to forensic analyses. The Pacifiplex assay comprises 29 ancestry-informative marker SNPs (AIM-SNPs) selected to complement the 34-plex test, that in a combined set distinguish Africans, Europeans, East Asians and Oceanians. Nine Pacific region study populations were genotyped with both SNP assays, then compared to four reference population groups from the HGDP-CEPH human diversity panel. STRUCTURE analyses estimated population cluster membership proportions that aligned with the patterns of variation suggested for each study population's currently inferred demographic histories. Aboriginal Taiwanese and Philippine samples indicated high East Asian ancestry components, Papua New Guinean and Aboriginal Australians samples were predominantly Oceanian, while other populations displayed cluster patterns explained by the distribution of divergence amongst Melanesians, Polynesians and Micronesians. Genotype data from Pacifiplex and 34-plex tests is particularly well suited to analysis of Australian Aboriginal populations and when combined with Y and mitochondrial DNA variation will provide a powerful set of markers for ancestry inference applied to modern Australian demographic profiles. On a broader geographic scale, Pacifiplex adds highly informative data for inferring the ancestry
Retief, D H [University of the Witwatersrand, Johannesburg (South Africa). Dental Research Unit; Turkstra, J [University of Fort Hare, Alice (South Africa). Department of Chemistry; Cleaton-Jones, P E; Biddlecombe, F [Atomic Energy Board, Pelindaba, Pretoria (South Africa). Chemistry Div.
The mineral composition of pooled bulk enamel from Black and White South Africans respectively, resident in the Johannesburg area, was determined by neutron activation analysis and high resolution gamma spectromety. The differences between the concentrations of Ca, Cl, Mg, Na, Br and Co in the enamel of the two population groups were apparently not significant. There was a trend for the concentrations of Al, Ag, Au, Fe, Sb, and Zn to be higher in the enamel from the White subjects and for the concentrations of Mn, Se and Sr to be higher in the enamel from the Black subjects.
Salard-Cheboldaeff, M.; Dejax, J.
The succession of spore-pollen assemblages during the Cretaceous and Tertiary, as defined in each of the basin from Senegal to Angola, gives the possibility to consider the intertropical African flora evolution for the past 120 M.a. During the Early Cretaceous, xeric-adapted gymnosperms and various ferns were predominant the flora which nevertheless comprises previously unknown early angiosperm pollen. During the Middle Cretaceous, gymnospers were gradually replaced by angiosperms; these became more and more abundant, along with the diversification of new genera and species. During the Paleocene, the radiation of the monocotyledons (mainly that of the palm-trees) as well as a greater diversification among the dicotyledons and ferms are noteworthy. Since gymnosperms had almost disappeared by the Eocene, the diversification of the dicotyledons went on until the neogene, when all extinct pollen types are already present. These important modifications of the vegetation reflect evolutionary trends as well as climatic changes during the Cretaceous: the climate, firstly hot, dry and perhaps arid, did probably induced salt deposition, and later became gradually more humid under oceanic influences which arose in connection with the Gondwana break-up.
Klingelhoefer, Frauke; Biari, Youssef; Sahabi, Mohamed; Aslanian, Daniel; Schnabel, Michael; Matias, Luis; Benabdellouahed, Massinissa; Funck, Thomas; Gutscher, Marc-André; Reichert, Christian; Austin, James A.
Deep seismic data represent a key to understand the geometry and mechanism of continental rifting. The passive continental margin of NW-Africa is one of the oldest on earth, formed during the Upper Triassic-Lower Liassic rifting of the central Atlantic Ocean over 200 Ma. We present new and existing wide-angle and reflection seismic data from four study regions along the margin located in the south offshore DAKHLA, on the central continental margin offshore Safi, in the northern Moroccan salt basin, and in the Gulf of Cadiz. The thickness of unthinned continental crust decreases from 36 km in the North to about 27 km in the South. Crustal thinning takes place over a region of 150 km in the north and only 70 km in the south. The North Moroccan Basin is underlain by highly thinned continental crust of only 6-8 km thickness. The ocean-continent transition zone shows a variable width between 40 and 70 km and is characterized by seismic velocities in between those of typical oceanic and thinned continental crust. The neighbouring oceanic crust is characterized by a thickness of 7-8 km along the complete margin. Relatively high velocities of up to 7.5 km/s have been imaged between magnetic anomalies S1 and M25, and are probably related to changes in the spreading velocities at the time of the Kimmeridgian/Tithonian plate reorganization. Volcanic activity seems to be mostly confined to the region next to the Canary Islands, and is thus not related to the initial opening of the ocean, which was associated to only weak volcanism. Comparison with the conjugate margin off Nova Scotia shows comparable continental crustal structures, but 2-3 km thinner oceanic crust on the American side than on the African margin.
Rishishwar, Lavanya; Conley, Andrew B.; Wigington, Charles H.; Wang, Lu; Valderrama-Aguirre, Augusto; King Jordan, I.
The human dimension of the Columbian Exchange entailed substantial genetic admixture between ancestral source populations from Africa, the Americas and Europe, which had evolved separately for many thousands of years. We sought to address the implications of the creation of admixed American genomes, containing novel allelic combinations, for human health and fitness via analysis of an admixed Colombian population from Medellin. Colombian genomes from Medellin show a wide range of three-way admixture contributions from ancestral source populations. The primary ancestry component for the population is European (average = 74.6%, range = 45.0%–96.7%), followed by Native American (average = 18.1%, range = 2.1%–33.3%) and African (average = 7.3%, range = 0.2%–38.6%). Locus-specific patterns of ancestry were evaluated to search for genomic regions that are enriched across the population for particular ancestry contributions. Adaptive and innate immune system related genes and pathways are particularly over-represented among ancestry-enriched segments, including genes (HLA-B and MAPK10) that are involved in defense against endemic pathogens such as malaria. Genes that encode functions related to skin pigmentation (SCL4A5) and cutaneous glands (EDAR) are also found in regions with anomalous ancestry patterns. These results suggest the possibility that ancestry-specific loci were differentially retained in the modern admixed Colombian population based on their utility in the New World environment. PMID:26197429
Full Text Available The years since 9/11 have been characterised by the increasing threat of terrorist action in the Middle East and South Asia. Yet Sub-Saharan Africa was has also become a region of concern. In 1998, it had been the scene of two Al-Qaeda attacks against US embassies; besides Africa is home to large Muslim populations. Since 9/11 African violent non-state groups unrelated to Al- Qaeda or to the wider Islamist movement have been recast as terrorist organisations. These groups primarily operate in conflict zones, an area of research that traditionally has not been the main focus of Terrorism Studies. Protagonists have at various times been called freedom fighters, rebels, warlords, insurgents or simply violent gangs. This article looks at the most notorious of African groups – the Lord’s Resistance Army (LRA. It argues that some groups like the LRA have been recast as terrorist organisations not because of a change in their activities but due to a change in the geo-strategic environment they found themselves in the post-9/11 period. The LRA’s ideology and tactics will be judged against a broad definition of terrorism in order to test whether the group can, in an objective way, be called a terrorist organisation. It is concluded that the LRA is too ambiguous an organisation to be simply labelled in such a way. It is also suggested that the terrorism label has in fact been an obstacle to attempts to end successfully a confrontation that is now going into its 24th year.
Full Text Available The East African Rift system (EARS provides a unique system with the juxtaposition of two contrasting yet simultaneously formed rift branches, the eastern, magma-rich, and the western, magma-poor, on either sides of the old thick Tanzanian craton embedded in a younger lithosphere. Data on the pre-rift, syn-rift and post-rift far-field volcanic and tectonic activity show that the EARS formed in the context of the interaction between a deep mantle plume and a horizontally and vertically heterogeneous lithosphere under far-field tectonic extension. We bring quantitative insights into this evolution by implementing high-resolution 3D thermo-mechanical numerical deformation models of a lithosphere of realistic rheology. The models focus on the central part of the EARS. We explore scenarios of plume-lithosphere interaction with plumes of various size and initial position rising beneath a tectonically pre-stretched lithosphere. We test the impact of the inherited rheological discontinuities (suture zones along the craton borders, of the rheological structure, of lithosphere plate thickness variations, and of physical and mechanical contrasts between the craton and the embedding lithosphere. Our experiments indicate that the ascending plume material is deflected by the cratonic keel and preferentially channeled along one of its sides, leading to the formation of a large rift zone along the eastern side of the craton, with significant magmatic activity and substantial melt amount derived from the mantle plume material. We show that the observed asymmetry of the central EARS, with coeval amagmatic (western and magmatic (eastern branches, can be explained by the splitting of warm material rising from a broad plume head whose initial position is slightly shifted to the eastern side of the craton. In that case, neither a mechanical weakness of the contact between the craton and the embedding lithosphere nor the presence of second plume are required to
Doebrich, J.L.; Al-Jehani, A. M.; Siddiqui, A.A.; Hayes, T.S.; Wooden, J.L.; Johnson, P.R.
characteristics of the Ar Rayn terrane are analogous to the Andean continental margin of Chile, with opposite subduction polarity. The Ar Rayn terrane represents a continental margin arc that lay above a west-dipping subduction zone along a continental block represented by the Afif composite terrane. The concentration of epithermal, porphyry Cu and IOCG mineral systems, of central arc affiliation, along the AAF suggests that the AAF is not an ophiolitic suture zone, but originated as a major intra-arc fault that localized magmatism and mineralization. West-directed oblique subduction and ultimate collision with a land mass from the east (East Gondwana?) resulted in major transcurrent displacement along the AAF, bringing the eastern part of the arc terrane to its present exposed position, juxtaposed across the AAF against a back-arc basin assemblage represented by the Abt schist of the Ad Dawadimi terrane. Our findings indicate that arc formation and accretionary processes in the Arabian shield were still ongoing into the latest Neoproterozoic (Ediacaran), to about 620-600 Ma, and lead us to conclude that evolution of the Ar Rayn terrane (arc formation, accretion, syn- to postorogenic plutonism) defines a final stage of assembly of the Gondwana supercontinent along the northeastern margin of the East African orogen. ?? 2007 Elsevier B.V. All rights reserved.
Remis, M J
The ranging and grouping patterns of a gorilla group were studied during 27 months from 1990-1992 at the Bai Hokou study site, Central African Republic. The study group ranged far daily (average = 2.3 km/day) and had a large home range (22.9 km2), relative to mountain gorillas, and ranging patterns differed between years. During 1990-1992, the bimale study group foraged less cohesively and had more flexible grouping patterns than mountain gorillas. The study group sometimes split into two distinct foraging subgroups, each led by a silverback, and these subgroups occasionally slept apart (mean = 950 m apart). Lowland gorillas rely on many of the same fruit resources as sympatric chimpanzees, and under certain demographic situations gorillas, like sympatric chimpanzees, may adapt their foraging group size to reduce intragroup feeding competition. However, the fiber content of the lowland gorilla diet likely relaxes constraints on foraging party size and facilitates group cohesion relative to chimpanzees.
Full Text Available Several authors have proposed haplotype motifs based on site variants at the mitochondrial genome (mtDNA and the non-recombining portion of the Y chromosome (NRY to trace the genealogies of Jewish people. Here, we analyzed their main approaches and test the feasibility of adopting motifs as ancestry markers through construction of a large database of mtDNA and NRY haplotypes from public genetic genealogical repositories. We verified the reliability of Jewish ancestry prediction based on the Cohen and Levite Modal Haplotypes in their classical 6 STR marker format or in the extended 12 STR format, as well as four founder mtDNA lineages (HVS-I segments accounting for about 40% of the current population of Ashkenazi Jews. For this purpose we compared haplotype composition in individuals of self-reported Jewish ancestry with the rest of European, African or Middle Eastern samples, to test for non-random association of ethno-geographic groups and haplotypes. Overall, NRY and mtDNA based motifs, previously reported to differentiate between groups, were found to be more represented in Jewish compared to non-Jewish groups. However, this seems to stem from common ancestors of Jewish lineages being rather recent respect to ancestors of non-Jewish lineages with the same haplotype signatures. Moreover, the polyphyly of haplotypes which contain the proposed motifs and the misuse of constant mutation rates heavily affected previous attempts to correctly dating the origin of common ancestries. Accordingly, our results stress the limitations of using the above haplotype motifs as reliable Jewish ancestry predictors and show its inadequacy for forensic or genealogical purposes.
Full Text Available Christian mission in African context, especially in the post-colonial era, can no longer afford to turn a blind eye to the fact that it co-exists with the African traditional religion(s. This article deals with the creative tension that exists between Christian mission and African worldview(s in the area of life after death. In this article we presuppose more than a mere dialogue between ideas or individuals or denominations, but the encounter of different praxes. This article concludes that the dead in the worldviews are not dead; they continue to live in a different form and they continue to speak from the grave even though their praxes differ.
Full Text Available The tropical African monophyletic group of Carex subsect. Elatae (sect. Spirostachyae is distributed in continental tropical Africa, Madagascar, the Mascarene archipelago, and Bioko Island (32 km off the coast of West Africa, in the Gulf of Guinea. The first monographic treatment of this Carex group, as well as of the tribe Cariceae, was published by Kükenthal (as sect. Elatae Kük.. Recently, the first molecular (nrDNA, cpDNA phylogeny of Carex sect. Elatae has been published, which also included the species of sect. Spirostachyae. In the resulting consensus trees, most species of sect. Elatae were embedded within core Spirostachyae and so this section was joined with sect. Spirostachyae as subsect. Elatae. Within subsect. Elatae, several groups were described, one of which was termed the “tropical African group”. Here we present a taxonomic revision of this group, based on more than 280 vouchers from 29 herbaria as well as in field trips in Tropical Africa. In the revision, we recognise 12 species (16 taxa within the tropical African group, and so have somewhat modified our previous view, in which 10 species, 12 taxa were listed. One new species from Tanzania is included in this treatment, C. uluguruensis Luceño & M. Escudero. Several combinations are made, C. cyrtosaccus is treated as a synonym of C. vallis-rosetto and, finally, the binomial C. greenwayi has been recognised.Las especies de la subsección Elatae (sección Spirostachyae del género Carex que se distribuyen por África tropical continental, Madagascar, el archipiélago de las Mascareñas y la isla de Bioko (a 32 km del litoral de África occidental, en el golfo de Guinea forman un grupo monofilético. El primer tratamiento taxonómico de este grupo de cárices, así como de la tribu Cariceae en su conjunto, fue elaborado por Kükenthal (sección Elatae Kük.; recientemente, se ha publicado el primer estudio de filogenia molecular (nrDNA, cpDNA de los táxones de este grupo
Wheaton, Joe E.; Hertzfeld, Jennifer
Examines effects of ancestry and severity of disability of vocational rehabilitation consumers. European Americans, individuals with higher costs, and persons who received assistive technology were more likely to be closed rehabilitated. Individuals from other ancestry groups, who were coded severely disabled, or who had been in the system for…
Eduardoff, M; Gross, T E; Santos, C; de la Puente, M; Ballard, D; Strobl, C; Børsting, C; Morling, N; Fusco, L; Hussing, C; Egyed, B; Souto, L; Uacyisrael, J; Syndercombe Court, D; Carracedo, Á; Lareu, M V; Schneider, P M; Parson, W; Phillips, C; Parson, W; Phillips, C
The EUROFORGEN Global ancestry-informative SNP (AIM-SNPs) panel is a forensic multiplex of 128 markers designed to differentiate an individual's ancestry from amongst the five continental population groups of Africa, Europe, East Asia, Native America, and Oceania. A custom multiplex of AmpliSeq™ PCR primers was designed for the Global AIM-SNPs to perform massively parallel sequencing using the Ion PGM™ system. This study assessed individual SNP genotyping precision using the Ion PGM™, the forensic sensitivity of the multiplex using dilution series, degraded DNA plus simple mixtures, and the ancestry differentiation power of the final panel design, which required substitution of three original ancestry-informative SNPs with alternatives. Fourteen populations that had not been previously analyzed were genotyped using the custom multiplex and these studies allowed assessment of genotyping performance by comparison of data across five laboratories. Results indicate a low level of genotyping error can still occur from sequence misalignment caused by homopolymeric tracts close to the target SNP, despite careful scrutiny of candidate SNPs at the design stage. Such sequence misalignment required the exclusion of component SNP rs2080161 from the Global AIM-SNPs panel. However, the overall genotyping precision and sensitivity of this custom multiplex indicates the Ion PGM™ assay for the Global AIM-SNPs is highly suitable for forensic ancestry analysis with massively parallel sequencing. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Parathyras, John; Gebhardt, Stefan; Hillermann-Rebello, Renate; Grobbelaar, Nelis; Venter, Mauritz; Warnich, Louise
South Africa, like many other Southern African countries, has one of the highest HIV infection rates in the world and many individuals consequently receive antiretroviral therapy (ART). However, knowledge regarding (i) the prevalence of functional single nucleotide polymorphisms (SNPs) in pharmacologically relevant genes, and (ii) variance in pharmacotherapy both within and between different populations and ethnic groups is limited. The aim of this study was to determine whether selected polymorphisms in cytochrome P450 (CYP) genes (CYP2B6 and CYP3A4) and the multidrug-resistance 1 (ABCB1) gene underlie altered antiretroviral (ARV) drug response in two South African populations. DNA samples from 182 HIV-positive individuals of Mixed-Ancestry and Xhosa ethnicity on ART were genotyped for the A-392G SNP in CYP3A4, the G516T and A785G SNPs in CYP2B6, and the T-129C, C1236T, G2677T/A and C3435T SNPs in ABCB1. Univariate two-way analysis of variance (ANOVA) testing revealed no apparent effect of ethnicity on immune recovery (in terms of CD4-cell count) in response to ART. Univariate one-way ANOVA testing revealed a discernible effect of genotype on immune recovery in the cases of the T-129C (P=0.03) and G2677A (P<0.01) polymorphisms in the ABCB1 gene. This study serves as a basis for better understanding and possible prediction of pharmacogenetic risk profiles and drug response in individuals and ethnic groups in South Africa.
Brown, Robert; Pasaniuc, Bogdan
Inferring the ancestry at each locus in the genome of recently admixed individuals (e.g., Latino Americans) plays a major role in medical and population genetic inferences, ranging from finding disease-risk loci, to inferring recombination rates, to mapping missing contigs in the human genome. Although many methods for local ancestry inference have been proposed, most are designed for use with genotyping arrays and fail to make use of the full spectrum of data available from sequencing. In addition, current haplotype-based approaches are very computationally demanding, requiring large computational time for moderately large sample sizes. Here we present new methods for local ancestry inference that leverage continent-specific variants (CSVs) to attain increased performance over existing approaches in sequenced admixed genomes. A key feature of our approach is that it incorporates the admixed genomes themselves jointly with public datasets, such as 1000 Genomes, to improve the accuracy of CSV calling. We use simulations to show that our approach attains accuracy similar to widely used computationally intensive haplotype-based approaches with large decreases in runtime. Most importantly, we show that our method recovers comparable local ancestries, as the 1000 Genomes consensus local ancestry calls in the real admixed individuals from the 1000 Genomes Project. We extend our approach to account for low-coverage sequencing and show that accurate local ancestry inference can be attained at low sequencing coverage. Finally, we generalize CSVs to sub-continental population-specific variants (sCSVs) and show that in some cases it is possible to determine the sub-continental ancestry for short chromosomal segments on the basis of sCSVs. PMID:24743331
Full Text Available The genus Vitis (the grapevine is a group of highly diverse, diploid woody perennial vines consisting of approximately 60 species from across the northern hemisphere. It is the world's most valuable horticultural crop with ~8 million hectares planted, most of which is processed into wine. To gain insights into the use of wild Vitis species during the past century of interspecific grape breeding and to provide a foundation for marker-assisted breeding programmes, we present a principal components analysis (PCA based ancestry estimation method to calculate admixture proportions of hybrid grapes in the United States Department of Agriculture grape germplasm collection using genome-wide polymorphism data. We find that grape breeders have backcrossed to both the domesticated V. vinifera and wild Vitis species and that reasonably accurate genome-wide ancestry estimation can be performed on interspecific Vitis hybrids using a panel of fewer than 50 ancestry informative markers (AIMs. We compare measures of ancestry informativeness used in selecting SNP panels for two-way admixture estimation, and verify the accuracy of our method on simulated populations of admixed offspring. Our method of ancestry deconvolution provides a first step towards selection at the seed or seedling stage for desirable admixture profiles, which will facilitate marker-assisted breeding that aims to introgress traits from wild Vitis species while retaining the desirable characteristics of elite V. vinifera cultivars.
Sawler, Jason; Reisch, Bruce; Aradhya, Mallikarjuna K.; Prins, Bernard; Zhong, Gan-Yuan; Schwaninger, Heidi; Simon, Charles; Buckler, Edward; Myles, Sean
The genus Vitis (the grapevine) is a group of highly diverse, diploid woody perennial vines consisting of approximately 60 species from across the northern hemisphere. It is the world’s most valuable horticultural crop with ~8 million hectares planted, most of which is processed into wine. To gain insights into the use of wild Vitis species during the past century of interspecific grape breeding and to provide a foundation for marker-assisted breeding programmes, we present a principal components analysis (PCA) based ancestry estimation method to calculate admixture proportions of hybrid grapes in the United States Department of Agriculture grape germplasm collection using genome-wide polymorphism data. We find that grape breeders have backcrossed to both the domesticated V. vinifera and wild Vitis species and that reasonably accurate genome-wide ancestry estimation can be performed on interspecific Vitis hybrids using a panel of fewer than 50 ancestry informative markers (AIMs). We compare measures of ancestry informativeness used in selecting SNP panels for two-way admixture estimation, and verify the accuracy of our method on simulated populations of admixed offspring. Our method of ancestry deconvolution provides a first step towards selection at the seed or seedling stage for desirable admixture profiles, which will facilitate marker-assisted breeding that aims to introgress traits from wild Vitis species while retaining the desirable characteristics of elite V. vinifera cultivars. PMID:24244717
Tandi E. Matsha
Full Text Available The aim of this study is to quantify global DNA methylation and investigate the relationship with diabetes status and polymorphisms in MTHFR C677T and NOS3 G894T genes in mixed ancestry subjects from South Africa. Global DNA methylation was measured, and MTHFR rs1801133 and NOS3 rs1799983 polymorphisms were genotyped using high throughput real-time polymerase chain reaction and direct DNA sequencing. Of the 564 participants, 158 (28% individuals had T2DM of which 97 (17.2% were screen-detected cases. Another 119 (21.1% had prediabetes, that is, impaired fasting glucose, impaired glucose tolerance, or the combination of both, and the remainder 287 (50.9% had normal glucose tolerance. Global DNA methylation was significantly higher in prediabetes and screen-detected diabetes than in normal glucose tolerance (both p≤0.033 and in screen-detected diabetes compared to known diabetes on treatment (p=0.019. There was no difference in global DNA methylation between known diabetes on treatment and normal glucose tolerance (p>0.999. In multivariable linear regression analysis, only NOS3 was associated with increasing global DNA methylation (β=0.943; 95% CI: 0.286 to 1.560. The association of global DNA methylation with screen-detected diabetes but not treated diabetes suggests that glucose control agents to some extent may be reversing DNA methylation. The association between NOS3 rs1799983 polymorphisms and DNA methylation suggests gene-epigenetic mechanisms through which vascular diabetes complications develop despite adequate metabolic control.
Mutize, Tinashe; Erasmus, Rajiv T.
The aim of this study is to quantify global DNA methylation and investigate the relationship with diabetes status and polymorphisms in MTHFR C677T and NOS3 G894T genes in mixed ancestry subjects from South Africa. Global DNA methylation was measured, and MTHFR rs1801133 and NOS3 rs1799983 polymorphisms were genotyped using high throughput real-time polymerase chain reaction and direct DNA sequencing. Of the 564 participants, 158 (28%) individuals had T2DM of which 97 (17.2%) were screen-detected cases. Another 119 (21.1%) had prediabetes, that is, impaired fasting glucose, impaired glucose tolerance, or the combination of both, and the remainder 287 (50.9%) had normal glucose tolerance. Global DNA methylation was significantly higher in prediabetes and screen-detected diabetes than in normal glucose tolerance (both p ≤ 0.033) and in screen-detected diabetes compared to known diabetes on treatment (p = 0.019). There was no difference in global DNA methylation between known diabetes on treatment and normal glucose tolerance (p > 0.999). In multivariable linear regression analysis, only NOS3 was associated with increasing global DNA methylation (β = 0.943; 95% CI: 0.286 to 1.560). The association of global DNA methylation with screen-detected diabetes but not treated diabetes suggests that glucose control agents to some extent may be reversing DNA methylation. The association between NOS3 rs1799983 polymorphisms and DNA methylation suggests gene-epigenetic mechanisms through which vascular diabetes complications develop despite adequate metabolic control. PMID:27990443
Clarence C Gravlee
Full Text Available The role of race in human genetics and biomedical research is among the most contested issues in science. Much debate centers on the relative importance of genetic versus sociocultural factors in explaining racial inequalities in health. However, few studies integrate genetic and sociocultural data to test competing explanations directly.We draw on ethnographic, epidemiologic, and genetic data collected in Southeastern Puerto Rico to isolate two distinct variables for which race is often used as a proxy: genetic ancestry versus social classification. We show that color, an aspect of social classification based on the culturally defined meaning of race in Puerto Rico, better predicts blood pressure than does a genetic-based estimate of continental ancestry. We also find that incorporating sociocultural variables reveals a new and significant association between a candidate gene polymorphism for hypertension (alpha(2C adrenergic receptor deletion and blood pressure.This study addresses the recognized need to measure both genetic and sociocultural factors in research on racial inequalities in health. Our preliminary results provide the most direct evidence to date that previously reported associations between genetic ancestry and health may be attributable to sociocultural factors related to race and racism, rather than to functional genetic differences between racially defined groups. Our results also imply that including sociocultural variables in future research may improve our ability to detect significant allele-phenotype associations. Thus, measuring sociocultural factors related to race may both empower future genetic association studies and help to clarify the biological consequences of social inequalities.
Hu, Hao; Huff, Chad D; Yamamura, Yuko; Wu, Xifeng; Strom, Sara S
Higher body mass index (BMI) is a well-established risk factor for type 2 diabetes, and rates of obesity and type 2 diabetes are substantially higher among Mexican-Americans relative to non-Hispanic European Americans. Mexican-Americans are genetically diverse, with a highly variable distribution of Native American, European, and African ancestries. Here, we evaluate the role of Native American ancestry on BMI and diabetes risk in a well-defined Mexican-American population. Participants were randomly selected among individuals residing in the Houston area who are enrolled in the Mexican-American Cohort study. Using a custom Illumina GoldenGate Panel, we genotyped DNA from 4,662 cohort participants for 87 Ancestry-Informative Markers. On average, the participants were of 50.2% Native American ancestry, 42.7% European ancestry and 7.1% African ancestry. Using multivariate linear regression, we found BMI and Native American ancestry were inversely correlated; individuals with ancestry were 2.5 times more likely to be severely obese compared to those with >80% Native American ancestry. Furthermore, we demonstrated an interaction between BMI and Native American ancestry in diabetes risk among women; Native American ancestry was a strong risk factor for diabetes only among overweight and obese women (OR = 1.190 for each 10% increase in Native American ancestry). This study offers new insight into the complex relationship between obesity, genetic ancestry, and their respective effects on diabetes risk. Findings from this study may improve the diabetes risk prediction among Mexican-American individuals thereby facilitating targeted prevention strategies.
Spector, Stephen A.; Brummel, Sean S.; Nievergelt, Caroline M.; Maihofer, Adam X.; Singh, Kumud K.; Purswani, Murli U.; Williams, Paige L.; Hazra, Rohan; Van Dyke, Russell; Seage, George R.
Abstract The Pediatric HIV/AIDS Cohort Study (PHACS), the largest ongoing longitudinal study of perinatal HIV-infected (PHIV) and HIV-exposed, uninfected (PHEU) children in the United States, comprises the Surveillance Monitoring of Antiretroviral Therapy [ART] Toxicities (SMARTT) Study in PHEU children and the Adolescent Master Protocol (AMP) that includes PHIV and PHEU children ≥7 years. Although race/ethnicity is often used to assess health outcomes, this approach remains controversial and may fail to accurately reflect the backgrounds of ancestry-diverse populations as represented in the PHACS participants. In this study, we compared genetically determined ancestry (GDA) and self-reported race/ethnicity (SRR) in the PHACS cohort. GDA was estimated using a highly discriminative panel of 41 single nucleotide polymorphisms and compared to SRR. Because SRR was similar between the PHIV and PHEU, and between the AMP and SMARTT cohorts, data for all unique 1958 participants were combined. According to SRR, 63% of study participants identified as Black/African-American, 27% White, and 34% Hispanic. Using the highest percentage of ancestry/ethnicity to identify GDA, 9.5% of subjects were placed in the incorrect superpopulation based on SRR. When ≥50% or ≥75% GDA of a given superpopulation was required, 12% and 25%, respectively, of subjects were placed in the incorrect superpopulation based on SRR, and the percent of subjects classified as multiracial increased. Of 126 participants with unidentified SRR, 71% were genetically identified as Eurasian. GDA provides a more robust assessment of race/ethnicity when compared to self-report, and study participants with unidentified SRR could be assigned GDA using genetic markers. In addition, identification of continental ancestry removes the taxonomic identification of race as a variable when identifying risk for clinical outcomes. PMID:27603370
Peprah, Emmanuel; Xu, Huichun; Tekola-Ayele, Fasil; Royal, Charmaine D.
Genomic research is one of the tools for elucidating the pathogenesis of diseases of global health relevance, and paving the research dimension to clinical and public health translation. Recent advances in genomic research and technologies have increased our understanding of human diseases, genes associated with these disorders, and the relevant mechanisms. Genome-wide association studies (GWAS) have proliferated since the first studies were published several years ago, and have become an important tool in helping researchers comprehend human variation and the role genetic variants play in disease. However, the need to expand the diversity of populations in GWAS has become increasingly apparent as new knowledge is gained about genetic variation. Inclusion of diverse populations in genomic studies is critical to a more complete understanding of human variation and elucidation of the underpinnings of complex diseases. In this review, we summarize the available data on GWAS in recent-African ancestry populations within the western hemisphere (i.e. African Americans and peoples of the Caribbean) and continental African populations. Furthermore, we highlight ways in which genomic studies in populations of recent African ancestry have led to advances in the areas of malaria, HIV, prostate cancer, and other diseases. Finally, we discuss the advantages of conducting GWAS in recent African ancestry populations in the context of addressing existing and emerging global health conditions. PMID:25427668
Peprah, Emmanuel; Xu, Huichun; Tekola-Ayele, Fasil; Royal, Charmaine D
Genomic research is one of the tools for elucidating the pathogenesis of diseases of global health relevance and paving the research dimension to clinical and public health translation. Recent advances in genomic research and technologies have increased our understanding of human diseases, genes associated with these disorders, and the relevant mechanisms. Genome-wide association studies (GWAS) have proliferated since the first studies were published several years ago and have become an important tool in helping researchers comprehend human variation and the role genetic variants play in disease. However, the need to expand the diversity of populations in GWAS has become increasingly apparent as new knowledge is gained about genetic variation. Inclusion of diverse populations in genomic studies is critical to a more complete understanding of human variation and elucidation of the underpinnings of complex diseases. In this review, we summarize the available data on GWAS in recent African ancestry populations within the western hemisphere (i.e. African Americans and peoples of the Caribbean) and continental African populations. Furthermore, we highlight ways in which genomic studies in populations of recent African ancestry have led to advances in the areas of malaria, HIV, prostate cancer, and other diseases. Finally, we discuss the advantages of conducting GWAS in recent African ancestry populations in the context of addressing existing and emerging global health conditions.
O. Lao Grueso (Oscar); P.M. Vallone (Peter); M.D. Coble (Michael); T.M. Diegoli (Toni); M. van Oven (Mannis); K. van der Gaag (Kristiaan); J. Pijpe (Jeroen); P. de Knijff (Peter); M.H. Kayser (Manfred)
textabstractThe current U.S. population represents an amalgam of individuals originating mainly from four continental regions (Africa, Europe, Asia and America). To study the genetic ancestry and compare with self-declared ancestry we have analyzed paternally, maternally and bi-parentally inherited
Thiago Magalhães da Silva
Full Text Available Racial inequalities are observed for different diseases and are mainly caused by differences in socioeconomic status between ethnoracial groups. Genetic factors have also been implicated, and recently, several studies have investigated the association between biogeographical ancestry (BGA and complex diseases. However, the role of BGA as a proxy for non-genetic health determinants has been little investigated. Similarly, studies comparing the association of BGA and self-reported skin colour with these determinants are scarce. Here, we report the association of BGA and self-reported skin colour with socioenvironmental conditions and infections. We studied 1246 children living in a Brazilian urban poor area. The BGA was estimated using 370,539 genome-wide autosomal markers. Standardised questionnaires were administered to the children’s guardians to evaluate socioenvironmental conditions. Infection (or pathogen exposure was defined by the presence of positive serologic test results for IgG to seven pathogens (Toxocara spp, Toxoplasma gondii, Helicobacter pylori, and hepatitis A, herpes simplex, herpes zoster and Epstein-Barr viruses and the presence of intestinal helminth eggs in stool samples (Ascaris lumbricoides and Trichiuris trichiura. African ancestry was negatively associated with maternal education and household income and positively associated with infections and variables, indicating poorer housing and living conditions. The self-reported skin colour was associated with infections only. In stratified analyses, the proportion of African ancestry was associated with most of the outcomes investigated, particularly among admixed individuals. In conclusion, BGA was associated with socioenvironmental conditions and infections even in a low-income and highly admixed population, capturing differences that self-reported skin colour miss. Importantly, our findings suggest caution in interpreting significant associations between BGA and diseases
Camilla Dutra Vieira-Machado
Full Text Available Abstract The presence of Native Americans, Europeans, and Africans has led to the development of a multi-ethnic, admixed population in Chile. This study aimed to contribute to the characterization of the uniparental genetic structure of three Chilean regions. Newborns from seven hospitals in Independencia, Providencia, Santiago, Curicó, Cauquenes, Valdívia, and Puerto Montt communes, belonging to the Chilean regions of Santiago, Maule, and Los Lagos, were studied. The presence of Native American mitochondrial DNA (mtDNA haplogroups and two markers present in the non-recombinant region of the Y chromosome, DYS199 and DYS287, indicative of Native American and African ancestry, respectively, was determined. A high Native American matrilineal contribution and a low Native American and African patrilineal contributions were found in all three studied regions. As previously found in Chilean admixed populations, the Native American matrilineal contribution was lower in Santiago than in the other studied regions. However, there was an unexpectedly higher contribution of Native American ancestry in one of the studied communes in Santiago, probably due to the high rate of immigration from other regions of the country. The population genetic sub-structure we detected in Santiago using few uniparental markers requires further confirmation, owing to possible stratification for autosomal and X-chromosome markers.
Cardena, M M S G; Ribeiro-Dos-Santos, A K; Santos, S E B; Mansur, A J; Bernardez-Pereira, S; Santos, P C J L; Pereira, A C; Fridman, C
There is a high prevalence of heart failure (HF) in the general population, but it is more common in black people. We evaluated the association between genomic ancestry and mitochondrial haplogroups (mt-haplogroups) with HF etiology in 503 Brazilian patients. We elicited Mt-haplogroups by analyzing the control region of mitochondrial DNA, and genomic ancestry, by using 48 autosomal insertion-deletion ancestry informative markers. Hypertensive (28.6%, n=144) and ischemic (28.4%, n=143) etiologies of HF were the most prevalent herein. Our results showed that 233 individuals (46.3%) presented African mitochondrial (mt)-haplogroups, and the major contribution in the genomic ancestry analysis was the European ancestry (57.5% (±22.1%)). African mt-haplogroups were positively associated with a diagnosis of hypertensive cardiomyopathy (odds ratio, OR 1.55, confidence interval, CI 95% 1.04-2.44, P=0.04) when compared with European mt-haplogroups. Regarding the genomic ancestry, the African ancestry variant had higher risks (OR 7.84, 95% CI 2.81-21.91, Pancestry variant had lower risks (OR 0.14, 95% CI 0.04-5.00, Pancestry showed an OR of 4.05 (CI 95% 1.53-10.74, P=0.005), whereas African ancestry showed an OR of 0.17 (CI 95% 0.06-0.48, P=0.001) for developing ischemic etiology. In conclusion, this study supports the importance of using ancestry informative markers and mitochondrial DNA to study the genetics of complex diseases in admixed populations to improve the management, treatment and prevention of these illnesses. Therefore, the ancestry informative markers and mt-haplogroups could provide new biomarkers to be associated with HF etiologies and be used as a premise for more specific management.
Johnson, Angela Marie; Kirk, Rosalind; Muzik, Maria
Persistent racial disparities in breastfeeding show that African American women breastfeed at the lowest rates. Return to work is a critical breastfeeding barrier for African American women who return to work sooner than other ethnic groups and more often encounter unsupportive work environments. They also face psychosocial burdens that make breastfeeding at work uniquely challenging. Participants share personal struggles with combining paid employment and breastfeeding and suggest workplace and personal support strategies that they believe will help continue breastfeeding after a return to work. To explore current perspectives on ways to support African American mothers' workplace breastfeeding behavior. Pregnant African American women (n = 8), African American mothers of infants (n = 21), and lactation support providers (n = 9) participated in 1 of 6 focus groups in the Greater Detroit area. Each focus group audiotape was transcribed verbatim. Thematic analysis was used to inductively analyze focus group transcripts and field notes. Focus groups explored thoughts, perceptions, and behavior on interventions to support African American women's breastfeeding. Participants indicate that they generally believed breastfeeding was a healthy option for the baby; however, paid employment is a critical barrier to successful breastfeeding for which mothers receive little help. Participants felt breastfeeding interventions that support working African American mothers should include education and training for health care professionals, regulation and enforcement of workplace breastfeeding support policies, and support from peers who act as breastfeeding role models. Culturally appropriate interventions are needed to support breastfeeding among working African American women. © The Author(s) 2015.
Earls, Melissa K.
The purpose of this study was to examine the effectiveness of Social Skills Group Play Therapy on remedying the social skills deficits of adolescent African-American males. Additionally, the study investigated whether age and grade level impacted the outcome of the intervention. The participants were adolescent African-American males ages 10 to…
Hernandez-Pacheco, Natalia; Flores, Carlos; Oh, Sam S; Burchard, Esteban G; Pino-Yanes, Maria
Differences in asthma prevalence have been described across different populations, suggesting that genetic ancestry can play an important role in this disease. In fact, several studies have demonstrated an association between African ancestry with increased asthma susceptibility and severity, higher immunoglobulin E levels, and lower lung function. In contrast, Native American ancestry has been shown to have a protective role for this disease. Genome-wide association studies have allowed the identification of population-specific genetic variants with varying allele frequency among populations. Additionally, the correlation of genetic ancestry at the chromosomal level with asthma and related traits by means of admixture mapping has revealed regions of the genome where ancestry is correlated with the disease. In this review, we discuss the evidence supporting the association of genetic ancestry with asthma susceptibility and asthma-related traits, and highlight the regions of the genome harboring ancestry-specific genetic risk factors.
Ruiz-Linares, Andrés; Adhikari, Kaustubh; Acuña-Alonzo, Victor; Quinto-Sanchez, Mirsha; Jaramillo, Claudia; Arias, William; Fuentes, Macarena; Pizarro, María; Everardo, Paola; de Avila, Francisco; Gómez-Valdés, Jorge; León-Mimila, Paola; Hunemeier, Tábita; Ramallo, Virginia; Silva de Cerqueira, Caio C; Burley, Mari-Wyn; Konca, Esra; de Oliveira, Marcelo Zagonel; Veronez, Mauricio Roberto; Rubio-Codina, Marta; Attanasio, Orazio; Gibbon, Sahra; Ray, Nicolas; Gallo, Carla; Poletti, Giovanni; Rosique, Javier; Schuler-Faccini, Lavinia; Salzano, Francisco M; Bortolini, Maria-Cátira; Canizales-Quinteros, Samuel; Rothhammer, Francisco; Bedoya, Gabriel; Balding, David; Gonzalez-José, Rolando
The current genetic makeup of Latin America has been shaped by a history of extensive admixture between Africans, Europeans and Native Americans, a process taking place within the context of extensive geographic and social stratification. We estimated individual ancestry proportions in a sample of 7,342 subjects ascertained in five countries (Brazil, Chile, Colombia, México and Perú). These individuals were also characterized for a range of physical appearance traits and for self-perception of ancestry. The geographic distribution of admixture proportions in this sample reveals extensive population structure, illustrating the continuing impact of demographic history on the genetic diversity of Latin America. Significant ancestry effects were detected for most phenotypes studied. However, ancestry generally explains only a modest proportion of total phenotypic variation. Genetically estimated and self-perceived ancestry correlate significantly, but certain physical attributes have a strong impact on self-perception and bias self-perception of ancestry relative to genetically estimated ancestry.
Livshultz, Tatyana; Mead, Jerry V; Goyder, David J; Brannin, Michelle
Climate change that increases mortality of plants and pollinators can create mate-finding Allee effects and thus act as a strong selective force on floral morphology. Milkweeds (Secamonoideae and Asclepiadoideae; Apocynaceae) are typically small plants of seasonally dry habitats, with pollinia and high pollen-transfer efficiency. Their sister group (tribe Baisseeae and Dewevrella) is mostly comprised of giant lianas of African rainforests, with pollen in monads. Comparison of the two groups motivated a new hypothesis: milkweeds evolved in the context of African aridification and the shifting of rainforest to dry forest. Pollinia and high pollen-transfer efficiency may have been adaptations that alleviated mate-finding Allee effects generated by high mortality during droughts. We formally tested whether milkweeds have a drier climate niche by comparing milkweeds with plesiomorphic traits (Secamonoideae) and the milkweed sister group in continental Africa. We georeferenced specimens of the milkweed sister group and Secamonoideae in continental Africa, extracted 19 climatic variables from the Worldclim model, conducted factor analysis to identify correlated suites of variables, and compared the frequency distributions of the two lineages relative to each factor. The distributions of Secamonoideae and the milkweed sister group differed significantly relative to four factors, each correlated with a distinct suite of climate parameters: (1) air temperature (Secamonoideae: cooler), (2) total and (3) summer precipitation (Secamonoideae: drier), and (4) temperature seasonality and isothermality (Secamonoideae: more seasonal and less isothermal). Secamonoideae in continental Africa inhabit drier, cooler sites than do the milkweed sister group, consistent with a shift from rainforests to dry forests in a cooling climate.
Muhammad T Salam
Full Text Available Asthma and rhinitis are common childhood health conditions. Being an understudied and rapidly growing population in the US, Hispanic children have a varying risk for these conditions that may result from sociocultural (including acculturative factors, exposure and genetic diversities. Hispanic populations have varying contributions from European, Amerindian and African ancestries. While previous literature separately reported associations between genetic ancestry and acculturation factors with asthma, whether Amerindian ancestry and acculturative factors have independent associations with development of early-life asthma and rhinitis in Hispanic children remains unknown. We hypothesized that genetic ancestry is an important determinant of early-life asthma and rhinitis occurrence in Hispanic children independent of sociodemographic, acculturation and environmental factors.Subjects were Hispanic children (5-7 years who participated in the southern California Children's Health Study. Data from birth certificates and questionnaire provided information on acculturation, sociodemographic and environmental factors. Genetic ancestries (Amerindian, European, African and Asian were estimated based on 233 ancestry informative markers. Asthma was defined by parental report of doctor-diagnosed asthma. Rhinitis was defined by parental report of a history of chronic sneezing or runny or blocked nose without a cold or flu. Sample sizes were 1,719 and 1,788 for investigating the role of genetic ancestry on asthma and rhinitis, respectively.Children had major contributions from Amerindian and European ancestries. After accounting for potential confounders, per 25% increase in Amerindian ancestry was associated with 17.6% (95% confidence interval [CI]: 0.74-0.99 and 13.6% (95% CI: 0.79-0.98 lower odds of asthma and rhinitis, respectively. Acculturation was not associated with either outcome.Earlier work documented that Hispanic children with significant
Wickline, Virginia B; Bailey, Wendy; Nowicki, Stephen
The authors explored whether there were in-group advantages in emotion recognition of faces and voices by culture or geographic region. Participants were 72 African American students (33 men, 39 women), 102 European American students (30 men, 72 women), 30 African international students (16 men, 14 women), and 30 European international students (15 men, 15 women). The participants determined emotions in African American and European American faces and voices. Results showed an in-group advantage-sometimes by culture, less often by race-in recognizing facial and vocal emotional expressions. African international students were generally less accurate at interpreting American nonverbal stimuli than were European American, African American, and European international peers. Results suggest that, although partly universal, emotional expressions have subtle differences across cultures that persons must learn.
Ramos, Bruna Ribeiro de Andrade; D'Elia, Maria Paula Barbieri; Amador, Marcos Antônio Trindade; Santos, Ney Pereira Carneiro; Santos, Sidney Emanuel Batista; da Cruz Castelli, Erick; Witkin, Steven S; Miot, Hélio Amante; Miot, Luciane Donida Bartoli; da Silva, Márcia Guimarães
Ancestry information can be useful in investigations of diseases with a genetic or infectious background. As the Brazilian population is highly admixed physical traits tend to be poor indicators of ancestry. The assessment of ancestry by ancestry informative markers (AIMs) can exclude the subjectivity of self-declared ethnicity and reported family origin. We aimed to evaluate the reliability of self-reported ethnicity or reported family origin as indicators of genomic ancestry in a female population from the Southeast of Brazil. Two cohorts were included: 404 women asked to self-report their ethnicity (Pop1) and 234 women asked to report their family's origin (Pop2). Identification of AIMs was performed using a panel of 61 markers and results were plotted against parental populations-Amerindian, Western European and Sub-Saharan African-using Structure v2.3.4. In Pop1 57.4 % of women self-reported as white, 34.6 % as brown and 8.0 % as black. Median global European, Amerindian and African contributions were 66.8, 12.6 and 16.6 %. In Pop2, 66.4 % of women declared European origin, 23.9 % African origin and 26.9 % Amerindian. Median global European, Amerindian and African contributions were 80.8, 7.3 and 7.6 %, respectively. Only 31.0 and 21.0 % of the global variation in African and European contributions, respectively, could be explained by self-reported ethnicity and reported family origin only accounted for 20.0 and 5.0 % of the variations observed in African and European ancestries, respectively. Amerindian ancestry did not influence self-reported ethnicity or declared family origin. Neither self-reported ethnicity nor declared family origin are reliable indicators of genomic ancestry in these Brazilian populations.
Santos, C; Fondevila, M; Ballard, D
that analyzes the genotype data alongside calculation of Bayes likelihood ratios. Exercise results indicated consistent genotyping performance from both tests, reaching a particularly high level of reliability for the Indel test. SNP genotyping gave 93.5% concordance (compared to the organizing laboratory...... relationship between input DNA and signal strength as each marker is detected with a single dye, so mixed DNA is more reliably detected. We report the results of a collaborative inter-laboratory exercise of 19 participants (15 from the EDNAP European DNA Profiling group) that assessed a 34-plex SNP test using...... the correct ancestry to the other samples using Snipper, with the exception of one laboratory with SNP miscalls that incorrectly assigned ancestry of two samples and did not obtain informative likelihood ratios for a third. Therefore, successful ancestry assignments were achieved by participants in 92 of 95...
The paper presents the history of the contribution of two American economists to a radical cause: the establishment of a socialist and politically united Africa. The setting is 1960s Ghana which under Kwame Nkrumah, the man who led the country to independence from British colonial rule, emerged as the epicentre of this Pan-African vision. Ann Seidman and Reginald H. Green became, as members of the research team on 'The Economics of African Unity' established at the University of Ghana in 1963...
Ulloa, Alvaro E; Chen, Jiayu; Vergara, Victor M; Calhoun, Vince; Liu, Jingyu
Copy number variations (CNVs) are structural genetic mutations consisting of segmental gains or losses in DNA sequence. Although CNVs contribute substantially to genomic variation, few genetic and imaging studies report association of CNVs with alcohol dependence (AD). Our purpose is to find evidence of this association across ethnic populations and genders. This work is the first AD-CNV study across ethnic groups and the first to include the African American (AA) population. This study considers 2 CNV data sets, one for discovery (2,345 samples) and the other for validation (239 samples), both including subjects with AD and healthy controls of European and African ancestry. Our analysis assesses the association between AD and CNV losses across ethnic groups and gender by examining the effect of overall losses across the whole genome, collective losses within individual cytogenetic bands, and specific losses in CNV regions. Results from the discovery data set showed an association between CNV losses within 16q12.2 and AD diagnosis (p = 4.53 × 10(-3) ). An overlapping CNV region from the validation data set exhibited the same direction of effect with respect to AD (p = 0.051). This CNV region affects the genes CES1p1 and CES1, which are members of the carboxylesterase (CES) family. The enzyme encoded by CES1 is a major liver enzyme that typically catalyzes the decomposition of ester into alcohol and carboxylic acid and is involved in drug or xenobiotics, fatty acid, and cholesterol metabolisms. In addition, the most significantly associated CNV region was located at 9p21.2 (p = 1.9 × 10(-3) ) in our discovery data set. Although not observed in the validation data set, probably due to small sample size, this result might hold potential connection to AD given its connection with neuronal death. In contrast, we did not find any association between AD and the overall total losses or the collective losses within individual cytogenetic bands. Overall, our study provides
Full Text Available The aim of this study is to investigate the shallow thermal field differences for two differently aged passive continental margins by analyzing regional variations in geothermal gradient and exploring the controlling factors for these variations. Hence, we analyzed two previously published 3-D conductive and lithospheric-scale thermal models of the Southwest African and the Norwegian passive margins. These 3-D models differentiate various sedimentary, crustal, and mantle units and integrate different geophysical data such as seismic observations and the gravity field. We extracted the temperature–depth distributions in 1 km intervals down to 6 km below the upper thermal boundary condition. The geothermal gradient was then calculated for these intervals between the upper thermal boundary condition and the respective depth levels (1, 2, 3, 4, 5, and 6 km below the upper thermal boundary condition. According to our results, the geothermal gradient decreases with increasing depth and shows varying lateral trends and values for these two different margins. We compare the 3-D geological structural models and the geothermal gradient variations for both thermal models and show how radiogenic heat production, sediment insulating effect, and thermal lithosphere–asthenosphere boundary (LAB depth influence the shallow thermal field pattern. The results indicate an ongoing process of oceanic mantle cooling at the young Norwegian margin compared with the old SW African passive margin that seems to be thermally equilibrated in the present day.
Gholamrezaie, Ershad; Scheck-Wenderoth, Magdalena; Sippel, Judith; Strecker, Manfred R.
The aim of this study is to investigate the shallow thermal field differences for two differently aged passive continental margins by analyzing regional variations in geothermal gradient and exploring the controlling factors for these variations. Hence, we analyzed two previously published 3-D conductive and lithospheric-scale thermal models of the Southwest African and the Norwegian passive margins. These 3-D models differentiate various sedimentary, crustal, and mantle units and integrate different geophysical data such as seismic observations and the gravity field. We extracted the temperature-depth distributions in 1 km intervals down to 6 km below the upper thermal boundary condition. The geothermal gradient was then calculated for these intervals between the upper thermal boundary condition and the respective depth levels (1, 2, 3, 4, 5, and 6 km below the upper thermal boundary condition). According to our results, the geothermal gradient decreases with increasing depth and shows varying lateral trends and values for these two different margins. We compare the 3-D geological structural models and the geothermal gradient variations for both thermal models and show how radiogenic heat production, sediment insulating effect, and thermal lithosphere-asthenosphere boundary (LAB) depth influence the shallow thermal field pattern. The results indicate an ongoing process of oceanic mantle cooling at the young Norwegian margin compared with the old SW African passive margin that seems to be thermally equilibrated in the present day.
Banda, Yambazi; Kvale, Mark N.; Hoffmann, Thomas J.; Hesselson, Stephanie E.; Ranatunga, Dilrini; Tang, Hua; Sabatti, Chiara; Croen, Lisa A.; Dispensa, Brad P.; Henderson, Mary; Iribarren, Carlos; Jorgenson, Eric; Kushi, Lawrence H.; Ludwig, Dana; Olberg, Diane; Quesenberry, Charles P.; Rowell, Sarah; Sadler, Marianne; Sakoda, Lori C.; Sciortino, Stanley; Shen, Ling; Smethurst, David; Somkin, Carol P.; Van Den Eeden, Stephen K.; Walter, Lawrence; Whitmer, Rachel A.; Kwok, Pui-Yan; Schaefer, Catherine; Risch, Neil
Using genome-wide genotypes, we characterized the genetic structure of 103,006 participants in the Kaiser Permanente Northern California multi-ethnic Genetic Epidemiology Research on Adult Health and Aging Cohort and analyzed the relationship to self-reported race/ethnicity. Participants endorsed any of 23 race/ethnicity/nationality categories, which were collapsed into seven major race/ethnicity groups. By self-report the cohort is 80.8% white and 19.2% minority; 93.8% endorsed a single race/ethnicity group, while 6.2% endorsed two or more. Principal component (PC) and admixture analyses were generally consistent with prior studies. Approximately 17% of subjects had genetic ancestry from more than one continent, and 12% were genetically admixed, considering only nonadjacent geographical origins. Self-reported whites were spread on a continuum along the first two PCs, indicating extensive mixing among European nationalities. Self-identified East Asian nationalities correlated with genetic clustering, consistent with extensive endogamy. Individuals of mixed East Asian–European genetic ancestry were easily identified; we also observed a modest amount of European genetic ancestry in individuals self-identified as Filipinos. Self-reported African Americans and Latinos showed extensive European and African genetic ancestry, and Native American genetic ancestry for the latter. Among 3741 genetically identified parent–child pairs, 93% were concordant for self-reported race/ethnicity; among 2018 genetically identified full-sib pairs, 96% were concordant; the lower rate for parent–child pairs was largely due to intermarriage. The parent–child pairs revealed a trend toward increasing exogamy over time; the presence in the cohort of individuals endorsing multiple race/ethnicity categories creates interesting challenges and future opportunities for genetic epidemiologic studies. PMID:26092716
Banda, Yambazi; Kvale, Mark N; Hoffmann, Thomas J; Hesselson, Stephanie E; Ranatunga, Dilrini; Tang, Hua; Sabatti, Chiara; Croen, Lisa A; Dispensa, Brad P; Henderson, Mary; Iribarren, Carlos; Jorgenson, Eric; Kushi, Lawrence H; Ludwig, Dana; Olberg, Diane; Quesenberry, Charles P; Rowell, Sarah; Sadler, Marianne; Sakoda, Lori C; Sciortino, Stanley; Shen, Ling; Smethurst, David; Somkin, Carol P; Van Den Eeden, Stephen K; Walter, Lawrence; Whitmer, Rachel A; Kwok, Pui-Yan; Schaefer, Catherine; Risch, Neil
Using genome-wide genotypes, we characterized the genetic structure of 103,006 participants in the Kaiser Permanente Northern California multi-ethnic Genetic Epidemiology Research on Adult Health and Aging Cohort and analyzed the relationship to self-reported race/ethnicity. Participants endorsed any of 23 race/ethnicity/nationality categories, which were collapsed into seven major race/ethnicity groups. By self-report the cohort is 80.8% white and 19.2% minority; 93.8% endorsed a single race/ethnicity group, while 6.2% endorsed two or more. Principal component (PC) and admixture analyses were generally consistent with prior studies. Approximately 17% of subjects had genetic ancestry from more than one continent, and 12% were genetically admixed, considering only nonadjacent geographical origins. Self-reported whites were spread on a continuum along the first two PCs, indicating extensive mixing among European nationalities. Self-identified East Asian nationalities correlated with genetic clustering, consistent with extensive endogamy. Individuals of mixed East Asian-European genetic ancestry were easily identified; we also observed a modest amount of European genetic ancestry in individuals self-identified as Filipinos. Self-reported African Americans and Latinos showed extensive European and African genetic ancestry, and Native American genetic ancestry for the latter. Among 3741 genetically identified parent-child pairs, 93% were concordant for self-reported race/ethnicity; among 2018 genetically identified full-sib pairs, 96% were concordant; the lower rate for parent-child pairs was largely due to intermarriage. The parent-child pairs revealed a trend toward increasing exogamy over time; the presence in the cohort of individuals endorsing multiple race/ethnicity categories creates interesting challenges and future opportunities for genetic epidemiologic studies. Copyright © 2015 by the Genetics Society of America.
Full Text Available Geologically, Panama belongs to the Central American land-bridge between North and South America crossed by Homo sapiens >14 ka ago. Archaeologically, it belongs to a wider Isthmo-Colombian Area. Today, seven indigenous ethnic groups account for 12.3% of Panama's population. Five speak Chibchan languages and are characterized by low genetic diversity and a high level of differentiation. In addition, no evidence of differential structuring between maternally and paternally inherited genes has been reported in isthmian Chibchan cultural groups. Recent data have shown that 83% of the Panamanian general population harbour mitochondrial DNAs (mtDNAs of Native American ancestry. Considering differential male/female mortality at European contact and multiple degrees of geographical and genetic isolation over the subsequent five centuries, the Y-chromosome Native American component is expected to vary across different geographic regions and communities in Panama. To address this issue, we investigated Y-chromosome variation in 408 modern males from the nine provinces of Panama and one indigenous territory (the comarca of Kuna Yala. In contrast to mtDNA data, the Y-chromosome Native American component (haplogroup Q exceeds 50% only in three populations facing the Caribbean Sea: the comarca of Kuna Yala and Bocas del Toro province where Chibchan languages are spoken by the majority, and the province of Colón where many Kuna and people of mixed indigenous-African-and-European descent live. Elsewhere the Old World component is dominant and mostly represented by western Eurasian haplogroups, which signal the strong male genetic impact of invaders. Sub-Saharan African input accounts for 5.9% of male haplotypes. This reflects the consequences of the colonial Atlantic slave trade and more recent influxes of West Indians of African heritage. Overall, our findings reveal a local evolution of the male Native American ancestral gene pool, and a strong but
Curtin, Kimberley D; Berry, Tanya R; Courneya, Kerry S; McGannon, Kerry R; Norris, Colleen M; Rodgers, Wendy M; Spence, John C
Ethnic minority groups including Asians in Canada have different knowledge and perceptions of heart disease and breast cancer compared with the ethnic majority group. Examine relationships between perceptions of heart disease and breast cancer, and lifestyle behaviors for Canadian women with British and with South Asian ancestry. Women with South Asian ( n = 170) and with British ( n = 373) ancestry ( M age = 33.01, SD = 12.86) reported leisure time physical activity, intended fruit and vegetable consumption, disease perceptions (ability to reduce risk, control over getting the diseases, and influence of family history), and demographic information. Mann-Whitney tests and multiple hierarchical linear regressions were used to examine the relationships between lifestyle behaviors and disease perceptions, with ancestry explored as a possible moderator. Participants with South Asian ancestry believed they had greater ability to reduce their risk and have control over getting breast cancer than participants with British ancestry. Family history influences on getting either disease was perceived as higher for women with British ancestry. Age was positively related to all three perceptions in both diseases. Intended fruit and vegetable consumption was positively related to perceptions of ability to reduce risk and control of both diseases, but was stronger for women with South Asian ancestry regarding perceptions of breast cancer. Leisure time physical activity was positively related to perceptions of control over getting heart disease for women with British ancestry. Women's disease perceptions can vary by ancestry and lifestyle behaviors. Accurate representation of diseases is essential in promoting effective preventative behaviors.
Wilson, Robin Taylor; Masters, Loren D; Barnholtz-Sloan, Jill S; Salzberg, Anna C; Hartman, Terryl J
We investigated the association between genetic polymorphisms in cytochrome P450 (CYP2R1, CYP24A1, and the CYP3A family) with nonsummer plasma concentrations of vitamin D metabolites (25-hydroxyvitamin D3 (25(OH)D3) and proportion 24,25-dihydroxyvitamin D3 (24,25(OH)2D3)) among healthy individuals of sub-Saharan African and European ancestry, matched on age (within 5 years; n = 188 in each ancestral group), in central suburban Pennsylvania (2006-2009). Vitamin D metabolites were measured using high-performance liquid chromatography with tandem mass spectrometry. Paired multiple regression and adjusted least-squares mean analyses were used to test for associations between genotype and log-transformed metabolite concentrations, adjusted for age, sex, proportion of West-African genetic ancestry, body mass index, oral contraceptive (OC) use, tanning bed use, vitamin D intake, days from summer solstice, time of day of blood draw, and isoforms of the vitamin D receptor (VDR) and vitamin D binding protein. Polymorphisms in CYP2R1, CYP3A43, vitamin D binding protein, and genetic ancestry proportion remained associated with plasma 25(OH)D3 after adjustment. Only CYP3A43 and VDR polymorphisms were associated with proportion 24,25(OH)2D3. Magnitudes of association with 25(OH)D3 were similar for CYP3A43, tanning bed use, and OC use. Significant least-squares mean interactions (CYP2R1/OC use (P = 0.030) and CYP3A43/VDR (P = 0.013)) were identified. A CYP3A43 genotype, previously implicated in cancer, is strongly associated with biomarkers of vitamin D metabolism. Interactive associations should be further investigated.
Fuentes, Macarena; Pulgar, Iván; Gallo, Carla; Bortolini, María-Cátira; Canizales-Quinteros, Samuel; Bedoya, Gabriel; González-José, Rolando; Ruiz-Linares, Andrés; Rothhammer, Francisco
The geographical distribution of genes plays a key role in genetic epidemiology. The Chilean population has three major stem groups (Native American, European and African). To estimate the regional rate of American, European and African admixture of the Chilean population. Forty single nucleotide polymorphisms (SNP´s) which exhibit substantially different frequencies between Amerindian populations (ancestry-informative markers or AIM´s), were genotyped in a sample of 923 Chilean participants to estimate individual genetic ancestry. The American, European and African individual average admixture estimates for the 15 Chilean Regions were relatively homogeneous and not statistically different. However, higher American components were found in northern and southern Chile and higher European components were found in central Chile. A negative correlation between African admixture and latitude was observed. On the average, American and European genetic contributions were similar and significantly higher than the African contribution. Weighted mean American, European and African genetic contributions of 44.34% ± 3 9%, 51.85% ± 5.44% and 3.81% ± 0.45%, were estimated. Fifty two percent of subjects harbor African genes. Individuals with Aymara and Mapuche surnames have an American admixture of 58.64% and 68.33%, respectively. Half of the Chilean population harbors African genes. Participants with Aymara and Mapuche surnames had a higher American genetic contribution than the general Chilean population. These results confirm the usefulness of surnames as a first approximation to determine genetic ancestry.
Royal, Charmaine D.; Novembre, John; Fullerton, Stephanie M.; Goldstein, David B.; Long, Jeffrey C.; Bamshad, Michael J.; Clark, Andrew G.
Increasing public interest in direct-to-consumer (DTC) genetic ancestry testing has been accompanied by growing concern about issues ranging from the personal and societal implications of the testing to the scientific validity of ancestry inference. The very concept of “ancestry” is subject to misunderstanding in both the general and scientific communities. What do we mean by ancestry? How exactly is ancestry measured? How far back can such ancestry be defined and by which genetic tools? How ...
... consumer genetic testing? What kinds of direct-to-consumer genetic tests are available? What is genetic ancestry testing? What are the benefits and risks of direct-to-consumer genetic testing? ...
Pasaniuc, Bogdan; Sankararaman, Sriram; Torgerson, Dara G.; Gignoux, Christopher; Zaitlen, Noah; Eng, Celeste; Rodriguez-Cintron, William; Chapela, Rocio; Ford, Jean G.; Avila, Pedro C.; Rodriguez-Santana, Jose; Chen, Gary K.; Le Marchand, Loic; Henderson, Brian; Reich, David; Haiman, Christopher A.; Gonzàlez Burchard, Esteban; Halperin, Eran
Motivation: Local ancestry analysis of genotype data from recently admixed populations (e.g. Latinos, African Americans) provides key insights into population history and disease genetics. Although methods for local ancestry inference have been extensively validated in simulations (under many unrealistic assumptions), no empirical study of local ancestry accuracy in Latinos exists to date. Hence, interpreting findings that rely on local ancestry in Latinos is challenging. Results: Here, we use 489 nuclear families from the mainland USA, Puerto Rico and Mexico in conjunction with 3204 unrelated Latinos from the Multiethnic Cohort study to provide the first empirical characterization of local ancestry inference accuracy in Latinos. Our approach for identifying errors does not rely on simulations but on the observation that local ancestry in families follows Mendelian inheritance. We measure the rate of local ancestry assignments that lead to Mendelian inconsistencies in local ancestry in trios (MILANC), which provides a lower bound on errors in the local ancestry estimates. We show that MILANC rates observed in simulations underestimate the rate observed in real data, and that MILANC varies substantially across the genome. Second, across a wide range of methods, we observe that loci with large deviations in local ancestry also show enrichment in MILANC rates. Therefore, local ancestry estimates at such loci should be interpreted with caution. Finally, we reconstruct ancestral haplotype panels to be used as reference panels in local ancestry inference and show that ancestry inference is significantly improved by incoroprating these reference panels. Availability and implementation: We provide the reconstructed reference panels together with the maps of MILANC rates as a public resource for researchers analyzing local ancestry in Latinos at http://bogdanlab.pathology.ucla.edu. Contact: email@example.com Supplementary information: Supplementary data are
Rizzo, Silvia Renata Cornelio Parolin; Gazito, Diana; Pott-Junior, Henrique; Latini, Flavia Roche Moreira; Castelo, Adauto
The recent development of interferon-free regimens based on direct-acting antivirals for the treatment of chronic hepatitis C virus infection has benefited many but not all patients. Some patients still experience treatment failure, possibly attributed to unknown host and viral factors, such as IFNL3 gene polymorphism. The present study assessed the prevalence of rs12979860-CC, rs12979860-CT, and rs12979860-TT genotypes of the IFNL3 gene, and its relationship with ancestry informative markers in 949 adult Brazilian healthy blood donors. Race was analyzed using ancestry informative markers as a surrogate for ancestry. IFNL3 gene was genotyped using the ABI TaqMan single nucleotide polymorphisms genotyping assays. The overall frequency of rs12979860-CC genotype was 36.9%. The contribution of African ancestry was significantly higher among donors from the northeast region in relation to southeast donors, whereas the influence of European ancestry was significantly higher in southeast donors. Donors with rs12979860-CC and rs12979860-CT genotypes had similar ancestry background. The contribution of African ancestry was higher among rs12979860-TT genotype donors in comparison to both rs12979860-CC and rs12979860-CT genotypes. The prevalence of rs12979860-CC genotype is similar to that found in the US, despite the Brazilian ancestry informative markers admixture. However, in terms of ancestry, rs12979860-CT genotype was much closer to rs12979860-CC individuals than to rs12979860-TT. Copyright © 2016 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. All rights reserved.
Wolf Yuri I
Full Text Available Abstract Background It is common belief that all cellular life forms on earth have a common origin. This view is supported by the universality of the genetic code and the universal conservation of multiple genes, particularly those that encode key components of the translation system. A remarkable recent study claims to provide a formal, homology independent test of the Universal Common Ancestry hypothesis by comparing the ability of a common-ancestry model and a multiple-ancestry model to predict sequences of universally conserved proteins. Results We devised a computational experiment on a concatenated alignment of universally conserved proteins which shows that the purported demonstration of the universal common ancestry is a trivial consequence of significant sequence similarity between the analyzed proteins. The nature and origin of this similarity are irrelevant for the prediction of "common ancestry" of by the model-comparison approach. Thus, homology (common origin of the compared proteins remains an inference from sequence similarity rather than an independent property demonstrated by the likelihood analysis. Conclusion A formal demonstration of the Universal Common Ancestry hypothesis has not been achieved and is unlikely to be feasible in principle. Nevertheless, the evidence in support of this hypothesis provided by comparative genomics is overwhelming. Reviewers this article was reviewed by William Martin, Ivan Iossifov (nominated by Andrey Rzhetsky and Arcady Mushegian. For the complete reviews, see the Reviewers' Report section.
Luizon, Marcelo Rizzatti; Mendes-Junior, Celso Teixeira; De Oliveira, Silviene Fabiana; Simões, Aguinaldo Luiz
Ancestry informative markers (AIMs) are genetic loci with large frequency differences between the major ethnic groups and are very useful in admixture estimation. However, their frequencies are poorly known within South American indigenous populations, making it difficult to use them in admixture studies with Latin American populations, such as the trihybrid Brazilian population. To minimize this problem, the frequencies of the AIMs FY-null, RB2300, LPL, AT3-I/D, Sb19.3, APO, and PV92 were determined via PCR and PCR-RFLP in four tribes from Brazilian Amazon (Tikúna, Kashinawa, Baníwa, and Kanamarí), to evaluate their potential for discriminating indigenous populations from Europeans and Africans, as well as discriminating each tribe from the others. Although capable of differentiating tribes, as evidenced by the exact test of population differentiation, a neighbor-joining tree suggests that the AIMs are useless in obtaining reliable reconstructions of the biological relationships and evolutionary history that characterize the villages and tribes studied. The mean allele frequencies from these AIMs were very similar to those observed for North American natives. They discriminated Amerindians from Africans, but not from Europeans. On the other hand, the neighbor-joining dendrogram separated Africans and Europeans from Amerindians with a high statistical support (bootstrap = 0.989). The relatively low diversity (G(ST) = 0.042) among North American natives and Amerindians from Brazilian Amazon agrees with the lack of intra-ethnic variation previously reported for these markers. Despite genetic drift effects, the mean allelic frequencies herein presented could be used as Amerindian parental frequencies in admixture estimates in urban Brazilian populations. (c) 2007 Wiley-Liss, Inc.
Maier, W. D.; O'Brien, H.; Peltonen, P.; Barnes, Sarah-Jane
We present high-precision isotope dilution data for Os, Ir, Ru, Pt, Pd and Re in Group I and Group II kimberlites from the Karelian craton, as well as 2 samples of the Premier Group I kimberlite pipe from the Kaapvaal craton. The samples have, on average, 1.38 ppb Pt and 1.33 ppb Pd, with Pt/Pd around unity. These PGE levels are markedly lower, by as much as 80%, than those reported previously for kimberlites from South Africa, Brazil and India, but overlap with PGE results reported recently from Canadian kimberlites. Primitive-mantle-normalised chalcophile element patterns are relatively flat from Os to Pt, but Cu, Ni and, somewhat less so, Au are enriched relative to the PGE (e.g., Cu/Pd > 25.000). Pd/Ir ratios are 3,6 on average, lower than in most other mantle melts. The PGE systematics can be largely explained by two components, (i) harzburgite/lherzolite detritus of the SCLM with relatively high IPGE (Os-Ir-Ru)/PPGE (Rh-Pt-Pd) ratios, and (ii) a melt component that has high PPGE/IPGE ratios. By using the concentrations of iridium in the kimberlites as a proxy for the proportion of mantle detritus in the magma, we estimate that the analysed kimberlites contain 3-27% entrained and partially dissolved detritus from the sub-continental lithospheric mantle, consistent with previous estimates of kimberlites elsewhere (Tappe S. et al., 2016, Chem. Geol. 10.1016/j.chemgeo.2016.08.019).
França, Giovanny Vinícius Araújo de; De Lucia Rolfe, Emanuella; Horta, Bernardo Lessa; Gigante, Denise Petrucci; Yudkin, John S; Ong, Ken K; Victora, Cesar Gomes
We aimed to identify the independent associations of genomic ancestry and education level with abdominal fat distributions in the 1982 Pelotas birth cohort study, Brazil. In 2,890 participants (1,409 men and 1,481 women), genomic ancestry was assessed using genotype data on 370,539 genome-wide variants to quantify ancestral proportions in each individual. Years of completed education was used to indicate socio-economic position. Visceral fat depth and subcutaneous abdominal fat thickness were measured by ultrasound at age 29-31y; these measures were adjusted for BMI to indicate abdominal fat distributions. Linear regression models were performed, separately by sex. Admixture was observed between European (median proportion 85.3), African (6.6), and Native American (6.3) ancestries, with a strong inverse correlation between the African and European ancestry scores (ρ = -0.93; pabdominal fat distributions in men (both P = 0.001), and inversely associated with subcutaneous abdominal fat distribution in women (p = 0.009). Independent of genomic ancestry, higher education level was associated with lower visceral fat, but higher subcutaneous fat, in both men and women (all pabdominal fat distribution in adults. African ancestry appeared to lower abdominal fat distributions, particularly in men.
Simon N Stacey
Full Text Available We used an approach that we term ancestry-shift refinement mapping to investigate an association, originally discovered in a GWAS of a Chinese population, between rs2046210[T] and breast cancer susceptibility. The locus is on 6q25.1 in proximity to the C6orf97 and estrogen receptor alpha (ESR1 genes. We identified a panel of SNPs that are correlated with rs2046210 in Chinese, but not necessarily so in other ancestral populations, and genotyped them in breast cancer case:control samples of Asian, European, and African origin, a total of 10,176 cases and 13,286 controls. We found that rs2046210[T] does not confer substantial risk of breast cancer in Europeans and Africans (OR = 1.04, P = 0.099, and OR = 0.98, P = 0.77, respectively. Rather, in those ancestries, an association signal arises from a group of less common SNPs typified by rs9397435. The rs9397435[G] allele was found to confer risk of breast cancer in European (OR = 1.15, P = 1.2 x 10(-3, African (OR = 1.35, P = 0.014, and Asian (OR = 1.23, P = 2.9 x 10(-4 population samples. Combined over all ancestries, the OR was 1.19 (P = 3.9 x 10(-7, was without significant heterogeneity between ancestries (P(het = 0.36 and the SNP fully accounted for the association signal in each ancestry. Haplotypes bearing rs9397435[G] are well tagged by rs2046210[T] only in Asians. The rs9397435[G] allele showed associations with both estrogen receptor positive and estrogen receptor negative breast cancer. Using early-draft data from the 1,000 Genomes project, we found that the risk allele of a novel SNP (rs77275268, which is closely correlated with rs9397435, disrupts a partially methylated CpG sequence within a known CTCF binding site. These studies demonstrate that shifting the analysis among ancestral populations can provide valuable resolution in association mapping.
Park, Danny S; Eskin, Itamar; Kang, Eun Yong; Gamazon, Eric R; Eng, Celeste; Gignoux, Christopher R; Galanter, Joshua M; Burchard, Esteban; Ye, Chun J; Aschard, Hugues; Eskin, Eleazar; Halperin, Eran; Zaitlen, Noah
Epistasis and gene-environment interactions are known to contribute significantly to variation of complex phenotypes in model organisms. However, their identification in human association studies remains challenging for myriad reasons. In the case of epistatic interactions, the large number of potential interacting sets of genes presents computational, multiple hypothesis correction, and other statistical power issues. In the case of gene-environment interactions, the lack of consistently measured environmental covariates in most disease studies precludes searching for interactions and creates difficulties for replicating studies. In this work, we develop a new statistical approach to address these issues that leverages genetic ancestry, defined as the proportion of ancestry derived from each ancestral population (e.g., the fraction of European/African ancestry in African Americans), in admixed populations. We applied our method to gene expression and methylation data from African American and Latino admixed individuals, respectively, identifying nine interactions that were significant at Pancestry can be a useful proxy for unknown and unmeasured covariates in the search for interaction effects. These results have important implications for our understanding of the genetic architecture of complex traits. © 2017 WILEY PERIODICALS, INC.
Lopera, Esteban A; Baena, Armando; Florez, Victor; Montiel, Jehidys; Duque, Constanza; Ramirez, Tatiana; Borrero, Mauricio; Cordoba, Carlos M; Rojas, Fredy; Pareja, Rene; Bedoya, Astrid M; Bedoya, Gabriel; Sanchez, Gloria I
European (E) variants of HPV 16 are evenly distributed among world regions, meanwhile Non-European variants such as European-Asian (EAs), Asian American (AA) and African (Af) are mostly confined to Eastern Asia, The Americas and African regions respectively. Several studies have shown that genetic variation of HPV 16 is associated with the risk of cervical cancer, which also seems to be dependent on the population. This relationship between ethnicity and variants have led to the suggestion that there is co-evolution of variants with humankind. Our aim was to evaluate the relationship between the individual ancestry proportion and infection with HPV 16 variants in cervical cancer. We examined the association between ancestry and HPV 16 variants in samples of 82 cervical cancer cases from different regions of Colombia. Individual ancestry proportions (European, African and Native American) were estimated by genotyping 106 ancestry informative markers. Variants were identified by PCR amplification of the E6 gene, followed by reverse line blot hybridization (RLB) with variants specific probes. Overall European (E) and Asian American (AA) variants frequency was 66.5% and 33.5% respectively. Similar distribution was observed in cases with higher proportions of European or African ancestry. A higher Native American ancestry was significantly associated with higher frequency of E variants (median ancestry>23.6%, Age and place of birth adjusted OR: 3.55, 95% CI: 1.26-10.03, p=0.01). Even further, an inverse geographic correlation between Native American ancestry and frequency of infections with AA variants was observed (ρ=-0.825, p=0.008). Regions with higher proportion of Native American ancestry had a lower frequency of AA variants of HPV 16. This study suggests replacement of AA variants by E variants of human papillomavirus 16 in cervical cancer cases with high Native American ancestry. Copyright © 2014 Elsevier B.V. All rights reserved.
Tishkoff, Sarah A.; Reed, Floyd A.; Friedlaender, Françoise R.; Ehret, Christopher; Ranciaro, Alessia; Froment, Alain; Hirbo, Jibril B.; Awomoyi, Agnes A.; Bodo, Jean-Marie; Doumbo, Ogobara; Ibrahim, Muntaser; Juma, Abdalla T.; Kotze, Maritha J.; Lema, Godfrey; Moore, Jason H.; Mortensen, Holly; Nyambo, Thomas B.; Omar, Sabah A.; Powell, Kweli; Pretorius, Gideon S.; Smith, Michael W.; Thera, Mahamadou A.; Wambebe, Charles; Weber, James L.; Williams, Scott M.
Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other African (~8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies. PMID:19407144
Thomas, Richard M; Parks, Connie L; Richard, Adam H
A common task in forensic anthropology involves the estimation of the ancestry of a decedent by comparing their skeletal morphology and measurements to skeletons of individuals from known geographic groups. However, the accuracy rates of ancestry estimation methods in actual forensic casework have rarely been studied. This article uses 99 forensic cases with identified skeletal remains to develop accuracy rates for ancestry estimations conducted by forensic anthropologists. The overall rate of correct ancestry estimation from these cases is 90.9%, which is comparable to most research-derived rates and those reported by individual practitioners. Statistical tests showed no significant difference in accuracy rates depending on examiner education level or on the estimated or identified ancestry. More recent cases showed a significantly higher accuracy rate. The incorporation of metric analyses into the ancestry estimate in these cases led to a higher accuracy rate. © 2017 American Academy of Forensic Sciences.
Bermingham, P. M.; Fairhead, J. D.; Stuart, G. W.
Gravity studies of the Darfur uplift, Western Sudan, show it to be associated with a circular negative Bouguer anomaly, 50 mGal in amplitude and 700 km across. A three-dimensional model interpretation of the Darfur anomaly, using constraints deduced from geophysical studies of similar but more evolved Kenya and Ethiopia domes, suggests either a low-density laccolithic body at mid-lithospheric depth (~ 60 km) or a thinned lithosphere with emplacement at high level of low-density asthenospheric material. The regional setting of the Darfur uplift is described in terms of it being an integral part of the Central African Rift System which is shown to be broadly equivalent to the early to middle Miocene stage in the development of the Afro-Arabian Rift System. Comparisons between these rift systems suggest that extensional tectonics and passive rifting, resulting in the subsiding sedimentary rift basins associated with the Ngaoundere, Abu Gabra, Red Sea and Gulf of Aden rifts, are more typical of the early stage development of passive continental margins than the active domal uplift and development of rifted features associated with the Darfur, Kenya and Ethiopia domes.
Heinsohn, Robert; Packer, Craig
Female lions (Panthera leo) showed persistent individual differences in the extent to which they participated in group-territorial conflict. When intergroup encounters were simulated by playback of aggressive vocalizations, some individuals consistently led the approach to the recorded intruder, whereas others lagged behind and avoided the risks of fighting. The lead females recognized that certain companions were laggards but failed to punish them, which suggests that cooperation is not maintained by reciprocity. Modification of the "odds" in these encounters revealed that some females joined the group response when they were most needed, whereas other lagged even farther behind. The complexity of these responses emphasizes the great diversity of individual behavior in this species and the inadequacy of current theory to explain cooperation in large groups.
Byun, Jinyoung; Han, Younghun; Gorlov, Ivan P; Busam, Jonathan A; Seldin, Michael F; Amos, Christopher I
Accurate inference of genetic ancestry is of fundamental interest to many biomedical, forensic, and anthropological research areas. Genetic ancestry memberships may relate to genetic disease risks. In a genome association study, failing to account for differences in genetic ancestry between cases and controls may also lead to false-positive results. Although a number of strategies for inferring and taking into account the confounding effects of genetic ancestry are available, applying them to large studies (tens thousands samples) is challenging. The goal of this study is to develop an approach for inferring genetic ancestry of samples with unknown ancestry among closely related populations and to provide accurate estimates of ancestry for application to large-scale studies. In this study we developed a novel distance-based approach, Ancestry Inference using Principal component analysis and Spatial analysis (AIPS) that incorporates an Inverse Distance Weighted (IDW) interpolation method from spatial analysis to assign individuals to population memberships. We demonstrate the benefits of AIPS in analyzing population substructure, specifically related to the four most commonly used tools EIGENSTRAT, STRUCTURE, fastSTRUCTURE, and ADMIXTURE using genotype data from various intra-European panels and European-Americans. While the aforementioned commonly used tools performed poorly in inferring ancestry from a large number of subpopulations, AIPS accurately distinguished variations between and within subpopulations. Our results show that AIPS can be applied to large-scale data sets to discriminate the modest variability among intra-continental populations as well as for characterizing inter-continental variation. The method we developed will protect against spurious associations when mapping the genetic basis of a disease. Our approach is more accurate and computationally efficient method for inferring genetic ancestry in the large-scale genetic studies.
A. J. R. Van De Vijver
Full Text Available It is argued that the 1998 Employment Equity Act, in which the onus of the proof to demonstrate the adequacy of psychometric instruments is on psychology as a profession, creates daunting tasks, but also creates unique opportunities. Recent developments in the assessment of multicultural groups are described, with an emphasis on procedures to enhance the validity of measures for all groups involved and on procedures to examine validity. Bias and equivalence are treated as key concepts in multicultural assessment. Four kinds of procedures for dealing with multicultural assessment (namely, establishing equivalence of existing instruments, defining new norms, developing new instruments, and studying validity-threatening factors in multicultural assessment are described and illustrated. Opsomming Daar word geredeneer dat die Wet op Billike Indiensneming, 1998, waarvolgens die onus om die geskiktheid van psigometriese instrumente te bewys na psigologie as professie verskuif, nie net oorweldigende take nie maar ook unieke geleenthede skep. Onlangse ontwikkelings rakende die evaluering van multikulturele groepe word beskryf, met die klem op prosedures om die geldigheid van metings vir alle groepe te verhoog en op prosedures om hierdie geldigheid te ondersoek. Sydigheid en ekwivalensie word as sleutelkonsepte in multikulturele evaluering behandel. Vier soorte prosedures om multikulturele evaluering te hanteer (te wete bepaling van die ekwivalensie van bestaande instrumente, definiëring van nuwe norme, ontwikkeling van nuwe instrumente en ‘n studie van faktore wat die geldigheid van multikulturele evaluering bedreig word beskryf en geïllustreer.
White, Nathan J.; Rayle, Andrea Dixon
This article describes the school-based, small group adaptation of the existing Strong Teens Curriculum (STC) for African American male adolescents in high schools. The STC was created to equip adolescents with skills that promote more effective social interaction and enhance personal emotional and psychological wellness. The authors present a…
Lionesses, Panthera leoin the Serengeti ecosystem, Tanzania, assess the odds of winning group-territorial contests by counting the number of opponents they hear roaring. They will approach intruders aggressively only if they outnumber them. Here the lionesses in the Serengeti are compared with another population living nearby but in strikingly different ecological circumstances. The lions of Ngorongoro Crater live at much higher densities owing to year-round availability of non-migratory prey species, but also suffer higher mortality from fighting. Playback experiments showed that lionesses in the crater differ from those in the Serengeti by approaching 'intruders' more quickly when the odds of winning are low. This increased aggression is interpreted in terms of the greater difficulty of holding a territory at high population density.
Williams, Christina Dawn; Satia, Jessie A; Adair, Linda S; Stevens, June; Galanko, Joseph; Keku, Temitope O; Sandler, Robert S
Associations between individual foods and nutrients and colorectal cancer have been inconsistent, and few studies have examined associations between food, nutrients, dietary patterns, and rectal cancer. We examined the relationship between food groups and dietary patterns and risk for rectal cancer in non-Hispanic Whites and African-Americans. Data were from the North Carolina Colon Cancer Study-Phase II and included 1,520 Whites (720 cases, 800 controls) and 384 African-Americans (225 cases, 159 controls). Diet was assessed using the Diet History Questionnaire. Multivariate logistic regression models were used to estimate odds ratios and 95% confidence intervals. Among Whites, non-whole grains and white potatoes were associated with elevated risk for rectal cancer whereas fruit, vegetables, dairy, fish, and poultry were associated with reduced risk. In African-Americans, high consumption of other fruit and added sugar suggested elevated risk. We identified three major dietary patterns in Whites and African-Americans. The high fat/meat/potatoes pattern was observed in both race groups but was only positively associated with risk in Whites (odds ratio, 1.84; 95% confidence interval, 1.03-3.15). The vegetable/fish/poultry and fruit/whole grain/dairy patterns in Whites had significant inverse associations with risk. In African-Americans, there was a positive dose-response for the fruit/vegetables pattern (P(trend) pattern (P(trend) dietary patterns with rectal cancer risk differ between Whites and African-Americans, highlighting the importance of examining diet and cancer relationships in racially diverse populations.
Eva Pérez Hernández
Full Text Available Desde la Antigüedad clásica hasta nuestros días se han multiplicado las representaciones cartográficas de la Tierra, sin embargo, no todos los territorios del planeta han recibido la misma atención. En el caso del continente africano son escasas las colecciones de mapas recientes y, especialmente, las que conforman atlas temáticos. Esta circunstancia fue determinante en la orientación de las prácticas desarrolladas en Casa África durante el curso académico 2012-2013, al amparo del Consorcio Casa África-Universidad de Las Palmas de Gran Canaria. El objetivo de las prácticas fue la elaboración de un atlas digital de África que tuvo como resultado la realización de cuarenta mapas temáticos basados en indicadores geográficos, ambientales, demográficos, económicos, sociales, geopolíticos, culturales y de sus relaciones económicas y políticas con España. La elaboración de dicho atlas se vio afectada por numerosas dificultades en cuanto a la búsqueda y tratamiento de las fuentes de información y por un trabajo de diseño y edición que requirió de la utilización de las nuevas tecnologías de la información geográfica. El presente artículo reflexiona acerca de la importancia de la cartografía como herramienta imprescindible de conocimiento geográfico y acerca de la superación de dificultades que entrañan retos como el de la realización de un atlas sobre el estado actual del continente africano.From Classical Antiquity to the present days, cartographic representations of the Earth have multiplied. However, not all the territories of the planet have received the same attention. In the case of the African continent, there are few collections of recent maps, especially, of those that are composed of thematic atlases. This circumstance was decisive in determining the focus of the internship in Casa África during academic year 2012-2013, under the auspices of the Consortium Casa África - University of Las Palmas de Gran
Qu, Haiyan; Shewchuk, Richard; Mannon, Roslyn B.; Gaston, Robert; Segev, Dorry L.; Mannon, Elinor C.; Martin, Michelle Y.
Background and objectives African Americans are disproportionately affected by ESRD, but few receive a living donor kidney transplant. Surveys assessing attitudes toward donation have shown that African Americans are less likely to express a willingness to donate their own organs. Studies aimed at understanding factors that may facilitate the willingness of African Americans to become organ donors are needed. Design, setting, participants, & measurements A novel formative research method was used (the nominal group technique) to identify and prioritize strategies for facilitating increases in organ donation among church-attending African Americans. Four nominal group technique panel interviews were convened (three community and one clergy). Each community panel represented a distinct local church; the clergy panel represented five distinct faith-based denominations. Before nominal group technique interviews, participants completed a questionnaire that assessed willingness to become a donor; 28 African-American adults (≥19 years old) participated in the study. Results In total, 66.7% of participants identified knowledge- or education-related strategies as most important strategies in facilitating willingness to become an organ donor, a view that was even more pronounced among clergy. Three of four nominal group technique panels rated a knowledge-based strategy as the most important and included strategies, such as information on donor involvement and donation-related risks; 29.6% of participants indicated that they disagreed with deceased donation, and 37% of participants disagreed with living donation. Community participants’ reservations about becoming an organ donor were similar for living (38.1%) and deceased (33.4%) donation; in contrast, clergy participants were more likely to express reservations about living donation (33.3% versus 16.7%). Conclusions These data indicate a greater opposition to living donation compared with donation after one’s death
Slaughter-Acey, Jaime C.; Caldwell, Cleopatra H.; Misra, Dawn P.
Background Racism has been hypothesized as a barrier to accessing healthcare. No quantitative study has directly assessed its influence on women's initiation of prenatal care (PNC). We examined the relationship between PNC entry and experiences of personal and group racism among low-income African American women. We also examined whether the use of denial of racism as coping mechanism was associated with a delay in accessing PNC. Methods Using a prospective/retrospective cohort design we collected data from 872 African American women (prenatally: n=484; postpartum: n=388). Multinomial logistic regression was used to assess the relationship between the overall denial of racism index and PNC initiation. Findings PNC entry was not significantly associated with personal experiences of racism (p=0.33); it was significantly associated with group experiences (pracism experienced by other AAs was a barrier to early PNC among low-income African American women. Delayed access to PNC may be rooted in the avoidance of racialized experiences among less empowered women when faced with discrimination. Our findings have important implication for the engagement of African American women into the PNC delivery system and the health care system postpartum. PMID:24041828
Amy Rebecca Bentley
Full Text Available Low levels of high-density cholesterol (HDLc accompany chronic kidney disease, but the association between HDLc and the estimated glomerular filtration rate (eGFR in the general population is unclear. We investigated the HDLc-eGFR association in nondiabetic Han Chinese (HC, n=1100, West Africans (WA, n=1497, and African Americans (AA, n=1539. There were significant differences by ancestry: HDLc was positively associated with eGFR in HC (β=0.13, P<0.0001, but negatively associated among African ancestry populations (WA: −0.19, P<0.0001; AA: −0.09, P=0.02. These differences were also seen in nationally-representative NHANES data (among European Americans: 0.09, P=0.005; among African Americans −0.14, P=0.03. To further explore the findings in African ancestry populations, we investigated the role of an African ancestry-specific nephropathy risk variant, rs73885319, in the gene encoding HDL-associated APOL1. Among AA, an inverse HDLc-eGFR association was observed only with the risk genotype (−0.38 versus 0.001; P=0.03. This interaction was not seen in WA. In summary, counter to expectation, an inverse HDLc-eGFR association was observed among those of African ancestry. Given the APOL1 × HDLc interaction among AA, genetic factors may contribute to this paradoxical association. Notably, these findings suggest that the unexplained mechanism by which APOL1 affects kidney-disease risk may involve HDLc.
Kwan, Marilyn L; Yao, Song; Lee, Valerie S; Roh, Janise M; Zhu, Qianqian; Ergas, Isaac J; Liu, Qian; Zhang, Yali; Kutner, Susan E; Quesenberry, Charles P; Ambrosone, Christine B; Kushi, Lawrence H
Breast cancer-related lymphedema (BCRL) is a serious chronic condition after breast cancer (BC) surgery and treatment. It is unclear if BCRL risk varies by race/ethnicity. In a multiethnic prospective cohort study of 2953 BC patients, we examined the association of self-reported BCRL status with self-reported race/ethnicity and estimated genetic ancestry. Hazard ratios (HR) and 95 % confidence intervals (CI) were calculated by multivariable Cox proportional hazards models, with follow-up starting 6 months post-BC diagnosis. Estimates were further stratified by body mass index (BMI). By 48 months of follow-up, 342 (11.6 %) women reported having BCRL. Younger age at BC diagnosis, higher BMI at baseline, and lower physical activity were associated with greater BCRL risk. African American (AA) women had a 2-fold increased risk of BCRL compared with White women (HR = 2.04; 95 % CI 1.35-3.08). African genetic ancestry was also associated with an increased risk (HR = 2.50; 95 % CI 1.43, 4.36). Both risks were attenuated but remained elevated after adjusting for known risk factors and became more pronounced when restricted to the nonobese women (adjusted HR = 2.31 for AA and HR = 3.70 for African ancestry, both p ancestry data, with a potential ancestry-obesity interaction.
Hollenbach, Jill A.; Saperstein, Aliya; Albrecht, Mark; Vierra-Green, Cynthia; Parham, Peter; Norman, Paul J.; Maiers, Martin
We conducted a nationwide study comparing self-identification to genetic ancestry classifications in a large cohort (n = 1752) from the National Marrow Donor Program. We sought to determine how various measures of self-identification intersect with genetic ancestry, with the aim of improving matching algorithms for unrelated bone marrow transplant. Multiple dimensions of self-identification, including race/ethnicity and geographic ancestry were compared to classifications based on ancestry informative markers (AIMs), and the human leukocyte antigen (HLA) genes, which are required for transplant matching. Nearly 20% of responses were inconsistent between reporting race/ethnicity versus geographic ancestry. Despite strong concordance between AIMs and HLA, no measure of self-identification shows complete correspondence with genetic ancestry. In certain cases geographic ancestry reporting matches genetic ancestry not reflected in race/ethnicity identification, but in other cases geographic ancestries show little correspondence to genetic measures, with important differences by gender. However, when respondents assign ancestry to grandparents, we observe sub-groups of individuals with well- defined genetic ancestries, including important differences in HLA frequencies, with implications for transplant matching. While we advocate for tailored questioning to improve accuracy of ancestry ascertainment, collection of donor grandparents’ information will improve the chances of finding matches for many patients, particularly for mixed-ancestry individuals. PMID:26287376
Jill A Hollenbach
Full Text Available We conducted a nationwide study comparing self-identification to genetic ancestry classifications in a large cohort (n = 1752 from the National Marrow Donor Program. We sought to determine how various measures of self-identification intersect with genetic ancestry, with the aim of improving matching algorithms for unrelated bone marrow transplant. Multiple dimensions of self-identification, including race/ethnicity and geographic ancestry were compared to classifications based on ancestry informative markers (AIMs, and the human leukocyte antigen (HLA genes, which are required for transplant matching. Nearly 20% of responses were inconsistent between reporting race/ethnicity versus geographic ancestry. Despite strong concordance between AIMs and HLA, no measure of self-identification shows complete correspondence with genetic ancestry. In certain cases geographic ancestry reporting matches genetic ancestry not reflected in race/ethnicity identification, but in other cases geographic ancestries show little correspondence to genetic measures, with important differences by gender. However, when respondents assign ancestry to grandparents, we observe sub-groups of individuals with well- defined genetic ancestries, including important differences in HLA frequencies, with implications for transplant matching. While we advocate for tailored questioning to improve accuracy of ancestry ascertainment, collection of donor grandparents' information will improve the chances of finding matches for many patients, particularly for mixed-ancestry individuals.
Sérgio D J Pena
Full Text Available Based on pre-DNA racial/color methodology, clinical and pharmacological trials have traditionally considered the different geographical regions of Brazil as being very heterogeneous. We wished to ascertain how such diversity of regional color categories correlated with ancestry. Using a panel of 40 validated ancestry-informative insertion-deletion DNA polymorphisms we estimated individually the European, African and Amerindian ancestry components of 934 self-categorized White, Brown or Black Brazilians from the four most populous regions of the Country. We unraveled great ancestral diversity between and within the different regions. Especially, color categories in the northern part of Brazil diverged significantly in their ancestry proportions from their counterparts in the southern part of the Country, indicating that diverse regional semantics were being used in the self-classification as White, Brown or Black. To circumvent these regional subjective differences in color perception, we estimated the general ancestry proportions of each of the four regions in a form independent of color considerations. For that, we multiplied the proportions of a given ancestry in a given color category by the official census information about the proportion of that color category in the specific region, to arrive at a "total ancestry" estimate. Once such a calculation was performed, there emerged a much higher level of uniformity than previously expected. In all regions studied, the European ancestry was predominant, with proportions ranging from 60.6% in the Northeast to 77.7% in the South. We propose that the immigration of six million Europeans to Brazil in the 19th and 20th centuries--a phenomenon described and intended as the "whitening of Brazil"--is in large part responsible for dissipating previous ancestry dissimilarities that reflected region-specific population histories. These findings, of both clinical and sociological importance for Brazil
Emile R Chimusa
Full Text Available Admixed populations can make an important contribution to the discovery of disease susceptibility genes if the parental populations exhibit substantial variation in susceptibility. Admixture mapping has been used successfully, but is not designed to cope with populations that have more than two or three ancestral populations. The inference of admixture proportions and local ancestry and the imputation of missing genotypes in admixed populations are crucial in both understanding variation in disease and identifying novel disease loci. These inferences make use of reference populations, and accuracy depends on the choice of ancestral populations. Using an insufficient or inaccurate ancestral panel can result in erroneously inferred ancestry and affect the detection power of GWAS and meta-analysis when using imputation. Current algorithms are inadequate for multi-way admixed populations. To address these challenges we developed PROXYANC, an approach to select the best proxy ancestral populations. From the simulation of a multi-way admixed population we demonstrate the capability and accuracy of PROXYANC and illustrate the importance of the choice of ancestry in both estimating admixture proportions and imputing missing genotypes. We applied this approach to a complex, uniquely admixed South African population. Using genome-wide SNP data from over 764 individuals, we accurately estimate the genetic contributions from the best ancestral populations: isiXhosa [Formula: see text], ‡Khomani SAN [Formula: see text], European [Formula: see text], Indian [Formula: see text], and Chinese [Formula: see text]. We also demonstrate that the ancestral allele frequency differences correlate with increased linkage disequilibrium in the South African population, which originates from admixture events rather than population bottlenecks.The collective term for people of mixed ancestry in southern Africa is "Coloured," and this is officially recognized in South
Ansari-Pour, Naser; Moñino, Yves; Duque, Constanza; Gallego, Natalia; Bedoya, Gabriel; Thomas, Mark G; Bradman, Neil
The Palenque, a black community in rural Colombia, have an oral history of fugitive African slaves founding a free village near Cartagena in the seventeenth century. Recently, linguists have identified some 200 words in regular use that originate in a Kikongo language, with Yombe, mainly spoken in the Congo region, being the most likely source. The non-recombining portion of the Y chromosome (NRY) and mitochondrial DNA were analysed to establish whether there was greater similarity between present-day members of the Palenque and Yombe than between the Palenque and 42 other African groups (for all individuals,n= 2799) from which forced slaves might have been taken. NRY data are consistent with the linguistic evidence that Yombe is the most likely group from which the original male settlers of Palenque came. Mitochondrial DNA data suggested substantial maternal sub-Saharan African ancestry and a strong founder effect but did not associate Palenque with any particular African group. In addition, based on cultural data including inhabitants' claims of linguistic differences, it has been hypothesized that the two districts of the village (Abajo and Arriba) have different origins, with Arriba founded by men originating in Congo and Abajo by those born in Colombia. Although significant genetic structuring distinguished the two from each other, no supporting evidence for this hypothesis was found. © 2016 The Author(s).
Full Text Available Northeast Africa has a long history of human habitation, with fossil-finds from the earliest anatomically modern humans, and housing ancient civilizations. The region is also the gate-way out of Africa, as well as a portal for migration into Africa from Eurasia via the Middle East and the Arabian Peninsula. We investigate the population history of northeast Africa by genotyping ~3.9 million SNPs in 221 individuals from 18 populations sampled in Sudan and South Sudan and combine this data with published genome-wide data from surrounding areas. We find a strong genetic divide between the populations from the northeastern parts of the region (Nubians, central Arab populations, and the Beja and populations towards the west and south (Nilotes, Darfur and Kordofan populations. This differentiation is mainly caused by a large Eurasian ancestry component of the northeast populations likely driven by migration of Middle Eastern groups followed by admixture that affected the local populations in a north-to-south succession of events. Genetic evidence points to an early admixture event in the Nubians, concurrent with historical contact between North Sudanese and Arab groups. We estimate the admixture in current-day Sudanese Arab populations to about 700 years ago, coinciding with the fall of Dongola in 1315/1316 AD, a wave of admixture that reached the Darfurian/Kordofanian populations some 400-200 years ago. In contrast to the northeastern populations, the current-day Nilotic populations from the south of the region display little or no admixture from Eurasian groups indicating long-term isolation and population continuity in these areas of northeast Africa.
Hollfelder, Nina; Schlebusch, Carina M; Günther, Torsten; Babiker, Hiba; Hassan, Hisham Y; Jakobsson, Mattias
Northeast Africa has a long history of human habitation, with fossil-finds from the earliest anatomically modern humans, and housing ancient civilizations. The region is also the gate-way out of Africa, as well as a portal for migration into Africa from Eurasia via the Middle East and the Arabian Peninsula. We investigate the population history of northeast Africa by genotyping ~3.9 million SNPs in 221 individuals from 18 populations sampled in Sudan and South Sudan and combine this data with published genome-wide data from surrounding areas. We find a strong genetic divide between the populations from the northeastern parts of the region (Nubians, central Arab populations, and the Beja) and populations towards the west and south (Nilotes, Darfur and Kordofan populations). This differentiation is mainly caused by a large Eurasian ancestry component of the northeast populations likely driven by migration of Middle Eastern groups followed by admixture that affected the local populations in a north-to-south succession of events. Genetic evidence points to an early admixture event in the Nubians, concurrent with historical contact between North Sudanese and Arab groups. We estimate the admixture in current-day Sudanese Arab populations to about 700 years ago, coinciding with the fall of Dongola in 1315/1316 AD, a wave of admixture that reached the Darfurian/Kordofanian populations some 400-200 years ago. In contrast to the northeastern populations, the current-day Nilotic populations from the south of the region display little or no admixture from Eurasian groups indicating long-term isolation and population continuity in these areas of northeast Africa.
King, Kimberly R.
This study examined the effects of three types of group consciousness among African American women ("ethnic," "feminist," and "womanist") on prejudice attributions and appraised personal significance ("centrality") of a negative intergroup event. African American female college students (N = 123) imagined themselves in an audiotaped scenario in…
Kristy R Crooks
Full Text Available Primary open-angle glaucoma (POAG is the most common form of glaucoma and one of the leading causes of vision loss worldwide. The genetic etiology of POAG is complex and poorly understood. The purpose of this work is to identify genomic regions of interest linked to POAG. This study is the largest genetic linkage study of POAG performed to date: genomic DNA samples from 786 subjects (538 Caucasian ancestry, 248 African ancestry were genotyped using either the Illumina GoldenGate Linkage 4 Panel or the Illumina Infinium Human Linkage-12 Panel. A total of 5233 SNPs was analyzed in 134 multiplex POAG families (89 Caucasian ancestry, 45 African ancestry. Parametric and non-parametric linkage analyses were performed on the overall dataset and within race-specific datasets (Caucasian ancestry and African ancestry. Ordered subset analysis was used to stratify the data on the basis of age of glaucoma diagnosis. Novel linkage regions were identified on chromosomes 1 and 20, and two previously described loci-GLC1D on chromosome 8 and GLC1I on chromosome 15--were replicated. These data will prove valuable in the context of interpreting results from genome-wide association studies for POAG.
Alkes L Price
Full Text Available Identifying the ancestry of chromosomal segments of distinct ancestry has a wide range of applications from disease mapping to learning about history. Most methods require the use of unlinked markers; but, using all markers from genome-wide scanning arrays, it should in principle be possible to infer the ancestry of even very small segments with exquisite accuracy. We describe a method, HAPMIX, which employs an explicit population genetic model to perform such local ancestry inference based on fine-scale variation data. We show that HAPMIX outperforms other methods, and we explore its utility for inferring ancestry, learning about ancestral populations, and inferring dates of admixture. We validate the method empirically by applying it to populations that have experienced recent and ancient admixture: 935 African Americans from the United States and 29 Mozabites from North Africa. HAPMIX will be of particular utility for mapping disease genes in recently admixed populations, as its accurate estimates of local ancestry permit admixture and case-control association signals to be combined, enabling more powerful tests of association than with either signal alone.
McClelland, Molly L; Weekes, Carmon V N; Bazzi, Hussein; Warwinsky, Joshua; Abouarabi, Wassim; Snell, Felicia; Salamey, Tarick
Effectiveness of health education programs and interventions, designed to improve obesity rates, may vary according to perceptions of health within cultural groups. A qualitative approach was used. Two minority cultural groups (Arab-American and African-American) living in the same county were studied to compare perceptions of health, nutrition, and obesity and subsequent health behaviors. Control, expectations, bias, acceptance, and access were the five themes identified. Arab-Americans that had lower weights, lower prevalence of chronic diseases, expected healthy weights, reported age and gender bias related to being overweight were not as accepting of being overweight and did not report difficulties in accessing healthy food choices compared to their African-American counterparts. Health interventions aimed at reducing obesity rates and related chronic diseases should be culturally specific and aimed at changing expected and accepted cultural norms. Cultural group's void of certain disease states should be studied and used as models to ameliorate the problem in other cultures. Changing health behaviors within a certain cultural group may produce better outcomes when initiated from a member of that same group. The impact of economic and environmental factors on health behaviors must also be considered.
Murphy, Eleanor; Hou, Liping; Maher, Brion S; Woldehawariat, Girma; Kassem, Layla; Akula, Nirmala; Laje, Gonzalo; McMahon, Francis J
The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) Study revealed poorer antidepressant treatment response among black compared with white participants. This racial disparity persisted even after socioeconomic and baseline clinical factors were taken into account. Some studies have suggested genetic contributions to this disparity, but none have attempted to disentangle race and genetic ancestry. Here we used genome-wide single-nucleotide polymorphism (SNP) data to examine independent contributions of race and genetic ancestry to citalopram response. Secondary data analyses included 1877 STAR*D participants who completed an average of 10 weeks of citalopram treatment and provided DNA samples. Participants reported their race as White (n=1464), black (n=299) or other/mixed (n=114). Genetic ancestry was estimated by multidimensional scaling (MDS) analyses of about 500 000 SNPs. Ancestry proportions were estimated by STRUCTURE. Structural equation modeling was used to examine the direct and indirect effects of observed and latent predictors of response, defined as change in the Quick Inventory of Depressive Symptomatology (QIDS) score from baseline to exit. Socioeconomic and baseline clinical factors, race, and anxiety significantly predicted response, as previously reported. However, direct effects of race disappeared in all models that included genetic ancestry. Genetic African ancestry predicted lower treatment response in all models. Although socioeconomic and baseline clinical factors drive racial differences in antidepressant response, genetic ancestry, rather than self-reported race, explains a significant fraction of the residual differences. Larger samples would be needed to identify the specific genetic mechanisms that may be involved, but these findings underscore the importance of including more African-American patients in drug trials. PMID:23827886
Warner, Wayne A; Morrison, Robert L; Lee, Tammy Y; Williams, Tanisha M; Ramnarine, Shelina; Roach, Veronica; Slovacek, Simeon; Maharaj, Ravi; Bascombe, Nigel; Bondy, Melissa L; Ellis, Matthew J; Toriola, Adetunji T; Roach, Allana; Llanos, Adana A M
Breast cancer (BC) is the most common newly diagnosed cancer among women in Trinidad and Tobago (TT) and BC mortality rates are among the highest in the world. Globally, racial/ethnic trends in BC incidence, mortality and survival have been reported. However, such investigations have not been conducted in TT, which has been noted for its rich diversity. In this study, we investigated associations among ancestry, geography and BC incidence, mortality and survival in TT. Data on 3767 incident BC cases, reported to the National Cancer Registry of TT, from 1995 to 2007, were analyzed in this study. Women of African ancestry had significantly higher BC incidence and mortality rates ( 66.96; 30.82 per 100,000) compared to women of East Indian ( 41.04, MORTALITY: 14.19 per 100,000) or mixed ancestry ( 36.72, MORTALITY: 13.80 per 100,000). Geographically, women residing in the North West Regional Health Authority (RHA) catchment area followed by the North Central RHA exhibited the highest incidence and mortality rates. Notable ancestral differences in survival were also observed. Women of East Indian and mixed ancestry experienced significantly longer survival than those of African ancestry. Differences in survival by geography were not observed. In TT, ancestry and geographical residence seem to be strong predictors of BC incidence and mortality rates. Additionally, disparities in survival by ancestry were found. These data should be considered in the design and implementation of strategies to reduce BC incidence and mortality rates in TT. © 2015 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.
Santos, C; Fondevila, M; Ballard, D; Banemann, R; Bento, A M; Børsting, C; Branicki, W; Brisighelli, F; Burrington, M; Capal, T; Chaitanya, L; Daniel, R; Decroyer, V; England, R; Gettings, K B; Gross, T E; Haas, C; Harteveld, J; Hoff-Olsen, P; Hoffmann, A; Kayser, M; Kohler, P; Linacre, A; Mayr-Eduardoff, M; McGovern, C; Morling, N; O'Donnell, G; Parson, W; Pascali, V L; Porto, M J; Roseth, A; Schneider, P M; Sijen, T; Stenzl, V; Court, D Syndercombe; Templeton, J E; Turanska, M; Vallone, P M; Oorschot, R A H van; Zatkalikova, L; Carracedo, Á; Phillips, C
There is increasing interest in forensic ancestry tests, which are part of a growing number of DNA analyses that can enhance routine profiling by obtaining additional genetic information about unidentified DNA donors. Nearly all ancestry tests use single nucleotide polymorphisms (SNPs), but these currently rely on SNaPshot single base extension chemistry that can fail to detect mixed DNA. Insertion-deletion polymorphism (Indel) tests have been developed using dye-labeled primers that allow direct capillary electrophoresis detection of PCR products (PCR-to-CE). PCR-to-CE maintains the direct relationship between input DNA and signal strength as each marker is detected with a single dye, so mixed DNA is more reliably detected. We report the results of a collaborative inter-laboratory exercise of 19 participants (15 from the EDNAP European DNA Profiling group) that assessed a 34-plex SNP test using SNaPshot and a 46-plex Indel test using PCR-to-CE. Laboratories were asked to type five samples with different ancestries and detect an additional mixed DNA sample. Statistical inference of ancestry was made by participants using the Snipper online Bayes analysis portal plus an optional PCA module that analyzes the genotype data alongside calculation of Bayes likelihood ratios. Exercise results indicated consistent genotyping performance from both tests, reaching a particularly high level of reliability for the Indel test. SNP genotyping gave 93.5% concordance (compared to the organizing laboratory's data) that rose to 97.3% excluding one laboratory with a large number of miscalled genotypes. Indel genotyping gave a higher concordance rate of 99.8% and a reduced no-call rate compared to SNP analysis. All participants detected the mixture from their Indel peak height data and successfully assigned the correct ancestry to the other samples using Snipper, with the exception of one laboratory with SNP miscalls that incorrectly assigned ancestry of two samples and did not obtain
Phillips, Christopher; Prieto, Lourdes; Fondevila, Manuel; Salas, Antonio; Gómez-Tato, Antonio; Álvarez-Dios, José; Alonso, Antonio; Blanco-Verea, Alejandro; Brión, María; Montesino, Marta; Carracedo, Ángel; Lareu, María Victoria
The 11-M Madrid commuter train bombings of 2004 constituted the second biggest terrorist attack to occur in Europe after Lockerbie, while the subsequent investigation became the most complex and wide-ranging forensic case in Spain. Standard short tandem repeat (STR) profiling of 600 exhibits left certain key incriminatory samples unmatched to any of the apprehended suspects. A judicial order to perform analyses of unmatched samples to differentiate European and North African ancestry became a critical part of the investigation and was instigated to help refine the search for further suspects. Although mitochondrial DNA (mtDNA) and Y-chromosome markers routinely demonstrate informative geographic differentiation, the populations compared in this analysis were known to show a proportion of shared mtDNA and Y haplotypes as a result of recent gene-flow across the western Mediterranean, while any two loci can be unrepresentative of the ancestry of an individual as a whole. We based our principal analysis on a validated 34plex autosomal ancestry-informative-marker single nucleotide polymorphism (AIM-SNP) assay to make an assignment of ancestry for DNA from seven unmatched case samples including a handprint from a bag containing undetonated explosives together with personal items recovered from various locations in Madrid associated with the suspects. To assess marker informativeness before genotyping, we predicted the probable classification success for the 34plex assay with standard error estimators for a naïve Bayesian classifier using Moroccan and Spanish training sets (each n = 48). Once misclassification error was found to be sufficiently low, genotyping yielded seven near-complete profiles (33 of 34 AIM-SNPs) that in four cases gave probabilities providing a clear assignment of ancestry. One of the suspects predicted to be North African by AIM-SNP analysis of DNA from a toothbrush was identified late in the investigation as Algerian in origin. The results
McGeorge, Cuan; Ginsberg, Samuel; Pichegru, Lorien; Pistorius, Pierre A.
Marine piscivores have evolved a variety of morphological and behavioural adaptations, including group foraging, to optimize foraging efficiency when targeting shoaling fish. For penguins that are known to associate at sea and feed on these prey resources, there is nonetheless a lack of empirical evidence to support improved foraging efficiency when foraging with conspecifics. We examined the hunting strategies and foraging performance of breeding African penguins equipped with animal-borne video recorders. Individuals pursued both solitary as well as schooling pelagic fish, and demonstrated independent as well as group foraging behaviour. The most profitable foraging involved herding of fish schools upwards during the ascent phase of a dive where most catches constituted depolarized fish. Catch-per-unit-effort was significantly improved when targeting fish schools as opposed to single fish, especially when foraging in groups. In contrast to more generalist penguin species, African penguins appear to have evolved specialist hunting strategies closely linked to their primary reliance on schooling pelagic fish. The specialist nature of the observed hunting strategies further limits the survival potential of this species if Allee effects reduce group size-related foraging efficiency. This is likely to be exacerbated by diminishing fish stocks due to resource competition and environmental change. PMID:28989785
Aambø, Arild; Klemsdal, Tor Ole
Population groups of different ancestry appear to have varying prevalence of diabetes, different risks of developing cardiovascular disease and different responses to certain drugs that are used for these conditions. We wished to review the literature in this field. We have performed searches in several databases for systematic review articles published from the year 2000 onwards, and supplemented these with articles from reference lists, our own literature archives and a pyramid search in the Norwegian Electronic Health Library database. Altogether 37 articles were included. With regard to diagnosed diabetes, the prevalence of coronary heart disease and stroke varies among groups of South Asian, East Asian, African and European ancestry. In patients of South Asian ancestry, the risk of coronary heart disease appears to be twice that of Europeans, and the disease occurs 5–10 years earlier. The prevalence of stroke is especially high in persons of African ancestry. Risk factors such as dyslipidemia and hypertension are distributed differently among these groups. The therapeutic response to drugs such as beta blockers, ACE inhibitors and various statins differs; for example, statin doses in Asians may often be halved in relation to those used for Caucasians, and ACE inhibitors are not recommended as monotherapy for hypertension in persons of African ancestry. These differences are partly attributable to variations in genetic disposition. The findings are clinically significant – better insight in this field enables optimal tailoring of treatment for each patient, with more rapid achievement of goals and reduced risk of adverse effects. The recommendations given in this article are consistent with and complement the Directorate of Health’s revised guidelines for the treatment of diabetes.
Céspedes-Garro, Carolina; Rodrigues-Soares, Fernanda; Jiménez-Arce, Gerardo; Naranjo, María-Eugenia G; Tarazona-Santos, Eduardo; Fariñas, Humberto; Barrantes, Ramiro; Llerena, Adrián
CYP2C9, CYP2C19 and CYP2D6 metabolize around 40% of drugs and their genes vary across populations. The Costa Rican population has a trihybrid ancestry and its key geographic location turns it into a suitable scenario to evaluate interethnic differences across populations. This study aims to describe the diversity of CYP2C9, CYP2C19 and CYP2D6 polymorphisms in Costa Rican populations in the context of their ancestry. A total of 448 healthy individuals were included in the study: Bribri (n= 47), Cabécar (n= 27), Maleku (n= 16), Guaymí (n= 30), Huetar (n= 48), Chorotega (n= 41), Admixed/Mestizos from the Central Valley/Guanacaste (n= 189), and Afro-Caribbeans (n= 50) from Limón. CYP2C9 (alleles *2, *3, *6) and CYP2C19 (*2, *3, *4, *5, *17) genotypes were determined by Real-Time PCR. African, European and Native American ancestry were inferred using 87 ancestry informative markers. The frequency of the decreased activity allele CYP2C9*2 is lower in the self-reported Amerindian groups compared to the admixed population, and the highest frequencies of CYP2C19*2 (null activity) and the CYP2C19*17 (increased activity) were found in the self-reported Afro-Caribbean population. Moreover, a frequency of 0.7 % CYP2C9 gPMs in the Admixed population and a variable frequency of CYP2C19 gUMs (0.0-32.6 %, more prevalent in Afro-Caribbeans) in Costa Rican populations, was found. Finally, the following alleles were positively correlated with genomic African ancestry and negatively correlated with genomic Native American ancestry: CYP2D6*5 (null activity), CYP2D6*17 (decreased activity), CYP2D6*29 (decreased activity) and CYP2C19*17 (increased activity). No correlation for CYP2C9 polymorphisms and genomic ancestry was found. Further studies assessing the CYP2C9 and CYP2C19 sequence in these populations, preferentially by sequencing these genes, are warranted.
Caple, Jodi; Stephan, Carl N
Graphic exemplars of cranial sex and ancestry are essential to forensic anthropology for standardizing casework, training analysts, and communicating group trends. To date, graphic exemplars have comprised hand-drawn sketches, or photographs of individual specimens, which risks bias/subjectivity. Here, we performed quantitative analysis of photographic data to generate new photo-realistic and objective exemplars of skull form. Standardized anterior and left lateral photographs of skulls for each sex were analyzed in the computer graphics program Psychomorph for the following groups: South African Blacks, South African Whites, American Blacks, American Whites, and Japanese. The average cranial form was calculated for each photographic view, before the color information for every individual was warped to the average form and combined to produce statistical averages. These mathematically derived exemplars-and their statistical exaggerations or extremes-retain the high-resolution detail of the original photographic dataset, making them the ideal casework and training reference standards. © 2016 American Academy of Forensic Sciences.
Kiffner, Christian; Kioko, John; Leweri, Cecilia; Krause, Stefan
Mixed mammal species groups are common in East African savannah ecosystems. Yet, it is largely unknown if co-occurrences of large mammals result from random processes or social preferences and if interspecific associations are consistent across ecosystems and seasons. Because species may exchange important information and services, understanding patterns and drivers of heterospecific interactions is crucial for advancing animal and community ecology. We recorded 5403 single and multi-species clusters in the Serengeti-Ngorongoro and Tarangire-Manyara ecosystems during dry and wet seasons and used social network analyses to detect patterns of species associations. We found statistically significant associations between multiple species and association patterns differed spatially and seasonally. Consistently, wildebeest and zebras preferred being associated with other species, whereas carnivores, African elephants, Maasai giraffes and Kirk's dik-diks avoided being in mixed groups. During the dry season, we found that the betweenness (a measure of importance in the flow of information or disease) of species did not differ from a random expectation based on species abundance. In contrast, in the wet season, we found that these patterns were not simply explained by variations in abundances, suggesting that heterospecific associations were actively formed. These seasonal differences in observed patterns suggest that interspecific associations may be driven by resource overlap when resources are limited and by resource partitioning or anti-predator advantages when resources are abundant. We discuss potential mechanisms that could drive seasonal variation in the cost-benefit tradeoffs that underpin the formation of mixed-species groups.
Ramoni Marco F
Full Text Available Abstract Background Recent studies have shown that when individuals are grouped on the basis of genetic similarity, group membership corresponds closely to continental origin. There has been considerable debate about the implications of these findings in the context of larger debates about race and the extent of genetic variation between groups. Some have argued that clustering according to continental origin demonstrates the existence of significant genetic differences between groups and that these differences may have important implications for differences in health and disease. Others argue that clustering according to continental origin requires the use of large amounts of genetic data or specifically chosen markers and is indicative only of very subtle genetic differences that are unlikely to have biomedical significance. Results We used small numbers of randomly selected single nucleotide polymorphisms (SNPs from the International HapMap Project to train naïve Bayes classifiers for prediction of ancestral continent of origin. Predictive accuracy was tested on two independent data sets. Genetically similar groups should be difficult to distinguish, especially if only a small number of genetic markers are used. The genetic differences between continentally defined groups are sufficiently large that one can accurately predict ancestral continent of origin using only a minute, randomly selected fraction of the genetic variation present in the human genome. Genotype data from only 50 random SNPs was sufficient to predict ancestral continent of origin in our primary test data set with an average accuracy of 95%. Genetic variations informative about ancestry were common and widely distributed throughout the genome. Conclusion Accurate characterization of ancestry is possible using small numbers of randomly selected SNPs. The results presented here show how investigators conducting genetic association studies can use small numbers of arbitrarily
Allegre, C.J.; Jaupart, C.; Paris-7 Univ., 75
We present a model of continental growth which combines the results of geochemical studies and tectonic ideas about the evolution of continents through geological time. The process of continental growth is mainly controlled by surface phenomena. Continental material is extracted from the mantle along subduction zones at the periphery of oceans, and is destroyed in collision zones where it is remobilized and made available for subduction. We derive an equation for S, the portion of the Earth's surface occupied by continents, which reads as follows: dS/dt=a . √(1-S)-b . S. Coefficients a and b depend on the geometry of plates, on their number and on their velocities. We assume that they decrease exponentially with time with the same time-scale α. This model satisfies both geochemical and tectonic constraints, and allows the integration of several current observations in a single framework. (orig.)
Wang, Heming; Choi, Yoonha; Tayo, Bamidele; Wang, Xuefeng; Morris, Nathan; Zhang, Xiang; Broeckel, Uli; Hanis, Craig; Kardia, Sharon; Redline, Susan; Cooper, Richard S; Tang, Hua; Zhu, Xiaofeng
The role played by epistasis between alleles at unlinked loci in shaping population fitness has been debated for many years and the existing evidence has been mainly accumulated from model organisms. In model organisms, fitness epistasis can be systematically inferred by detecting nonindependence of genotypic values between loci in a population and confirmed through examining the number of offspring produced in two-locus genotype groups. No systematic study has been conducted to detect epistasis of fitness in humans owing to experimental constraints. In this study, we developed a novel method to detect fitness epistasis by testing the correlation between local ancestries on different chromosomes in an admixed population. We inferred local ancestry across the genome in 16,252 unrelated African Americans and systematically examined the pairwise correlations between the genomic regions on different chromosomes. Our analysis revealed a pair of genomic regions on chromosomes 4 and 6 that show significant local ancestry correlation (P-value = 4.01 × 10 -8 ) that can be potentially attributed to fitness epistasis. However, we also observed substantial local ancestry correlation that cannot be explained by systemic ancestry inference bias. To our knowledge, this study is the first to systematically examine evidence of fitness epistasis across the human genome. © 2016 WILEY PERIODICALS, INC.
Biari, Y.; Klingelhoefer, F.; Sahabi, M.; Aslanian, D.; Philippe, S.; Louden, K. E.; Berglar, K.; Moulin, M.; Mehdi, K.; Graindorge, D.; Evain, M.; Benabellouahed, M.; Reichert, C. J.
Deep seismic data represent a key to understand the geometry and mechanism of continental rifting. The passive continental margin of NW-Africa is one of the oldest on earth, formed during the Upper Triassic-Lower Liassic rifting of the central Atlantic Ocean over 200 Ma. We present new and existing wide-angle and reflection seismic data from three study regions along the margin located in the North Moroccan salt basin, on the central continental margin offshore Safi and in the south, offshore Dakhla. In each of the study areas several combined wide-angle and reflection seismic profiles perpendicular and parallel to the margin have been acquired and forward modelled using comparable methods. The thickness of unthinned continental crust decreases from 36 km in the North to about 27 km in the South. In the North Moroccan Basin continental crust thins from originally 36 km to about 8 km in a 150 km wide zone. The basin itself is underlain by highly thinned continental crust. Offshore safi thinning of the continental crust is confined to a 130 km wide zone with no neighboring sedimentary basin underlain by continental crust. In both areas the zone of crustal thinning is characterised by the presence of large blocks and abundant salt diapirs. In the south crustal thinning is more rapid in a zone of 90 km and asymmetric with the upper crust thinning more closely to the continent than the lower crust, probably due to depth-dependent stretching and the presence of the precambrian Reguibat Ridge on land. Oceanic crust is characterised by a thickness of 7-8 km along the complete margin. Relatively high velocities of up to 7.5 km/s have been imaged between magnetic anomalies S1 and M25, and are probably related to changes in the spreading velocities at the time of the Kimmeridgian/Tithonian plate reorganisation. Volcanic activity seems to be confined to the region next to the Canary Islands, and is thus not related to the initial opening of the oceanic, which was related to no
Ruiz-Linares, Andrés; Adhikari, Kaustubh; Acuña-Alonzo, Victor; Quinto-Sanchez, Mirsha; Jaramillo, Claudia; Arias, William; Fuentes, Macarena; Pizarro, María; Everardo, Paola; de Avila, Francisco; Gómez-Valdés, Jorge; León-Mimila, Paola; Hunemeier, Tábita; Ramallo, Virginia; Silva de Cerqueira, Caio C.; Burley, Mari-Wyn; Konca, Esra; de Oliveira, Marcelo Zagonel; Veronez, Mauricio Roberto; Rubio-Codina, Marta; Attanasio, Orazio; Gibbon, Sahra; Ray, Nicolas; Gallo, Carla; Poletti, Giovanni; Rosique, Javier; Schuler-Faccini, Lavinia; Salzano, Francisco M.; Bortolini, Maria-Cátira; Canizales-Quinteros, Samuel; Rothhammer, Francisco; Bedoya, Gabriel; Balding, David; Gonzalez-José, Rolando
The current genetic makeup of Latin America has been shaped by a history of extensive admixture between Africans, Europeans and Native Americans, a process taking place within the context of extensive geographic and social stratification. We estimated individual ancestry proportions in a sample of 7,342 subjects ascertained in five countries (Brazil, Chile, Colombia, México and Perú). These individuals were also characterized for a range of physical appearance traits and for self-perception of ancestry. The geographic distribution of admixture proportions in this sample reveals extensive population structure, illustrating the continuing impact of demographic history on the genetic diversity of Latin America. Significant ancestry effects were detected for most phenotypes studied. However, ancestry generally explains only a modest proportion of total phenotypic variation. Genetically estimated and self-perceived ancestry correlate significantly, but certain physical attributes have a strong impact on self-perception and bias self-perception of ancestry relative to genetically estimated ancestry. PMID:25254375
Gomes, Verónica; Pala, Maria; Salas, Antonio; Álvarez-Iglesias, Vanesa; Amorim, António; Gómez-Carballa, Alberto; Carracedo, Ángel; Clarke, Douglas J; Hill, Catherine; Mormina, Maru; Shaw, Marie-Anne; Dunne, David W; Pereira, Rui; Pereira, Vânia; Prata, Maria João; Sánchez-Diz, Paula; Rito, Teresa; Soares, Pedro; Gusmão, Leonor; Richards, Martin B
The Great Lakes lie within a region of East Africa with very high human genetic diversity, home of many ethno-linguistic groups usually assumed to be the product of a small number of major dispersals. However, our knowledge of these dispersals relies primarily on the inferences of historical, linguistics and oral traditions, with attempts to match up the archaeological evidence where possible. This is an obvious area to which archaeogenetics can contribute, yet Uganda, at the heart of these developments, has not been studied for mitochondrial DNA (mtDNA) variation. Here, we compare mtDNA lineages at this putative genetic crossroads across 409 representatives of the major language groups: Bantu speakers and Eastern and Western Nilotic speakers. We show that Uganda harbours one of the highest mtDNA diversities within and between linguistic groups, with the various groups significantly differentiated from each other. Despite an inferred linguistic origin in South Sudan, the data from the two Nilotic-speaking groups point to a much more complex history, involving not only possible dispersals from Sudan and the Horn but also large-scale assimilation of autochthonous lineages within East Africa and even Uganda itself. The Eastern Nilotic group also carries signals characteristic of West-Central Africa, primarily due to Bantu influence, whereas a much stronger signal in the Western Nilotic group suggests direct West-Central African ancestry. Bantu speakers share lineages with both Nilotic groups, and also harbour East African lineages not found in Western Nilotic speakers, likely due to assimilating indigenous populations since arriving in the region ~3000 years ago.
Full Text Available Abstract Background The question of a genetic contribution to the higher prevalence and incidence of end stage kidney disease (ESKD among African Americans (AA remained unresolved, until recent findings using admixture mapping pointed to the association of a genomic locus on chromosome 22 with this disease phenotype. In the current study we utilize this example to demonstrate the utility of applying a multi-step admixture mapping approach. Methods A multi-step case only admixture mapping study, consisted of the following steps was designed: 1 Assembly of the sample dataset (ESKD AA; 2 Design of the estimated mutual information ancestry informative markers (n = 2016 screening panel 3; Genotyping the sample set whose size was determined by a power analysis (n = 576 appropriate for the initial screening panel; 4 Inference of local ancestry for each individual and identification of regions with increased AA ancestry using two different ancestry inference statistical approaches; 5 Enrichment of the initial screening panel; 6 Power analysis of the enriched panel 7 Genotyping of additional samples. 8 Re-analysis of the genotyping results to identify a genetic risk locus. Results The initial screening phase yielded a significant peak using the ADMIXMAP ancestry inference program applying case only statistics. Subgroup analysis of 299 ESKD patients with no history of diabetes yielded peaks using both the ANCESTRYMAP and ADMIXMAP ancestry inference programs. The significant peak was found on chromosome 22. Genotyping of additional ancestry informative markers on chromosome 22 that took into account linkage disequilibrium in the ancestral populations, and the addition of samples increased the statistical significance of the finding. Conclusions A multi-step admixture mapping analysis of AA ESKD patients replicated the finding of a candidate risk locus on chromosome 22, contributing to the heightened susceptibility of African Americans to develop non
Mundell, Jonathan P; Visser, Maretha J; Makin, Jennifer D; Kershaw, Trace S; Forsyth, Brian W C; Jeffery, Bridget; Sikkema, Kathleen J
The authors of this study evaluated a structured 10-session psychosocial support group intervention for newly HIV-diagnosed pregnant South African women. Participants were expected to display increases in HIV disclosure, self-esteem, active coping and positive social support, and decreases in depression, avoidant coping, and negative social support. Three hundred sixty-one pregnant HIV-infected women were recruited from four antenatal clinics in Tshwane townships from April 2005 to September 2006. Using a quasi-experimental design, assessments were conducted at baseline and two and eight months post-intervention. A series of random effects regression analyses were conducted, with the three assessment points treated as a random effect of time. At both follow-ups, the rate of disclosure in the intervention group was significantly higher than that of the comparison group (p<0.001). Compared to the comparison group at the first follow-up, the intervention group displayed higher levels of active coping (t=2.68, p<0.05) and lower levels of avoidant coping (t=-2.02, p<0.05), and those who attended at least half of the intervention sessions exhibited improved self-esteem (t=2.11, p<0.05). Group interventions tailored for newly HIV positive pregnant women, implemented in resource-limited settings, may accelerate the process of adjusting to one's HIV status, but may not have sustainable benefits over time.
Homburger, Julian R.; Moreno-Estrada, Andrés; Gignoux, Christopher R.; Nelson, Dominic; Sanchez, Elena; Ortiz-Tello, Patricia; Pons-Estel, Bernardo A.; Acevedo-Vasquez, Eduardo; Miranda, Pedro; Langefeld, Carl D.; Gravel, Simon; Alarcón-Riquelme, Marta E.; Bustamante, Carlos D.
South America has a complex demographic history shaped by multiple migration and admixture events in pre- and post-colonial times. Settled over 14,000 years ago by Native Americans, South America has experienced migrations of European and African individuals, similar to other regions in the Americas. However, the timing and magnitude of these events resulted in markedly different patterns of admixture throughout Latin America. We use genome-wide SNP data for 437 admixed individuals from 5 countries (Colombia, Ecuador, Peru, Chile, and Argentina) to explore the population structure and demographic history of South American Latinos. We combined these data with population reference panels from Africa, Asia, Europe and the Americas to perform global ancestry analysis and infer the subcontinental origin of the European and Native American ancestry components of the admixed individuals. By applying ancestry-specific PCA analyses we find that most of the European ancestry in South American Latinos is from the Iberian Peninsula; however, many individuals trace their ancestry back to Italy, especially within Argentina. We find a strong gradient in the Native American ancestry component of South American Latinos associated with country of origin and the geography of local indigenous populations. For example, Native American genomic segments in Peruvians show greater affinities with Andean indigenous peoples like Quechua and Aymara, whereas Native American haplotypes from Colombians tend to cluster with Amazonian and coastal tribes from northern South America. Using ancestry tract length analysis we modeled post-colonial South American migration history as the youngest in Latin America during European colonization (9–14 generations ago), with an additional strong pulse of European migration occurring between 3 and 9 generations ago. These genetic footprints can impact our understanding of population-level differences in biomedical traits and, thus, inform future medical
Homburger, Julian R; Moreno-Estrada, Andrés; Gignoux, Christopher R; Nelson, Dominic; Sanchez, Elena; Ortiz-Tello, Patricia; Pons-Estel, Bernardo A; Acevedo-Vasquez, Eduardo; Miranda, Pedro; Langefeld, Carl D; Gravel, Simon; Alarcón-Riquelme, Marta E; Bustamante, Carlos D
South America has a complex demographic history shaped by multiple migration and admixture events in pre- and post-colonial times. Settled over 14,000 years ago by Native Americans, South America has experienced migrations of European and African individuals, similar to other regions in the Americas. However, the timing and magnitude of these events resulted in markedly different patterns of admixture throughout Latin America. We use genome-wide SNP data for 437 admixed individuals from 5 countries (Colombia, Ecuador, Peru, Chile, and Argentina) to explore the population structure and demographic history of South American Latinos. We combined these data with population reference panels from Africa, Asia, Europe and the Americas to perform global ancestry analysis and infer the subcontinental origin of the European and Native American ancestry components of the admixed individuals. By applying ancestry-specific PCA analyses we find that most of the European ancestry in South American Latinos is from the Iberian Peninsula; however, many individuals trace their ancestry back to Italy, especially within Argentina. We find a strong gradient in the Native American ancestry component of South American Latinos associated with country of origin and the geography of local indigenous populations. For example, Native American genomic segments in Peruvians show greater affinities with Andean indigenous peoples like Quechua and Aymara, whereas Native American haplotypes from Colombians tend to cluster with Amazonian and coastal tribes from northern South America. Using ancestry tract length analysis we modeled post-colonial South American migration history as the youngest in Latin America during European colonization (9-14 generations ago), with an additional strong pulse of European migration occurring between 3 and 9 generations ago. These genetic footprints can impact our understanding of population-level differences in biomedical traits and, thus, inform future medical
Julian R Homburger
Full Text Available South America has a complex demographic history shaped by multiple migration and admixture events in pre- and post-colonial times. Settled over 14,000 years ago by Native Americans, South America has experienced migrations of European and African individuals, similar to other regions in the Americas. However, the timing and magnitude of these events resulted in markedly different patterns of admixture throughout Latin America. We use genome-wide SNP data for 437 admixed individuals from 5 countries (Colombia, Ecuador, Peru, Chile, and Argentina to explore the population structure and demographic history of South American Latinos. We combined these data with population reference panels from Africa, Asia, Europe and the Americas to perform global ancestry analysis and infer the subcontinental origin of the European and Native American ancestry components of the admixed individuals. By applying ancestry-specific PCA analyses we find that most of the European ancestry in South American Latinos is from the Iberian Peninsula; however, many individuals trace their ancestry back to Italy, especially within Argentina. We find a strong gradient in the Native American ancestry component of South American Latinos associated with country of origin and the geography of local indigenous populations. For example, Native American genomic segments in Peruvians show greater affinities with Andean indigenous peoples like Quechua and Aymara, whereas Native American haplotypes from Colombians tend to cluster with Amazonian and coastal tribes from northern South America. Using ancestry tract length analysis we modeled post-colonial South American migration history as the youngest in Latin America during European colonization (9-14 generations ago, with an additional strong pulse of European migration occurring between 3 and 9 generations ago. These genetic footprints can impact our understanding of population-level differences in biomedical traits and, thus, inform
Hubel, Tatjana Y; Myatt, Julia P; Jordan, Neil R; Dewhirst, Oliver P; McNutt, J Weldon; Wilson, Alan M
African wild dogs (Lycaon pictus) are described as highly collaborative endurance pursuit hunters based on observations derived primarily from the grass plains of East Africa. However, the remaining population of this endangered species mainly occupies mixed woodland savannah where hunting strategies appear to differ from those previously described. We used high-resolution GPS and inertial technology to record fine-scale movement of all members of a single pack of six adult African wild dogs in northern Botswana. The dogs used multiple short-distance hunting attempts with a low individual kill rate (15.5%), but high group feeding rate due to the sharing of prey. Use of high-level cooperative chase strategies (coordination and collaboration) was not recorded. In the mixed woodland habitats typical of their current range, simultaneous, opportunistic, short-distance chasing by dogs pursuing multiple prey (rather than long collaborative pursuits of single prey by multiple individuals) could be the key to their relative success in these habitats.
Full Text Available Mixed mammal species groups are common in East African savannah ecosystems. Yet, it is largely unknown if co-occurrences of large mammals result from random processes or social preferences and if interspecific associations are consistent across ecosystems and seasons. Because species may exchange important information and services, understanding patterns and drivers of heterospecific interactions is crucial for advancing animal and community ecology. We recorded 5403 single and multi-species clusters in the Serengeti-Ngorongoro and Tarangire-Manyara ecosystems during dry and wet seasons and used social network analyses to detect patterns of species associations. We found statistically significant associations between multiple species and association patterns differed spatially and seasonally. Consistently, wildebeest and zebras preferred being associated with other species, whereas carnivores, African elephants, Maasai giraffes and Kirk's dik-diks avoided being in mixed groups. During the dry season, we found that the betweenness (a measure of importance in the flow of information or disease of species did not differ from a random expectation based on species abundance. In contrast, in the wet season, we found that these patterns were not simply explained by variations in abundances, suggesting that heterospecific associations were actively formed. These seasonal differences in observed patterns suggest that interspecific associations may be driven by resource overlap when resources are limited and by resource partitioning or anti-predator advantages when resources are abundant. We discuss potential mechanisms that could drive seasonal variation in the cost-benefit tradeoffs that underpin the formation of mixed-species groups.
Wei, Yi-Liang; Wei, Li; Zhao, Lei; Sun, Qi-Fan; Jiang, Li; Zhang, Tao; Liu, Hai-Bo; Chen, Jian-Gang; Ye, Jian; Hu, Lan; Li, Cai-Xia
A single-tube multiplex assay of a small set of ancestry-informative markers (AIMs) for effectively estimating individual ancestry and admixture is an ideal forensic tool to trace the population origin of an unknown DNA sample. We present a newly developed 27-plex single nucleotide polymorphism (SNP) panel with highly robust and balanced differential power to perfectly assign individuals to African, European, and East Asian ancestries. Evaluating 968 previously described intercontinental AIMs from three HapMap population genotyping datasets (Yoruban in Ibadan, Nigeria (YRI); Utah residents with Northern and Western European ancestry from the Centre de'Etude du Polymorphism Humain (CEPH) collection (CEU); and Han Chinese in Beijing, China (CHB)), the best set of markers was selected on the basis of Hardy-Weinberg equilibrium (p > 0.00001), population-specific allele frequency (two of three δ values >0.5), according to linkage disequilibrium (r (2) ancestry of the 11 populations in the HapMap project. Then, we tested the 27-plex SNP assay with 1164 individuals from 17 additional populations. The results demonstrated that the SNP panel was successful for ancestry inference of individuals with African, European, and East Asian ancestry. Furthermore, the system performed well when inferring the admixture of Eurasians (EUR/EAS) after analyzing admixed populations from Xinjiang (Central Asian) as follows: Tajik (68:27), Uyghur (49:46), Kirgiz (40:57), and Kazak (36:60). For individual analyses, we interpreted each sample with a three-ancestry component percentage and a population match probability sequence. This multiplex assay is a convenient and cost-effective tool to assist in criminal investigations, as well as to correct for the effects of population stratification for case-control studies.
Crawford, Nicholas; Prendergast, D'Arcy; Oehlert, John W; Shaw, Gary M; Stevenson, David K; Rappaport, Nadav; Sirota, Marina; Tishkoff, Sarah A; Sondheimer, Neal
To examine linkages between mitochondrial genetics and preterm birth by assessing the risk for preterm birth associated with the inheritance of nuclear haplotypes that are ancestrally distinct from mitochondrial haplogroup. Genome-wide genotyping studies of cohorts of preterm and term individuals were evaluated. We determined the mitochondrial haplogroup and nuclear ancestry for individuals and developed a scoring for the degree to which mitochondrial ancestry is divergent from nuclear ancestry. Infants with higher degrees of divergent mitochondrial ancestry were at increased risk for preterm birth (0.124 for preterm vs 0.105 for term infants; Pancestry correlated with earlier delivery within the primary study population, but this finding was not replicated in secondary cohorts born preterm. Individuals with divergent patterns of mitochondrial and nuclear ancestry are at increased risk for preterm birth. These findings may in part explain the higher rates of preterm birth in African Americans and in individuals with a matrilineal family history of preterm birth. Copyright © 2017 Elsevier Inc. All rights reserved.
Rotimi, Charles N; Tekola-Ayele, Fasil; Baker, Jennifer L; Shriner, Daniel
The trans-Atlantic slave trade brought millions of Africans to the New World. Advances in genomics are providing novel insights into the history and health of Africans and the diasporan populations. Recent examples reviewed here include the unraveling of substantial hunter-gatherer and 'Eurasian' admixtures across sub-Saharan Africa, expanding our understanding of ancestral African genetics; the global ubiquity of mixed ancestry; the revealing of African ancestry in Latin Americans that likely derived from the slave trade; and understanding of the ancestral backgrounds of APOL1 and LPL found to influence kidney disease and lipid levels, respectively, providing specific insights into disease etiology and health disparities. Published by Elsevier Ltd.
Black, Beverly M.; Weisz, Arlene N.; Jayasundara, Dheeshana S.
A dating violence and sexual assault prevention program was presented to 396, predominately African American, middle schoolers in two inner city schools in the United States. In one school the program was offered with a same-gender group composition; in the other school, the same program was offered with mixed-gender group composition. A…
Vieira-Machado, Camilla D; de Carvalho, Flavia M; Santana da Silva, Luiz C; Dos Santos, Sidney E; Martins, Claudia; Poletta, Fernando A; Mereb, Juan C; Vieira, Alexandre R; Castilla, Eduardo E; Orioli, Iêda M
Increased susceptibility to cleft lip, with or without cleft palate (CL±P) has been observed in South America, as related to Amerindian ancestry, using epidemiological data, uniparental markers, and blood groups. In this study, it was evaluated whether this increased risk remains when Amerindian ancestry is estimated using autosomal markers and considered in the predictive model. Ancestry was estimated through genotyping 62 insertion and deletion (INDEL) markers in sample sets of patients with CL±P, patients with cleft palate (CP), and controls, from Patagonia in southern Argentina and Belém in northern Brazil. The Amerindian ancestry in patients from Patagonia with CL±P was greater than in controls although it did not reach statistical significance. The European ancestry in patients with CL±P from Belém and in patients with CP from Belém and Patagonia was higher than in controls and statistically significant for patients with CP who were from Belém. This high contribution of European genetic ancestry among patients with CP who were from Belém has not been previously observed in American populations. Our results do not corroborate the currently accepted risks for CL±P and CP estimated by epidemiological studies in the North American populations and probably reflect the higher admixture found in South American ethnic groups when compared with the same ethnic groups from the North American populations. © 2016 Eur J Oral Sci.
To facilitate the development of EMD systems appropriate for the African setting, the African Federation for Emergency Medicine (AFEM and the International Academies of Emergency Dispatch (IAED convened a working group in November 2014 to provide conceptual, technical, and innovative recommendations for contextually appropriate EMD systems for African settings. It is hoped that these recommendations will augment efficiency, effectiveness, and standardisation within and among African EMD systems, thereby improving health outcomes for sufferers of acute illness or injury.
Joanne McVeigh, Rebecca Meiring
Full Text Available Few studies have examined physical activity and inactivity levels in an urban South African setting across 12 years of formal schooling. This information is important for implementing strategies to curb increasing trends of physical inactivity and related negative consequences, especially in low to middle income countries facing multiple challenges on overburdened health care systems. We examined levels of physical activity and sedentary behaviour cross-sectionally over 12 school years from childhood to adolescence in Black, White and Indian boys and girls. The aim of our study was to describe gender and race related patterns of physical and sedentary activity levels in a sample of South African children and to determine whether there were associations between these variables and body mass status. Physical activity questionnaires, previously validated in a South African setting, were used to gather information about activity and sedentary behaviours among 767 Black, White and Indian children (5-18 years of age across the 12 grades of formal schooling. Body mass and height were also measured. Time spent in moderate-vigorous physical activity declined over the school years for all race groups and was consistently lower for girls than boys (p = 0.03, while time spent in sedentary activity increased with increasing grade (p 0.05 whereas time spent in sedentary activities was significantly and positively correlated with body mass across all race groups: Indian (r = 0.25, p < 0.001, White (r = 0.22, p < 0.001 and Black (r = 0.37, p = 0.001. The strength of the associations was similar for boys and girls. Black and Indian children were less physically active than their white peers (p < 0.05, and Black children also spent more time in sedentary activity (p < 0.05. Additionally, Black children had the highest proportion of overweight participants (30%, and Indian children the most number of underweight children (13%. Regardless of ethnicity, children who
Jarvis, Benjamin; Kawalerowicz, Juta; Valdez, Sarah
Country-of-birth data contained in registers are often aggregated to create broad ancestry group categories. We examine how measures of residential segregation vary according to levels of aggregation. We use Swedish register data to calculate pairwise dissimilarity indices from 1990 to 2012 for ancestry groups defined at four nested levels of aggregation: (1) micro-groups containing 50 categories, (2) meso-groups containing 16 categories, (3) macro-groups containing six categories and (4) a broad Western/non-Western binary. We find variation in segregation levels between ancestry groups that is obscured by data aggregation. This study demonstrates that the practice of aggregating country-of-birth statistics in register data can hinder the ability to identify highly segregated groups and therefore design effective policy to remedy both intergroup and intergenerational inequalities.
Matoba, Tomoyuki; Kutsukake, Nobuyuki; Hasegawa, Toshikazu
Many social animals have a species-specific repertoire of affiliative behaviours that characterise individualised relationships within a group. To date, however, quantitative studies on intragroup affiliative behaviours in social carnivores have been limited. Here, we investigated the social functions of the two most commonly observed affiliative behaviours in captive African lions (Panthera leo): head rubbing and licking. We conducted behavioural observations on a captive group of lions composed of 7 males and 14 females, and tested hypotheses regarding three social functions: tension reduction, social bonding, and social status expression. Disproportionately frequent male-male and female-to-male head rubbing was observed, while more than 95% of all licking interactions occurred in female-female dyads. In accordance with the social bond hypothesis, and in disagreement with the social status expression hypothesis, both head rubbing and licking interactions were reciprocal. After controlling for spatial association, the dyadic frequency of head rubbing was negatively correlated with age difference while licking was positively correlated with relatedness. Group reunion after daily separation did not affect the frequencies of the affiliative behaviours, which was in disagreement with the predictions from the tension reduction hypothesis. These results support the social bond hypothesis for the functions of head rubbing and licking. Different patterns of affiliative behaviour between the sexes may reflect differences in the relationship quality in each sex or the differential predisposition to licking due to its original function in offspring care.
Full Text Available Many social animals have a species-specific repertoire of affiliative behaviours that characterise individualised relationships within a group. To date, however, quantitative studies on intragroup affiliative behaviours in social carnivores have been limited. Here, we investigated the social functions of the two most commonly observed affiliative behaviours in captive African lions (Panthera leo: head rubbing and licking. We conducted behavioural observations on a captive group of lions composed of 7 males and 14 females, and tested hypotheses regarding three social functions: tension reduction, social bonding, and social status expression. Disproportionately frequent male-male and female-to-male head rubbing was observed, while more than 95% of all licking interactions occurred in female-female dyads. In accordance with the social bond hypothesis, and in disagreement with the social status expression hypothesis, both head rubbing and licking interactions were reciprocal. After controlling for spatial association, the dyadic frequency of head rubbing was negatively correlated with age difference while licking was positively correlated with relatedness. Group reunion after daily separation did not affect the frequencies of the affiliative behaviours, which was in disagreement with the predictions from the tension reduction hypothesis. These results support the social bond hypothesis for the functions of head rubbing and licking. Different patterns of affiliative behaviour between the sexes may reflect differences in the relationship quality in each sex or the differential predisposition to licking due to its original function in offspring care.
Corbett-Detig, Russell; Nielsen, Rasmus
Admixture-the mixing of genomes from divergent populations-is increasingly appreciated as a central process in evolution. To characterize and quantify patterns of admixture across the genome, a number of methods have been developed for local ancestry inference. However, existing approaches have a number of shortcomings. First, all local ancestry inference methods require some prior assumption about the expected ancestry tract lengths. Second, existing methods generally require genotypes, which is not feasible to obtain for many next-generation sequencing projects. Third, many methods assume samples are diploid, however a wide variety of sequencing applications will fail to meet this assumption. To address these issues, we introduce a novel hidden Markov model for estimating local ancestry that models the read pileup data, rather than genotypes, is generalized to arbitrary ploidy, and can estimate the time since admixture during local ancestry inference. We demonstrate that our method can simultaneously estimate the time since admixture and local ancestry with good accuracy, and that it performs well on samples of high ploidy-i.e. 100 or more chromosomes. As this method is very general, we expect it will be useful for local ancestry inference in a wider variety of populations than what previously has been possible. We then applied our method to pooled sequencing data derived from populations of Drosophila melanogaster on an ancestry cline on the east coast of North America. We find that regions of local recombination rates are negatively correlated with the proportion of African ancestry, suggesting that selection against foreign ancestry is the least efficient in low recombination regions. Finally we show that clinal outlier loci are enriched for genes associated with gene regulatory functions, consistent with a role of regulatory evolution in ecological adaptation of admixed D. melanogaster populations. Our results illustrate the potential of local ancestry
Lyke, M M; Dubach, J; Briggs, M B
The recent incorporation of molecular methods into analyses of social and mating systems has provided evidence that mating patterns often differ from those predicted by group social organization. Based on field studies and paternity analyses at a limited number of sites, African lions are predicted to exhibit a strict within-pride mating system. Extra-group paternity has not been previously reported in African lions; however, observations of extra-group associations among lions inhabiting Etosha National Park in Namibia suggest deviation from the predicted within-pride mating pattern. We analysed variation in 14 microsatellite loci in a population of 164 African lions in Etosha National Park. Genetic analysis was coupled with demographic and observational data to examine pride structure, relatedness and extra-group paternity (EGP). EGP was found to occur in 57% of prides where paternity was analysed (n = 7), and the overall rate of EGP in this population was 41% (n = 34). Group sex ratio had a significant effect on the occurrence of EGP (P African lion mating systems and provide evidence that social structure may not reflect breeding structure in some social mammals. © 2013 Blackwell Publishing Ltd.
Stoeger, Angela S.; Zeppelzauer, Matthias; Baotic, Anton
Animal vocal signals are increasingly used to monitor wildlife populations and to obtain estimates of species occurrence and abundance. In the future, acoustic monitoring should function not only to detect animals, but also to extract detailed information about populations by discriminating sexes, age groups, social or kin groups, and potentially individuals. Here we show that it is possible to estimate age groups of African elephants (Loxodonta africana) based on acoustic parameters extracte...
Elizabeti Y. Muto
Full Text Available The temporal and spatial variations of feeding habits and trophic groups of demersal fish species of Santos Bay and the adjacent continental shelf were investigated. The samples were taken in September 2005 and March 2006 by bottom otter trawling. The stomach content analysis of 2,328 specimens of 49 species showed most fish fed on a large range of food items but relied heavily on shrimp, crabs/swimming-crabs, amphipods, mysids, polychaetes, ophiuroids, squids, and teleosteans. The species were classified into ten trophic groups. Shrimp were an important food source in the Santos bay and inner shelf, while ophiuroids were important prey for predators of the middle shelf. Many species relied on crabs/swimming-crabs during the summer, especially on the middle shelf. The spatial and temporal variability in food resource utilization by fish were related to the pattern of distribution and abundance of their prey. The predation on shrimp and crabs/swimming-crabs seems to be related to the water mass dynamics of the region. Intraspecific comparisons demonstrated that most of the species display spatial and/or temporal variation in their diet. The demersal ichtyofauna can also be divided into the more general categories of piscivores, nektonic invertebrate feeders, benthic invertebrate feeders and planktonic invertebrate feeders.
Yako, Y Y; Fanampe, B L; Hassan, M S; Erasmus, R T; van der Merwe, L; van Rensburg, S J; Matsha, T E
Obesity has increased rapidly in South African children and adolescents. Genes involved in appetite regulation have been extensively studied worldwide, but their role in the obesity phenotype in South African Black and mixed-ancestry school adolescents is unknown. Seven common polymorphisms in LEP, GHRL, CART and LEPR were analysed for genotype and haplotype association with anthropometric obesity phenotype indicators in South African Black and mixed-ancestry adolescent school learners. The CART c.517A→G polymorphism was significantly associated with obesity susceptibility. The LEPR Lys(109)Arg G allele was associated with an average reduction of 2.36 kg/m(2) in body mass index (BMI), 5.66 cm in waist circumference (WC) and 1.61 cm in mid-upper-arm circumference (MUAC). This was confirmed by haplotype analysis. Additionally, a haplotype of the LEP polymorphisms significantly increased BMI, MUAC and hip circumference, while LEPR haplotypes were associated with differences in MUAC. Our findings suggest that c.517A→G and Lys(109)Arg contribute to the variation in anthropometric obesity phenotype indicators observed among Black African and mixed-ancestry South African learners. Furthermore, haplotypes of LEP, LEPR and GHRL polymorphisms were associated with varying measurements of weight, BMI and WC. Further studies are required to confirm our results in a larger and homogeneous study population group. Copyright © 2011 S. Karger AG, Basel.
Integrative genomic analysis identifies ancestry-related expression quantitative trait loci on DNA polymerase β and supports the association of genetic ancestry with survival disparities in head and neck squamous cell carcinoma.
Ramakodi, Meganathan P; Devarajan, Karthik; Blackman, Elizabeth; Gibbs, Denise; Luce, Danièle; Deloumeaux, Jacqueline; Duflo, Suzy; Liu, Jeffrey C; Mehra, Ranee; Kulathinal, Rob J; Ragin, Camille C
African Americans with head and neck squamous cell carcinoma (HNSCC) have a lower survival rate than whites. This study investigated the functional importance of ancestry-informative single-nucleotide polymorphisms (SNPs) in HNSCC and also examined the effect of functionally important genetic elements on racial disparities in HNSCC survival. Ancestry-informative SNPs, RNA sequencing, methylation, and copy number variation data for 316 oral cavity and laryngeal cancer patients were analyzed across 178 DNA repair genes. The results of expression quantitative trait locus (eQTL) analyses were also replicated with a Gene Expression Omnibus (GEO) data set. The effects of eQTLs on overall survival (OS) and disease-free survival (DFS) were evaluated. Five ancestry-related SNPs were identified as cis-eQTLs in the DNA polymerase β (POLB) gene (false discovery rate [FDR] ancestry (P = .002). An association was observed between these eQTLs and OS (P ancestry-related alleles could act as eQTLs in HNSCC and support the association of ancestry-related genetic factors with survival disparities in patients diagnosed with oral cavity and laryngeal cancer. Cancer 2017;123:849-60. © 2016 American Cancer Society. © 2016 American Cancer Society.
Fejerman, Laura; Stern, Mariana C; John, Esther M; Torres-Mejía, Gabriela; Hines, Lisa M; Wolff, Roger K; Baumgartner, Kathy B; Giuliano, Anna R; Ziv, Elad; Pérez-Stable, Eliseo J; Slattery, Martha L
Most genetic variants associated with breast cancer risk have been discovered in women of European ancestry, and only a few genome-wide association studies (GWAS) have been conducted in minority groups. This research disparity persists in post-GWAS gene-environment interaction analyses. We tested the interaction between hormonal and lifestyle risk factors for breast cancer, and ten GWAS-identified SNPs among 2,107 Hispanic women with breast cancer and 2,587 unaffected controls, to gain insight into a previously reported gene by ancestry interaction in this population. We estimated genetic ancestry with a set of 104 ancestry-informative markers selected to discriminate between Indigenous American and European ancestry. We used logistic regression models to evaluate main effects and interactions. We found that the rs13387042-2q35(G/A) SNP was associated with breast cancer risk only among postmenopausal women who never used hormone therapy [per A allele OR: 0.94 (95% confidence intervals, 0.74-1.20), 1.20 (0.94-1.53), and 1.49 (1.28-1.75) for current, former, and never hormone therapy users, respectively, Pinteraction 0.002] and premenopausal women who breastfed >12 months [OR: 1.01 (0.72-1.42), 1.19 (0.98-1.45), and 1.69 (1.26-2.26) for never, 12 months breastfeeding, respectively, Pinteraction 0.014]. The correlation between genetic ancestry, hormone replacement therapy use, and breastfeeding behavior partially explained a previously reported interaction between a breast cancer risk variant and genetic ancestry in Hispanic women. These results highlight the importance of understanding the interplay between genetic ancestry, genetics, and nongenetic risk factors and their contribution to breast cancer risk. ©2015 American Association for Cancer Research.
Baker, B; Ross, E; Girson, J
The present study aimed to examine the attitudes of a group of South African speech-language pathologists towards stuttering and stuttering therapy. Further aims were to investigate whether a stereotype of stutterers was found among these speech-language pathologists, and to determine whether there was any relationship between the attitudes held about stutterers, and the therapists' training and experience. A random probability sample of respondents was selected from the population of speech therapists registered with the Interim Medical and Dental Council of South Africa (I.M.D.C.S.A.). A self-administered mailed questionnaire was employed to realise the aims of the study. The main result of this investigation indicated that almost 50% of the sample of qualified clinicians surveyed, viewed stutterers as a group characterised by specific personality traits and psychological problems. This belief held true irrespective of the number of years of experience working in the field, the time of graduation, the frequency of treating stutterers, or the training emphasis. Implications of these results are considered with respect to student training, continuing education of qualified practitioners and future research.
Slaughter-Acey, Jaime C; Caldwell, Cleopatra H; Misra, Dawn P
Racism has been hypothesized as a barrier to accessing health care. No quantitative study has directly assessed its influence on women's initiation of prenatal care (PNC). We examined the relationship between PNC entry and experiences of personal and group racism among low-income, African-American (AA) women. We also examined whether the use of denial of racism as a coping mechanism was associated with a delay in accessing PNC. Using a prospective/retrospective cohort design we collected data from 872 AA women (prenatally, n = 484; postpartum, n = 388). Multinomial logistic regression was used to assess the relationship between the overall denial of racism index and PNC initiation. PNC entry was not associated with personal experiences of racism (p = .33); it was significantly associated with group experiences (p racism experienced by other AAs was a barrier to early PNC among low-income, AA women. Delayed access to PNC may be rooted in the avoidance of racialized experiences among less empowered women when faced with discrimination. Our findings have important implication for the engagement of AA women into the PNC delivery system and the health care system postpartum. Copyright © 2013 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.
Reams R Renee
Full Text Available Abstract Background African American men have the highest prostate cancer morbidity and mortality rates than any other racial or ethnic group in the US. Although the overall incidence of and mortality from prostate cancer has been declining in White men since 1991, the decline in African American men lags behind White men. Of particular concern is the growing literature on the disproportionate burden of prostate cancer among other Black men of West African ancestry in the Caribbean Islands, United Kingdom and West Africa. This higher incidence of prostate cancer observed in populations of African descent may be attributed to the fact that these populations share ancestral genetic factors. To better understand the burden of prostate cancer among men of West African Ancestry, we conducted a review of the literature on prostate cancer incidence, prevalence, and mortality in the countries connected by the Transatlantic Slave Trade. Results Several published studies indicate high prostate cancer burden in Nigeria and Ghana. There was no published literature for the countries Benin, Gambia and Senegal that met our review criteria. Prostate cancer morbidity and/or mortality data from the Caribbean Islands and the United Kingdom also provided comparable or worse prostate cancer burden to that of US Blacks. Conclusion The growing literature on the disproportionate burden of prostate cancer among other Black men of West African ancestry follows the path of the Transatlantic Slave Trade. To better understand and address the global prostate cancer disparities seen in Black men of West African ancestry, future studies should explore the genetic and environmental risk factors for prostate cancer among this group.
Baggerly, Jennifer; Parker, Max
African American boys face numerous challenges in society within the United States, including prejudice, discrimination, racism, economic hardship, limited access to support services, educational biases, and community violence. According to Pierce (1988), the psychic assault of subtle racism against African American boys erode their…
Packer-Williams, Catherine L.; Evans, Kathy M.
This article reports on the results of a qualitative study of new African American female professors' participation in a peer mentoring group. Three key themes that emerged from the data included peer mentoring as a vehicle to process and cope effectively with microaggressions, increase positive self-identity and self-efficacy as a scholar, and…
Puneet Dwivedi; Arundhati Jagadish; John Schelhas
This study examines perceptions of three stakeholder groups (African American Family Forest Landowner,Â Government Agency, and Nonprofit) regarding federal landowner assistance programs in the southern UnitedÂ States by combining a SWOT (strength, weakness, opportunity, and threat) analysis with the AHP (analyticalÂ hierarchy process). Factors with the highest priority...
Wehby, George L; Trujillo, Antonio J
We examine disparities in early child cognitive and receptive-expressive skills by ethnic ancestry among infants aged 3-24 months from Brazil and Argentina. We employ unique data on the neurodevelopment of children who were seeking routine well-child care at a set of pediatric clinics in these countries. The sample included children who had normal birth outcomes and no major health complications, allowing us to focus on variation in neurodevelopment among children without major physical health limitations. The physicians attending the pediatric clinics were trained in administering the Bayley Infant Neurodevelopmental Screener, a standardized instrument used to screen an infant's risk of neurodevelopmental problems on various domains of abilities. We evaluate disparities in overall neurodevelopmental scores and risk for neurodevelopmental problems as well as in cognitive functioning and receptive-expressive neurodevelopment. We also examine the extent to which household demographic and socioeconomic characteristics and geographic location explain these disparities. We find large gaps in both cognitive and receptive-expressive neurodevelopment by ancestry. In Brazil, children of African ancestry have lower scores on both cognitive and receptive-expressive domains and on overall neurodevelopment than children of European ancestry. In Argentina, children of Native ancestry have lower scores on these outcomes than children of European ancestry. These gaps however are largely explained by differences in geographic location and household characteristics, highlighting the importance of policies that reduce socioeconomic and geographic disparities in social capital and economic development for eliminating ethnic disparities in infant neurodevelopment. Copyright © 2016. Published by Elsevier Inc.
Joanna L Davies
Full Text Available Genome-wide association study (GWAS data on a disease are increasingly available from multiple related populations. In this scenario, meta-analyses can improve power to detect homogeneous genetic associations, but if there exist ancestry-specific effects, via interactions on genetic background or with a causal effect that co-varies with genetic background, then these will typically be obscured. To address this issue, we have developed a robust statistical method for detecting susceptibility gene-ancestry interactions in multi-cohort GWAS based on closely-related populations. We use the leading principal components of the empirical genotype matrix to cluster individuals into "ancestry groups" and then look for evidence of heterogeneous genetic associations with disease or other trait across these clusters. Robustness is improved when there are multiple cohorts, as the signal from true gene-ancestry interactions can then be distinguished from gene-collection artefacts by comparing the observed interaction effect sizes in collection groups relative to ancestry groups. When applied to colorectal cancer, we identified a missense polymorphism in iron-absorption gene CYBRD1 that associated with disease in individuals of English, but not Scottish, ancestry. The association replicated in two additional, independently-collected data sets. Our method can be used to detect associations between genetic variants and disease that have been obscured by population genetic heterogeneity. It can be readily extended to the identification of genetic interactions on other covariates such as measured environmental exposures. We envisage our methodology being of particular interest to researchers with existing GWAS data, as ancestry groups can be easily defined and thus tested for interactions.
Tailce K M Leite
Full Text Available A current concern in genetic epidemiology studies in admixed populations is that population stratification can lead to spurious results. The Brazilian census classifies individuals according to self-reported "color", but several studies have demonstrated that stratifying according to "color" is not a useful strategy to control for population structure, due to the dissociation between self-reported "color" and genomic ancestry. We report the results of a study in a group of Brazilian siblings in which we measured skin pigmentation using a reflectometer, and estimated genomic ancestry using 21 Ancestry Informative Markers (AIMs. Self-reported "color", according to the Brazilian census, was also available for each participant. This made it possible to evaluate the relationship between self-reported "color" and skin pigmentation, self-reported "color" and genomic ancestry, and skin pigmentation and genomic ancestry. We observed that, although there were significant differences between the three "color" groups in genomic ancestry and skin pigmentation, there was considerable dispersion within each group and substantial overlap between groups. We also saw that there was no good agreement between the "color" categories reported by each member of the sibling pair: 30 out of 86 sibling pairs reported different "color", and in some cases, the sibling reporting the darker "color" category had lighter skin pigmentation. Socioeconomic status was significantly associated with self-reported "color" and genomic ancestry in this sample. This and other studies show that subjective classifications based on self-reported "color", such as the one that is used in the Brazilian census, are inadequate to describe the population structure present in recently admixed populations. Finally, we observed that one of the AIMs included in the panel (rs1426654, which is located in the known pigmentation gene SLC24A5, was strongly associated with skin pigmentation in this sample.
Leite, Tailce K M; Fonseca, Rômulo M C; de França, Nanci M; Parra, Esteban J; Pereira, Rinaldo W
A current concern in genetic epidemiology studies in admixed populations is that population stratification can lead to spurious results. The Brazilian census classifies individuals according to self-reported "color", but several studies have demonstrated that stratifying according to "color" is not a useful strategy to control for population structure, due to the dissociation between self-reported "color" and genomic ancestry. We report the results of a study in a group of Brazilian siblings in which we measured skin pigmentation using a reflectometer, and estimated genomic ancestry using 21 Ancestry Informative Markers (AIMs). Self-reported "color", according to the Brazilian census, was also available for each participant. This made it possible to evaluate the relationship between self-reported "color" and skin pigmentation, self-reported "color" and genomic ancestry, and skin pigmentation and genomic ancestry. We observed that, although there were significant differences between the three "color" groups in genomic ancestry and skin pigmentation, there was considerable dispersion within each group and substantial overlap between groups. We also saw that there was no good agreement between the "color" categories reported by each member of the sibling pair: 30 out of 86 sibling pairs reported different "color", and in some cases, the sibling reporting the darker "color" category had lighter skin pigmentation. Socioeconomic status was significantly associated with self-reported "color" and genomic ancestry in this sample. This and other studies show that subjective classifications based on self-reported "color", such as the one that is used in the Brazilian census, are inadequate to describe the population structure present in recently admixed populations. Finally, we observed that one of the AIMs included in the panel (rs1426654), which is located in the known pigmentation gene SLC24A5, was strongly associated with skin pigmentation in this sample.
Rosendahl, B. R.
Continental Rifts, edited by A. M. Quennell, is a new member of the Benchmark Papers in Geology Series, edited in toto by R. W. Fairbridge. In this series the individual volume editors peruse the literature on a given topic, select a few dozen papers of ostensibly benchmark quality, and then reorder them in some sensible fashion. Some of the original papers are republished intact, but many are chopped into “McNuggets™” of information. Depending upon the volume editor, the chopping process can range from a butchering job to careful and prudent pruning. The collecting, sifting, and reorganizing tasks are, of course, equally editor-sensitive. The end product of this series is something akin to a set of Reader's Digest of Geology.
Archie, Elizabeth A; Moss, Cynthia J; Alberts, Susan C
Many social animals live in stable groups. In contrast, African savannah elephants (Loxodonta africana) live in unusually fluid, fission-fusion societies. That is, 'core' social groups are composed of predictable sets of individuals; however, over the course of hours or days, these groups may temporarily divide and reunite, or they may fuse with other social groups to form much larger social units. Here, we test the hypothesis that genetic relatedness predicts patterns of group fission and fusion among wild, female African elephants. Our study of a single Kenyan population spans 236 individuals in 45 core social groups, genotyped at 11 microsatellite and one mitochondrial DNA (mtDNA) locus. We found that genetic relatedness predicted group fission; adult females remained with their first order maternal relatives when core groups fissioned temporarily. Relatedness also predicted temporary fusion between social groups; core groups were more likely to fuse with each other when the oldest females in each group were genetic relatives. Groups that shared mtDNA haplotypes were also significantly more likely to fuse than groups that did not share mtDNA. Our results suggest that associations between core social groups persist for decades after the original maternal kin have died. We discuss these results in the context of kin selection and its possible role in the evolution of elephant sociality.
Loose, Florence; Tiboulet, Marie; Maisonneuve, Christelle; Taillandier-Schmitt, Anne; Dambrun, Michael
The purpose of this study was to examine the associations between perceived ethnic discrimination and (physical and mental) health indicators among North African women and men living in France. This study included 82 North Africans, aged 18-64 years. Perceived discrimination was measured at both group level (PGD) and personal level (PPD). The physical health indicator was blood pressure. The mental health indicator was self-reported psychological distress. Multiple regression analyses showed that higher levels of PGD predicted higher blood pressure. PPD was not related to blood pressure. PPD was positively related to psychological distress among women, but not among men. PPD and PGD are associated with physical and mental health indicators in different ways among North African women and men in France. © 2017 Wiley Periodicals, Inc.
Michard, André; Soulaimani, Abderrahmane; Ouanaimi, Hassan; Raddi, Youssef; Aït Brahim, Lahsen; Rjimati, Ech-Cherki; Baidder, Lahssen; Saddiqi, Omar
The Saghro Group (SG) is a folded, low-grade volcano-sedimentary series up to 8 km thick that crops out within and to the north of the Pan-African suture zone in the central and eastern Anti-Atlas. Here we describe the SG of the Ougnat inliers that are exposed in the easternmost Anti-Atlas beneath the unconformable, Late Ediacaran Ouarzazate Group (OZG) volcanic rocks. The Ougnat SG mostly consists of volcaniclastic greywackes accumulated in a peritidal-to-shallow basin. The basin infilling was deformed by NNE-trending, mostly upright folds with axial-planar slaty cleavage and low-grade metamorphism. The deformed SG rocks were intruded by the ∼550 Ma Mellab hypovolcanic granodiorite. The latter also crosscuts the lowest OZG rocks that are dated to 574-571 Ma in the western Saghro region. The SG rocks that form the Siroua and Saghro inliers have an oldest age of 620-610 Ma and were folded at ∼610-580 Ma at the onset of the Cadomian orogenic events. We show that the SG rocks are similar to the ;Série verte; (SV) rocks that are exposed in the Ougarta and western Hoggar east of the Pan-African suture. We infer that the SG and SV rocks accumulated in a same, continuous basin that was bounding the West African Craton to the north and the east. This strongly subsiding basin formed close to a volcanic arc and was folded during the last Pan-African synmetamorphic events. Fold orientation and age of folding differ however along the edge of the West African Craton. The orogenic greywackes that form the remnants of the SG-SV basin thus constitute a precious record of the diachronic Cadomian event s.l. along the West African Craton northern margin.
In networks among black South Africans, sexual partnerships are more likely to be ... concurrent partners has contributed to the connectedness of sexual networks ... epidemiology, khwapeni, liberalism, marriage, monogamy, polygamy, social ...
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.
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
The historical precedents to the idea of continent-wide diversion of water in North America are reviewed, starting from early perceptions of continental drainage and the era of canal building that reached its peak in the mid-1800s. The attitude that natural landscapes can be rearranged to suit human needs has persisted from that era with the proposal for continent-wide water diversion megaprojects, many involving the movement of water from Canada to the southwestern USA. Over 50 water diversions exist in Canada, with a total diverted flow of 4,400 m 3 /s. The density of interconnected and almost-connected lakes and rivers has favored such diversions. Of these diversions, 95% of their storage capacity and 96% of their flow is for hydroelectric power generation. The number of diversions in the USA is similar but water volumes are only a sixth of those in Canada, and the water is mainly used for irrigation or water supply. Experience in both countries shows that diversions are contained by political boundaries. No large-scale diversion of fresh water across the international boundary has received any government support, and no significant change in this policy is anticipated. In the water-short areas of the USA, conservation and reallocation of water resources are receiving priority. 19 refs., 2 figs., 2 tabs
Baby, Guillaume; Guillocheau, François; Boulogne, Carl; Robin, Cécile; Dall'Asta, Massimo
The south and southeast coast of southern Africa (from 28°S to 33°S) forms a high-elevated transform passive margin bounded to the east by the Agulhas-Falkland Fracture Zone (AFFZ). We analysed the stratigraphic record of the Outeniqua and Durban (Thekwini) Basins, located on the African side of the AFFZ, to determine the evolution of these margins from the rifting stage to present-day. The goal was to reconstruct the strike-slip evolution of the Agulhas Margin and the uplift of the inland high-elevation South African Plateau. The Agulhas transform passive margin results from four successive stages: Rifting stage, from Late Triassic to Early Cretaceous ( 200?-134 Ma), punctuated by three successive rifting episodes related to the Gondwana breakup; Wrench stage (134-131 Ma), evidenced by strike- and dip-slip deformations increasing toward the AFFZ; Active transform margin stage (131-92 Ma), during which the Falkland/Malvinas Plateau drifts away along the AFFZ, with an uplift of the northeastern part of the Outeniqua Basin progressively migrating toward the west; Thermal subsidence stage (92-0 Ma), marked by a major change in the configuration of the margin (onset of the shelf-break passive margin morphology). Two main periods of uplift were documented during the thermal subsidence stage of the Agulhas Margin: (1) a 92 Ma short-lived margin-scale uplift, followed by a second one at 76 Ma located along the Outeniqua Basin and; (2) a long-lasting uplift from 40 to 15 Ma limited to the Durban (Thekwini) Basin. This suggests that the South African Plateau is an old Upper Cretaceous relief (90-70 Ma) reactivated during Late Eocene to Early Miocene times (40-15 Ma).
Stoneking, Mark; Qin, Pengfei
Although initial studies suggested that Denisovan ancestry was found only in modern human populations from island Southeast Asia and Oceania, more recent studies have suggested that Denisovan ancestry may be more widespread. However, the geographic extent of Denisovan ancestry has not been determined, and moreover the relationship between the Denisovan ancestry in Oceania and that elsewhere has not been studied. Here we analyze genome-wide SNP data from 2493 individuals from 221 worldwide pop...
B. Dhamo (Brunilda); L. Kragt (Lea); Grgic, O. (Olja); S. Vucic (Strahinja); M.C. Medina-Gomez (Carolina); Rivadeneira, F. (Fernando); V.W.V. Jaddoe (Vincent); E.B. Wolvius (Eppo); E.M. Ongkosuwito (Edwin)
textabstractObjective: In this study, we investigated the influence of ancestry on dental development in the Generation R Study. Methods: Information on geographic ancestry was available in 3,600 children (1,810 boys and 1,790 girls, mean age 9.81±0.35 years) and information about genetic ancestry
Ba, Djibril Marie; Sow, Mamadou Saidou; Diack, Aminata; Dia, Khadidiatou; Mboup, Mouhamed Cherif; Fall, Pape Diadie; Fall, Moussa Daouda
Since the discovery of the ABO blood group system by Karl Landsteiner in 1901, several reports have suggested an important involvement of the ABO blood group system in the susceptibility to thrombosis. Assessing that non-O blood groups in particular A blood group confer a higher risk of venous and arterial thrombosis than group O.Epidemiologic data are typically not available for all racial and ethnics groups.The purpose of this pilot study was to identify a link between ABO blood group and ischemic disease (ID) in Africans, and to analyze whether A blood group individuals were at higher risk of ischemic disease or not. A total of 299 medical records of patients over a three-year period admitted to the cardiology and internal medicine department of military hospital of Ouakam in Senegal were reviewed. We studied data on age, gender, past history of hypertension, diabetes, smoking, sedentarism, obesity, hyperlipidemia, use of estrogen-progestin contraceptives and blood group distribution.In each blood group type, we evaluated the prevalence of ischemic and non-ischemic cardiovascular disease. The medical records were then stratified into two categories to evaluate incidence of ischemic disease: Group 1: Patients carrying blood-group A and Group 2: Patients carrying blood group non-A (O, AB and B). Of the 299 patients whose medical records were reviewed, 92 (30.8%) were carrying blood group A, 175 (58.5%) had blood group O, 13 (4.3%) had blood group B, and 19 (6.4%) had blood group AB.The diagnosis of ischemic disease (ID) was higher in patients with blood group A (61.2%) than in other blood groups, and the diagnosis of non-ischemic disease (NID) was higher in patients with blood group O (73.6%) compared to other groups. In patients with blood group B or AB compared to non-B or non-AB, respectively there was no statistically significant difference in ID incidence.Main risk factor for ID was smoking (56.5%), hypertension (18.4%) and diabetes (14.3%).In our study
Students compare banding patterns on hominid chromosomes and see striking evidence of their common ancestry. To test this, human chromosome no. 2 is matched with two shorter chimpanzee chromosomes, leading to the hypothesis that human chromosome 2 resulted from the fusion of the two shorter chromosomes. Students test that hypothesis by looking for…
Qin, Pengfei; Stoneking, Mark
Although initial studies suggested that Denisovan ancestry was found only in modern human populations from island Southeast Asia and Oceania, more recent studies have suggested that Denisovan ancestry may be more widespread. However, the geographic extent of Denisovan ancestry has not been determined, and moreover the relationship between the Denisovan ancestry in Oceania and that elsewhere has not been studied. Here we analyze genome-wide single nucleotide polymorphism data from 2,493 individuals from 221 worldwide populations, and show that there is a widespread signal of a very low level of Denisovan ancestry across Eastern Eurasian and Native American (EE/NA) populations. We also verify a higher level of Denisovan ancestry in Oceania than that in EE/NA; the Denisovan ancestry in Oceania is correlated with the amount of New Guinea ancestry, but not the amount of Australian ancestry, indicating that recent gene flow from New Guinea likely accounts for signals of Denisovan ancestry across Oceania. However, Denisovan ancestry in EE/NA populations is equally correlated with their New Guinea or their Australian ancestry, suggesting a common source for the Denisovan ancestry in EE/NA and Oceanian populations. Our results suggest that Denisovan ancestry in EE/NA is derived either from common ancestry with, or gene flow from, the common ancestor of New Guineans and Australians, indicating a more complex history involving East Eurasians and Oceanians than previously suspected. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
Banks, Reginald; Hogue, Aaron; Liddle, Howard; Timberlake, Terri
Compared the effectiveness for inner-city African-American youth (n=64) of two social-skills training curricula focusing on problem solving, anger management, and conflict resolution. Both the Afrocentric curriculum and the one that was merely culturally relevant yielded similar decreases in anger and increases in assertiveness and self-control.…
Couvreur, T.L.P.; Botermans, M.; Heuven, Van B.J.; Ham, van der R.W.J.M.
Pollen morphology has played a major role in elucidating infrafamiliar-level systematics and evolution within Annonaceae, especially within the African genera. The Monodora clade is composed of five genera, Asteranthe, Hexalobus, Isolona, Monodora and Uvariastrum, which are restricted to Africa and
Fondevila, M; Phillips, C; Santos, C; Freire Aradas, A; Vallone, P M; Butler, J M; Lareu, M V; Carracedo, A
A revision of an established 34 SNP forensic ancestry test has been made by swapping the under-performing rs727811 component SNP with the highly informative rs3827760 that shows a near-fixed East Asian specific allele. We collated SNP variability data for the revised SNP set in 66 reference populations from 1000 Genomes and HGDP-CEPH panels and used this as reference data to analyse four U.S. populations showing a range of admixture patterns. The U.S. Hispanics sample in particular displayed heterogeneous values of co-ancestry between European, Native American and African contributors, likely to reflect in part, the way this disparate group is defined using cultural as well as population genetic parameters. The genotyping of over 700 U.S. population samples also provided the opportunity to thoroughly gauge peak mobility variation and peak height ratios observed from routine use of the single base extension chemistry of the 34-plex test. Finally, the genotyping of the widely used DNA profiling Standard Reference Material samples plus other control DNAs completes the audit of the 34-plex assay to allow forensic practitioners to apply this test more readily in their own laboratories. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Hu, Youna; Willer, Cristen; Zhan, Xiaowei; Kang, Hyun Min; Abecasis, Gonçalo R.
Estimates of the ancestry of specific chromosomal regions in admixed individuals are useful for studies of human evolutionary history and for genetic association studies. Previously, this ancestry inference relied on high-quality genotypes from genome-wide association study (GWAS) arrays. These high-quality genotypes are not always available when samples are exome sequenced, and exome sequencing is the strategy of choice for many ongoing genetic studies. Here we show that off-target reads generated during exome-sequencing experiments can be combined with on-target reads to accurately estimate the ancestry of each chromosomal segment in an admixed individual. To reconstruct local ancestry, our method SEQMIX models aligned bases directly instead of relying on hard genotype calls. We evaluate the accuracy of our method through simulations and analysis of samples sequenced by the 1000 Genomes Project and the NHLBI Grand Opportunity Exome Sequencing Project. In African Americans, we show that local-ancestry estimates derived by our method are very similar to those derived with Illumina’s Omni 2.5M genotyping array and much improved in relation to estimates that use only exome genotypes and ignore off-target sequencing reads. Software implementing this method, SEQMIX, can be applied to analysis of human population history or used for genetic association studies in admixed individuals. PMID:24210252
Edwards, Melissa; Cha, David; Krithika, S.; Johnson, Monique; Parra, Esteban J.
There are many textural elements that can be found in the human eye, including Fuchs’ crypts, Wolfflin nodules, pigment spots, contraction furrows and conjunctival melanosis. Although iris surface features have been well-studied in populations of European ancestry, the worldwide distribution of these traits is poorly understood. In this paper, we develop a new method of characterizing iris features from photographs of the iris. We then apply this method to a diverse sample of East Asian, European and South Asian ancestry. All five iris features showed significant differences in frequency between the three populations, indicating that iris features are largely population dependent. Although none of the features were correlated with each other in the East and South Asian groups, Fuchs’ crypts were significantly correlated with contraction furrows and pigment spots and contraction furrows were significantly associated with pigment spots in the European group. The genetic marker SEMA3A rs10235789 was significantly associated with Fuchs’ crypt grade in the European, East Asian and South Asian samples and a borderline association between TRAF3IP1 rs3739070 and contraction furrow grade was found in the European sample. The study of iris surface features in diverse populations may provide valuable information of forensic, biomedical and ophthalmological interest. PMID:26909168
Wang, Zheng; He, Guanglin; Luo, Tao; Zhao, Xueying; Liu, Jing; Wang, Mengge; Zhou, Di; Chen, Xu; Li, Chengtao; Hou, Yiping
The Tibeto-Burman language, one subfamily of the Sino-Tibetan languages, is spoken by over 60 million people all over East Asia. Yet the ethnic origin and genetic architecture of Tibeto-Burman speaking populations remain largely unexplored. In the present study, 169 Chinese individuals from Tibeto-Burman speaking populations (two ethnic groups: Tibetan and Yi) in four different geographic regions in western China were analyzed using the Precision ID Ancestry Panel (165 AISNPs) and the Ion PGM System. The performance and corresponding forensic statistical parameters of this AISNPs panel were investigated. Comprehensive population genetic comparisons (143 populations based on Kidd' SNPs, 92 populations on the basis of Seldin' SNPs and 31 populations based on the Precision ID Ancestry Panel) and ancestry inference were further performed. Sequencing performance demonstrated that the Precision ID Ancestry Panel is effective and robust. Forensic characteristics suggested that this panel not only can be used for ancestry estimation of Tibeto-Burman populations but also for individual identification. Tibetan and Yi shared a common genetic ancestry origin but experienced the complex history of gene flow, local adaptation, and isolation, and constructed the specific genetic landscape of human genetic diversity of Highlander and Lowlander populations. Tibetan-Burman populations and other East Asian populations showed sufficient genetic difference and could be distinguished into three distinct groups. Furthermore, analysis of population structure revealed that significant genetic difference was existed inter-continent populations and strong genetic affinity was observed within-continent populations. Additional population-specific AISNPs and a relatively more comprehensive database with sufficient reference population data remain necessary to get better-scale resolution within a geographically proximate populations in East Asia. Copyright © 2018 Elsevier B.V. All rights
Drabik-Clary, Kathryn; Reddy, Vishnu V B; Benjamin, William H; Boctor, Fouad N
Maternal-fetal ABO incompatibility is a common hematological problem affecting the newborn. In general, hemolysis is minimal and the clinical course is relatively benign, rarely causing the escalating levels of hyperbilirubinemia and significant anemia commonly associated with Rh hemolytic disease of the newborn (HDN). The incidence of HDN ranges from one in 150 births to 1:3000 births, depending on the degree of anemia and level of serum bilirubin. The etiology of ABO hemolytic disease of the newborn (ABO-HDN) is complex because anti-A and anti-B antibodies are composed mainly of IgM. Since only IgG antibodies cross the placenta, those pregnant women with high levels of IgG anti-A,B, anti-A, or anti-B with an ABO incompatible fetus will be the ones to give birth to an infant with ABO-HDN. We describe a case of a B/Rh positive term newborn born to an O/Rh negative African-American mother demonstrating aggressive hemolysis and a robust response of the bone marrow. This case was successfully managed with phototherapy and simple RBC transfusion without the need for exchange transfusion.
This study describes how group dynamics and diet have influenced the ranging patterns of a western gorilla group at Bai Hokou, Central African Republic. The results are compared with those from an earlier study [Cipolletta, International Journal of Primatology, 2003], when the same group was larger and undergoing the process of habituation to humans. Data were obtained from maps of the gorillas' travel routes, direct observations, and analysis of fecal samples. Through the years, the group has experienced a decrease in size, from eight to three individuals, with periods of membership fluctuation. The male's search for new mates resulted in a larger home range than was recorded when the group consisted of more individuals. Moreover, despite an average group size of three throughout this study, the monthly range and mean daily path length (DPL) were also larger when the group was acquiring/losing members in new areas, than when no new members joined or left the group. Fruit was consumed year-round, although more heavily so during wet months. The influence of fruit consumption on the ranging patterns was concealed initially by the effect of habituation [Cipolletta, International Journal of Primatology, 2003], and later (at least partially) by the male's search for new mates. In the last 14 months of the study, when the group numbered only three individuals and was ranging in a restricted area, the average DPL, but not the monthly range, increased when the gorillas were consuming more fruit.
Fanconi anaemia (FA) is a rare genetic condition of impaired DNA ... An earlier age of diagnosis of FA in Afrikaner patients, a high frequency of somatic anomalies and a ... median current age and median age of presentation with symptoms in.
Muthivhi, T. N.; Olmsted, M. G.; Park, H.; Sha, M.; Raju, V.; Mokoena, T.; Bloch, E. M.; Murphy, E. L.; Reddy, R.
SUMMARY Background and Objectives South Africa has a markedly skewed representation where the majority of blood (62%) is presently collected from an ethnically White minority. This study seeks to identify culturally specific factors affecting motivation of donors in South Africa. Materials and Methods We performed a qualitative study to evaluate motivators and deterrents to blood donation among Black South Africans. A total of 13 focus groups, comprising a total of 97 Black South Africans, stratified by age and geographic location were conducted. Transcripts of the interviews were analysed using a coding framework by Bednall & Bove. Results Participants made 463 unique comments about motivators focusing primarily on promotional communications (28%), incentives (20%) and prosocial motivation (16%). Participants made 376 comments about deterrents which focused primarily on fear (41%), negative attitudes (14%) and lack of knowledge (10%). Conclusion Although prosocial motivation (altruism) was the most frequently mentioned individual motivator, promotional communication elicited more overall comments by participants. As reported by many authors, fear and lack of awareness were strong deterrents, but scepticism engendered by perceived racial discrimination in blood collection were unique to the South African environment. PMID:26104809
Muthivhi, T N; Olmsted, M G; Park, H; Sha, M; Raju, V; Mokoena, T; Bloch, E M; Murphy, E L; Reddy, R
South Africa has a markedly skewed representation where the majority of blood (62%) is presently collected from an ethnically White minority. This study seeks to identify culturally specific factors affecting motivation of donors in South Africa. We performed a qualitative study to evaluate motivators and deterrents to blood donation among Black South Africans. A total of 13 focus groups, comprising a total of 97 Black South Africans, stratified by age and geographic location were conducted. Transcripts of the interviews were analysed using a coding framework by Bednall & Bove. Participants made 463 unique comments about motivators focusing primarily on promotional communications (28%), incentives (20%) and prosocial motivation (16%). Participants made 376 comments about deterrents which focused primarily on fear (41%), negative attitudes (14%) and lack of knowledge (10%). Although prosocial motivation (altruism) was the most frequently mentioned individual motivator, promotional communication elicited more overall comments by participants. As reported by many authors, fear and lack of awareness were strong deterrents, but scepticism engendered by perceived racial discrimination in blood collection were unique to the South African environment. © 2015 British Blood Transfusion Society.
Loret de Mola, Christian; Hartwig, Fernando Pires; Gonçalves, Helen; Quevedo, Luciana de Avila; Pinheiro, Ricardo; Gigante, Denise Petrucci; Motta, Janaína Vieira Dos Santos; Pereira, Alexandre C; Barros, Fernando C; Horta, Bernardo Lessa
Evidence suggests that there is an association between ethnicity/skin color and depression; however, many contextual and individual variables, like sense of discrimination and socioeconomic position (SEP), might influence the direction of this association. We assessed the association between African ancestry and major depression among young adults that have been followed-up since birth in a Southern Brazilian city, and the mediating effect of SEP and discrimination. In 1982, all hospital deliveries in Pelotas (Southern Brazil) were identified; liveborns were examined and their mothers interviewed (n = 5914). In 2012-13, at 30 years of age, we used the Mini International Neuropsychiatric Interview (MINI) for major depression diagnosis. In addition, DNA samples were genotyped for approximately 2.5 million single nucleotide polymorphisms (SNPs) using Illumina (CA, USA) HumanOmni2.5-8v1 array. Genomic ancestry estimation was based on approximately 370 000 single nucleotide polymorphisms (SNPs) mutually available for the Pelotas cohort and selected samples (used as reference panels) of the HapMap and Human Genome Diversity (HGDP). We estimated prevalence ratios (PR) using Poisson regression models and evaluated the association between percentage of African ancestry and major depression. We used G-computation for mediation analysis. At 30 years, 3576 individuals were evaluated for major depression (prevalence = 7.9 %). Only individuals in the highest SEP, who had a percentage of African ancestry between >5-30 % and >30 % had a prevalence of major depression 2.16 (PR = 2.16 95 % CI [1.05-4.45]) and 2.74 (PR = 2.74 95 % CI [1.06-7.06]) times higher, than those with 5 % or less, respectively. Among these subjects, sense of discrimination by skin color, captured 84 % of the association between African ancestry and major depression. SEP is an important effect modifier of the positive association between African ancestry and major depression. In addition
Cantarero Arevalo, Lourdes; Holstein, Bjørn Evald; Andersen, Anette
Investigations in several Western countries have reported ethnic differences in asthma prevalence and treatment among children and in some countries these differences are increasing. The aim of this study was to analyse whether there are inequalities in asthma treatment by country of birth...... and ancestry among children residing in Denmark, and whether this potential association may vary between different household income groups....
Earth Data Analysis Center, University of New Mexico — This shapefile was created to show the proximity of the Continental Divide to the Continental Divide National Scenic Trail in New Mexico. This work was done as part...
Full Text Available Barrett's esophagus (BE and esophageal adenocarcinoma (EAC are far more prevalent in European Americans than in African Americans. Hypothesizing that this racial disparity in prevalence might represent a genetic susceptibility, we used an admixture mapping approach to interrogate disease association with genomic differences between European and African ancestry.Formalin fixed paraffin embedded samples were identified from 54 African Americans with BE or EAC through review of surgical pathology databases at participating Barrett's Esophagus Translational Research Network (BETRNet institutions. DNA was extracted from normal tissue, and genotyped on the Illumina OmniQuad SNP chip. Case-only admixture mapping analysis was performed on the data from both all 54 cases and also on a subset of 28 cases with high genotyping quality. Haplotype phases were inferred with Beagle 3.3.2, and local African and European ancestries were inferred with SABER plus. Disease association was tested by estimating and testing excess European ancestry and contrasting it to excess African ancestry.Both datasets, the 54 cases and the 28 cases, identified two admixture regions. An association of excess European ancestry on chromosome 11p reached a 5% genome-wide significance threshold, corresponding to -log10(P = 4.28. A second peak on chromosome 8q reached -log10(P = 2.73. The converse analysis examining excess African ancestry found no genetic regions with significant excess African ancestry associated with BE and EAC. On average, the regions on chromosomes 8q and 11p showed excess European ancestry of 15% and 20%, respectively.Chromosomal regions on 11p15 and 8q22-24 are associated with excess European ancestry in African Americans with BE and EAC. Because GWAS have not reported any variants in these two regions, low frequency and/or rare disease associated variants that confer susceptibility to developing BE and EAC may be driving the observed European ancestry
Williams, Edith M; Bruner, Larisa; Adkins, Alyssa; Vrana, Caroline; Logan, Ayaba; Kamen, Diane; Oates, James C
Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disorder that can cause significant morbidity and mortality. A large body of evidence has shown that African-Americans experience the disease more severely than other racial-ethnic groups. Relevant literature for the years 2000 to August 2015 were obtained from systematic searches of PubMed, Scopus, and the EBSCOHost platform that includes MEDLINE, CINAHL, etc. to evaluate research focused on SLE in African-Americans. Thirty-six of the 1502 articles were classified according to their level of evidence. The systematic review of the literature reported a wide range of adverse outcomes in African-American SLE patients and risk factors observed in other mono and multi-ethnic investigations. Studies limited to African-Americans with SLE identified novel methods for more precise ascertainment of risk and observed novel findings that hadn't been previously reported in African-Americans with SLE. Both environmental and genetic studies included in this review have highlighted unique African-American populations in an attempt to isolate risk attributable to African ancestry and observed increased genetic influence on overall disease in this cohort. The review also revealed emerging research in areas of quality of life, race-tailored interventions, and self-management. This review reemphasizes the importance of additional studies to better elucidate the natural history of SLE in African-Americans and optimize therapeutic strategies for those who are identified as being at high risk. PMID:27651918
Pool, John E.
North American populations of Drosophila melanogaster derive from both European and African source populations, but despite their importance for genetic research, patterns of ancestry along their genomes are largely undocumented. Here, I infer geographic ancestry along genomes of the Drosophila Genetic Reference Panel (DGRP) and the D. melanogaster reference genome, which may have implications for reference alignment, association mapping, and population genomic studies in Drosophila. Overall, the proportion of African ancestry was estimated to be 20% for the DGRP and 9% for the reference genome. Combining my estimate of admixture timing with historical records, I provide the first estimate of natural generation time for this species (approximately 15 generations per year). Ancestry levels were found to vary strikingly across the genome, with less African introgression on the X chromosome, in regions of high recombination, and at genes involved in specific processes (e.g., circadian rhythm). An important role for natural selection during the admixture process was further supported by evidence that many unlinked pairs of loci showed a deficiency of Africa–Europe allele combinations between them. Numerous epistatic fitness interactions may therefore exist between African and European genotypes, leading to ongoing selection against incompatible variants. By focusing on hubs in this network of fitness interactions, I identified a set of interacting loci that include genes with roles in sensation and neuropeptide/hormone reception. These findings suggest that admixed D. melanogaster samples could become an important study system for the genetics of early-stage isolation between populations. PMID:26354524
Lemouel, J. L. (Principal Investigator); Galdeano, A.; Ducruix, J.
Anomaly maps of high quality are needed to display unambiguously the so called long wave length anomalies. The anomalies were analyzed in terms of continental drift and the nature of their sources is discussed. The map presented confirms the thinness of the oceanic magnetized layer. Continental magnetic anomalies are characterized by elongated structures generally of east-west trend. Paleomagnetic reconstruction shows that the anomalies found in India, Australia, and Antarctic exhibit a fair consistency with the African anomalies. It is also shown that anomalies are locked under the continents and have a fixed geometry.
Motswaledi, Modisa Sekhamo; Kasvosve, Ishmael; Oguntibeju, Oluwafemi Omoniyi
Botswana is among the world's countries with the highest rates of HIV infection. It is not known whether or not this susceptibility to infection is due to genetic factors in the population. Accumulating evidence, however, points to the role of erythrocytes as potential mediators of infection. We therefore sought to establish the role, if any, of some erythrocyte antigens in HIV infection in a cross-section of the population. 348 (346 HIV-negative and 2 HIV-positive) samples were obtained from the National Blood Transfusion Service as residual samples, while 194 HIV-positive samples were obtained from the Botswana-Harvard HIV Reference Laboratory. Samples were grouped for twenty three antigens. Chi-square or Fischer Exact analyses were used to compare the frequencies of the antigens in the two groups. A stepwise, binary logistic regression was used to study the interaction of the various antigens in the light of HIV-status. The Rh antigens C and E were associated with HIV-negative status, while blood group Jka, P1 and Lub were associated with HIV-positive status. A stepwise binary logistic regression analysis yielded group C as the most significant protective blood group while Lub and P1 were associated with significantly higher odds ratio in favor of HIV-infection. The lower-risk-associated group C was significantly lower in Africans compared to published data for Caucasians and might partially explain the difference in susceptibility to HIV-1. The most influential antigen C, which also appears to be protective, is significantly lower in Africans than published data for Caucasians or Asians. On the other hand, there appear to be multiple antigens associated with increased risk that may override the protective role of C. A study of the distribution of these antigens in other populations may shed light on their roles in the HIV pandemic.
Guimarães, Lilian O; Bajay, Miklos Maximiliano; Monteiro, Eliana F; Wunderlich, Gerhard; Santos, Sidney E; Kirchgatter, Karin
The innate immune system governed by toll-like receptors (TLRs) provides the first line of defense against pathogens. Surface-localized TLR1 and TLR6 are known to detect parasite components. TLR encoding genes were shown to display signatures of recent positive selection in Europeans and might be involved in local adaptation at immune-related genes. To verify the influence of Brazilian population admixture on the distribution of polymorphisms in TLRs, we analyzed the genotype frequencies of 24 polymorphisms distributed across five TLR genes in a Southeastern Brazilian population where autochthonous cases of malaria occur in small foci of transmission. The estimation of ancestry showed mainly European ancestry (63%) followed by African ancestry (22%). Mean proportions of European ancestry differed significantly between the genotypes of the TLR1 (I602S) gene and in the TLR6 (P249S) gene. The chance of having the G allele in TLR1 gene increases as European ancestry increases as well as the chance of having the T allele in the TLR6 gene. The 602S allele is related to a ''hypo-responsiveness'' possibly explaining the high prevalence of asymptomatic malaria cases in areas of Southeastern Brazil. Our results underline the necessity to include informative ancestry markers in genetic association studies in order to avoid biased results. Copyright © 2017 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.
Full Text Available By virtue of being the product of the genetic admixture of three ancestral roots: Europeans, Africans and Amerindians, the present day Brazilian population displays very high levels of genomic diversity, which have important pharmacogenetic/-genomic (PGx implications. Recognition of this fact has prompted the creation of the Brazilian Pharmacogenomics Network (Refargen, a nationwide consortium of research groups, with the mission to provide leadership in PGx research and education in Brazil, with a population heath impact. Here, we present original data and review published results from a Refargen comprehensive study of the distribution of PGx polymorphisms in a representative cohort of the Brazilian people, comprising 1,034 healthy, unrelated adults, self-identified as white, brown or black, according to the Color categories adopted by the Brazilian Census. Multinomial log-linear regression analysis was applied to infer the statistical association between allele, genotype and haplotype distributions among Brazilians (response variables and self-reported Color, geographical region and biogeographical ancestry (explanatory variables, whereas Wright´s FST statistics was used to assess the extent of PGx divergence among different strata of the Brazilian population. Major PGx implications of these findings are: first, extrapolation of data from relatively well-defined ethnic groups is clearly not applicable to the majority of Brazilians; second, the frequency distribution of polymorphisms in several pharmacogenes of clinical relevance (e.g. ABCB1, CYP3A5, CYP2C9, VKORC varies continuously among Brazilians and is not captured by race/Color self-identification; third, the intrinsic heterogeneity of the Brazilian population must be acknowledged in the design and interpretation of PGx studies in order to avoid spurious conclusions based on improper matching of study cohorts.
Leite, Tailce K. M.; Fonseca, Rômulo M. C.; de França, Nanci M.; Parra, Esteban J.; Pereira, Rinaldo W.
A current concern in genetic epidemiology studies in admixed populations is that population stratification can lead to spurious results. The Brazilian census classifies individuals according to self-reported “color”, but several studies have demonstrated that stratifying according to “color” is not a useful strategy to control for population structure, due to the dissociation between self-reported “color” and genomic ancestry. We report the results of a study in a group of Brazilian siblings in which we measured skin pigmentation using a reflectometer, and estimated genomic ancestry using 21 Ancestry Informative Markers (AIMs). Self-reported “color”, according to the Brazilian census, was also available for each participant. This made it possible to evaluate the relationship between self-reported “color” and skin pigmentation, self-reported “color” and genomic ancestry, and skin pigmentation and genomic ancestry. We observed that, although there were significant differences between the three “color” groups in genomic ancestry and skin pigmentation, there was considerable dispersion within each group and substantial overlap between groups. We also saw that there was no good agreement between the “color” categories reported by each member of the sibling pair: 30 out of 86 sibling pairs reported different “color”, and in some cases, the sibling reporting the darker “color” category had lighter skin pigmentation. Socioeconomic status was significantly associated with self-reported “color” and genomic ancestry in this sample. This and other studies show that subjective classifications based on self-reported “color”, such as the one that is used in the Brazilian census, are inadequate to describe the population structure present in recently admixed populations. Finally, we observed that one of the AIMs included in the panel (rs1426654), which is located in the known pigmentation gene SLC24A5, was strongly associated with
Gabriela E. S. Felix
Full Text Available A complete blood count is very useful in clinical diagnoses when reference ranges are well established for the population. Complete blood counts and allele frequencies of Ancestry Informative Markers (AIMs were analyzed in Brazilians with the aim of characterizing the hematological values of an admixed population. Positive associations were observed between gender and neutrophils, monocytes, eosinophils, erythrocytes, hemoglobin, hematocrit, MCV, MCHC and platelet counts. No significant differences were found for age, alcohol consumption, educational status, ethnicity, smoking in respect to the complete blood count values. In general, men had higher red blood cell values, while women had higher values for white blood cells and platelets. The study of the population was highly heterogeneous with mean proportions (± SE of African, European and Amerindian ancestry being 49.0 ± 3.0%, 44.0 ± 9.0% and 7.0 ± 9.0%, respectively. Amerindian ancestry showed limited contribution to the makeup of the population, but estimated ancestral proportions were statistically significant (r = 0.9838; P<0.001. These hematologic values are similar to Afro-Americans, another admixed population.
LeCuyer, Elizabeth A.; Swanson, Dena Phillips
Research suggests that higher levels of authoritarian parenting exist in African American (AA) families than in European American (EA) families, and that authoritarian attitudes may be associated with more positive outcomes in AA families than EA families. However, less is known about authoritarian attitudes and children's development within AA families. This within-group study of 50 African American mothers and their 3-year-old children examined associations between maternal authoritarian attitudes, observed maternal limit-setting strategies, and children's self-regulation during a limit-setting interaction. The findings indicate that while AA families may hold more authoritarian attitudes than EA families, the direction of effect of authoritarian attitudes on children's outcomes appears to be the same in both ethnic groups. In this sample, when examining AA authoritarian attitudes relative to those of other AA mothers, less or lower authoritarian attitudes were associated with authoritative limit-setting behavior (firm limits within the context of overall warmth and responsiveness) and better children's self-regulation. PMID:28408794
LeCuyer, Elizabeth A; Swanson, Dena Phillips
Research suggests that higher levels of authoritarian parenting exist in African American (AA) families than in European American (EA) families, and that authoritarian attitudes may be associated with more positive outcomes in AA families than EA families. However, less is known about authoritarian attitudes and children's development within AA families. This within-group study of 50 African American mothers and their 3-year-old children examined associations between maternal authoritarian attitudes, observed maternal limit-setting strategies, and children's self-regulation during a limit-setting interaction. The findings indicate that while AA families may hold more authoritarian attitudes than EA families, the direction of effect of authoritarian attitudes on children's outcomes appears to be the same in both ethnic groups. In this sample, when examining AA authoritarian attitudes relative to those of other AA mothers, less or lower authoritarian attitudes were associated with authoritative limit-setting behavior (firm limits within the context of overall warmth and responsiveness) and better children's self-regulation.
Santos, Deborah Conte; Pizarro, Marcela Haas; Barros, Bianca S V; de Melo, Laura G Nunes; Porto, Luis Cristovão; Silva, Dayse A; Gomes, Marilia Brito
The aim of the present study was to evaluate the relationship between self-reported color/race and genomic ancestry with HRQoL of patients with type 1 diabetes in a highly admixed population. This was a nationwide, cross-sectional study conducted with 1760 patients with type 1 diabetes from 2011 to 2014 at public clinics in all five Brazilian geographical regions. Information on HRQoL was obtained from two self-completed questionnaires: Short Form-6 Dimensions (SF-6D) and EuroQol-5 Dimensions (EQ-5D) with a visual analogue scale (EQ-VAS). Genomic ancestry was assessed using a Multiplex PCR methodology. Utility scores generated from the questionnaires were analyzed with multivariate logistic regression models. We included 1698 patients. Those patients who self-reported as black had lower EQ-VAS scores compared to the patients who self-reported as white (67.46 ± 18.45; 72.37 ± 16.44, respectively, p = 0.02). In a linear regression model, each 1% increase in African ancestry resulted in a 9.5 point decrease in EQ-VAS score (p ancestry remained associated with lower EQ-VAS scores. A higher level of African ancestry implicates on lower quality of life even after adjustments for sociodemographic and diabetes-related data. Gender, physical activity and diabetes-related microvascular complications were strongly associated with low HRQoL in all three questionnaires used. This fact highlights the importance of social aspects when assessing quality of life, as well as the need for regular practice of physical activity and prevention of chronic complications to improve patients' quality of life.
Sawyer, L M
Using grounded theory methodology, 17 first-time African American mothers were interviewed to elicit their experiences of pregnancy and motherhood. Participants had a mean age of 30 years, were mostly married, employed, middle income, college educated, and all received adequate prenatal care. Engaged Mothering was identified as the core category, denoting the active, involved, and mutual process in which a woman prepares to be a mother, cares for herself and her infant, and dreams about and plans for the future to have a good life for her child. Strategies women used in this process included getting ready, dealing with the reality, settling in, and dreaming. Conditions of intentionality of the pregnancy and prior history of miscarriage or health problems of the mother affected the process. Women described the effects of racism on their daily lives and on the criteria they used to choose providers. Nursing interventions are proposed based on these results.
Smart, Andrew; Bolnick, Deborah A; Tutton, Richard
It is becoming increasingly difficult to keep information about genetic ancestry separate from information about health, and consumers of genetic ancestry tests are becoming more aware of the potential health risks associated with particular ancestral lineages. Because some of the proposed associations have received little attention from oversight agencies and professional genetic associations, scientific developments are currently outpacing governance regimes for consumer genetic testing. We highlight the recent and unremarked upon emergence of biomedical studies linking markers of genetic ancestry to disease risks, and show that this body of scientific research is becoming part of public discourse connecting ancestry and health. For instance, data on genome-wide ancestry informative markers are being used to assess health risks, and we document over 100 biomedical research articles that propose associations between mitochondrial DNA and Y chromosome markers of genetic ancestry and a wide variety of disease risks. Taking as an example an association between coronary heart disease and British men belonging to Y chromosome haplogroup I, we show how this science was translated into mainstream and online media, and how it circulates among consumers of genetic tests for ancestry. We find wide variations in how the science is interpreted, which suggests the potential for confusion or misunderstanding. We recommend that stakeholders involved in creating and using estimates of genetic ancestry reconsider their policies for communicating with each other and with the public about the health implications of ancestry information.
Qiu, Jingya; Moore, Jason H; Darabos, Christian
Genome-wide association studies (GWAS) have led to the discovery of over 200 single nucleotide polymorphisms (SNPs) associated with type 2 diabetes mellitus (T2DM). Additionally, East Asians develop T2DM at a higher rate, younger age, and lower body mass index than their European ancestry counterparts. The reason behind this occurrence remains elusive. With comprehensive searches through the National Human Genome Research Institute (NHGRI) GWAS catalog literature, we compiled a database of 2,800 ancestry-specific SNPs associated with T2DM and 70 other related traits. Manual data extraction was necessary because the GWAS catalog reports statistics such as odds ratio and P-value, but does not consistently include ancestry information. Currently, many statistics are derived by combining initial and replication samples from study populations of mixed ancestry. Analysis of all-inclusive data can be misleading, as not all SNPs are transferable across diverse populations. We used ancestry data to construct ancestry-specific human phenotype networks (HPN) centered on T2DM. Quantitative and visual analysis of network models reveal the genetic disparities between ancestry groups. Of the 27 phenotypes in the East Asian HPN, six phenotypes were unique to the network, revealing the underlying ancestry-specific nature of some SNPs associated with T2DM. We studied the relationship between T2DM and five phenotypes unique to the East Asian HPN to generate new interaction hypotheses in a clinical context. The genetic differences found in our ancestry-specific HPNs suggest different pathways are involved in the pathogenesis of T2DM among different populations. Our study underlines the importance of ancestry in the development of T2DM and its implications in pharmocogenetics and personalized medicine. © 2016 The Authors. *Genetic Epidemiology Published by Wiley Periodicals, Inc.
Full Text Available Disclaimer: These guidelines do not aim to provide a comprehensive review of all the pertinent literature comprising the evidence base and, as such, should be utilised in conjunction with other guidelines as well as the responsibility of practitioners to maintain a high level of personal knowledge and expertise. Despite the known efficacy of treatment and the substantial costs of untreated attention-deficit/hyperactivity disorder (ADHD, access to healthcare and treatment is not a given for many patients in South Africa (SA. In SA, there is poor identification and treatment of common mental disorders at primary healthcare level and limited access to specialist resources with a service delivery and treatment gap of up to 75%. Medication options are also often limited in emerging markets and in SA psychiatrists, and patients do not have access to the medication armamentarium available in established markets. Furthermore, the majority of South Africans currently utilise the public healthcare sector and may not have access to treatment options referred to in these guidelines. These guidelines should therefore not be seen as a policy document. The process: The South African Society of Psychiatrists’ Special Interest Group (SIG for adult ADHD was launched on 25 September 2015, with doctors Rykie Liebenberg and Renata Schoeman as convenor and co-convenor, respectively. The overall objective of the ADHD SIG is to improve the basket of care available to patients with ADHD. This is only possible through a combined and concerted effort of individuals with a special interest in and passion for ADHD to improve knowledge about and funding for the care of individuals with the disorder. One of the specific aims of the ADHD SIG was to develop South African guidelines for the diagnosis and treatment of adult ADHD specifically and update guidelines for the treatment of child, adolescent and adult ADHD. Dr Schoeman has recently completed her MBA at the University
Full Text Available We present a comprehensive assessment of genomic diversity in the African-American population by studying three genotyped cohorts comprising 3,726 African-Americans from across the United States that provide a representative description of the population across all US states and socioeconomic status. An estimated 82.1% of ancestors to African-Americans lived in Africa prior to the advent of transatlantic travel, 16.7% in Europe, and 1.2% in the Americas, with increased African ancestry in the southern United States compared to the North and West. Combining demographic models of ancestry and those of relatedness suggests that admixture occurred predominantly in the South prior to the Civil War and that ancestry-biased migration is responsible for regional differences in ancestry. We find that recent migrations also caused a strong increase in genetic relatedness among geographically distant African-Americans. Long-range relatedness among African-Americans and between African-Americans and European-Americans thus track north- and west-bound migration routes followed during the Great Migration of the twentieth century. By contrast, short-range relatedness patterns suggest comparable mobility of ∼15-16km per generation for African-Americans and European-Americans, as estimated using a novel analytical model of isolation-by-distance.
Alexander Pushkin, Russia's most celebrated literary figure, descended from an African slave. On both parents' sides, he was related to Avram Petrovich Gannibal, who was born to an African prince and abducted to become a slave to a Russian diplomat. Pushkin chose to pride himself on both his aristocratic life and his African ancestry. (SM)
Schwella, E.; van Nieuwenhuyzen, Bernard J.
Are South Africans financially literate, and how can this be measured? Until 2009 there was no South African financial literacy measure and, therefore, the aim was to develop a South African measurement instrument that is scientific, socially acceptable, valid and reliable. To achieve this aim a contextual and conceptual analysis of financial…
Full Text Available The rising prevalence of obesity and excessive adiposity are global public health concerns. Understanding determinants of changes in adiposity over time is critical for informing effective evidence-based prevention or treatment. However, limited information is available to achieve this objective. Cultural, demographic, environmental, and behavioral factors including socio-economic status (SES likely account for obesity development. To this end, we related these variables to anthropometric measures in 1058 black adult Tswana-speaking South Africans who were HIV negative in a prospective study over five years. Body mass index (BMI and waist circumference increased in both sexes, whereas triceps skinfold thickness remained the same. Over the five years, women moved to higher BMI categories and more were diagnosed with central obesity. Age correlated negatively, whereas SES, physical activity, energy, and fat intake correlated positively with adiposity markers in women. In men, SES, marital status, physical activity, and being urban predicted increases in adiposity. For women, SES and urbanicity increased, whereas menopause and smoking decreased adiposity. Among men, smokers had less change in BMI than those that never smoked over five years. Our findings suggest that interventions, focusing on the urban living, the married and those with the highest SES—the high-risk groups identified herein—are of primary importance to contain morbidity and premature mortality due to obesity in black South Africans.
Valeix, Marion; Loveridge, Andrew J; MacDonald, David W
Empirical tests of the resource dispersion hypothesis (RDH), a theory to explain group living based on resource heterogeneity, have been complicated by the fact that resource patch dispersion and richness have proved difficult to define and measure in natural systems. Here, we studied the ecology of African lions Panthera leo in Hwange National Park, Zimbabwe, where waterholes are prey hotspots, and where dispersion of water sources and abundance of prey at these water sources are quantifiable. We combined a 10-year data set from GPS-collared lions for which information of group composition was available concurrently with data for herbivore abundance at waterholes. The distance between two neighboring waterholes was a strong determinant of lion home range size, which provides strong support for the RDH prediction that territory size increases as resource patches are more dispersed in the landscape. The mean number of herbivore herds using a waterhole, a good proxy of patch richness, determined the maximum lion group biomass an area can support. This finding suggests that patch richness sets a maximum ceiling on lion group size. This study demonstrates that landscape ecology is a major driver of ranging behavior and suggests that aspects of resource dispersion limit group sizes.
A study analyzed family decision-making style, peer group affiliation, and academic achievement in 10th grade as predictors of academic achievement of African American students in 12th grade. Findings indicated that though peer groups were known to influence academic performance, affiliation with learning oriented peers in 10th grade did not…
Full Text Available the necessity to re-design ICT to suit small groups as part of participative e-governance rather than the normative ICT design that suits individual work styles. Additionally, the research reveals that by working in groups, communities are more willing to accept...
Full Text Available Non-Hispanic (nH Black and Hispanic women are disproportionately affected by early onset disease, later stage, and with more aggressive, higher grade and ER/PR negative breast cancers. The purpose of this analysis was to examine whether genetic ancestry could account for these variation in breast cancer characteristics, once data were stratified by self-reported race/ethnicity and adjusted for potential confounding by social and behavioral factors.We used a panel of 100 ancestry informative markers (AIMs to estimate individual genetic ancestry in 656 women from the "Breast Cancer Care in Chicago" study, a multi-ethnic cohort of breast cancer patients to examine the association between individual genetic ancestry and breast cancer characteristics. In addition we examined the association of individual AIMs and breast cancer to identify genes/regions that may potentially play a role in breast cancer disease disparities.As expected, nH Black and Hispanic patients were more likely than nH White patients to be diagnosed at later stages, with higher grade, and with ER/PR negative tumors. Higher European genetic ancestry was protective against later stage at diagnosis (OR 0.7 95%CI: 0.54-0.92 among Hispanic patients, and higher grade (OR 0.73, 95%CI: 0.56-0.95 among nH Black patients. After adjustment for multiple social and behavioral risk factors, the association with later stage remained, while the association with grade was not significant. We also found that the AIM SNP rs10954631 on chromosome 7 was associated with later stage (p = 0.02 and higher grade (p = 0.012 in nH Whites and later stage (p = 0.03 in nH Blacks.Non-European genetic ancestry was associated with later stage at diagnosis in ethnic minorities. The relation between genetic ancestry and stage at diagnosis may be due to genetic factors and/or unmeasured environmental factors that are overrepresented within certain racial/ethnic groups.
Bonnie N Young
Full Text Available Diverse socioeconomic and clinical factors influence susceptibility to tuberculosis (TB disease in Mexico. The role of genetic factors, particularly those that differ between the parental groups that admixed in Mexico, is unclear. The objectives of this study are to identify the socioeconomic and clinical predictors of the transition from latent TB infection (LTBI to pulmonary TB disease in an urban population in northeastern Mexico, and to examine whether genetic ancestry plays an independent role in this transition. We recruited 97 pulmonary TB disease patients and 97 LTBI individuals from a public hospital in Monterrey, Nuevo León. Socioeconomic and clinical variables were collected from interviews and medical records, and genetic ancestry was estimated for a subset of 142 study participants from 291,917 single nucleotide polymorphisms (SNPs. We examined crude associations between the variables and TB disease status. Significant predictors from crude association tests were analyzed using multivariable logistic regression. We also compared genetic ancestry between LTBI individuals and TB disease patients at 1,314 SNPs in 273 genes from the TB biosystem in the NCBI BioSystems database. In crude association tests, 12 socioeconomic and clinical variables were associated with TB disease. Multivariable logistic regression analyses indicated that marital status, diabetes, and smoking were independently associated with TB status. Genetic ancestry was not associated with TB disease in either crude or multivariable analyses. Separate analyses showed that LTBI individuals recruited from hospital staff had significantly higher European genetic ancestry than LTBI individuals recruited from the clinics and waiting rooms. Genetic ancestry differed between individuals with LTBI and TB disease at SNPs located in two genes in the TB biosystem. These results indicate that Monterrey may be structured with respect to genetic ancestry, and that genetic
Young, Bonnie N; Rendón, Adrian; Rosas-Taraco, Adrian; Baker, Jack; Healy, Meghan; Gross, Jessica M; Long, Jeffrey; Burgos, Marcos; Hunley, Keith L
Diverse socioeconomic and clinical factors influence susceptibility to tuberculosis (TB) disease in Mexico. The role of genetic factors, particularly those that differ between the parental groups that admixed in Mexico, is unclear. The objectives of this study are to identify the socioeconomic and clinical predictors of the transition from latent TB infection (LTBI) to pulmonary TB disease in an urban population in northeastern Mexico, and to examine whether genetic ancestry plays an independent role in this transition. We recruited 97 pulmonary TB disease patients and 97 LTBI individuals from a public hospital in Monterrey, Nuevo León. Socioeconomic and clinical variables were collected from interviews and medical records, and genetic ancestry was estimated for a subset of 142 study participants from 291,917 single nucleotide polymorphisms (SNPs). We examined crude associations between the variables and TB disease status. Significant predictors from crude association tests were analyzed using multivariable logistic regression. We also compared genetic ancestry between LTBI individuals and TB disease patients at 1,314 SNPs in 273 genes from the TB biosystem in the NCBI BioSystems database. In crude association tests, 12 socioeconomic and clinical variables were associated with TB disease. Multivariable logistic regression analyses indicated that marital status, diabetes, and smoking were independently associated with TB status. Genetic ancestry was not associated with TB disease in either crude or multivariable analyses. Separate analyses showed that LTBI individuals recruited from hospital staff had significantly higher European genetic ancestry than LTBI individuals recruited from the clinics and waiting rooms. Genetic ancestry differed between individuals with LTBI and TB disease at SNPs located in two genes in the TB biosystem. These results indicate that Monterrey may be structured with respect to genetic ancestry, and that genetic differences in TB
surveillance, in Contingency planning exercises and many efforts is done to keep the group updated on the current international situation for swine fevers. The group has been very stabile and especially our participation in a Taiex workshop in 2005 in Romania was a very good basis for our fruitful...... collaboration. In many later discussions our experiences then when we observed the problems in vivo. The obligations of the expert group are both to follow the progress of eradication but definitely also to take care of some of the more time consuming discussions that could otherwise burden the Veterinary...
Atzmon, Gil; Hao, Li; Pe'er, Itsik; Velez, Christopher; Pearlman, Alexander; Palamara, Pier Francesco; Morrow, Bernice; Friedman, Eitan; Oddoux, Carole; Burns, Edward; Ostrer, Harry
For more than a century, Jews and non-Jews alike have tried to define the relatedness of contemporary Jewish people. Previous genetic studies of blood group and serum markers suggested that Jewish groups had Middle Eastern origin with greater genetic similarity between paired Jewish populations. However, these and successor studies of monoallelic Y chromosomal and mitochondrial genetic markers did not resolve the issues of within and between-group Jewish genetic identity. Here, genome-wide analysis of seven Jewish groups (Iranian, Iraqi, Syrian, Italian, Turkish, Greek, and Ashkenazi) and comparison with non-Jewish groups demonstrated distinctive Jewish population clusters, each with shared Middle Eastern ancestry, proximity to contemporary Middle Eastern populations, and variable degrees of European and North African admixture. Two major groups were identified by principal component, phylogenetic, and identity by descent (IBD) analysis: Middle Eastern Jews and European/Syrian Jews. The IBD segment sharing and the proximity of European Jews to each other and to southern European populations suggested similar origins for European Jewry and refuted large-scale genetic contributions of Central and Eastern European and Slavic populations to the formation of Ashkenazi Jewry. Rapid decay of IBD in Ashkenazi Jewish genomes was consistent with a severe bottleneck followed by large expansion, such as occurred with the so-called demographic miracle of population expansion from 50,000 people at the beginning of the 15th century to 5,000,000 people at the beginning of the 19th century. Thus, this study demonstrates that European/Syrian and Middle Eastern Jews represent a series of geographical isolates or clusters woven together by shared IBD genetic threads.
Ewing, J.; Heirtzler, J.; Purdy, M.; Klitgord, Kim D.
In contrast to the rarity of such observations a decade ago, seismic reflecting and refracting horizons are now being observed to Moho depths under continental shelves in a number of places. These observations provide knowledge of the entire crustal thickness from the shoreline to the oceanic crust on passive margins and supplement Consortium for Continental Reflection Profiling (COCORP)-type measurements on land.
Full Text Available Background. Genetic variants in the nuclear transcription receptor, PPARG, are associated with cardiometabolic traits, but reports remain conflicting. We determined the frequency and the clinical relevance of PPARG SNPs in an African mixed ancestry population. Methods. In a cross-sectional study, 820 participants were genotyped for rs1800571, rs72551362, rs72551363, rs72551364, and rs3856806, using allele-specific TaqMan technology. The homeostatic model assessment of insulin (HOMA-IR, β-cells function (HOMA-B%, fasting insulin resistance index (FIRI, and the quantitative insulin-sensitivity check index (QUICKI were calculated. Results. No sequence variants were found except for the rs3856806. The frequency of the PPARG-His447His variant was 23.8% in the overall population group, with no difference by diabetes status (P=0.215. The His447His allele T was associated with none of the markers of insulin resistance overall and by diabetes status. In models adjusted for 2-hour insulin, the T allele was associated with lower prevalent diabetes risk (odds ratio 0.56 (95% CI 0.31–0.95. Conclusion. Our study confirms the almost zero occurrences of known rare PPARG SNPs and has shown for the first time in an African population that one of the common SNPs, His447His, may be protective against type 2 diabetes.
Pomeroy, Emma; Wells, Jonathan C K; Stanojevic, Sanja; Miranda, J Jaime; Moore, Lorna G; Cole, Tim J; Stock, Jay T
Native Andean ancestry gives partial protection from reduced birthweight at high altitude in the Andes compared with European ancestry. Whether Andean ancestry is also associated with body proportions and greater postnatal body size at altitude is unknown. Therefore, we tested whether a greater proportion of Andean ancestry is associated with stature and body proportions among Peruvian children at high and low altitude. Height, head circumference, head-trunk height, upper and lower limb lengths, and tibia, ulna, hand and foot lengths, were measured in 133 highland and 169 lowland children aged 6 months to 8.5 years. For highland and lowland groups separately, age-sex-adjusted anthropometry z scores were regressed on the number of indigenous parental surnames as a proxy for Andean ancestry, adjusting for potential confounders (maternal age and education, parity, altitude [highlands only]). Among highland children, greater Andean ancestry was negatively associated with stature and tibia, ulna, and lower limb lengths, independent of negative associations with greater altitude for these measurements. Relationships were strongest for tibia length: each additional Andean surname or 1,000 m increase at altitude among highland children was associated with 0.18 and 0.65 z score decreases in tibia length, respectively. Anthropometry was not significantly associated with ancestry among lowland children. Greater Andean ancestry is associated with shorter stature and limb measurements at high but not low altitude. Gene-environment interactions between high altitude and Andean ancestry may exacerbate the trade-off between chest dimensions and stature that was proposed previously, though we could not test this directly. © 2015 Wiley Periodicals, Inc.
Martins, C.I.; Schrama, J.W.; Verreth, J.A.J.
Within fish farming grading, i.e. the process of sorting to approximate size, changes the group composition from heterogeneous to homogeneous. Although this procedure is considered an acute stressor, the long-term consequences of grading on aggression and stress levels have not yet been
Padmanabhanunni, Anita; Jaffer, Labeeqah; Steenkamp, Jeanette
A growing body of research has emphasised the salience of cultural beliefs and traditional practices to women's experiences of menstruation. Relatively less research has, however, been undertaken in South Africa. This study explored the experience of menstruation among women from the ama-Xhosa ethnic group, one of the largest ethnic groups in the country. Among the ama-Xhosa, there are distinct cultural practices associated with menstruation, including the female rite of passage (intonjane) and virginity testing (inkciyo). However, few studies have explored the experience of menstruation for women from this cultural group. This study involved the synthesis of data from individual interviews and focus group discussions conducted among a sample of ama-Xhosa women. The data were analysed using thematic analysis. Distinctive findings included women's participation in traditional cultural practices of intonjane and inkciyo and the presence of cultural taboos associated with menstruation. Women's narratives revealed strong ambivalence regarding these practices. On the one hand, they wanted to adhere to traditional practices but experienced these customs as evoking discomfort and shame. The study confirmed the prevalence of negative constructions of menstruation. Positive appraisals of menstruation as evoking joy and happiness were also encountered.
Akinsulure-Smith, Adeyinka M.
The number of refugees and asylum seekers admitted to the United States has grown, with significant numbers arriving from sub-Saharan Africa. Given this reality, it is important that mental health professionals are equipped to provide culturally relevant services. This article describes the development and implementation of a group treatment model…
This ethnography is about the way in which Xhosa migrants in the townships of Cape Town, South Africa, collectively manage their money in financial self-help groups, also known as financial mutuals. This is an umbrella term for a myriad of collective financial arrangements that are mostly informal.
Woods-Burnham, Leanne; Basu, Anamika; Cajigas-Du Ross, Christina K; Love, Arthur; Yates, Clayton; De Leon, Marino; Roy, Sourav; Casiano, Carlos A
Understanding how biological factors contribute to prostate cancer (PCa) health disparities requires mechanistic functional analysis of specific genes or pathways in pre-clinical cellular and animal models of this malignancy. The 22Rv1 human prostatic carcinoma cell line was originally derived from the parental CWR22R cell line. Although 22Rv1 has been well characterized and used in numerous mechanistic studies, no racial identifier has ever been disclosed for this cell line. In accordance with the need for racial diversity in cancer biospecimens and recent guidelines by the NIH on authentication of key biological resources, we sought to determine the ancestry of 22RV1 and authenticate previously reported racial identifications for four other PCa cell lines. We used 29 established Ancestry Informative Marker (AIM) single nucleotide polymorphisms (SNPs) to conduct DNA ancestry analysis and assign ancestral proportions to a panel of five PCa cell lines that included 22Rv1, PC3, DU145, MDA-PCa-2b, and RC-77T/E. We found that 22Rv1 carries mixed genetic ancestry. The main ancestry proportions for this cell line were 0.41 West African (AFR) and 0.42 European (EUR). In addition, we verified the previously reported racial identifications for PC3 (0.73 EUR), DU145 (0.63 EUR), MDA-PCa-2b (0.73 AFR), and RC-77T/E (0.74 AFR) cell lines. Considering the mortality disparities associated with PCa, which disproportionately affect African American men, there remains a burden on the scientific community to diversify the availability of biospecimens, including cell lines, for mechanistic studies on potential biological mediators of these disparities. This study is beneficial by identifying another PCa cell line that carries substantial AFR ancestry. This finding may also open the door to new perspectives on previously published studies using this cell line. © 2017 Wiley Periodicals, Inc.
Engmann, Natalie J; Ergas, Isaac J; Yao, Song; Kwan, Marilyn L; Roh, Janise M; Ambrosone, Christine B; Kushi, Lawrence H; Fejerman, Laura
Background: The U.S. Hispanic/Latino population is heterogeneous both socioculturally and by the proportion of European, Indigenous American, and African ancestry of the regions from which individuals originate. A previous study reported that genetic ancestry was associated with breast cancer survival among Latinas, independent of sociodemographic and tumor characteristics, suggesting that a genetic factor associated with ancestry may affect breast cancer survival. Methods: We evaluated the association of genetic ancestry with breast cancer outcomes among 506 Latina women with invasive breast cancer in the Pathways Study, a cohort study within Kaiser Permanente, an integrated health care delivery system. Proportional hazards models were used to assess the effect of ancestry on breast cancer recurrence (53 events), breast cancer-specific mortality (31 events) and all-cause mortality (54 events), with a mean follow-up time of 6 years. Results: Indigenous American ancestry was not associated with breast cancer recurrence [HR = 1.00 per 10% increase; 95% confidence interval (CI), 0.86-1.16], breast cancer mortality (HR = 0.95; 95% CI, 0.77-1.17), or all-cause mortality (HR = 0.93; 95% CI, 0.80-1.08). Adjustment for sociodemographic variables, tumor characteristics, and treatment did not alter the associations. Conclusions: Our results suggest that previously reported differences in breast cancer survival by genetic ancestry may be overcome by improving health care access and/or quality. Impact: Improving health care access and quality may reduce breast cancer disparities among U.S. Latinas. Cancer Epidemiol Biomarkers Prev; 26(9); 1466-9. ©2017 AACR . ©2017 American Association for Cancer Research.
Gross, Jessica M
African American populations in the U.S. formed primarily by mating between Africans and Europeans over the last 500 years. To date, studies of admixture have focused on either a one-time admixture event or continuous input into the African American population from Europeans only. Our goal is to gain a better understanding of the admixture process by examining models that take into account (a) assortative mating by ancestry in the African American population, (b) continuous input from both Europeans and Africans, and (c) historically informed variation in the rate of African migration over time. We used a model-based clustering method to generate distributions of African ancestry in three samples comprised of 147 African Americans from two published sources. We used a log-likelihood method to examine the fit of four models to these distributions and used a log-likelihood ratio test to compare the relative fit of each model. The mean ancestry estimates for our datasets of 77% African/23% European to 83% African/17% European ancestry are consistent with previous studies. We find admixture models that incorporate continuous gene flow from Europeans fit significantly better than one-time event models, and that a model involving continuous gene flow from Africans and Europeans fits better than one with continuous gene flow from Europeans only for two samples. Importantly, models that involve continuous input from Africans necessitate a higher level of gene flow from Europeans than previously reported. We demonstrate that models that take into account information about the rate of African migration over the past 500 years fit observed patterns of African ancestry better than alternative models. Our approach will enrich our understanding of the admixture process in extant and past populations. © 2017 Wiley Periodicals, Inc.
With steadily mounting evidence that points to a cosmic origin of terrestrial life, a cultural barrier prevails against admitting that such a connection exists. Astronomy continues to reveal the presence of organic molecules and organic dust on a huge cosmic scale, amounting to a third of interstellar carbon tied up in this form. Just as the overwhelming bulk of organics on Earth stored over geological timescales are derived from the degradation of living cells, so it seems most likely that interstellar organics in large measure also derive from biology. As we enter a new decade -- the year 2010 -- a clear pronouncement of our likely alien ancestry and of the existence of extraterrestrial life on a cosmic scale would seem to be overdue.
Hlongwana, K; Mkhize, S
HIV is one of the most obscure viruses that humankind has had to face in recent times. Compounding this obscurity are often contesting perspectives on what it means to be HIV infected, and these perspectives are largely constituted by people's rationalisation of complex situations or experiences. Using qualitative research methods and ethnography in particular, this paper reflects on a broad understanding of what it means to live with HIV in the context of Christianity, using research participants' perspectives in an urban support group setting. Two fundamental patterns are evident in this paper: (1) as support group members rationalise their HIV infection, they continuously construct and reconstruct their identities; and (2) support group members rationalise their HIV infection to enhance their coping abilities, using Christianity and the Bible in particular, as a reference. Whilst rationalising HIV infection, three viewpoints emerge. The first viewpoint perceives HIV infection as an affliction by Satan; the second viewpoint sees it as originating from God; while the last viewpoint interprets HIV infection as a negotiated settlement between God and Satan. The paper is intended to trigger debate, and hopefully also to seek and provide answers from various sectors of society, and religious communities in particular, in order to help other HIV positive people in similar situations better manage their HIV condition.
Fetvadjiev, Velichko H; Meiring, Deon; van de Vijver, Fons J R; Nel, J Alewyn; Hill, Carin
We present the development and the underlying structure of a personality inventory for the main ethnocultural groups of South Africa, using an emic-etic approach. The South African Personality Inventory (SAPI) was developed based on an extensive qualitative study of the implicit personality conceptions in the country's 11 official languages (Nel et al., 2012). Items were generated and selected (to a final set of 146) with a continuous focus on cultural adequacy and translatability. Students and community adults (671 Blacks, 198 Coloreds, 104 Indians, and 391 Whites) completed the inventory. A 6-dimensional structure (comprising a positive and a negative Social-Relational factor, Neuroticism, Extraversion, Conscientiousness, and Openness) was equivalent across groups and replicated in an independent sample of 139 Black and 270 White students. The SAPI correlated highly overall with impression-management aspects, but lower with lying aspects of social desirability. The SAPI social-relational factors were distinguishable from the Big Five in a joint factor analysis; the multiple correlations with the Big Five were .64 (positive) and .51 (negative social-relational). Implications and suggestions for emic-etic instrument and model development are discussed. (c) 2015 APA, all rights reserved.
Mahajan, Anubha; Go, Min Jin; Zhang, Weihua
To further understanding of the genetic basis of type 2 diabetes (T2D) susceptibility, we aggregated published meta-analyses of genome-wide association studies (GWAS), including 26,488 cases and 83,964 controls of European, east Asian, south Asian and Mexican and Mexican American ancestry. We obs...... and characterization of complex trait loci and emphasize an exciting opportunity to extend insight into the genetic architecture and pathogenesis of human diseases across populations of diverse ancestry....... observed a significant excess in the directional consistency of T2D risk alleles across ancestry groups, even at SNPs demonstrating only weak evidence of association. By following up the strongest signals of association from the trans-ethnic meta-analysis in an additional 21,491 cases and 55,647 controls...
Walls, Jill K.; Hall, Scott S.
Past research has drawn attention to the unique challenges for students of color attending predominantly white colleges and universities, yet few have focused on the classroom as a micro-context in which race-related discussions often occur. Using a focus group methodology, 22 African American undergraduate students from a variety of academic…
Sorokowska, Agnieszka; Sorokowski, Piotr; Mberira, Mara; Bartels, Astrid; Gallup, Gordon G.
Evolutionary accounts of human traits are often based on proxies for genetic fitness (e.g., number of sex partners, facial attractiveness). Instead of using proxies, actual differences in reproductive success is a more direct measure of Darwinian fitness. Certain voice acoustics such as fundamental frequency and measures of health such as handgrip strength correlate with proxies of fitness, yet there are few studies showing the relation of these traits to reproduction. Here, we explore whether the fundamental frequency of the voice and handgrip strength account for differences in actual reproduction among a population of natural fertility humans. Our results show that both fundamental frequency and handgrip strength predict several measures of reproductive success among a group of indigenous Namibian females, particularly amongst the elderly, with weight also predicting reproductive outcomes among males. These findings demonstrate that both hormonally regulated and phenotypic quality markers can be used as measures of Darwinian fitness among humans living under conditions that resemble the evolutionary environment of Homo sapiens. We also argue that these findings provide support for the Grandmother Hypothesis. PMID:22870251
Punyadeera, C; van der Merwe, M T; Crowther, N J; Toman, M; Immelman, A R; Schlaphoff, G P; Gray, I P
The effects of free fatty acids (FFA), leptin, tumour necrosis factor (TNF) alpha and body fat distribution on in vivo oxidation of a glucose load were studied in two South African ethnic groups. Anthropometric and various metabolic indices were measured at fasting and during a 7 h oral glucose tolerance test (OGTT). Body composition was measured using bioelectrical impedance analysis and subcutaneous and visceral fat mass was assessed using a five- and two-level CT-scan respectively. Glucose oxidation was evaluated by measuring the ratio of (13)CO(2) to (12)CO(2) in breath following ingestion of 1-(13)C-labelled glucose. Ten lean black women (LBW), ten obese black women (OBW), nine lean white women (LWW) and nine obese white women (OWW) were investigated after an overnight fast. Visceral fat levels were significantly higher (Pdifferences in glucose oxidation however; in the lean subjects of both ethnic groups the area under the curve (AUC) was higher than in obese subjects (Pgroups. Percentage suppression of FFAs at 30 min of the OGTT was 24+/-12% in OWW and -38+/-23% (Pgroup. AUC for FFAs during the late postprandial period (120--420 min) was significantly higher in OWW than OBW (Pgroups compared to the lean women. Glucose oxidation is reduced in obese subjects of both ethnic groups; inter- and intra-ethnic differences were observed in visceral fat mass and FFA production and it is possible that such differences may play a role in the differing prevalences of obesity-related disorders that have been reported in these two populations.
Full Text Available Abstract Our knowledge of pharmacogenetic variability in diverse populations is scarce, especially in sub-Saharan Africa. To bridge this gap in knowledge, we characterised population frequencies of clinically relevant pharmacogenetic traits in two distinct South African population groups. We genotyped 211 tagging single nucleotide polymorphisms (tagSNPs in 12 genes that influence antiretroviral drug disposition, in 176 South African individuals belonging to two distinct population groups residing in the Western Cape: the Xhosa (n = 109 and Cape Mixed Ancestry (CMA (n = 67 groups. The minor allele frequencies (MAFs of eight tagSNPs in six genes (those encoding the ATP binding cassette sub-family B, member 1 [ABCB1], four members of the cytochrome P450 family [CYP2A7P1, CYP2C18, CYP3A4, CYP3A5] and UDP-glucuronosyltransferase 1 [UGT1A1] were significantly different between the Xhosa and CMA populations (Bonferroni p CYP2C18, CYP3A4, the gene encoding solute carrier family 22 member 6 [SLC22A6] and UGT1A1 between the two South African populations. Characterising the Xhosa and CMA population frequencies of variant alleles important for drug transport and metabolism can help to establish the clinical relevance of pharmacogenetic testing in these populations.
McDowell, Jennifer L; Kenyhercz, Michael W; L'Abbé, Ericka N
Reliable and valid population specific standards are necessary to accurately develop a biological profile, which includes an estimation of peer-reported social identification (Hefner, 2009). During the last 300 years, colonialism, slavery and apartheid created geographic, physical and social divisions of population groups in South Africa. The purpose of this study was to evaluate variation in nasal bone and aperture shape in a modern population of black, white, and coloured South Africans using standard craniometric variables and geometric morphometrics, namely general Procrustes and elliptical Fourier analyses. Fourteen standard landmarks were digitally recorded or computationally derived from 310 crania using a 3D coordinate digitizer for discriminant function, principal components and generalized Procrustes analyses. For elliptical Fourier analysis, outlines of the nasal aperture were generated from standardized photographs. All classification accuracies were better than chance; the lowest accuracies were for coloured and the highest accuracies were for white South Africans. Most difficulties arose in distinguishing coloured and black South African groups from each other. Generally, misclassifications were noted between the sexes within each group rather than among groups, which suggests that sex has less influence on nasal bone and aperture shape than ancestry. Quantifiable variation in shape of the nasal aperture region between white and non-white South African groups was observed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Beynon, June; Toohey, Kelleen
Students of Chinese and Punjabi-Sikh ancestry are underrepresented in teacher education programs in British Columbia. Interviews with 34 college students from these ethnic groups found that career choice was influenced most strongly by parental expectations, and was also affected by cultural sex role attitudes, English language proficiency, and…
Wehby, George L.; Gili, Juan A.; Pawluk, Mariela; Castilla, Eduardo E.; López-Camelo, Jorge S.
Objective We examine disparities in birth weight and gestational age by ethnic ancestry in 2000–2011 in eight South American countries. Methods The sample included 60480 singleton live-births. Regression models were estimated to evaluate differences in birth outcomes by ethnic ancestry controlling for time trends. Results Significant disparities were found in seven countries. In four countries – Brazil, Ecuador, Uruguay, and Venezuela – we found significant disparities in both low birth weight and preterm birth. Disparities in preterm birth alone were observed in Argentina, Bolivia, and Colombia. Several differences in continuous birth weight, gestational age, and fetal growth rate were also observed. There were no systematic patterns of disparities between the evaluated ethnic ancestry groups across the study countries, in that no racial/ethnic group consistently had the best or worst outcomes in all countries. Conclusions Racial/ethnic disparities in infant health are common in several South American countries. Differences across countries suggest that racial/ethnic disparities are driven by social and economic mechanisms. Researchers and policymakers should acknowledge these disparities and develop research and policy programs to effectively target them. PMID:25542227
Cavallari, Larisa H; Perera, Minoli A
Genotype-based dosing recommendations are provided in the US FDA-approved warfarin labeling. However, data that informed these recommendations were from predominately Caucasian populations. Studies show that variants contributing to warfarin dose requirements in Caucasians provide similar contributions to dose requirements in US Hispanics, but significantly lesser contributions in African–Americans. Further data demonstrate that variants occurring commonly in individuals of African ancestry, but rarely in other racial groups, significantly influence dose requirements in African–Americans. These data suggest that it is important to consider variants specific for African–Americans when implementing genotype-guided warfarin dosing in this population. PMID:22871196
Gary, Faye A; Yarandi, Hossein; Evans, Edris; Still, Carolyn; Mickels, Prince; Hassan, Mona; Campbell, Doris; Conic, Ruzica
This research encompasses a factor analysis of the Beck Depression Inventory-II (BDI-II), which involves three groups of midlife women of African descent who reside in the Midwest, the South, and the U.S. Virgin Islands. The purpose of the study was to determine the factor structure of the BDI-II when administered to a sample of women aged 40-65 of African descent who reside in the three distinct geographical regions of the United States. A correlational, descriptive design was used, and 536 women of African descent were invited to participate in face-to-face interviews that transpired in community settings. Results of the factor analysis revealed a two-factor explanation. Factor one included symptoms such as punishment feelings and pessimism (cognitive), and the second factor included symptoms such as tiredness and loss of energy (somatic-affective). The application of the Beck Depression Inventory-II among the three groups of women generated specific information about each group and common findings across the groups. Knowledge gained from the research could help to guide specific intervention programs for the three groups of women, and explicate the common approaches that could be used for the three groups.
Kirkpatrick, Brianne E; Rashkin, Misha D
Ancestry testing is a home DNA test with many dimensions; in some cases, the implications and outcomes of testing cross over into the health sphere. Common reasons for seeking ancestry testing include determining an estimate of customer's ethnic background, identifying genetic relatives, and securing a raw DNA data file that can be used for other purposes. As the ancestry test marketplace continues to grow, and third-party vendors empower the general public to analyze their own genetic material, the role of the genetic counselor is likely to evolve dramatically. Roles of the genetic counselor may include assisting clients with the interpretation of and adaptation to these results, as well as advising the companies involved in this sector on the ethical, legal, and social issues associated with testing. This paper reviews the history, fundamentals, intended uses, and unintended consequences of ancestry genetic testing. It also discusses the types of information in an ancestry testing result, situations that might involve a clinical genetic counselor, and the benefits, limitations, and functions that ancestry genetic testing can play in a clinical genetics setting.
.... It will discuss in detail the common causes of the conflicts, highlight the roles of external players, the challenges and roles of the international community, the Organization of African Unity (OAU...
Durandt, Justin; Green, Mervin; Masimla, Herman; Lambert, Mike
The purpose of this study was to determine whether there are differences between racial groups for body mass, stature and body mass index (BMI) in South African elite U18 rugby players and whether there were significant changes in these measurements between 2002 and 2012. Self-reported body mass and stature were obtained from U18 players (n = 4007) who attended the national tournament during this period. BMI was calculated for each player.White players were 9.8 kg heavier than black players, who were 2.3 kg heavier than coloured players (P body mass of all groups increased from 2002 to 2012 (P body mass, stature and BMI of elite under-18 rugby players in South Africa were significantly different between racial groups. This has implications for transforming the game to make it representative of the South African population.
Rao, Roshni; Rivers, Aeisha; Rahimi, Asal; Wooldridge, Rachel; Rao, Madhu; Leitch, Marilyn; Euhus, David; Haley, Barbara B
Triple-negative breast cancer (TNBC) lacks estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2)/neu receptors, and is aggressive and therapeutically challenging. Genetic ancestry testing is an emerging medical field. Mitochondrial DNA (mtDNA), which is distinct from nuclear DNA, is maternally inherited and allows for origin determination. Patients with TNBC tend to be younger and are more likely to be African American, making this an ideal disease for mtDNA exploration. To the authors' knowledge, the current study is the first to perform mtDNA for self-described African American, White, and Hispanic patients with TNBC to identify mtDNA patterns. Patients with TNBC who were at any stage of therapy/survivorship were included. Self-reported ethnicity was confirmed at the time of the prospective buccal swab. Haplogroup prediction was performed on sequencing of hypervariable region 1. Using sequence similarity scores and lineage databases, sequence patterns were determined. Data regarding presentation and treatment, tumor features, and outcomes was collected. A total of 92 patients were included: 31 self-described African American, 31 White, and 30 Hispanic individuals. Hispanic patients were found to have the largest tumor size (4.5 cm; P = .01) and youngest age (41 years; Pancestry and haplogroups A, U, H, or B to be the most common mtDNA patterns. Twelve discordances (13%) between mtDNA analysis and self-described ethnicity were identified among the 92 patients. The highest discordance (26%; 8 patients) was noted in self-described Hispanic patients: 3 had Nigerian ancestry, and 1 individual demonstrated haplogroup K mtDNA (Ashkenazi Jewish ancestry). Discordance between self-reported ethnicity and mtDNA analysis was identified in 13% of patients with TNBC. The identification of mtDNA patterns with a predisposition toward TNBC may allow for risk stratification. Cancer 2017;107-113. © 2016 American Cancer Society. © 2016 American Cancer
Zemlin Annalise E
Full Text Available Background: High molecular weight (HMW adiponectin has antiatherogenic, antiinflammatory and antidiabetic properties and these effects have been linked to its effect on high density lipoprotein cholesterol (HDL-c. Single nucleotide polymorphisms (SNPs in the adiponectin gene influence adiponectin levels. We examined the relationship between HMW-adiponectin levels and cardiometabolic traits in normo- and hyperglycemic mixed ancestry South Africans and correlated these levels to two common polymorphisms.
Pool, John E
North American populations of Drosophila melanogaster derive from both European and African source populations, but despite their importance for genetic research, patterns of ancestry along their genomes are largely undocumented. Here, I infer geographic ancestry along genomes of the Drosophila Genetic Reference Panel (DGRP) and the D. melanogaster reference genome, which may have implications for reference alignment, association mapping, and population genomic studies in Drosophila. Overall, the proportion of African ancestry was estimated to be 20% for the DGRP and 9% for the reference genome. Combining my estimate of admixture timing with historical records, I provide the first estimate of natural generation time for this species (approximately 15 generations per year). Ancestry levels were found to vary strikingly across the genome, with less African introgression on the X chromosome, in regions of high recombination, and at genes involved in specific processes (e.g., circadian rhythm). An important role for natural selection during the admixture process was further supported by evidence that many unlinked pairs of loci showed a deficiency of Africa-Europe allele combinations between them. Numerous epistatic fitness interactions may therefore exist between African and European genotypes, leading to ongoing selection against incompatible variants. By focusing on hubs in this network of fitness interactions, I identified a set of interacting loci that include genes with roles in sensation and neuropeptide/hormone reception. These findings suggest that admixed D. melanogaster samples could become an important study system for the genetics of early-stage isolation between populations. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
Araujo, Luiz H.; Timmers, Cynthia; Bell, Erica Hlavin; Shilo, Konstantin; Lammers, Philip E.; Zhao, Weiqiang; Natarajan, Thanemozhi G.; Miller, Clinton J.; Zhang, Jianying; Yilmaz, Ayse S.; Liu, Tom; Coombes, Kevin; Amann, Joseph; Carbone, David P.
Purpose Technologic advances have enabled the comprehensive analysis of genetic perturbations in non–small-cell lung cancer (NSCLC); however, African Americans have often been underrepresented in these studies. This ethnic group has higher lung cancer incidence and mortality rates, and some studies have suggested a lower incidence of epidermal growth factor receptor mutations. Herein, we report the most in-depth molecular profile of NSCLC in African Americans to date. Methods A custom panel was designed to cover the coding regions of 81 NSCLC-related genes and 40 ancestry-informative markers. Clinical samples were sequenced on a massively parallel sequencing instrument, and anaplastic lymphoma kinase translocation was evaluated by fluorescent in situ hybridization. Results The study cohort included 99 patients (61% males, 94% smokers) comprising 31 squamous and 68 nonsquamous cell carcinomas. We detected 227 nonsilent variants in the coding sequence, including 24 samples with nonoverlapping, classic driver alterations. The frequency of driver mutations was not significantly different from that of whites, and no association was found between genetic ancestry and the presence of somatic mutations. Copy number alteration analysis disclosed distinguishable amplifications in the 3q chromosome arm in squamous cell carcinomas and pointed toward a handful of targetable alterations. We also found frequent SMARCA4 mutations and protein loss, mostly in driver-negative tumors. Conclusion Our data suggest that African American ancestry may not be significantly different from European/white background for the presence of somatic driver mutations in NSCLC. Furthermore, we demonstrated that using a comprehensive genotyping approach could identify numerous targetable alterations, with potential impact on therapeutic decisions. PMID:25918285
Djibril Marie BA
In African countries, where most of health facilities are understaffed, more rigorous studies with a larger population are needed to give a high level of evidence to confirm this association in order to establish the need to be more aggressive in risk factor control in these individuals.
Tambling, Craig J; Druce, Dave J; Hayward, Matt W; Castley, J Guy; Adendorff, John; Kerley, Graham I H
The reintroduction of large predators provides a framework to investigate responses by prey species to predators. Considerable research has been directed at the impact that reintroduced wolves (Canis lupus) have on cervids, and to a lesser degree, bovids, in northern temperate regions. Generally, these impacts alter feeding, activity, and ranging behavior, or combinations of these. However, there are few studies on the response of African bovids to reintroduced predators, and thus, there is limited data to compare responses by tropical and temperate ungulates to predator reintroductions. Using the reintroduction of lion (Panthera leo) into the Addo Elephant National Park (AENP) Main Camp Section, South Africa, we show that Cape buffalo (Syncerus caffer) responses differ from northern temperate ungulates. Following lion reintroduction, buffalo herds amalgamated into larger, more defendable units; this corresponded with an increase in the survival of juvenile buffalo. Current habitat preference of buffalo breeding herds is for open habitats, especially during the night and morning, when lion are active. The increase in group size and habitat preference countered initial high levels of predation on juvenile buffalo, resulting in a return in the proportion of juveniles in breeding herds to pre-lion levels. Our results show that buffalo responses to reintroduced large predators in southern Africa differ to those of northern temperate bovids or cervids in the face of wolf predation. We predict that the nature of the prey response to predator reintroduction is likely to reflect the trade-off between the predator selection and hunting strategy of predators against the life history and foraging strategies of each prey species.
Richard J Pearce
Full Text Available Although the molecular basis of resistance to a number of common antimalarial drugs is well known, a geographic description of the emergence and dispersal of resistance mutations across Africa has not been attempted. To that end we have characterised the evolutionary origins of antifolate resistance mutations in the dihydropteroate synthase (dhps gene and mapped their contemporary distribution.We used microsatellite polymorphism flanking the dhps gene to determine which resistance alleles shared common ancestry and found five major lineages each of which had a unique geographical distribution. The extent to which allelic lineages were shared among 20 African Plasmodium falciparum populations revealed five major geographical groupings. Resistance lineages were common to all sites within these regions. The most marked differentiation was between east and west African P. falciparum, in which resistance alleles were not only of different ancestry but also carried different resistance mutations.Resistant dhps has emerged independently in multiple sites in Africa during the past 10-20 years. Our data show the molecular basis of resistance differs between east and west Africa, which is likely to translate into differing antifolate sensitivity. We have also demonstrated that the dispersal patterns of resistance lineages give unique insights into recent parasite migration patterns.
Mathias, Rasika Ann; Taub, Margaret A; Gignoux, Christopher R; Fu, Wenqing; Musharoff, Shaila; O'Connor, Timothy D; Vergara, Candelaria; Torgerson, Dara G; Pino-Yanes, Maria; Shringarpure, Suyash S; Huang, Lili; Rafaels, Nicholas; Boorgula, Meher Preethi; Johnston, Henry Richard; Ortega, Victor E; Levin, Albert M; Song, Wei; Torres, Raul; Padhukasahasram, Badri; Eng, Celeste; Mejia-Mejia, Delmy-Aracely; Ferguson, Trevor; Qin, Zhaohui S; Scott, Alan F; Yazdanbakhsh, Maria; Wilson, James G; Marrugo, Javier; Lange, Leslie A; Kumar, Rajesh; Avila, Pedro C; Williams, L Keoki; Watson, Harold; Ware, Lorraine B; Olopade, Christopher; Olopade, Olufunmilayo; Oliveira, Ricardo; Ober, Carole; Nicolae, Dan L; Meyers, Deborah; Mayorga, Alvaro; Knight-Madden, Jennifer; Hartert, Tina; Hansel, Nadia N; Foreman, Marilyn G; Ford, Jean G; Faruque, Mezbah U; Dunston, Georgia M; Caraballo, Luis; Burchard, Esteban G; Bleecker, Eugene; Araujo, Maria Ilma; Herrera-Paz, Edwin Francisco; Gietzen, Kimberly; Grus, Wendy E; Bamshad, Michael; Bustamante, Carlos D; Kenny, Eimear E; Hernandez, Ryan D; Beaty, Terri H; Ruczinski, Ingo; Akey, Joshua; Barnes, Kathleen C
The African Diaspora in the Western Hemisphere represents one of the largest forced migrations in history and had a profound impact on genetic diversity in modern populations. To date, the fine-scale population structure of descendants of the African Diaspora remains largely uncharacterized. Here we present genetic variation from deeply sequenced genomes of 642 individuals from North and South American, Caribbean and West African populations, substantially increasing the lexicon of human genomic variation and suggesting much variation remains to be discovered in African-admixed populations in the Americas. We summarize genetic variation in these populations, quantifying the postcolonial sex-biased European gene flow across multiple regions. Moreover, we refine estimates on the burden of deleterious variants carried across populations and how this varies with African ancestry. Our data are an important resource for empowering disease mapping studies in African-admixed individuals and will facilitate gene discovery for diseases disproportionately affecting individuals of African ancestry.
Buseh, A; Kelber, S; Millon-Underwood, S; Stevens, P; Townsend, L
Reasons for low participation of ethnic minorities in genetic studies are multifactorial and often poorly understood. Based on published literature, participation in genetic testing is low among Black African immigrants/refugees although they are purported to bear disproportionate disease burden. Thus, research involving Black African immigrant/refugee populations that examine their perspectives on participating in genetic studies is needed. This report examines and describes the knowledge of medical genetics, group-based medical mistrust, and future expectations of genetic research and the influence of these measures on the perceived disadvantages of genetic testing among Black African immigrants/refugees. Using a cross-sectional survey design, a nonprobability sample (n = 212) of Black African immigrants/refugees was administered a questionnaire. Participants ranged in age from 18 to 61 years (mean = 38.91, SD = 9.78). The questionnaire consisted of 5 instruments: (a) sociodemographic characteristics, (b) Knowledge of Medical Genetics scale, (c) Group-Based Medical Mistrust Scale, (d) Future Expectations/Anticipated Consequences of Genetics Research scale, and (e) Perceived Disadvantages of Genetic Testing scale. Participants were concerned that genetic research may result in scientists 'playing God,' interfering with the natural order of life. In multivariate analyses, the perceived disadvantages of genetic testing increased as medical mistrust and anticipated negative impacts of genetic testing increased. Increase in genetic knowledge contributed to a decrease in perceived disadvantages. Our findings suggest that recruitment of Black African immigrants/refugees in genetic studies should address potential low knowledge of genetics, concerns about medical mistrust, the expectations/anticipated consequences of genetic research, and the perceived disadvantages of genetic testing.
Steele, Christopher D; Court, Denise Syndercombe; Balding, David J
We estimate the population genetics parameter FST (also referred to as the fixation index) from short tandem repeat (STR) allele frequencies, comparing many worldwide human subpopulations at approximately the national level with continental-scale populations. FST is commonly used to measure population differentiation, and is important in forensic DNA analysis to account for remote shared ancestry between a suspect and an alternative source of the DNA. We estimate FST comparing subpopulations with a hypothetical ancestral population, which is the approach most widely used in population genetics, and also compare a subpopulation with a sampled reference population, which is more appropriate for forensic applications. Both estimation methods are likelihood-based, in which FST is related to the variance of the multinomial-Dirichlet distribution for allele counts. Overall, we find low FST values, with posterior 97.5 percentiles estimates, and are also about half the magnitude of STR-based estimates from population genetics surveys that focus on distinct ethnic groups rather than a general population. Our findings support the use of FST up to 3% in forensic calculations, which corresponds to some current practice.
With the great strides made in the last ten years in the understanding of human population variation and the detailed characterization of the genome, it is now possible to identify sets of ancestry informative markers suitable for relatively small-scale PCR-based assays and use them to analyze the ancestry of an individual from forensic DNA. This review outlines some of the current understanding of past human population structure and how it may have influenced the complex distribution of contemporary human diversity. A simplified description of human diversity can provide a suitable basis for choosing the best ancestry-informative markers, which is important given the constraints of multiplex sizes in forensic DNA tests. It is also important to decide the level of geographic resolution that is realistic to ensure the balance between informativeness and an over-simplification of complex human diversity patterns. A detailed comparison is made of the most informative ancestry markers suitable for forensic use and assessments are made of the data analysis regimes that can provide statistical inferences of a DNA donor's bio-geographical ancestry. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
This article describes the activities of the Continental Mathematics League, which offers a series of meets for children in grades 3 though 9. In addition, a Calculus League and a Computer Contest are offered. The league allows schools to participate by mail so that rural schools can participate. (CR)
Full Text Available The study aims to investigate sleep duration in four different population groups in a national probability sample of older South Africans who participated in the Study of Global Ageing and Adult Health (SAGE Wave 1. A national population-based cross-sectional study with a sample of 3284 aged 50 years or older in South Africa was conducted in 2008. The questionnaire included socio-demographic characteristics, health variables, and self-reported sleep duration. Results indicate that White Africans compared to other population groups had the lowest mean sleep duration (7.88 h among men and 7.46 h among women. The prevalence of short sleep was the highest among both men and women among the White African (18.8% in men and 16.9% in women and Indian or Asian African population groups (14.5% in men and 17.1% in women, and lowest among both men and women in the Black African (7.0% in men and 6.5% in women and multi-ancestry population groups (15.6% in men and 12.7% in women. The prevalence of long sleep was among both men and women the highest in the Black African population group (56.2% in men and 58.5% in women, and the lowest in the White African population group (36.4% in men and 24.3% in women. In a Poisson regression model, adjusted for sociodemographics and chronic disease status, coming from the male and female White African population group was associated with short sleep. In addition, coming from the Indian or Asian African population group was associated with short sleep. No population group differences were found regarding long sleep prevalence. White Africans reported more short sleep duration than the other population groups, while there were no racial or ethnic differences in long sleep. White Africans are more likely to have sleep durations that are associated with negative health outcomes. An explanation of the high short sleep prevalence among White Africans may be related to their racial or ethnic minority status in South Africa.
The study aims to investigate sleep duration in four different population groups in a national probability sample of older South Africans who participated in the Study of Global Ageing and Adult Health (SAGE) Wave 1. A national population-based cross-sectional study with a sample of 3284 aged 50 years or older in South Africa was conducted in 2008. The questionnaire included socio-demographic characteristics, health variables, and self-reported sleep duration. Results indicate that White Africans compared to other population groups had the lowest mean sleep duration (7.88 h among men and 7.46 h among women). The prevalence of short sleep was the highest among both men and women among the White African (18.8% in men and 16.9% in women) and Indian or Asian African population groups (14.5% in men and 17.1% in women), and lowest among both men and women in the Black African (7.0% in men and 6.5% in women) and multi-ancestry population groups (15.6% in men and 12.7% in women). The prevalence of long sleep was among both men and women the highest in the Black African population group (56.2% in men and 58.5% in women), and the lowest in the White African population group (36.4% in men and 24.3% in women). In a Poisson regression model, adjusted for sociodemographics and chronic disease status, coming from the male and female White African population group was associated with short sleep. In addition, coming from the Indian or Asian African population group was associated with short sleep. No population group differences were found regarding long sleep prevalence. White Africans reported more short sleep duration than the other population groups, while there were no racial or ethnic differences in long sleep. White Africans are more likely to have sleep durations that are associated with negative health outcomes. An explanation of the high short sleep prevalence among White Africans may be related to their racial or ethnic minority status in South Africa.
Jackson, Jennifer V.; Cothran, Mary E.
Surveyed people of African descent regarding relationships among African, African-American, and African-Caribbean persons, focusing on contact and friendship, travel to countries of the diaspora, cross-cultural communication, thoughts and stereotypes, and education. Most respondents had contacts with the other groups, but groups had preconceived…
Smith, Sherry P.
Examines a set of characteristics that African American inner-city high school students may or may not value in a dating partner. A total of 80 students indicated how important they perceived certain qualities to be in a person they would like to date. The results are in contrast to the previous literature regarding dating-partner preferences…
National Oceanic and Atmospheric Administration, Department of Commerce — This data represents geographic terms used within the Outer Continental Shelf Lands Act (OCSLA or Act). The Act defines the United States outer continental shelf...
Association of the ENPP1 rs997509 polymorphism with obesity in South African mixed ancestry learners · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. T Matsha, B Fanampe, Y Yako, S Hassan, M Hoffmann, L Van der Merwe, RT Erasmus ...
Djingarey, Mamoudou H.; Diomandé, Fabien V. K.; Barry, Rodrigue; Kandolo, Denis; Shirehwa, Florence; Lingani, Clement; Novak, Ryan T.; Tevi-Benissan, Carol; Perea, William; Preziosi, Marie-Pierre; LaForce, F. Marc
Background. A group A meningococcal conjugate vaccine (PsA-TT) was developed specifically for the African “meningitis belt” and was prequalified by the World Health Organization (WHO) in June 2010. The vaccine was first used widely in Burkina Faso, Mali, and Niger in December 2010 with great success. The remaining 23 meningitis belt countries wished to use this new vaccine. Methods. With the help of African countries, WHO developed a prioritization scheme and used or adapted existing immunization guidelines to mount PsA-TT vaccination campaigns. Vaccine requirements were harmonized with the Serum Institute of India, Ltd. Results. Burkina Faso was the first country to fully immunize its 1- to 29-year-old population in December 2010. Over the next 4 years, vaccine coverage was extended to 217 million Africans living in 15 meningitis belt countries. Conclusions. The new group A meningococcal conjugate vaccine was well received, with country coverage rates ranging from 85% to 95%. The rollout proceeded smoothly because countries at highest risk were immunized first while attention was paid to geographic contiguity to maximize herd protection. Community participation was exemplary. PMID:26553672
Darling, Natalie J; Barker, Lawrence E; Shefer, Abigail M; Chu, Susan Y
The Hispanic population is increasing and heterogeneous (Hispanic refers to persons of Spanish, Hispanic, or Latino descent). The objective was to examine immunization rates among Hispanic ancestry for the 4:3:1:3:3 series (> or = 4 doses diphtheria, tetanus toxoids, and pertussis vaccine; > or = 3 doses poliovirus vaccine; > or = 1 doses measles-containing vaccine; > or = 3 doses Haemophilus influenzae type b vaccine; and > or = 3 doses hepatitis B vaccine). The National Immunization Survey measures immunization coverage among 19- to 35-month-old U.S. children. Coverage was compared from combined 2001-2003 data among Hispanics and non-Hispanic whites using t-tests, and among Hispanic ancestry using a chi-square test. Hispanics were categorized as Mexican, Mexican American, Central American, South American, Puerto Rican, Cuban, Spanish Caribbean (primarily Dominican Republic), other, and multiple ancestry. Children of Hispanic ancestry increased from 21% in 1999 to 25% in 2003. These Hispanic children were less well immunized than non-Hispanic whites (77.0%, +/-2.1% [95% confidence interval] compared to 82.5%, +/-1.1% (95% CI) > in 2003). Immunization coverage did not vary significantly among Hispanics of varying ancestries (p=0.26); however, there was substantial geographic variability. In some areas, immunization coverage among Hispanics was significantly higher than non-Hispanic whites. Hispanic children were less well immunized than non-Hispanic whites; however, coverage varied notably by geographic area. Although a chi-square test found no significant differences in coverage among Hispanic ancestries, the range of coverage, 79.2%, +/-5.1% for Cuban Americans to 72.1%, +/-2.4% for Mexican descent, may suggest a need for improved and more localized monitoring among Hispanic communities.
Sánchez, Elena; García de la Torre, Ignacio; Sacnún, Mónica; Goñi, Mario; Berbotto, Guillermo; Paira, Sergio; Musuruana, Jorge Luis; Graf, César; Alvarellos, Alejandro; Messina, Osvaldo D; Babini, Alejandra; Strusberg, Ingrid; Marcos, Juan Carlos; Scherbarth, Hugo; Spindler, Alberto; Quinteros, Ana; Toloza, Sergio; Moreno, José Luis C; Catoggio, Luis J; Tate, Guillermo; Eimon, Alicia; Citera, Gustavo; Pellet, Antonio Catalán; Nasswetter, Gustavo; Cardiel, Mario H; Miranda, Pedro; Ballesteros, Francisco; Esquivel-Valerio, Jorge A; Maradiaga-Ceceña, Marco A; Acevedo-Vásquez, Eduardo M; García, Conrado García; Tusié-Luna, Teresa; Pons-Estel, Bernardo A; Alarcón-Riquelme, Marta E
To define whether Amerindian genetic ancestry correlates with clinical and therapeutic variables in admixed individuals with rheumatoid arthritis (RA) from Latin America. Patients with RA (n = 1347) and healthy controls (n = 1012) from Argentina, Mexico, Chile, and Peru were included. Samples were genotyped for the Immunochip v1 using the Illumina platform. Clinical data were obtained through interviews or the clinical history. Percentage of Amerindian ancestry was comparable between cases and controls. Morning stiffness (p ancestry after Bonferroni correction. Higher Amerindian ancestry correlated only with weight loss (p Bonferroni ancestry correlated with higher doses of azathioprine (p ancestry protects against most major clinical criteria of RA, but regarding the association of RF with increased European ancestry, age, sex, and smoking are modifiers. Ancestry also correlates with the therapeutic profiles.
The rifting of continents and the transition to seafloor spreading is characterised by extensional faulting and thinning of the lithosphere, and is sometimes accompanied by voluminous intrusive and extrusive magmatism. In order to understand how these processes develop over time to break continents apart, we have traditionally relied on interpreting the geological record at the numerous fully developed, ancient rifted margins around the world. In these settings, however, it is difficult to discriminate between different mechanisms of extension and magmatism because the continent-ocean transition is typically buried beneath thick layers of volcanic and sedimentary rocks, and the tectonic and volcanic activity that characterised breakup has long-since ceased. Ongoing continental breakup in the African and Arabian rift systems offers a unique opportunity to address these problems because it exposes several sectors of tectonically active rift sector development spanning the transition from embryonic continental rifting in the south to incipient seafloor spreading in the north. Here I synthesise exciting, multidisciplinary observational and modelling studies using geophysical, geodetic, petrological and numerical techniques that uniquely constrain the distribution, time-scales, and interactions between extension and magmatism during the progressive breakup of the African Plate. This new research has identified the previously unrecognised role of rapid and episodic dike emplacement in accommodating a large proportion of extension during continental rifting. We are now beginning to realise that changes in the dominant mechanism for strain over time (faulting, stretching and magma intrusion) impact dramatically on magmatism and rift morphology. The challenge now is to take what we're learned from East Africa and apply it to the rifted margins whose geological record documents breakup during entire Wilson Cycles.
Ramaswamy, V.; Rao, P.S.
reveal a minimum of 18 m thick strata of modern muds (Fig. 2g). At the outer boundary of the Gulf of Myanmar Continental Shelf 8 Martaban (15oN Latitude), brown muds overlie coarse sands indicating that modern deltaic sediments... on the Myeik Bank (Rodolfo, 1969a). Modern sediments on the Ayeyarwady shelf General composition, Texture and Grain-size: The distribution and sediment texture on the Ayeyarwady shelf shows fine-grained sediments comprising silty-clay and clayey...
Bader, Alyssa C; Malhi, Ripan S
Understanding the complexities of ancestry-related identity is a necessary component of ethically sound research related to the genetic ancestry of modern-day communities. This is especially true when working with indigenous populations, given the legal and social implications that genetic ancestry interpretations may have in these communities. This study employs a multicomponent approach to explore the intricacies of ancestry-related identity within one extended family with members who identify as Alaskan Native. The seven participants were interviewed about their own self-identity, perceptions regarding genetic ancestry estimation, and their knowledge of oral family history. Additionally, each participant consented to having his or her genetic ancestry estimated. The researchers also surveyed ancestry-related documents, such as census records, birth certificates, and Certificates of Indian Blood. These three different perspectives-oral family history and self-identity, genetic ancestry estimation, historical and legal documentation-illustrate the complex nature of ancestry-related identity within the context of indigenous and colonial interactions in North America. While estimates of genetic ancestry broadly reflected each individual's self-reported biogeographic ancestry and supported all described and historically reported biological relationships, the estimates did not always match federally recorded blood quantum values, nor did they provide any information on relationships at the tribe or clan level. Employing a multicomponent approach and engaging study participants may help to safeguard against genetic essentialism and provide a more nuanced understanding of ancestry-related identity within a larger political, legal, and historical context.
Behar, Doron M; Metspalu, Ene; Kivisild, Toomas; Rosset, Saharon; Tzur, Shay; Hadid, Yarin; Yudkovsky, Guennady; Rosengarten, Dror; Pereira, Luisa; Amorim, Antonio; Kutuev, Ildus; Gurwitz, David; Bonne-Tamir, Batsheva; Villems, Richard; Skorecki, Karl
The history of the Jewish Diaspora dates back to the Assyrian and Babylonian conquests in the Levant, followed by complex demographic and migratory trajectories over the ensuing millennia which pose a serious challenge to unraveling population genetic patterns. Here we ask whether phylogenetic analysis, based on highly resolved mitochondrial DNA (mtDNA) phylogenies can discern among maternal ancestries of the Diaspora. Accordingly, 1,142 samples from 14 different non-Ashkenazi Jewish communities were analyzed. A list of complete mtDNA sequences was established for all variants present at high frequency in the communities studied, along with high-resolution genotyping of all samples. Unlike the previously reported pattern observed among Ashkenazi Jews, the numerically major portion of the non-Ashkenazi Jews, currently estimated at 5 million people and comprised of the Moroccan, Iraqi, Iranian and Iberian Exile Jewish communities showed no evidence for a narrow founder effect, which did however characterize the smaller and more remote Belmonte, Indian and the two Caucasus communities. The Indian and Ethiopian Jewish sample sets suggested local female introgression, while mtDNAs in all other communities studied belong to a well-characterized West Eurasian pool of maternal lineages. Absence of sub-Saharan African mtDNA lineages among the North African Jewish communities suggests negligible or low level of admixture with females of the host populations among whom the African haplogroup (Hg) L0-L3 sub-clades variants are common. In contrast, the North African and Iberian Exile Jewish communities show influence of putative Iberian admixture as documented by mtDNA Hg HV0 variants. These findings highlight striking differences in the demographic history of the widespread Jewish Diaspora.
Gaieski, Jill B; Owings, Amanda C; Vilar, Miguel G; Dulik, Matthew C; Gaieski, David F; Gittelman, Rachel M; Lindo, John; Gau, Lydia; Schurr, Theodore G
Discovered in the early 16th century by European colonists, Bermuda is an isolated set of islands located in the mid-Atlantic. Shortly after its discovery, Bermuda became the first English colony to forcibly import its labor by trafficking in enslaved Africans, white ethnic minorities, and indigenous Americans. Oral traditions circulating today among contemporary tribes from the northeastern United States recount these same events, while, in Bermuda, St. David's Islanders consider their histories to be linked to a complex Native American, European, and African past. To investigate the influence of historical events on biological ancestry and native cultural identity, we analyzed genetic variation in 111 members of Bermuda's self-proclaimed St. David's Island Native Community. Our results reveal that the majority of mitochondrial DNA (mtDNA) and Y-chromosome haplotypes are of African and West Eurasian origin. However, unlike other English-speaking New World colonies, most African mtDNA haplotypes appear to derive from central and southeast Africa, reflecting the extent of maritime activities in the region. In light of genealogical and oral historical data from the St. David's community, the low frequency of Native American mtDNA and NRY lineages may reflect the influence of genetic drift, the demographic impact of European colonization, and historical admixture with persons of non-native backgrounds, which began with the settlement of the islands. By comparing the genetic data with genealogical and historical information, we are able to reconstruct the complex history of this Bermudian community, which is unique among New World populations. Copyright © 2011 Wiley-Liss, Inc.
Holme, Daniel; Findlow, Helen; Sow, Samba O.; Idoko, Olubukola T.; Preziosi, Marie-Pierre; Carlone, George; Plikaytis, Brian D.; Borrow, Ray
Background. A group A meningococcal conjugate vaccine, PsA-TT, was licensed in 2010 and was previously studied in a phase 2 clinical trial to evaluate its safety and immunogenicity in African children 12–23 months of age. Methods. Subjects received either PsA-TT; meningococcal group A, C, W, Y polysaccharide vaccine (PsACWY); or Haemophilus influenzae type b conjugate vaccine (Hib-TT). Forty weeks following primary vaccination, the 3 groups were further randomized to receive either PsA-TT, one-fifth dose of PsACWY, or Hib-TT. Group A–specific immunoglobulin G (IgG) subclass response was characterized using an enzyme-linked immunosorbent assay. Results. The predominant IgG subclass response, regardless of vaccine, was IgG1. One month following primary vaccination, the geometric mean concentrations (GMCs) of IgG1 and IgG2 in the PsA-TT group were 21.73 µg/mL and 6.27 µg/mL, whereas in the PsACWY group the mean GMCs were 2.01 µg/mL and 0.97 µg/mL, respectively (P Group A–specific IgG1 and IgG2 GMCs remained greater in the PsA-TT group than in the PsACWY group 40 weeks following primary vaccination (P vaccines. Conclusions. Vaccination of African children aged 12–24 months with either PsA-TT or PsACWY elicited a predominantly IgG1 response. The IgG1:IgG2 mean ratio decreased following successive vaccination with PsACWY, indicating a shift toward IgG2, suggestive of the T-cell–independent immune response commonly associated with polysaccharide antigens. Clinical Trials Registration. SRCTN78147026. PMID:26553689
Lampard, Amy M; Nishi, Akihiro; Baskin, Monica L; Carson, Tiffany L; Davison, Kirsten K
This study aimed to assess the psychometric properties of a child-report, multidimensional measure of physical activity (PA) parenting, the Activity Support Scale for Multiple Groups (ACTS-MG), in African American and non-Hispanic white families. The ACTS-MG was administered to children aged 5 to 12 years. A three factor model of PA parenting (Modeling of PA, Logistic Support, and Restricting Access to Screen-based Activities) was tested separately for mother's and fathers' PA parenting. The proposed three-factor structure was supported in both racial groups for mothers' PA parenting and in the African American sample for fathers' PA parenting. Factorial invariance between racial groups was demonstrated for mother's PA parenting. Building on a previous study examining the ACTS-MG parent-report, this study supports the use of the ACTS-MG child-report for mothers' PA parenting. However, further research is required to investigate the measurement of fathers' PA parenting across racial groups.
Bolhar, R.; Hergt, J.; Woodhead, J.
Full text: Magnesian- to Fe-rich tholeiitic basalts represent the dominant lithology in the Marble Bar Greenstone Belt, E-Pilbara Craton, and are locally associated with komatiitic basalts and rare komatiitic cumulates. Based on trace element characteristics, the extrusive and intrusive rocks from all three major stratigraphic units can be subdivided into LREE enriched and unfractionated to weakly LREE depleted groups. The former group is characterized by La/Sm pm = 1.7-4.6, Gd/Yb pm = 1.23.2 and Nb/Th pm 0.1-0.5, while the latter rocks possess ratios of La/Sm pm = 0.5-1.7, Gd/Yb pm = 0.8-1.9 and Nb/Th pm = 0.4-1.3. Nb/La -Nb/Th relationships in the LREE enriched samples indicate 7-28% contamination by crustal material similar in composition to Pilbara granitoids. LREE enrichment and strong negative HFSE anomalies, along with MgO = 2.2-22.0 wt% and SiO 2 = 39.2-63.5 wt%, have been observed in numerous Archaean greenstone belts, and can be successfully modeled in this study by AFC processes. In contrast, strong HFSE depletion combined with unfractionated to slightly depleted LREE in rocks of the latter group require different processes. Melting of mantle material previously depleted by melt extraction, enrichment of LILE and LREE relative to the HFSE in an arc-like environment and HFSE fractionation as a result of garnet retention in the melting source cannot account for negative Nb, Ta, Ti, P and strong positive Pb anomalies. Introduction of small amounts of crustal material into a depleted or primitive mantle, as possibly indicated by Nb/Ta ratios between 12 and 18, also fails to reproduce the trace element abundances of the second group of rocks. Recycling of oceanic crust previously processed through a subduction zone (low Th/Nb, La/Nb) and sub-arc lithospheric mantle (high Th/Nb, La/Nb), and subsequent mixing into the Archaean mantle has been recently invoked by several workers (e.g. Kerrich et al., EPSL, 168, 101-115; 1999) to explain the origin of
Cai, Qiuyin; Wen, Wanqing; Qu, Shimian; Li, Guoliang; Egan, Kathleen M; Chen, Kexin; Deming, Sandra L; Shen, Hongbing; Shen, Chen-Yang; Gammon, Marilie D; Blot, William J; Matsuo, Keitaro; Haiman, Christopher A; Khoo, Ui Soon; Iwasaki, Motoki; Santella, Regina M; Zhang, Lina; Fair, Alecia Malin; Hu, Zhibin; Wu, Pei-Ei; Signorello, Lisa B; Titus-Ernstoff, Linda; Tajima, Kazuo; Henderson, Brian E; Chan, Kelvin Y K; Kasuga, Yoshio; Newcomb, Polly A; Zheng, Hong; Cui, Yong; Wang, Furu; Shieh, Ya-Lan; Iwata, Hiroji; Le Marchand, Loic; Chan, Sum Yin; Shrubsole, Martha J; Trentham-Dietz, Amy; Tsugane, Shoichiro; Garcia-Closas, Montserrat; Long, Jirong; Li, Chun; Shi, Jiajun; Huang, Bo; Xiang, Yong-Bing; Gao, Yu-Tang; Lu, Wei; Shu, Xiao-Ou; Zheng, Wei
We evaluated the generalizability of a single nucleotide polymorphism (SNP), rs2046210 (A/G allele), associated with breast cancer risk that was initially identified at 6q25.1 in a genome-wide association study conducted among Chinese women. In a pooled analysis of more than 31,000 women of East-Asian, European, and African ancestry, we found a positive association for rs2046210 and breast cancer risk in Chinese women [ORs (95% CI) = 1.30 (1.22-1.38) and 1.64 (1.50-1.80) for the AG and AA genotypes, respectively, P for trend = 1.54 × 10⁻³⁰], Japanese women [ORs (95% CI) = 1.31 (1.13-1.52) and 1.37 (1.06-1.76), P for trend = 2.51 × 10⁻⁴], and European-ancestry American women [ORs (95% CI) = 1.07 (0.99-1.16) and 1.18 (1.04-1.34), P for trend = 0.0069]. No association with this SNP, however, was observed in African American women [ORs (95% CI) = 0.81 (0.63-1.06) and 0.85 (0.65-1.11) for the AG and AA genotypes, respectively, P for trend = 0.4027]. In vitro functional genomic studies identified a putative functional variant, rs6913578. This SNP is 1,440 bp downstream of rs2046210 and is in high linkage disequilibrium with rs2046210 in Chinese (r(2) = 0.91) and European-ancestry (r² = 0.83) populations, but not in Africans (r² = 0.57). SNP rs6913578 was found to be associated with breast cancer risk in Chinese and European-ancestry American women. After adjusting for rs2046210, the association of rs6913578 with breast cancer risk in African Americans approached borderline significance. Results from this large consortium study confirmed the association of rs2046210 with breast cancer risk among women of Chinese, Japanese, and European ancestry. This association may be explained in part by a putatively functional variant (rs6913578) identified in the region. ©2011 AACR.
Phillips, C; Parson, W; Lundsberg, Birgitte Møller
Emerging next-generation sequencing technologies will enable DNA analyses to add pigmentation predictive and ancestry informative (AIM) SNPs to the range of markers detectable from a single PCR test. This prompted us to re-appraise current forensic and genomics AIM-SNPs and from the best sets, to...
Canada has a large beekeeping industry comprised of 8483 beekeepers managing 672094 23 colonies. Canadian honey bees, like all honey bees in the New World, originate from centuries of importation of predominately European honey bees, but their precise ancestry remains unknown. There have been no i...
Dahlgaard, Søren; Knudsen, Mathias Bæk Tejs; Rotbart, Noy Galil
We present a lg n + 2 lg lg n + 3 ancestry labeling scheme for trees. The problem was first presented by Kannan et al. [STOC 88’] along with a simple 2 lg n solution. Motivated by applications to XML files, the label size was improved incrementally over the course of more than 20 years by a series...
Bhatia, Gaurav; Tandon, Arti; Patterson, Nick; Aldrich, Melinda C; Ambrosone, Christine B; Amos, Christopher; Bandera, Elisa V; Berndt, Sonja I; Bernstein, Leslie; Blot, William J; Bock, Cathryn H; Caporaso, Neil; Casey, Graham; Deming, Sandra L; Diver, W Ryan; Gapstur, Susan M; Gillanders, Elizabeth M; Harris, Curtis C; Henderson, Brian E; Ingles, Sue A; Isaacs, William; De Jager, Phillip L; John, Esther M; Kittles, Rick A; Larkin, Emma; McNeill, Lorna H; Millikan, Robert C; Murphy, Adam; Neslund-Dudas, Christine; Nyante, Sarah; Press, Michael F; Rodriguez-Gil, Jorge L; Rybicki, Benjamin A; Schwartz, Ann G; Signorello, Lisa B; Spitz, Margaret; Strom, Sara S; Tucker, Margaret A; Wiencke, John K; Witte, John S; Wu, Xifeng; Yamamura, Yuko; Zanetti, Krista A; Zheng, Wei; Ziegler, Regina G; Chanock, Stephen J; Haiman, Christopher A; Reich, David; Price, Alkes L
The extent of recent selection in admixed populations is currently an unresolved question. We scanned the genomes of 29,141 African Americans and failed to find any genome-wide-significant deviations in local ancestry, indicating no evidence of selection influencing ancestry after admixture. A recent analysis of data from 1,890 African Americans reported that there was evidence of selection in African Americans after their ancestors left Africa, both before and after admixture. Selection after admixture was reported on the basis of deviations in local ancestry, and selection before admixture was reported on the basis of allele-frequency differences between African Americans and African populations. The local-ancestry deviations reported by the previous study did not replicate in our very large sample, and we show that such deviations were expected purely by chance, given the number of hypotheses tested. We further show that the previous study's conclusion of selection in African Americans before admixture is also subject to doubt. This is because the FST statistics they used were inflated and because true signals of unusual allele-frequency differences between African Americans and African populations would be best explained by selection that occurred in Africa prior to migration to the Americas. Copyright © 2014 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.
Christopher A Haiman
Full Text Available GWAS of prostate cancer have been remarkably successful in revealing common genetic variants and novel biological pathways that are linked with its etiology. A more complete understanding of inherited susceptibility to prostate cancer in the general population will come from continuing such discovery efforts and from testing known risk alleles in diverse racial and ethnic groups. In this large study of prostate cancer in African American men (3,425 prostate cancer cases and 3,290 controls, we tested 49 risk variants located in 28 genomic regions identified through GWAS in men of European and Asian descent, and we replicated associations (at p≤0.05 with roughly half of these markers. Through fine-mapping, we identified nearby markers in many regions that better define associations in African Americans. At 8q24, we found 9 variants (p≤6×10(-4 that best capture risk of prostate cancer in African Americans, many of which are more common in men of African than European descent. The markers found to be associated with risk at each locus improved risk modeling in African Americans (per allele OR = 1.17 over the alleles reported in the original GWAS (OR = 1.08. In summary, in this detailed analysis of the prostate cancer risk loci reported from GWAS, we have validated and improved upon markers of risk in some regions that better define the association with prostate cancer in African Americans. Our findings with variants at 8q24 also reinforce the importance of this region as a major risk locus for prostate cancer in men of African ancestry.
Kharat, D U; Saini, T S; Mokeem, S
Shovelling of the incisors is considered to be a polygenic inheritable trait. Shovelling differs considerably between groups of racial populations but is relatively stable within each group. Presence or absence of shovelling helps in racial identification and in exploration of ancestry. Periapical radiographs of patients of several nationalities from Asian and African continents were obtained. Shovelling and invaginations associated with the shovel-shaped incisors was studied according to nationality. Results indicated that the incidence of shovelling in Syrians, Jordanians, Palestinians and Filipinos was 5-6 per cent. In Saudi Arabians, Pakistanis and Indians, the incidence of shovelling was 10-12 per cent. Among Yemenis, Sudanese and Egyptians, the incidence of shovelling was 20-25 percent. The occurrence of invaginations in shovel-shaped incisors was 11 per cent.
Marsily, G. de
This work deals with the continental water pollution. The sewage affect considerably the quality of some rivers water and of some basins. Moreover, a slow and general damage of natural waters has been established. The direct effects on men and on the natural medium (climatic change, aquatic ecosystems, water cycle) are given as well as the protection means (waste processing, the water-bearing bed and underground water protection, the aquatic ecosystems protection and planning) used and future to abate the water pollution. (O.L.). 17 refs., 6 tabs
Wonkam, A; Makubalo, N; Roberts, T; Chetty, M
Pyle disease (OMIM 265900), also known as metaphyseal dysplasia, is a rare autosomal recessive disorder with no known gene mutation. We report a case of Pyle disease in a 7-year-old African boy of mixed ancestry who presented with finger and wrist fractures following minor trauma. The radiological findings revealed abnormally broad metaphyses of the tubular bones, known as Erlenmeyer-flask bone deformity, and mild cranial sclerosis, both hallmarks of the condition. We report the first case in a patient with African ancestry, which could help in the gene discovery of this rare autosomal recessive skeletal dysplasia with unknown mutations.
Chatterjee, Koushik; Dandara, Collet; Hoffman, Margaret; Williamson, Anna-Lise
Cervical cancer, caused by specific oncogenic types of human papillomavirus (HPV), is the second most common cancer in women worldwide. A large number of young sexually active women get infected by HPV but only a small fraction of them have persistent infection and develop cervical cancer pointing to co- factors including host genetics that might play a role in outcome of the HPV infection. This study investigated the role of CCR2-V64I polymorphism in cervical cancer, pre-cancers and HPV infection in South African women resident in Western Cape. CCR2-V64I polymorphism has been previously reported to influence the progression to cervical cancer in some populations and has also been associated with decreased progression from HIV infection to AIDS. Genotyping for CCR2-V64I was done by PCR-SSP in a case-control study of 446 women (106 black African and 340 mixed-ancestry) with histologically confirmed invasive cervical cancer and 1432 controls (322 black African and 1110 mixed-ancestry) group-matched (1:3) by age, ethnicity and domicile status. In the control women HPV was detected using the Digene Hybrid Capture II test and cervical disease was detected by cervical cytology. The CCR2-64I variant was significantly associated with cervical cancer when cases were compared to the control group (P = 0.001). Further analysis comparing selected groups within the controls showed that individuals with abnormal cytology and high grade squamous intraepitleial neoplasia (HSIL) did not have this association when compared to women with normal cytology. HPV infection also showed no association with CCR2-64I variant. Comparing SIL positive controls with the cases showed a significant association of CCR2-64I variant (P = 0.001) with cervical cancer. This is the first study of the role of CCR2-V64I polymorphism in cervical cancer in an African population. Our results show that CCR2-64I variant is associated with the risk of cervical cancer but does not affect the susceptibility to HPV
Dorn, Alexander; Musilová, Zuzana; Platzer, Matthias; Reichwald, Kathrin; Cellerino, Alessandro
Annual Nothobranchius fishes are distributed in East and Southern Africa and inhabit ephemeral pools filled during the monsoon season. Nothobranchius show extreme life-history adaptations: embryos survive by entering diapause and they are the vertebrates with the fastest maturation and the shortest lifespan. The distribution of Nothobranchius overlaps with the East Africa Rift System. The geological and paleoclimatic history of this region is known in detail: in particular, aridification of East Africa and expansion of grassland habitats started 8 Mya and three humid periods between 3 and 1 Mya are superimposed on the longer-term aridification. These climatic oscillations are thought to have shaped evolution of savannah African mammals. We reconstructed the phylogeny of Nothobranchius and dated the different stages of diversification in relation to these paleoclimatic events. We sequenced one mitochondrial locus and five nuclear loci in 63 specimens and obtained a robust phylogeny. Nothobranchius can be divided in four geographically separated clades whose boundaries largely correspond to the East Africa Rift system. Statistical analysis of dispersal and vicariance identifies a Nilo-Sudan origin with southwards dispersion and confirmed that these four clades are the result of vicariance events In the absence of fossil Nothobranchius, molecular clock was calibrated using more distant outgroups (secondary calibration). This method estimates the age of the Nothobranchius genus to be 8.3 (6.0 - 10.7) My and the separation of the four clades 4.8 (2.7-7.0) Mya. Diversification within the clades was estimated to have started ~3 Mya and most species pairs were estimated to have an age of 0.5-1 My. The mechanism of Nothobranchius diversification was allopatric and driven by geographic isolation. We propose a scenario where diversification of Nothobranchius started in rough coincidence with aridification of East Africa, establishment of grassland habitats and the appearance
We present a two-layer hidden Markov model to detect the structure of haplotypes for unrelated individuals. This allows us to model two scales of linkage disequilibrium (one within a group of haplotypes and one between groups), thereby taking advantage of rich haplotype information to infer local an...
Full Text Available Based predominantly on Pierre Bourdieu’s social and cultural reproduction theory, particularly his notions of cultural capital and symbolic violence, this paper explores how first year post graduate Diploma in Higher Education (PGDHE university students from diverse socio-linguistic backgrounds differ in the levels at which they understand and express themselves in classroom activities. The paper’s thesis is that the diverse nature of South African classrooms presents a number of challenges not only for students but also for educators in terms of the use of English as a medium of instruction or the language for learning and teaching (LOLT. Owing to the fact that the South African Language in Education Policy (LiEP of 1997 empowers both learners and educators in schools to use any of the eleven South African official languages as a LOLT wherever that is reasonably possible, students whose English backgrounds were deficient in enculturating them in the use of English as a learning tool often encounter challenges in expressing their ideas in the classroom, whether in writing or in oral presentations. The discussion is anchored in the data elicited through two data collection methods, lesson observations in a Diploma in Higher Education, Research class composed of students from diverse racial and ethnic backgrounds and through focus group discussion sessions with 40 multi-ethnic Diploma in Higher Education students from the same classroom. The data management and analysis for this study was done thematically, with views emerging from the observations and focus group discussions being clustered into superordinate themes for convenience of the discussion of the findings. The findings of this study were that students from affluent socio-economic backgrounds who enter university with a rich and relevant English linguistic capital, values and attitudes enjoy an enormous advantage compared to their counterparts whose social class and linguistic
Hall, W D; Reed, J W; Flack, J M; Yunis, C; Preisser, J
Hypertension is a prevalent disease among African Americans, and successful treatment rates are low. Since calcium channel blockers are well-tolerated and efficacious in African Americans, we undertook this study to compare the efficacy, safety, and tolerability of 3 commonly prescribed calcium channel blockers: amlodipine besylate (Norvasc), nifedipine coat core (CC) (Adalat CC), and nifedipine gastrointestinal therapeutic system (GITS) (Procardia XL). One hundred ninety-two hypertensive patients across 10 study centers were randomly assigned to double-blind monotherapy with amlodipine besylate (5 mg/d), nifedipine CC (30 mg/d), or nifedipine GITS (30 mg/d) for 8 weeks. Patients not achieving therapeutic response after 4 weeks had their dose doubled for the next 4 weeks. The primary end point was a comparison of the average reduction (week 8 minus baseline) in 24-hour ambulatory diastolic blood pressure (DBP). Secondary end points included a comparison of average 24-hour ambulatory systolic blood pressure (SBP), office SBP or DBP reduction, responder rates, safety, and tolerability. One hundred sixty-three patients were evaluable for efficacy after 8 weeks. There was no significant difference in the average 24-hour ambulatory DBP (-8.5, -9.0, and -6.1 mm Hg, respectively) or SBP (-14.3, -15.7, and -11.8 mm Hg, respectively) reduction. Average office SBP and DBP were reduced to a comparable degree (19-22 mm Hg [P =.50] and 12-14 mm Hg [P =.51], respectively). Responder rates (DBP or = 10 mm Hg) were similar (P = .38). Discontinuation rates and adverse event frequency were distributed similarly across the 3 treatment groups. The efficacy, safety, and tolerability of the 3 dihydropyridine calcium channel blockers are equivalent in African Americans with stages 1 and 2 hypertension.
Lopes, Camile de Barros; Barroso, Regina Fatima Feio; Burbano, Rommel Mario Rodrigues; Garcia, Patricia Aleixo; Pinto, Pablo Diego do Carmo; Santos, Ney Pereira Carneiro Dos; Santos, Sidney Emanuel Batista; Ribeiro-Dos-Santos, Andrea Kely Campos
Chronic periodontitis is caused by an inflammatory reaction of the periodontal tissues and alveolar bone. This inflammation is caused by periodontopathic bacteria located in the subgingival biofilm, resulting in inflammatory reactions that may lead to loss of attachment. This tissue destruction is a consequence of host immune and inflammatory responses to specific periodontal pathogens and their metabolic products. Cytokines modulate the immune response, altering its efficiency in the competition against pathogens and increasing periodontal susceptibility. This study investigated genetic polymorphisms in Interleukin 10 (A-1082G, C-819T and C-592A) in 205 individuals from an admixed Brazilian population. A significantly increased risk of developing chronic periodontitis was observed in individuals with low IL-10 production and Amerindian ancestry. These results suggest that the polymorphisms A-1082G, C-819T, and C-592A, which are associated with ancestry, are involved in the susceptibility to the development of chronic periodontitis in an admixed northern Brazilian population.
Stead, John D. H.; Jeffreys, Alec J.
The insulin minisatellite (INS VNTR) associates with susceptibility to a variety of diseases. We have developed a high-resolution system for analyzing variant repeat distributions applicable to all known minisatellite alleles, irrespective of size, which allows lineages of related alleles to be identified. This system has previously revealed extremely low structural diversity in the minisatellite among northern Europeans from the United Kingdom, with all alleles belonging to one of only three highly diverged lineages called “I,” “IIIA,” and “IIIB.” To explore the origins of this remarkably limited lineage diversity, we have characterized an additional 780 alleles from three non-African and three African populations. In total, 22 highly diverged lineages were identified, with structural intermediates absent from extant populations, suggesting a bottleneck within the ancestry of all humans. The difference between levels of diversity in Africans and non-Africans is unusually large, with all 22 lineages identified in Africa compared with only three lineages seen not only in the United Kingdom but also in the other non-African populations. We also find evidence for overrepresentation of lineage I chromosomes in non-Africans. These data are consistent with a common out-of-Africa origin and an unusually tight bottleneck within the ancestry of all non-African populations, possibly combined with differential and positive selection for lineage I alleles in non-Africans. The important implications of these data for future disease-association studies are discussed. PMID:12404181
Martin, Eden R; Tunc, Ilker; Liu, Zhi; Slifer, Susan H; Beecham, Ashley H; Beecham, Gary W
Population substructure can lead to confounding in tests for genetic association, and failure to adjust properly can result in spurious findings. Here we address this issue of confounding by considering the impact of global ancestry (average ancestry across the genome) and local ancestry (ancestry at a specific chromosomal location) on regression parameters and relative power in ancestry-adjusted and -unadjusted models. We examine theoretical expectations under different scenarios for population substructure; applying different regression models, verifying and generalizing using simulations, and exploring the findings in real-world admixed populations. We show that admixture does not lead to confounding when the trait locus is tested directly in a single admixed population. However, if there is more complex population structure or a marker locus in linkage disequilibrium (LD) with the trait locus is tested, both global and local ancestry can be confounders. Additionally, we show the genotype parameters of adjusted and unadjusted models all provide tests for LD between the marker and trait locus, but in different contexts. The local ancestry adjusted model tests for LD in the ancestral populations, while tests using the unadjusted and the global ancestry adjusted models depend on LD in the admixed population(s), which may be enriched due to different ancestral allele frequencies. Practically, this implies that global-ancestry adjustment should be used for screening, but local-ancestry adjustment may better inform fine mapping and provide better effect estimates at trait loci. © 2017 WILEY PERIODICALS, INC.
Chen, Chia-Yen; Han, Jiali; Hunter, David J; Kraft, Peter; Price, Alkes L
Polygenic prediction using genome-wide SNPs can provide high prediction accuracy for complex traits. Here, we investigate the question of how to account for genetic ancestry when conducting polygenic prediction. We show that the accuracy of polygenic prediction in structured populations may be partly due to genetic ancestry. However, we hypothesized that explicitly modeling ancestry could improve polygenic prediction accuracy. We analyzed three GWAS of hair color (HC), tanning ability (TA), and basal cell carcinoma (BCC) in European Americans (sample size from 7,440 to 9,822) and considered two widely used polygenic prediction approaches: polygenic risk scores (PRSs) and best linear unbiased prediction (BLUP). We compared polygenic prediction without correction for ancestry to polygenic prediction with ancestry as a separate component in the model. In 10-fold cross-validation using the PRS approach, the R(2) for HC increased by 66% (0.0456-0.0755; P ancestry, which prevents ancestry effects from entering into each SNP effect and being overweighted. Surprisingly, explicitly modeling ancestry produces a similar improvement when using the BLUP approach, which fits all SNPs simultaneously in a single variance component and causes ancestry to be underweighted. We validate our findings via simulations, which show that the differences in prediction accuracy will increase in magnitude as sample sizes increase. In summary, our results show that explicitly modeling ancestry can be important in both PRS and BLUP prediction. © 2015 WILEY PERIODICALS, INC.
Hedrick, Philip W
European ancestry in many populations in Latin America at autosomal loci is often higher than that from X-linked loci indicating more European male ancestry and more Amerindian female ancestry. Generally, this has been attributed to more European male gene flow but could also result from an advantage to European mating or reproductive success. Population genetic models were developed to investigate the dynamics of gene flow and mating or reproductive success. Using estimates of autosomal and X-chromosome European ancestry, the amount of male gene flow or mating or reproductive advantage for Europeans, or those with European ancestry, was estimated. In a population from Antioquia, Colombia with an estimated 79% European autosomal ancestry and an estimated 69% European X-chromosome ancestry, about 15% male gene flow from Europe or about 20% mating or reproductive advantage of Europeans over Amerindians resulted in these levels of European ancestry in the contemporary population. Combinations of gene flow and mating advantage were nearly additive in their impact. Gene flow, mating advantage, or a combination of both factors, are consistent with observed levels of European ancestry in a Latin American population. This approach provides a general methodology to determine the levels of gene flow and mating differences that can explain the observed contemporary differences in ancestry from autosomes and X-chromosomes. © 2017 Wiley Periodicals, Inc.
The goal of the present study is to extract non-thermal signal from seismic tomography models in order to distinguish compositional variations in the continental lithosphere and to examine if geochemical and petrologic constraints on global-scale compositional variations in the mantle...... are consistent with modern geophysical data. In the lithospheric mantle of the continents, seismic velocity variations of a non-thermal origin (calculated from global Vs seismic tomography data [Grand S.P., 2002. Mantle shear-wave tomography and the fate of subducted slabs. Philosophical Transactions...... and evolution of Precambrian lithosphere: A global study. Journal of Geophysical Research 106, 16387–16414.] show strong correlation with tectono-thermal ages and with regional variations in lithospheric thickness constrained by surface heat flow data and seismic velocities. In agreement with xenolith data...
Schaefer, Nathan K; Shapiro, Beth; Green, Richard E
Inferring the ancestry of each region of admixed individuals' genomes is useful in studies ranging from disease gene mapping to speciation genetics. Current methods require high-coverage genotype data and phased reference panels, and are therefore inappropriate for many data sets. We present a software application, AD-LIBS, that uses a hidden Markov model to infer ancestry across hybrid genomes without requiring variant calling or phasing. This approach is useful for non-model organisms and in cases of low-coverage data, such as ancient DNA. We demonstrate the utility of AD-LIBS with synthetic data. We then use AD-LIBS to infer ancestry in two published data sets: European human genomes with Neanderthal ancestry and brown bear genomes with polar bear ancestry. AD-LIBS correctly infers 87-91% of ancestry in simulations and produces ancestry maps that agree with published results and global ancestry estimates in humans. In brown bears, we find more polar bear ancestry than has been published previously, using both AD-LIBS and an existing software application for local ancestry inference, HAPMIX. We validate AD-LIBS polar bear ancestry maps by recovering a geographic signal within bears that mirrors what is seen in SNP data. Finally, we demonstrate that AD-LIBS is more effective than HAPMIX at inferring ancestry when preexisting phased reference data are unavailable and genomes are sequenced to low coverage. AD-LIBS is an effective tool for ancestry inference that can be used even when few individuals are available for comparison or when genomes are sequenced to low coverage. AD-LIBS is therefore likely to be useful in studies of non-model or ancient organisms that lack large amounts of genomic DNA. AD-LIBS can therefore expand the range of studies in which admixture mapping is a viable tool.
Huff, Chad D; Witherspoon, David J; Simonson, Tatum S; Xing, Jinchuan; Watkins, W Scott; Zhang, Yuhua; Tuohy, Therese M; Neklason, Deborah W; Burt, Randall W; Guthery, Stephen L; Woodward, Scott R; Jorde, Lynn B
Accurate estimation of recent shared ancestry is important for genetics, evolution, medicine, conservation biology, and forensics. Established methods estimate kinship accurately for first-degree through third-degree relatives. We demonstrate that chromosomal segments shared by two individuals due to identity by descent (IBD) provide much additional information about shared ancestry. We developed a maximum-likelihood method for the estimation of recent shared ancestry (ERSA) from the number and lengths of IBD segments derived from high-density SNP or whole-genome sequence data. We used ERSA to estimate relationships from SNP genotypes in 169 individuals from three large, well-defined human pedigrees. ERSA is accurate to within one degree of relationship for 97% of first-degree through fifth-degree relatives and 80% of sixth-degree and seventh-degree relatives. We demonstrate that ERSA's statistical power approaches the maximum theoretical limit imposed by the fact that distant relatives frequently share no DNA through a common ancestor. ERSA greatly expands the range of relationships that can be estimated from genetic data and is implemented in a freely available software package.
Wilson-O'Brien, Amy L; Patron, Nicola; Rogers, Suzanne
In general, sugar porters function by proton-coupled symport or facilitative transport modes. Symporters, coupled to electrochemical energy, transport nutrients against a substrate gradient. Facilitative carriers transport sugars along a concentration gradient, thus transport is dependent upon extracellular nutrient levels. Across bacteria, fungi, unicellular non-vertebrates and plants, proton-coupled hexose symport is a crucial process supplying energy under conditions of nutrient flux. In mammals it has been assumed that evolution of whole body regulatory mechanisms would eliminate this need. To determine whether any isoforms bearing this function might be conserved in mammals, we investigated the relationship between the transporters of animals and the proton-coupled hexose symporters found in other species. We took a comparative genomic approach and have performed the first comprehensive and statistically supported phylogenetic analysis of all mammalian glucose transporter (GLUT) isoforms. Our data reveals the mammalian GLUT proteins segregate into five distinct classes. This evolutionary ancestry gives insight to structure, function and transport mechanisms within the groups. Combined with biological assays, we present novel evidence that, in response to changing nutrient availability and environmental pH, proton-coupled, active glucose symport function is maintained in mammalian cells. The analyses show the ancestry, evolutionary conservation and biological importance of the GLUT classes. These findings significantly extend our understanding of the evolution of mammalian glucose transport systems. They also reveal that mammals may have conserved an adaptive response to nutrient demand that would have important physiological implications to cell survival and growth.
The genus Vitis (the grapevine) is a group of highly diverse, diploid woody perennial vines consisting of approximately 60 species from across the northern hemisphere. It is the world’s most valuable horticultural crop with ~8 million hectares planted, most of which is processed into wine. To gain i...
Admixture and recombination create populations and genomes with genetic ancestry from multiple source populations. Analyses of genetic ancestry in admixed populations are relevant for trait and disease mapping, studies of speciation, and conservation efforts. Consequently, many methods have been developed to infer genome-average ancestry and to deconvolute ancestry into continuous local ancestry blocks or tracts within individuals. Current methods for local ancestry inference perform well when admixture occurred recently or hybridization is ongoing, or when admixture occurred in the distant past such that local ancestry blocks have fixed in the admixed population. However, methods to infer local ancestry frequencies in isolated admixed populations still segregating for ancestry do not exist. In the current paper, I develop and test a continuous correlated beta process model to fill this analytical gap. The method explicitly models autocorrelations in ancestry frequencies at the population-level and uses discriminant analysis of SNP windows to take advantage of ancestry blocks within individuals. Analyses of simulated data sets show that the method is generally accurate such that ancestry frequency estimates exhibited low root-mean-square error and were highly correlated with the true values, particularly when large (±10 or ±20) SNP windows were used. Along these lines, the proposed method outperformed post hoc inference of ancestry frequencies from a traditional hidden Markov model (i.e., the linkage model in structure), particularly when admixture occurred more distantly in the past with little on-going gene flow or was followed by natural selection. The reliability and utility of the method was further assessed by analyzing genetic ancestry in an admixed human population (Uyghur) and three populations from a hybrid zone between Mus domesticus and M. musculus. Considerable variation in ancestry frequencies was detected within and among chromosomes in the Uyghur
Full Text Available Admixture and recombination create populations and genomes with genetic ancestry from multiple source populations. Analyses of genetic ancestry in admixed populations are relevant for trait and disease mapping, studies of speciation, and conservation efforts. Consequently, many methods have been developed to infer genome-average ancestry and to deconvolute ancestry into continuous local ancestry blocks or tracts within individuals. Current methods for local ancestry inference perform well when admixture occurred recently or hybridization is ongoing, or when admixture occurred in the distant past such that local ancestry blocks have fixed in the admixed population. However, methods to infer local ancestry frequencies in isolated admixed populations still segregating for ancestry do not exist. In the current paper, I develop and test a continuous correlated beta process model to fill this analytical gap. The method explicitly models autocorrelations in ancestry frequencies at the population-level and uses discriminant analysis of SNP windows to take advantage of ancestry blocks within individuals. Analyses of simulated data sets show that the method is generally accurate such that ancestry frequency estimates exhibited low root-mean-square error and were highly correlated with the true values, particularly when large (±10 or ±20 SNP windows were used. Along these lines, the proposed method outperformed post hoc inference of ancestry frequencies from a traditional hidden Markov model (i.e., the linkage model in structure, particularly when admixture occurred more distantly in the past with little on-going gene flow or was followed by natural selection. The reliability and utility of the method was further assessed by analyzing genetic ancestry in an admixed human population (Uyghur and three populations from a hybrid zone between Mus domesticus and M. musculus. Considerable variation in ancestry frequencies was detected within and among
...), had used traditional conflict resolution mechanisms to resolve conflicts. These notwithstanding, with the outbreak of conflict in Liberia in November 1989, ECOWAS employed ECOWAS Ceasefire Monitoring Group (ECOMOG...
El-Sayed, Abdulrahman M; Lauderdale, Diane S; Galea, Sandro
Data about Arab-Americans, a growing ethnic minority, are not routinely collected in vital statistics, registry, or administrative data in the USA. The difficulty in identifying Arab-Americans using publicly available data sources is a barrier to health research about this group. Here, we validate an empirically based probabilistic Arab name algorithm (ANA) for identifying Arab-Americans in health research. We used data from all Michigan birth certificates between 2000 and 2005. Fathers' surnames and mothers' maiden names were coded as Arab or non-Arab according to the ANA. We calculated sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) of Arab ethnicity inferred using the ANA as compared to self-reported Arab ancestry. Statewide, the ANA had a specificity of 98.9%, a sensitivity of 50.3%, a PPV of 57.0%, and an NPV of 98.6%. Both the false-positive and false-negative rates were higher among men than among women. As the concentration of Arab-Americans in a study locality increased, the ANA false-positive rate increased and false-negative rate decreased. The ANA is highly specific but only moderately sensitive as a means of detecting Arab ancestry. Future research should compare health characteristics among Arab-American populations defined by Arab ancestry and those defined by the ANA.
El-Sayed, Abdulrahman M.; Lauderdale, Diane S.; Galea, Sandro
Objective Data about Arab-Americans, a growing ethnic minority, is not routinely collected in vital statistics, registry, or administrative data in the US. The difficulty in identifying Arab-Americans using publicly available data sources is a barrier to health research about this group. Here, we validate an empirically-based, probabilistic Arab name algorithm (ANA) for identifying Arab-Americans in health research. Design We used data from all Michigan birth certificates between 2000-2005. Fathers’ surnames and mothers’ maiden names were coded as Arab or non-Arab according to the ANA. We calculated sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) of Arab ethnicity inferred using the ANA as compared to self-reported Arab ancestry. Results State-wide, the ANA had a specificity of 98.9%, a sensitivity of 50.3%, a PPV of 57.0%, and a NPV of 98.6%. Both the false positive and false negative rates were higher among men than among women. As the concentration of Arab-Americans in a study locality increased, the ANA false positive rate increased and false-negative rate decreased. Conclusion The ANA is highly specific but only moderately sensitive as a means of detecting Arab ancestry. Future research should compare health characteristics among Arab-American populations defined by Arab ancestry and those defined by the ANA. PMID:20845117
Janelle R. Finley
Full Text Available The ancestry of the violin is a subject that has been studied, researched, debated, and written about in great detail. However, despite all of the research and study, the ancestry of the violin is still not certain. This paper presents two schools of thought that propose different theories as to how the ancestry of the violin should be determined and what instruments should be included in the ancestry of the violin. The first school of thought proposes that the violin’s ancestry should be traced through the bow. The second theory proposes that the violin’s ancestry should be traced through the sound-chest of the violin. This paper also presents the different arguments for and against each theory, the importance of this topic, and the paper’s position on this topic. Research for this paper was accomplished through the use of scholarly books on the subject of the history of the violin.
This book is an introduction to palaeomagnetism offering treatment of theory and practice. It analyzes the palaeomagnetic record over the whole of geological time, from the Archaean to the Cenozoic, and goes on to examine the impact of past geometries and movements of the continental crust at each geological stage. Topics covered include theory of rock and mineral magnetism, field and laboratory methods, growth and consolidation of the continental crust in Archaean and Proterozoic times, Palaeozoic palaeomagnetism and the formation of Pangaea, the geomagnetic fields, continental movements, configurations and mantle convection.
George, Jaya A; Micklesfield, L K; Norris, S A; Crowther, N J
There are few data on the contribution of body composition to bone mineral density (BMD) in non-Caucasian populations. We therefore studied the contribution of body composition, and possible confounding of 25-hydroxyvitamin D and PTH, to BMD at various skeletal sites in black African (BA) and Asian Indian (AI) subjects. This was a cross-sectional study in Johannesburg, South Africa. BMD, body fat, and lean mass were measured using dual x-ray absorptiometry and abdominal fat distribution by ultrasound in 714 healthy subjects, aged 18-65 years. Whole-body (subtotal), hip, femoral neck, and lumbar spine (lumbar) BMD were significantly higher in BA than AI subjects (P < .001 for all). Whole-body lean mass positively associated with BMD at all sites in both ethnic groups (P < .001 for all) and partially explained the higher BMD in BA females compared with AI females. Whole-body fat mass correlated positively with lumbar BMD in BA (P = .001) and inversely with subtotal BMD in AI subjects (P < .0001). Visceral adiposity correlated inversely with subtotal BMD in the BA (P = .037) and with lumbar BMD in the AI group (P = .005). No association was found between serum 25-hydroxyvitamin D and BMD. PTH was inversely associated with hip BMD in the BA group (P = .01) and with subtotal (P = .002), hip (P = .001), and femoral BMD (P < .0001) in the AI group. Significant differences in whole-body and site-specific BMD between the BA and AI groups were observed, with lean mass the major contributor to BMD at all sites in both groups. The contribution of other components of body composition differed by site and ethnic group.
Silva-Malta, M C F; Araujo, N C Fidélis; Vieira, O V Neves; Schmidt, L Cayres; Gonçalves, P de Cassia; Martins, M Lobato
In this study, we present a strategy for RHD gene screening based on real-time polymerase chain reaction (PCR) using dried blood spots of pooled samples. Molecular analysis of blood donors may be used to detect RHD variants among the presumed D-negative individuals. RHD genotyping using pooled samples is a strategy to test a large number of samples at a more reasonable cost. RHD gene detection based on real-time PCR using dried blood spots of pooled samples was standardised and used to evaluate 1550 Brazilian blood donors phenotyped as RhD-negative. Positive results were re-evaluated by retesting single samples using real-time PCR and conventional multiplex PCR to amplify five RHD-specific exons. PCR-sequence-specific primers was used to amplify RHDψ allele. We devised a strategy for RHD gene screening using dried blood spots of five pooled samples. Among 1550 serologically D-negative blood donors, 58 (3.74%) had the RHD gene. The non-functional RHDψ allele was detected in 47 samples (3.02%). The present method is a promising strategy to detect the RHD gene among presumed RhD-negative blood donors, particularly for populations with African ancestry. © 2015 British Blood Transfusion Society.
Martínez-Cruzado, J C; Toro-Labrador, G; Ho-Fung, V; Estévez-Montero, M A; Lobaina-Manzanet, A; Padovani-Claudio, D A; Sánchez-Cruz, H; Ortiz-Bermúdez, P; Sánchez-Crespo, A
To estimate the maternal contribution of Native Americans to the human gene pool of Puerto Ricans--a population of mixed African, European, and Amerindian ancestry--the mtDNAs of two sample sets were screened for restriction fragment length polymorphisms (RFLPs) defining the four major Native American haplogroups. The sample set collected from people who claimed to have a maternal ancestor with Native American physiognomic traits had a statistically significant higher frequency of Native American mtDNAs (69.6%) than did the unbiased sample set (52.6%). This higher frequency suggests that, despite the fact that the native Taíno culture has been extinct for centuries, the Taíno contribution to the current population is considerable and some of the Taíno physiognomic traits are still present. Native American haplogroup frequency analysis shows a highly structured distribution, suggesting that the contribution of Native Americans foreign to Puerto Rico is minimal. Haplogroups A and C cover 56.0% and 35.6% of the Native American mtDNAs, respectively. No haplogroup D mtDNAs were found. Most of the linguistic, biological, and cultural evidence suggests that the Ceramic culture of the Taínos originated in or close to the Yanomama territory in the Amazon. However, the absence of haplogroup A in the Yanomami suggests that the Yanomami are not the only Taíno ancestors.
Bond, Mariano; Tejedor, Marcelo F.; Campbell, Kenneth E.; Chornogubsky, Laura; Novo, Nelson; Goin, Francisco
The platyrrhine primates, or New World monkeys, are immigrant mammals whose fossil record comes from Tertiary and Quaternary sediments of South America and the Caribbean Greater Antilles. The time and place of platyrrhine origins are some of the most controversial issues in primate palaeontology, although an African Palaeogene ancestry has been presumed by most primatologists. Until now, the oldest fossil records of New World monkeys have come from Salla, Bolivia, and date to approximately 26 million years ago, or the Late Oligocene epoch. Here we report the discovery of new primates from the ?Late Eocene epoch of Amazonian Peru, which extends the fossil record of primates in South America back approximately 10 million years. The new specimens are important for understanding the origin and early evolution of modern platyrrhine primates because they bear little resemblance to any extinct or living South American primate, but they do bear striking resemblances to Eocene African anthropoids, and our phylogenetic analysis suggests a relationship with African taxa. The discovery of these new primates brings the first appearance datum of caviomorph rodents and primates in South America back into close correspondence, but raises new questions about the timing and means of arrival of these two mammalian groups.
National Oceanic and Atmospheric Administration, Department of Commerce — The Continental U.S. Hurricane Strikes Poster is our most popular poster which is updated annually. The poster includes all hurricanes that affected the U.S. since...
Feng, Ye; Stram, Daniel O; Rhie, Suhn Kyong; Millikan, Robert C; Ambrosone, Christine B; John, Esther M; Bernstein, Leslie; Zheng, Wei; Olshan, Andrew F; Hu, Jennifer J; Ziegler, Regina G; Nyante, Sarah; Bandera, Elisa V; Ingles, Sue A; Press, Michael F; Deming, Sandra L; Rodriguez-Gil, Jorge L; Palmer, Julie R; Olopade, Olufunmilayo I; Huo, Dezheng; Adebamowo, Clement A; Ogundiran, Temidayo; Chen, Gary K; Stram, Alex; Park, Karen; Rand, Kristin A; Chanock, Stephen J; Le Marchand, Loic; Kolonel, Laurence N; Conti, David V; Easton, Douglas; Henderson, Brian E; Haiman, Christopher A
Genome-wide association studies have identified 73 breast cancer risk variants mainly in European populations. Given considerable differences in linkage disequilibrium structure between populations of European and African ancestry, the known risk variants may not be informative for risk in African ancestry populations. In a previous fine-mapping investigation of 19 breast cancer loci, we were able to identify SNPs in four regions that better captured risk associations in African American women. In this study of breast cancer in African American women (3016 cases, 2745 controls), we tested an additional 54 novel breast cancer risk variants. Thirty-eight variants (70%) were found to have an association with breast cancer in the same direction as previously reported, with eight (15%) replicating at P University Press. All rights reserved. For Permissions, please email: email@example.com.
Chen, Christina T.L.; Liu, Ching-Ti; Chen, Gary K.; Andrews, Jeanette S.; Arnold, Alice M.; Dreyfus, Jill; Franceschini, Nora; Garcia, Melissa E.; Kerr, Kathleen F.; Li, Guo; Lohman, Kurt K.; Musani, Solomon K.; Nalls, Michael A.; Raffel, Leslie J.; Smith, Jennifer; Ambrosone, Christine B.; Bandera, Elisa V.; Bernstein, Leslie; Britton, Angela; Brzyski, Robert G.; Cappola, Anne; Carlson, Christopher S.; Couper, David; Deming, Sandra L.; Goodarzi, Mark O.; Heiss, Gerardo; John, Esther M.; Lu, Xiaoning; Le Marchand, Loic; Marciante, Kristin; Mcknight, Barbara; Millikan, Robert; Nock, Nora L.; Olshan, Andrew F.; Press, Michael F.; Vaiyda, Dhananjay; Woods, Nancy F.; Taylor, Herman A.; Zhao, Wei; Zheng, Wei; Evans, Michele K.; Harris, Tamara B.; Henderson, Brian E.; Kardia, Sharon L.R.; Kooperberg, Charles; Liu, Yongmei; Mosley, Thomas H.; Psaty, Bruce; Wellons, Melissa; Windham, Beverly G.; Zonderman, Alan B.; Cupples, L. Adrienne; Demerath, Ellen W.; Haiman, Christopher; Murabito, Joanne M.; Rajkovic, Aleksandar
Age at menopause marks the end of a woman's reproductive life and its timing associates with risks for cancer, cardiovascular and bone disorders. GWAS and candidate gene studies conducted in women of European ancestry have identified 27 loci associated with age at menopause. The relevance of these loci to women of African ancestry has not been previously studied. We therefore sought to uncover additional menopause loci and investigate the relevance of European menopause loci by performing a GWAS meta-analysis in 6510 women with African ancestry derived from 11 studies across the USA. We did not identify any additional loci significantly associated with age at menopause in African Americans. We replicated the associations between six loci and age at menopause (P-value < 0.05): AMHR2, RHBLD2, PRIM1, HK3/UMC1, BRSK1/TMEM150B and MCM8. In addition, associations of 14 loci are directionally consistent with previous reports. We provide evidence that genetic variants influencing reproductive traits identified in European populations are also important in women of African ancestry residing in USA. PMID:24493794
Items 1 - 50 of 221 ... African Journal of Clinical and Experimental Microbiology ... The African Journal of Drug & Alcohol Studies is an international scientific journal ... d) Critical or analytical reviews in the area of theory, policy, or research in Dentistry. e) Reviews of recently published books or group of books which would be of ...
Jiang, Li; Peng, Jianxiong; Huang, Meisha; Liu, Jing; Wang, Ling; Ma, Quan; Zhao, Hui; Yang, Xin; Ji, Anquan; Li, Caixia
Tibetans have adapted to the extreme environment of high altitude for hundreds of generations. A highly differentiated 5-SNP (Single Nucleotide Polymorphism) haplotype motif (AGGAA) on a hypoxic pathway gene, EPAS1, is observed in Tibetans and lowlanders. To evaluate the potential usage of the 5-SNP haplotype in ancestry inference for Tibetan or Tibetan-related populations, we analyzed this haplotype in 1053 individuals of 12 Chinese populations residing on the Tibetan Plateau, peripheral regions of Tibet, and plain regions. These data were integrated with the genotypes from the 1000 Genome populations and populations in a previously reported paper for population structure analyses. We found that populations representing highland and lowland groups have different dominant ancestry components. The core Denisovan haplotype (AGGAA) was observed at a frequency of 72.32% in the Tibetan Plateau, with a frequency range from 9.48 to 21.05% in the peripheral regions and Tibetan Plateau carried the archaic haplotype, while < 5% of the Chinese Han people carried the haplotype. Our findings indicate that the 5-SNP haplotype has a special distribution pattern in populations of Tibet and peripheral regions and could be integrated into AISNP (Ancestry Informative Single Nucleotide Polymorphism) panels to enhance ancestry resolution.
Mägi, Reedik; Horikoshi, Momoko; Sofer, Tamar; Mahajan, Anubha; Kitajima, Hidetoshi; Franceschini, Nora; McCarthy, Mark I; Morris, Andrew P
Trans-ethnic meta-analysis of genome-wide association studies (GWAS) across diverse populations can increase power to detect complex trait loci when the underlying causal variants are shared between ancestry groups. However, heterogeneity in allelic effects between GWAS at these loci can occur that is correlated with ancestry. Here, a novel approach is presented to detect SNP association and quantify the extent of heterogeneity in allelic effects that is correlated with ancestry. We employ trans-ethnic meta-regression to model allelic effects as a function of axes of genetic variation, derived from a matrix of mean pairwise allele frequency differences between GWAS, and implemented in the MR-MEGA software. Through detailed simulations, we demonstrate increased power to detect association for MR-MEGA over fixed- and random-effects meta-analysis across a range of scenarios of heterogeneity in allelic effects between ethnic groups. We also demonstrate improved fine-mapping resolution, in loci containing a single causal variant, compared to these meta-analysis approaches and PAINTOR, and equivalent performance to MANTRA at reduced computational cost. Application of MR-MEGA to trans-ethnic GWAS of kidney function in 71,461 individuals indicates stronger signals of association than fixed-effects meta-analysis when heterogeneity in allelic effects is correlated with ancestry. Application of MR-MEGA to fine-mapping four type 2 diabetes susceptibility loci in 22,086 cases and 42,539 controls highlights: (i) strong evidence for heterogeneity in allelic effects that is correlated with ancestry only at the index SNP for the association signal at the CDKAL1 locus; and (ii) 99% credible sets with six or fewer variants for five distinct association signals. © The Author 2017. Published by Oxford University Press.
Unterländer, Martina; Palstra, Friso; Lazaridis, Iosif; Pilipenko, Aleksandr; Hofmanová, Zuzana; Groß, Melanie; Sell, Christian; Blöcher, Jens; Kirsanow, Karola; Rohland, Nadin; Rieger, Benjamin; Kaiser, Elke; Schier, Wolfram; Pozdniakov, Dimitri; Khokhlov, Aleksandr; Georges, Myriam; Wilde, Sandra; Powell, Adam; Heyer, Evelyne; Currat, Mathias; Reich, David; Samashev, Zainolla; Parzinger, Hermann; Molodin, Vyacheslav I.; Burger, Joachim
During the 1st millennium before the Common Era (BCE), nomadic tribes associated with the Iron Age Scythian culture spread over the Eurasian Steppe, covering a territory of more than 3,500 km in breadth. To understand the demographic processes behind the spread of the Scythian culture, we analysed genomic data from eight individuals and a mitochondrial dataset of 96 individuals originating in eastern and western parts of the Eurasian Steppe. Genomic inference reveals that Scythians in the east and the west of the steppe zone can best be described as a mixture of Yamnaya-related ancestry and an East Asian component. Demographic modelling suggests independent origins for eastern and western groups with ongoing gene-flow between them, plausibly explaining the striking uniformity of their material culture. We also find evidence that significant gene-flow from east to west Eurasia must have occurred early during the Iron Age.
Gotay, Carolyn Cook; Shimizu, Hiroyuki; Muraoka, Miles; Ishihara, Yoko; Tsuboi, Koji; Ogawa, Hiroshi
Adults living in Japan (N = 357) and the US (N = 223) completed semi-structured interviews assessing health-related attitudes and practices. The US respondents were of Japanese (N = 106) and European (N = 117) ancestry