Showing papers in "Human Biology in 2006"
TL;DR: Evidence for higher hemoglobin concentration and percent of oxygen saturation of hemoglobin among Andean highlanders as compared with Tibetans at the same altitude and evidence that Ethiopian highlanders do not differ from sea-level in these two traits are presented.
Abstract: Synopsis Research on humans at high-altitudes contributes to understanding the processes of human adaptation to the environment and evolution. The unique stress at high altitude is hypobaric hypoxia caused by the fall in barometric pressure with increasing altitude and the consequently fewer oxygen molecules in a breath of air, as compared with sea level. The natural experiment of human colonization of high-altitude plateaus on three continents has resulted in two—perhaps three—quantitatively different arterial-oxygen-content phenotypes among indigenous Andean, Tibetan and Ethiopian high-altitude populations. This paper illustrates these contrasting phenotypes by presenting evidence for higher hemoglobin concentration and percent of oxygen saturation of hemoglobin among Andean highlanders as compared with Tibetans at the same altitude and evidence that Ethiopian highlanders do not differ from sea-level in these two traits. Evolutionary processes may have acted differently on the colonizing populations to cause the different patterns of adaptation. Hemoglobin concentration has significant heritability in Andean and Tibetan samples. Oxygen saturation has no heritability in the Andean sample, but does among Tibetans where an autosomal dominant major gene for higher oxygen saturation has been detected. Women estimated with high probability to have high oxygen saturation genotypes have more surviving children than women estimated with high probability to have the low oxygen saturation genotype. These findings suggest the hypothesis that ongoing natural selection is increasing the frequency of the high saturation allele at this major gene locus.
452 citations
TL;DR: New variance formulas for the monozygotic and dizygotic twinning rates obtained using Weinberg's differential rule are presented and it is shown that despite its simplicity, it gives reliable results when official birth registers are analyzed.
Abstract: A central problem in research on twins is the estimation of the rates of monozygotic and dizygotic twin maternities. The estimation usually follows Weinberg's differential rule. According to this rule, the rate of dizygotic twinning is twice the rate of twin maternities in which the twins are of opposite sex. The monozygotic twinning rate is the difference between the rates of same-sex and opposite-sex twin sets. Weinberg's differential rule is implicitly based on the assumptions that the probability of a male equals the probability of a female and that the sexes in a dizygotic twin set are independent. Although Weinberg's differential rule has been the target of continuing discussions, the reliability of these assumptions has never been conclusively verified or rejected. In this study we present new variance formulas for the monozygotic and dizygotic twinning rates obtained using Weinberg's differential rule and stress that these new formulas have to be used. We analyze the accuracy of Weinberg's differential rule by considering alternative attempts. Especially, we build a general likelihood function and show that the maximum-likelihood estimates differ only slightly from the rates obtained using Weinberg's differential rule. In addition, our methods are applied to twinning data from Finland and Sweden. We compare our results with findings in the literature. In conclusion, our findings indicate that Weinberg's differential rule is rather robust and that despite its simplicity, it gives reliable results when official birth registers are analyzed.
71 citations
TL;DR: In a heuristic comparison of multilevel versus dichotomous trait forms, most of the nonmetric characters showed no differences in heritability between the two methods used for parsing the phenotypic variation, although where differences were noted, the presence-absence version had higher heritabilities.
Abstract: Nonmetric traits of the cranium are often used to support hypotheses of the history and divergence of human populations. These studies rely on the assumption that nonmetric traits are heritable, yet few skeletal series exist with associated pedigree information that allow for the calculation of additive genetic variance, or heritability. In addition, traits for which heritabilities have been published represent dichotomous present/absent forms instead of the range of expression that can be observed for many nonmetric characters. In the present study I use a maximum-likelihood variance components analysis to calculate univariate narrow-sense heritability estimates on the skeletal series from Hallstatt, Austria, for 9 sutural bones, 27 multilevel traits, and dichotomized present/absent forms for 19 of these multilevel characters. Most of the trait heritabilities do not differ significantly from a model of h2 = 0, and they have large standard errors. In a heuristic comparison of multilevel versus dichotomous trait forms, most of the nonmetric characters showed no differences in heritability between the two methods used for parsing the phenotypic variation, although where differences were noted, the presence-absence version had higher heritabilities. These results have implications not only for the use of particular nonmetric traits in population studies but also for the practice of character dichotomization in data collection.
54 citations
TL;DR: The multidimensional scaling of FST genetic distances of related sub-Saharan populations and the analysis of molecular variance (AMOVA) show clear and close relationships between all pairs of the four Fulani nomad samples, irrespective of their geographic origin.
Abstract: Despite the large size of the contemporary nomadic Fulani population (roughly 13 million people), the genetic diversity and degree of differentiation of Fulanis compared to other sub-Saharan populations remain unknown. We sampled four Fulani nomad populations (n = 186) in three countries of sub-Saharan Africa (Chad, Cameroon, and Burkina Faso) and analyzed sequences of the first hypervariable segment of the mitochondrial DNA. Most of the haplotypes belong to haplogroups of West African origin, such as L1b, L3b, L3d, L2b, L2c, and L2d (79.6% in total), which are all well represented in each of the four geographically separated samples. The haplogroups of Western Eurasian origin, such as J1b, U5, H, and V, were also detected but in rather low frequencies (8.1% in total). As in African hunter-gatherers (Pygmies and Khoisan) and some populations from central Tunisia (Kesra and Zriba), three of the Fulani nomad samples do not reveal significant negative values of Fu's selective neutrality test. The multidimensional scaling of FST genetic distances of related sub-Saharan populations and the analysis of molecular variance (AMOVA) show clear and close relationships between all pairs of the four Fulani nomad samples, irrespective of their geographic origin. The only group of nomadic Fulani that manifests some similarities with geographically related agricultural populations (from Guinea-Bissau and Nigeria) comes from Tcheboua in northern Cameroon.
49 citations
TL;DR: The heterogeneity of the Mexican population is shown, where the frequency of the APOE*2 allele is higher in Guadalajara than in other urban areas of Mexico and is similar to frequencies described in the Caucasian population.
Abstract: Mexico has approximately 100 million inhabitants. Most of the urban Mexican population has been considered mestizo (Indian and Spanish descent), whereas the Indian population predominates in rural areas and small towns in the countryside. In this study we analyzed the apolipoprotein E (APOE) polymorphism in Guadalajara (the second largest metropolitan area of Mexico) and its surrounding areas, two adjoining states (Nayarit and Durango), and an Indian town (Huichol Indians) from western Mexico. APOE*3 was the most common allele, and APOE*3/*3 was the most common genotype in all populations studied. Guadalajara revealed the highest frequency of the APOE*2 allele (7.8%); the frequency decreased in the rural area (4.4%), followed by Nayarit (1.6%), and was absent in Durango and in the Huichols. On the contrary, the lowest frequency of the APOE*4 allele was in Guadalajara (8.4%); the frequency increased in the rural area (9.3%), in Nayarit and Durango (11.5% and 11.7%), and reached a high frequency in the Huichol Indians (28%). The distribution of the APOE allele in the western population of Mexico is similar to those described in Mexican American migrants living in the United States but is different from those populations living in Mexico City. This study shows the heterogeneity of the Mexican population, where the frequency of the APOE*2 allele is higher in Guadalajara than in other urban areas of Mexico and is similar to frequencies described in the Caucasian population. On the contrary, the Huichols revealed the highest frequency of the APOE*4 allele in Mexico and in the Americas. This information could be useful for the study of dyslipidemias associated with chronic diseases and as markers of ethnic variation in the Americas.
45 citations
TL;DR: The results indicate different sources of African slaves for the four major Brazilian regions and reveal patterns that differ from those expected on the basis of historical registers, thus suggesting the role of ethnic sex differences in the slave trade.
Abstract: Seventy individuals from two African and four black Brazilian populations were studied for the first hypervariable segment of mtDNA. To delineate a more complete phylogeographic scenario of the African mtDNA haplogroups in Brazil and to provide additional information on the nature of the Atlantic slave trade, we analyzed our data together with previously published data. The results indicate different sources of African slaves for the four major Brazilian regions. In addition, the data revealed patterns that differ from those expected on the basis of historical registers, thus suggesting the role of ethnic sex differences in the slave trade.
42 citations
TL;DR: It is suggested that the presence of East Eurasian mtDNA haplotypes is not an original feature of the gene pool of the proto-Slavs but rather may be mostly a consequence of admixture with Central Asian nomadic tribes, who migrated into Central and Eastern Europe in the early Middle Ages.
Abstract: Mitochondrial DNA (mtDNA) variability was studied in a sam- ple of 179 individuals representing the Czech population of Western Bohe- mia. Sequencing of two hypervariable segments, HVS I and HVS II, in combination with screening of coding-region haplogroup-specific RFLP markers revealed that most Czech mtDNAs belong to the common West Eurasian mitochondrial haplogroups (H, pre-V, HV*, J, T, U, N1, W, and X). However, about 3% of Czech mtDNAs encompass East Eurasian lineages (A, N9a, D4, M*). A comparative analysis with published data showed that different Slavonic populations in Central and Eastern Europe contain small but marked amounts of East Eurasian mtDNAs. We suggest that the presence of East Eurasian mtDNA haplotypes is not an original feature of the gene pool of the proto-Slavs but rather may be mostly a consequence of admixture with Central Asian nomadic tribes, who migrated into Central and Eastern Europe in the early Middle Ages.
37 citations
TL;DR: From the Y-chromosome data in particular, major demographic changes, such as the Neolithic population expansion and more recent historical events including migration along the Silk Road, could be inferred.
Abstract: Genomic data have increasingly been used to complement linguistic, archeological, and anthropological evidence in reconstructing the origins and migratory patterns of modern humans. East Asia is a particular hotspot of human migration, especially mainland China, where a large number of human fossils have been unearthed and more than 20% of the world's population now resides. There are 56 officially recognized ethnic populations (minzu) in China. In the present study we investigated the ancestry and genetic diversity of nine populations: the majority Han of Liaoning Province; the Miao, Yao, Kucong, and Tibetan communities of Yunnan Province in southwest China; and four Muslim populations, the Hui, Bonan, Dongxiang, and Sala from central and northern China. We used both biparental and uniparental markers to determine patterns of diversity at autosomal, mitochondrial, and Y-chromosome loci. The study populations displayed several paternal origins but restricted maternal ancestries. From the Y-chromosome data in particular, major demographic changes, such as the Neolithic population expansion and more recent historical events including migration along the Silk Road, could be inferred. Specific aspects of the internal structure and organization of the study populations, including endogamy and consanguinity, were uncovered using autosomal markers. However, we encountered interpretive problems in terms of the definition of the present-day ethnic study populations in China, which appear to reflect past and present political as well as genetic influences.
37 citations
TL;DR: The βS mutation in southern Iran is associated with multiple mutational events and is likely that the influx of βS genes linked to the Benin and Bantu haplotypes, of African origin, must have occurred during the Arab slave trade.
Abstract: To determine the origin of sickle cell mutation in different ethnic groups living in southern Iran, we studied the haplotype background of the βS and βA genes in subjects from the provinces of Fars, Khuzestan, Bushehr, Hormozgan, and Kerman and from the islands of Khark and Qeshm. β-globin gene cluster haplotypes were determined using the PCR-RFLP technique. Detection of −α3.7 deletion and β-thalassemia mutations were defined by PCR and reverse dot blot techniques, respectively. The framework of the β-globin gene was determined using denaturing gradient gel electrophoresis. We found that the βS mutation in southern Iran is associated with multiple mutational events. Most of the patients were from two ethnic groups: Farsi speakers (presumably Persian in origin) from Fars province and patients of Arab origin from Khuzestan province. In both ethnic groups the Arab-Indian haplotype was the most prevalent. The frequencies of the Arab-Indian and African haplotypes in sickle cell anemia patients from th...
36 citations
TL;DR: There is a positive but statistically insignificant correlation between Cormic index and BMI, and the five social groups differ more in size distance than in shape distance, which suggests that the people within a population are more homogeneous than the people between populations.
Abstract: Data on body weight, height, and sitting height from 11,496 adult males, age 18-62 years, belonging to 38 different populations of five major social groups (scheduled tribes, scheduled castes, ''other backward castes,'' general castes, and Muslims) of Central India were taken for our analysis to assess the nutritional status of these groups. Cormic index and body mass index (BMI) were computed, and an analysis of variance (ANOVA) was carried out among different populations as well as among social groups separately on Cormic index and BMI. Shape, size, and general- ized distances among the different social groups were computed and dendro- grams were drawn. The level of malnutrition is the lowest among the general castes. The opposite is the case with the scheduled castes and scheduled tribes. Comparison of the coefficient of variation shows that there is variation in weight and BMI but that there is no marked variation in the other anthro- pometric variables. The ANOVA on Cormic index and BMI suggests that the people within a population are more homogeneous than the people between populations. There is a positive but statistically insignificant correlation be- tween Cormic index and BMI. The five social groups differ more in size distance than in shape distance. According to the dendrogram of generalized distance values, the Muslims and the general castes can be grouped into one cluster and the scheduled castes, scheduled tribes, and other backward castes can be grouped into another cluster. In the assessment of the nutritional status of individuals and communities, an- thropometric measurements play an important role. The assessment is done by observing the departure of the anthropometric measures from the normal stan- dards. The basic causes of undernutrition in developing countries are poverty,
36 citations
TL;DR: The frequencies of the *I and *D alleles of the ACE gene among Sudanese, Somalis, and Arab nationals of the United Arab Emirates and Oman using previously described methods indicate a preponderance of the *.D allele among the Arab and African populations studied.
Abstract: The angiotensin-converting enzyme (ACE) gene in humans contains an insertion-deletion polymorphism in its intron 16. Because of its involvement with the renin-angiotensin system, the insertion-deletion polymorphism of the ACE gene has been widely investigated in different populations and in case-control studies. However, similar studies for Arab populations are limited in number. Therefore we have investigated the frequencies of the *I and *D alleles of the ACE gene among Sudanese, Somalis, and Arab nationals of the United Arab Emirates and Oman using previously described methods. Our data indicate a preponderance of the *D allele among the Arab and African populations studied (Sudanese, 0.64; Somalis, 0.73; Emiratis, 0.61; and Omanis, 0.71).
TL;DR: This primarily nonvegetarian, nonsmoking endogamous caste group has presented an unusual clinical picture of uneven distribution of adiposity and a high rate of T2DM with secondary complications, which may offer unique advantages in mapping genes for common complex diseases.
Abstract: Non-insulin-dependent diabetes mellitus, or type 2 diabetes (T2DM), has become a major public health problem in India. The high prevalence, relatively young age of onset, and strong familial aggregation of T2DM in some Indian communities remains to be explained. Many of the traditional risk factors established for European populations do not appear to be present in Asian Indians. Phase I of the Sikh Diabetes Study (SDS) was launched to build the population resources required to initiate a large-scale genetic epidemiological study of diabetes in an Asian Indian population. The SDS is focused on the Khatri Sikh population of North India. In all, 1,892 subjects were enrolled to participate in the family-based study; 1,623 of these subjects belong to 324 families, each of which has at least 2 siblings affected with T2DM. The sample included 1,288 individuals affected with T2DM (siblings, parents, or relatives) and 335 unaffected siblings, parents, or relatives. The remaining 269 subjects were unrelated nondiabetic control subjects, including unaffected spouses of probands or siblings. This primarily nonvegetarian, nonsmoking endogamous caste group has presented an unusual clinical picture of uneven distribution of adiposity and a high rate of T2DM with secondary complications. Such well-characterized population isolates may offer unique advantages in mapping genes for common complex diseases.
TL;DR: It is shown that these three populations are similar in their internal genetic characteristics, as revealed by analyses of mtDNA and Y-chromosome STR diversity, and that these populations are related through their maternal lineage in a stronger way than through their paternal lineage, as indicated by shared haplotypes and polymorphisms.
Abstract: Two hundred seventeen male subjects from Costa Rica, Mexico, and the Hispanic population of the southwestern United States were studied. Twelve Y-chromosome STRs and the HVSI sequence of the mtDNA were analyzed to describe their genetic structure and to compare maternal and paternal lineages. All subjects are part of two NIMH-funded studies to localize schizophrenia susceptibility genes in Hispanic populations of Mexican and Central American ancestry. We showed that these three populations are similar in their internal genetic characteristics, as revealed by analyses of mtDNA and Y-chromosome STR diversity. These populations are related through their maternal lineage in a stronger way than through their paternal lineage, because a higher number of shared haplotypes and polymorphisms are seen in the mtDNA (compared to Y-chromosome STRs). These results provide evidence of previous contact between the three populations and shared histories. An analysis of molecular variance revealed no genetic differentiation for the mtDNA for the three populations, but differentiation was detected in the Y-chromosome STRs. Genetic distance analysis showed that the three populations are closely related, probably as a result of migration between close neighbors, as indicated by shared haplotypes and their demographic histories. This relationship could be an important common feature for genetic studies in Latin American and Hispanic populations.
TL;DR: An approach for collecting pedigree data in stable isolate populations is outlined and the pedigree for the Jirel population, which was obtained using the methods presented, is described.
Abstract: Pedigree data are useful for a wealth of research purposes in human population biology and genetics. The collection of extended pedigrees represents the most powerful sampling design for quantitative genetic and linkage studies of both normal and disease-related quantitative traits. In this paper we outline an approach for collecting pedigree data in stable isolate populations. As an example, the pedigree for the Jirel population, which was obtained using the methods presented, is described. The Jirel pedigree contains 2,000 study participants and more than 62,000 pairwise relationships that are informative for genetic analysis. Once such pedigrees are genetically characterized by a genome scan for a given trait, they become an invaluable resource for future genetic studies of any quantitative trait.
TL;DR: The results of the analysis of variance showed that monthly household income, birth order, and number of siblings had significant effects on anthropometric variables, indicating differences in adult body dimensions, the adiposity index, and body composition in relation to income.
Abstract: The purpose of the present cross-sectional study was to examine the relationship and effect of monthly household income, birth order, and number of siblings on adult body dimensions, adiposity index, and body composition among adult Bengali females. One hundred seventy-one adult Bengali females, age 20.35 ±1.51 years (mean ±SD; range: 18–21 years) from Kolkata (formerly Calcutta) were studied. Anthropometric measures (weight, height, waist circumference, hip circumference, and triceps, biceps, subscapular, suprailiac, and medial calf skinfold thicknesses) were taken from all participants using standard protocols. BMI and log10 of the sum of the five skinfold thicknesses were computed subsequently. Percentage of body fat was estimated from the triceps skinfold thickness following the equation of Durnin and Womersley (1974), and fat mass was then calculated. Results of the correlation analysis revealed that monthly household income had significant (p < 0.05) positive association with all anthropome...
TL;DR: In Iberia there is a gradient of decreasing frequencies in latitude for both subhaplotypes Va and Vb, related to eight centuries of Muslim domination in southern IberIA.
Abstract: We have analyzed Y-chromosome diversity in the western Mediterranean area, examining p49a,f TaqI haplotype V and subhaplotypes Vb (Berber) and Va (Arab). A total of 2,196 unrelated DNA samples, belonging to 22 populations from North Africa and the southern Mediterranean coast of occidental Europe, have been typed. Subhaplotype Vb, predominant in a Berber population of Morocco (63.5%), was also found at high frequencies in southern Portugal (35.9%) and Andalusia (25.4%). The Arab subhaplotype Va, predominant in Algeria (53.9%) and Tunisia (50.6%), was also found at a relatively high frequency in Sicily (23.1%) and Naples (16.4%); its highest frequency in Iberia was in northern Portugal (22.8%) and Andalusia (15.5%). In Iberia there is a gradient of decreasing frequencies in latitude for both subhaplotypes Va and Vb, related to eight centuries of Muslim domination (8th to 15th centuries) in southern Iberia.
TL;DR: The reduced genetic diversity and a high genetic differentiation in the Rhaetoroman- and German-speaking South Tyrolean populations may constitute an important basis for future medical genetic research and gene mapping studies in South Tyrol.
Abstract: Most of the inhabitants of South Tyrol in the eastern Italian Alps can be considered isolated populations because of their physical separation by mountain barriers and their sociocultural heritage. We analyzed the genetic structure of South Tyrolean populations using three types of genetic markers: Y-chromosome, mitochondrial DNA (mtDNA), and autosomal Alu markers. Using random samples taken from the populations of Val Venosta, Val Pusteria, Val Isarco, Val Badia, and Val Gardena, we calculated genetic diversity within and among the populations. Microsatellite diversity and unique event polymorphism diversity (on the Y chromosome) were substantially lower in the Ladin-speaking population of Val Badia compared to the neighboring German-speaking populations. In contrast, the genetic diversity of mtDNA haplotypes was lowest for the upper Val Venosta and Val Pusteria. These data suggest a low effective population size, or little admixture, for the gene pool of the Ladin-speaking population from Val Badia. Interestingly, this is more pronounced for Ladin males than for Ladin females. For the pattern of genetic Alu variation, both Ladin samples (Val Gardena and Val Badia) are among the samples with the lowest diversity. An admixture analysis of one German-speaking valley (Val Venosta) indicates a relatively high genetic contribution of Ladin origin. The reduced genetic diversity and a high genetic differentiation in the Rhaetoroman- and German-speaking South Tyrolean populations may constitute an important basis for future medical genetic research and gene mapping studies in South Tyrol.
TL;DR: A probable application of HP in human population genetics appears legitimate as it was present only in Africans and Europeans, whereas HP*del was unique to Chinese.
Abstract: We investigated the distribution of haptoglobin (HP) alleles and haplotypes among Africans (Ghanaians), Europeans (from South Africa), and Chinese. HP*1F was present only in Africans and Europeans, whereas HP*del was unique to Chinese. Six base substitutions at the promoter region were population specific. Only 3 out of 18 haplotypes were shared among the populations. A probable application of HP in human population genetics appears legitimate.
TL;DR: A replication study in a Mexican American cohort where the original linkage signal was first detected finds significant associations between UBL5 genetic variants and waist-to-hip ratio, and the circulating concentrations of insulin and total cholesterol in fasted individuals.
Abstract: The BEACON gene was initially identified using the differential display polymerase chain reaction on hypothalamic mRNA samples collected from lean and obese Psammomys obesus, a polygenic animal model of obesity. Hypothalamic BEACON gene expression was positively correlated with percentage of body fat, and intracerebroventricular infusion of the Beacon protein resulted in a dose-dependent increase in food intake and body weight. The human homolog of BEACON, UBL5, is located on chromosome 19p in a region previously linked to quantitative traits related to obesity. Our previous studies showed a statistically significant association between UBL5 sequence variation and several obesity- and diabetes-related quantitative physiological measures in Asian Indian and Micronesian cohorts. Here we undertake a replication study in a Mexican American cohort where the original linkage signal was first detected. We exhaustively resequenced the complete gene plus the putative promoter region for genetic variation in 55 individuals and identified five single nucleotide polymorphisms (SNPs), one of which was novel. These SNPs were genotyped in a Mexican American cohort of 900 individuals from 40 families. Using a quantitative trait linkage disequilibrium test, we found significant associations between UBL5 genetic variants and waist-to-hip ratio (p = 0.027), and the circulating concentrations of insulin (p = 0.018) and total cholesterol (p = 0.023) in fasted individuals. These data are consistent with our earlier published studies and further support a functional role for the UBL5 gene in influencing physiological traits that underpin the development of metabolic syndrome.
TL;DR: It is found that a strong role for the EPHX1 polymorphisms in respiratory disease is unlikely, and doubt shed on the accuracy of other studies that have demonstrated positive associations is suggested.
Abstract: Microsomal epoxide hydrolase (EPHX1) is an important gene because of its role in the metabolism of components of cigarette smoke; thus it may be an important potential modifier of the risk of developing smoking-related lung disease, such as chronic obstructive pulmonary disease (COPD). Several studies have investigated EPHX1 and COPD, but some of these studies have potentially been affected by genotyping error. We investigated the influence of single nucleotide polymorphisms (SNPs) in EPHX1 on well-characterized COPD and intermediate phenotypes. A total of 1,232 participants completed a detailed respiratory questionnaire and spirometry. From this sample, 72 COPD cases (FEV1/FVC < 0.70 and FEV1 < 80% predicted) and 220 control subjects (no respiratory symptoms and normal lung function) were selected for analysis. The EPHX1 exon 3 and EPHX1 exon 4 polymorphisms were carefully genotyped to avoid error using several methods. We found that the EPHX1 exon 3 polymorphism was not associated with an increased risk of COPD, nor was the EPHX1 exon 4 polymorphism. In addition, none of the EPHX1 haplotypes were associated with an increased risk of any COPD phenotype. This finding, along with doubt shed on the accuracy of other studies that have demonstrated positive associations, suggests that a strong role for the EPHX1 polymorphisms in respiratory disease is unlikely.
TL;DR: Results suggest that a QTL on chromosome 12q23–q24 influences the variation of plasma TG and HDL-C levels, and a bivariate multipoint linkage analysis with 654 polymorphic markers in 99 white and 101 black families showed that TG, LDL-C, and IGF1 are significantly associated.
Abstract: To determine whether a common quantitative trait locus (QTL) influences the variation of fasting triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) levels, we used a bivariate multipoint linkage analysis with 654 polymorphic markers in 99 white and 101 black families. The phenotypes were investigated under two conditions: at baseline and after a 20-week exercise training intervention. A maximum genome-wide bivariate LOD score of 3.0 (p = 0.00010) was found on chromosome 12q23-q24, located within the IGF1 gene (insulin-like growth factor 1, at 107 cM) for TG and HDL-C at baseline in whites. This bivariate linkage peak is considerably higher than the univariate linkage results at the same chromosome location for either trait (for TG, LOD = 2.07, p = 0.00108; for HDL-C, LOD = 2.04, p = 0.00101). The genetic correlations between baseline TG and HDL-C levels were -0.14 for the residual and -0.33 for the QTL components. Moreover, association analysis showed that TG, HDL-C, and IGF1 are significantly associated (p = 0.04). In conclusion, these results suggest that a QTL on chromosome 12q23-q24 influences the variation of plasma TG and HDL-C levels. Further investigation should confirm whether IGF1 or another nearby gene is responsible for the concomitant variation in TG and HDL-C levels.
TL;DR: Neighbor-joining trees and multidimensional-scaling plots of DA genetic distances indicate that the Vizcayan Basques are an outlier relative to both neighboring Iberians and North African populations.
Abstract: We have characterized 68 unrelated Basque individuals from Vizcaya, Spain, for 13 tetrameric short tandem repeat (STR) loci: CSF1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, FGA, TH01, TPOX, and VWA. Interpopulational analyses were also performed for 21 European and North African population data sets for nine of the STRs typed in the Basque sample. Heterozygosity values for the Vizcayan Basques were found to be high, ranging from 0.662 to 0.882, and none of the STR loci significantly deviated from Hardy-Weinberg equilibrium. Based on the comparative population data set, the average GST score is 0.7%, indicating a low degree of genetic differentiation. However, neighbor-joining trees and multidimensional-scaling plots of DA genetic distances indicate that the Vizcayan Basques are an outlier relative to both neighboring Iberians and North African populations.
TL;DR: The authors compared the serological phenotypic frequencies of ABO, MNSs, and Duffy in 417 blood donors and 309 malaria patients from four Brazilian Amazon areas and found no correlation between ABO phenotype and malaria infection in all areas studied.
Abstract: We compared the serological phenotypic frequencies of ABO, MNSs, and Duffy in 417 blood donors and 309 malaria patients from four Brazilian Amazon areas. Our results suggest no correlation between ABO phenotype and malaria infection in all areas studied. We observed significant correlation between the S+s+, S+s−, and S−s+ phenotypes and malaria infection in three areas. Some of the Duffy phenotypes showed significant correlation between donors and malaria patients in different areas. These data are an additional contribution to the establishment of differential host susceptibility to malaria.
TL;DR: The exceptional combination of various artifacts and the mitochondrial DNA data extracted from the bone remains of the Pokrovsk man might prove the existence of previous contacts between autochthonous hunters of Oriental Siberia and the nomadic horse breeders from the Altai-Baikal area (Mongolia and Buryatia).
Abstract: The Yakuts, Middle Age Turkic speakers (15th–16th centuries), are widely accepted as the first settlers of the Altai-Baikal area in eastern Siberia. They are supposed to have introduced horses and developed metallurgy in this geographic area during the 15th or 16th century a.d. The analysis of the Siberian grave of Pokrovsk, recently discovered near the Lena River (61°29′ N) and dated by accelerator mass spectrometry from 2,400 to 2,200 years b.p., may provide new elements to test this hypothesis. The exceptional combination of various artifacts and the mitochondrial DNA data extracted from the bone remains of the Pokrovsk man might prove the existence of previous contacts between autochthonous hunters of Oriental Siberia and the nomadic horse breeders from the Altai-Baikal area (Mongolia and Buryatia). Indeed, the stone arrowhead and the harpoons relate this Pokrovsk man to the traditional hunters of the Taiga. Some artifacts made of horse bone and the pieces of armor, however, are related to th...
TL;DR: The chi-square test indicated significant deviation from Hardy-Weinberg equilibrium, suggesting high heterogeneity among the tribes, and blood group AB was found to be the least frequent group in all three studied populations.
Abstract: We studied the distribution of ABO blood groups among three little known subtribes of the Adi tribe, namely, the Panggi, Komkar, and Padam, of the East and Upper Siang districts of Arunachal Pradesh, India. Blood group O was the predominant group in the Komkar and Padam, whereas group A was the predominant group in the Panggi. Blood group AB was found to be the least frequent group in all three studied populations. The populations showed significant differences in blood groups A (43% in Panggi, 23% in Komkar, and 18% in Padam) and O (33% in Panggi, 54% in Komkar, and 61% in Padam). The chi-square test indicated significant deviation from Hardy-Weinberg equilibrium, suggesting high heterogeneity among the tribes.
TL;DR: The most striking finding is the high frequency among the Mbyá-Guaraní of Q3 lineages with the usually rare alleles DYS391*11 and DYS393*11, which could be the result of a founder effect, given the recent history of the population.
Abstract: To assess the paternal history of the Mbya-Guarani Amerindians of northeast Argentina, we examined the genetic variation in seven Y-chromosome loci: the binary marker M3 at locus DYS199, and six short tandem repeats (DYS19, DYS389I, DYS389II, DYS390, DYS391, and DYS393). The most striking finding is the high frequency among the Mbya-Guarani of Q3 lineages with the usually rare alleles DYS391*11 and DYS393*11, which could be the result of a founder effect, given the recent history of the population.
TL;DR: During early adulthood, when articular cartilage is healthy and at its peak thickness, men have thicker knee cartilage than women, and at this young age body size accounts for a modest proportion of the variation observed in knee Cartilage thickness.
Abstract: The primary objective of this study was to characterize normal variation in radiographic joint space of the knee in a large sample of healthy young adults and to identify factors that contribute to this variation. We measured radiographic knee joint space in 279 skeletally mature subjects, age between 16 and 22 years, who participated in the Fels Longitudinal Study. Minimum joint space was measured in the medial and lateral knee compartments. Independent sample t tests and correlation analyses were performed to examine sex differences and associations between joint space, joint size, and body size [weight, stature, body mass index (BMI)]. Results show that young men have thicker articular cartilage than young women in both the medial and lateral compartments of the knee. Significant positive correlations were found between joint space and body size measures in the total sample. When the sexes were considered independently, however, correlations between joint space and body size were significant in men only. Regression analyses of the combined-sex sample identified sex, BMI, and joint width as significant explanatory factors of medial joint space, together accounting for 26% of the observed variance. In contrast, sex was the sole significant explanatory factor of lateral joint space, explaining 19% of the observed variance. Results of this study show that during early adulthood, when articular cartilage is healthy and at its peak thickness, men have thicker knee cartilage than women. At this young age body size accounts for a modest proportion of the variation observed in knee cartilage thickness.
TL;DR: The results suggest that polymorphisms in the TAFi structural gene or its nearby regulatory elements may contribute strongly to TAFI level variation in the general population, although several genes in other regions of the genome may also influence variation in this phenotype.
Abstract: When activated, thrombin activatable fibrinolysis inhibitor (TAFI) inhibits fibrinolysis by modifying fibrin, depressing its plasminogen binding potential. Polymorphisms in the TAFI structural gene (CPB2) have been associated with variation in TAFI levels, but the potential occurrence of influential quantitative trait loci (QTLs) located elsewhere in the genome has been explored only in families ascertained in part through probands affected by thrombosis. We report the results of the first genome-wide linkage screen for QTLs that influence TAFI phenotypes. Data are from 635 subjects from 21 randomly ascertained Mexican American families participating in the San Antonio Family Heart Study. Potential QTLs were localized through a genome-wide multipoint linkage scan using 417 highly informative autosomal short tandem repeat markers spaced at approximately 10-cM intervals. We observed a maximum multipoint LOD score of 3.09 on chromosome 13q, the region of the TAFI structural gene. A suggestive linkage signal (LOD = 2.04) also was observed in this region, but may be an artifact. In addition, weak evidence for linkage occurred on chromosomes 17p and 9q. Our results suggest that polymorphisms in the TAFI structural gene or its nearby regulatory elements may contribute strongly to TAFI level variation in the general population, although several genes in other regions of the genome may also influence variation in this phenotype. Our findings support those of the Genetic Analysis of Idiopathic Thrombophilia (GAIT) project, which identified a potential TAFI QTL on chromosome 13q in a genome-wide linkage scan in Spanish thrombophilia families.
TL;DR: Analysis of the GM system has shown that the Andalusian population from Huelva, as a result of its complex history, is not simply an outstanding part of the Mediterranean world but rather the genetic center of gravity of that world.
Abstract: An understanding of population relationships in the Mediterranean region is crucial to the reconstruction of recent human evolution. Andalusia, the most southern region of Spain, has been continuously and densely occupied since ancient times and has a rich history of contacts with many different Mediterranean populations. Thus, to understand the Mediterranean peopling process, investigators should analyze the population relationships between the Iberian peninsula and northern Africa based on an assessment of genetic diversity that takes Andalusia into consideration. The aim of this study was to address the extent of genetic variation in the Iberian peninsula between its geographic extremes (Huelva and the Basque area) and to explain the intensity of the phylogenetic relationships between Andalusians and other neighboring populations, such as those from North Africa. We present, for the first time, results on allotype markers (GM and KM) of human immunoglobulins in the Andalusian population from Huelva. The most frequent GM haplotypes in Andalusia correspond to those that are also the most common in Europe. A sub-Saharan haplotype was found at a relatively high frequency compared to other Iberian samples, and a North Asian marker did not reach polymorphic frequencies in the study sample. A hierarchical cluster analysis based on the first two principal components (94.1% of the total genetic variance) revealed an interesting geographic structure for the 49 populations selected from the literature. The Huelva sample showed a central position in the multivariate space--despite being geographically located at one of the extremes of the Mediterranean basin--and clustered with most Western European populations. Western Europe and Eastern Europe (the latter group paradoxically including Italy and the major islands of the western Mediterranean) were differentiated. North African populations were grouped in two clusters that did not separate either Arabs and Berbers or their present-day countries. Analysis of immunoglobulin allotype markers shows that gene flow among human populations should generally be interpreted in terms of complex patterns, with the observed frequencies being the consequence of the entire genetic and demographic history of the population. Single historical events rarely determine gene frequencies in large human populations. Analysis of the GM system has shown that the Andalusian population from Huelva, as a result of its complex history, is not simply an outstanding part of the Mediterranean world but rather the genetic center of gravity of that world.
TL;DR: The present results support the hypothesis that both types of asymmetry have a genetic basis and are influenced by the intrauterine environment.
Abstract: In this study of the genetics of dermatoglyphic asymmetry, we collected bilateral finger and palm prints of 824 individuals from 200 families including 2 generations from an endogamous caste (Vaidya) in Barasat, North 24-Parganas District, West Bengal. Two main types of asymmetry (fluctuating asymmetry and directional asymmetry) were calculated between the two hands. The study includes familial correlation between first-degree relatives, principal-components analysis, and maximum-likelihood-based heritabilities (by pedigree analysis). We found, first, that familial correlations in all possible pairs of relationships (except spouse correlation) were weak but positive; some were even statistically significant. No indication of assortative mating was observed, but the influence of maternal environment could not be discarded. The results also showed that X-chromosome linkage does not seem to be involved. A second major finding is that five principal factors could be extracted from all these asymmetric traits, explaining 74.207% of the overall cumulative variance. Asymmetry of finger and palmar areas were clearly separated by factor. In addition, the heritabilities of the extracted five factors were in the range of 8-24%. These estimates are in agreement with some previously published data. The heritabilities of the factors describing palmar asymmetry are slightly lower than those describing finger asymmetry. The present results support the hypothesis that both types of asymmetry have a genetic basis and are influenced by the intrauterine environment.