High frequencies and grade expressions of Carabelli's trait in a sample of the Croatian population

Although it is generally accepted that Europeans exhibit the highest frequencies of Carabelli's trait (70-90%), these values represent the expression of all possible morphological grades. When only a well-defined trait expression is considered (grades 5th, 6th and 7th), the frequency is much lower, not more than 19.2% for the 5th grade, and significantly less for the 6th and 7th grades. Our observations based on the study of the Croatian (Central European) populations show the highest frequencies for grade of the trait (exceeding 23%). Comparative data for European or European derived populations demonstrate significant variation in grade expression. While the previously published data suggest that the highest grade of the trait expression does not exceed 10%, our figures show the highest yet known frequency of a well-defined trait.     

Canine root development and morphology inMacaca nemestrina

Recently,Yoshikawa andDeguchi (1992) reported an unusually high frequency (40%) of two-rooted maxillary canines inMacaca fuscata females and a complete absence of this trait in males. In the present study, canine root development and morphology was examined using cephalographs taken on 50 male and 50 femaleMacaca nemestrina, and 20 male and 20 femalePapio cynocephalus for comparison with the Japanese macaque. The results showed no double-rooted canines present in either species in the upper or lower canines. This supports the general rule that, among primates, canines possess a single-root. It was further suggested that the two-rooted canines inM. fuscata may be the result of the founder effect, i.e. that the genes for this trait may have been carried by the initial populations when they arrived on the islands sometime during the middle to late Pleistocene.     

African DNA lineages in mitochondrial gene pool of Europeans

Mitochondrial DNA (mtDNA) nucleotide sequences of African origin have been found at low frequency (1%, in average) in different European populations. In the present study, data on mtDNA variability in populations of Eurasia and Africa are analyzed and search of African-specific lineages present in Europeans is conducted. The results of analysis indicate that, despite a high diversity of African mtDNA haplotypes found in Europeans, monophyletic clusters of African mtDNA lineages, arisen in Europe and characterized by long-term diversity, are nearly absent in Europe. Only two respective clusters (belonging to haplogroups L1b and L3b), which evolutionary age does not exceed 6.5 thousands years, were revealed. Comparative analysis of distribution of frequencies of autosomal microsatellite alleles found in Russian individuals, carrying the African-specific mitochondrial haplotypes, in populations of Europe and Africa has indicated that autosomal genotypes of those Russian individuals are characterized by the presence of alleles characteristic mostly for Europeans.     

Crown dimensions of deciduous teeth from prehistoric India

Mean mesiodistal and buccolingual diameters are presented for deciduous teeth from the important Chalcolithic site of Inamgaon (1400–700 B.C.), a prehistoric farming community on the Deccan Plateau of western India. The deciduous teeth from Inamgaon are consistently larger than deciduous teeth of modern populations of European descent and smaller than the deciduous teeth of modern Australian aboriginals. Comparative data for prehistoric deciduous teeth are rare, especially for populations of southern Asia. The deciduous teeth of Mesolithic Europeans are comparable in size to certain dimensions of the Inamgaon teeth, and a small sample of deciduous teeth from the Iron Age site of Pomparippu (Sri Lanka) exhibits larger anterior teeth and smaller molar teeth than does the sample from Inamgaon.     

Phosphoglycolate phosphatase in several population groups in Israel

The genetic polymorphism of phosphoglycolate phosphatase (PGP) found in red blood cells has been investigated in several population groups in Israel: Ashkenazi Jews, non-Ashkenazi Jews from Iraq, Yemen, Turkey, Iran, Balkan, North Africa and Arabs. The distribution of the PGP genes was not homogeneous (chi 2 = 40.545; d.f. = 20; p less than 0.005). The PGP2 gene frequency varied between 0.0185 in the Yemenite and 0.0688 in the Iranian Jews. PGP3 gene frequency ranged between 0.0062 in the Iranian and 0.0547 in the Moroccan Jews. Depsite this heterogeneity all the Israeli population groups showed some unifying characteristics which differentiated them from a random European population sample, namely higher frequencies of PGP1 gene (92-97% as opposed to 82% in th European sample) and lower frequencies of PGP2 gene (1.8-6.8% compared to 12.9% among Europeans).     

G-6-PD polymorphism and racial admixture in the Cuban population

Summary Esterase D phenotypes were determined in 1082 non-related individuals from the western region of Germany by agarose-gel electrophoresis. Gene frequencies were compared with previous data and all European populations studied so far agreed with the Hardy-Weinberg equilibrium. Mean gene frequencies for Europeans are: EsD ¹ 0.8888, EsD ² 0.1112.     

Biological relationships derived from morphology of permanent teeth: recent evidence from prehistoric India

Morphological variation in permanent teeth of prehistoric populations yields clues to their relationships with other prehistoric and living people. This paper documents variation in fourteen variants of the permanent tooth crown for the late Chalcolithic skeletal series from Inamgaon (1600-700 BC), an early farming settlement in western India. In comparison of the dental morphology profile at Inamgaon with American Indians and American Whites, the people of Inamgaon were found to more closely resemble American Whites. However, specific traits deviated in the direction of Amerindian dental trait frequencies, suggesting gene flow from north and east Asian populations. The dental morphology of the Inamgaon sample is similar to dental patterns characteristic of prehistoric Pakistani samples from Sarai Khola and Timargarha. However, Inamgaon and Timargarha exhibit somewhat more complex crown morphology than the Sarai Khola sample, suggesting a closer relationship between them and greater antiquity of residence in the subcontinent, in contrast to Sarai Khola sample.     

Enamel and dentine dimensions of the Pleistocene hominins from Atapuerca (Burgos,Spain): A comparative study of canine teeth

Enamel and dentin patterns have awakened a considerable interest in phylogenetic studies. However, almost nothing is known about the dental tissue proportions of European Pleistocene hominins, apart from Neanderthal populations. This study aims to assess the three-dimensional dental tissue proportions of permanent canines belonging to the extensive sample of hominin teeth at Sierra de Atapuerca (Spain) through the use of microtomographic techniques. Our results show that early and middle Pleistocene populations from Atapuerca exhibit large coronal and root dentine dimensions, as well as a thinly enamelled pattern, which has been traditionally considered an autapomorphic Neanderthal trait. Therefore, these results might support an early enamel thickness decrease which is already observed 800 kyr ago in Homo antecessor and maintained in later groups such as Sima de los Huesos and Neanderthal populations during the middle Pleistocene.     

Genome-wide SNP typing reveals signatures of population history

Single-nucleotide polymorphism (SNP) arrays have become a popular technology for disease-association studies, but they also have potential for studying the genetic differentiation of human populations. Application of the Affymetrix GeneChip Human Mapping 500K Array Set to a population of 102 individuals representing the major ethnic groups in the United States (African, Asian, European, and Hispanic) revealed patterns of gene diversity and genetic distance that reflected population history. We analyzed allelic frequencies at 388,654 autosomal SNP sites that showed some variation in our study population and 10% or fewer missing values. Despite the small size (23-31 individuals) of each subpopulation, there were no fixed differences at any site between any two subpopulations. As expected from the African origin of modern humans, greater gene diversity was seen in Africans than in either Asians or Europeans, and the genetic distance between the Asian and the European populations was significantly lower than that between either of these two populations and Africans. Principal components analysis applied to a correlation matrix among individuals was able to separate completely the major continental groups of humans (Africans, Asians, and Europeans), while Hispanics overlapped all three of these groups. Genes containing two or more markers with extraordinarily high genetic distance between subpopulations were identified as candidate genes for health differences between subpopulations. The results show that, even with modest sample sizes, genome-wide SNP genotyping technologies have great promise for capturing signatures of gene frequency difference between human subpopulations, with applications in areas as diverse as forensics and the study of ethnic health disparities.     

Common Variants in the Trichohyalin Gene Are Associated with Straight Hair in Europeans

Hair morphology is highly differentiated between populations and among people of European ancestry. Whereas hair morphology in East Asian populations has been studied extensively, relatively little is known about the genetics of this trait in Europeans. We performed a genome-wide association scan for hair morphology (straight, wavy, curly) in three Australian samples of European descent. All three samples showed evidence of association implicating the Trichohyalin gene (TCHH), which is expressed in the developing inner root sheath of the hair follicle, and explaining ∼6% of variance (p = 1.5 × 10⁻³¹). These variants are at their highest frequency in Northern Europeans, paralleling the distribution of the straight-hair EDAR variant in Asian populations.     

Microevolution of African American dental morphology

The African American (AA) gene pool is primarily the result of gene flow between two biologically disparate groups: West Africans (WA) and Americans of western European descent (EA). This research utilizes characteristics of dental morphology to trace genetic relationships among WA, western Europeans (EU), AA, and European Americans. Dental morphological traits are useful for this purpose because they are heritable, do not remodel during life (although they can be lost to wear or pathology), and can be compared equally among samples from past and present populations. The results of this research provide new information about human microevolution through time and space in a biocultural setting. The mean measure of divergence is used to analyze dental morphological data from 1,265 individuals in 25 samples grouped by ancestry and time. Three hypotheses associated with admixture in AA are tested. When compared with known history, results from dental morphological data are equivocal in documenting admixture in AA. Dental morphological traits do appear to reflect admixture in AA. However, changes in trait frequencies do not closely correspond with important cultural events and trends such as the institutionalized racism of the Civil War and Jim Crow era. Results are mixed concerning whether AA with greater admixture were more likely to take part in the Great Migration to southern urban centers and to the North.     

Interaction between ABO and haptoglobin systems in a Bengalee population.

Blood samples from 2,232 individuals of a Bengalee Caste Hindu population were investigated in an attempt to confirm the association between the ABO and haptoglobin (HP) systems previously found in populations of European origin. Indians differ from Europeans in having lower HP*1 and higher ABO*B frequencies. In spite of this, as in previous studies, a weak HP/ABO association was found with a significantly lower HP*1 allele frequency in blood group O versus other ABO groups.     

Genome-wide Characterization of Shared and Distinct Genetic Components that Influence Blood Lipid Levels in Ethnically Diverse Human Populations

Blood lipid concentrations are heritable risk factors associated with atherosclerosis and cardiovascular diseases. Lipid traits exhibit considerable variation among populations of distinct ancestral origin as well as between individuals within a population. We performed association analyses to identify genetic loci influencing lipid concentrations in African American and Hispanic American women in the Women’s Health Initiative SNP Health Association Resource. We validated one African-specific high-density lipoprotein cholesterol locus at CD36 as well as 14 known lipid loci that have been previously implicated in studies of European populations. Moreover, we demonstrate striking similarities in genetic architecture (loci influencing the trait, direction and magnitude of genetic effects, and proportions of phenotypic variation explained) of lipid traits across populations. In particular, we found that a disproportionate fraction of lipid variation in African Americans and Hispanic Americans can be attributed to genomic loci exhibiting statistical evidence of association in Europeans, even though the precise genes and variants remain unknown. At the same time, we found substantial allelic heterogeneity within shared loci, characterized both by population-specific rare variants and variants shared among multiple populations that occur at disparate frequencies. The allelic heterogeneity emphasizes the importance of including diverse populations in future genetic association studies of complex traits such as lipids; furthermore, the overlap in lipid loci across populations of diverse ancestral origin argues that additional knowledge can be gleaned from multiple populations.     

Paternal European ancestry in French Polynesia detected by Y-chromosome haplotypes

Y-chromosome-specific polymorphisms p49f-a/TaqI were studied in a sample of 68 French Polynesians, and five haplotypes were observed. Three of them were haplotypes characteristic of European ancestry. The mean haplotype (45.6%) in French Polynesia is haplotype XV, a typical western European haplotype. Such an elevated frequency of European haplotypes is due to male gene flow from Europeans in French Polynesia.     

Herders of Indian and European cattle share their predominant allele for lactase persistence

Milk consumption and lactose digestion after weaning are exclusively human traits made possible by the continued production of the enzyme lactase in adulthood. Multiple independent mutations in a 100-bp region--part of an enhancer--approximately 14-kb upstream of the LCT gene are associated with this trait in Europeans and pastoralists from Saudi Arabia and Africa. However, a single mutation of purported western Eurasian origin accounts for much of observed lactase persistence outside Africa. Given the high levels of present-day milk consumption in India, together with archaeological and genetic evidence for the independent domestication of cattle in the Indus valley roughly 7,000 years ago, we sought to determine whether lactase persistence has evolved independently in the subcontinent. Here, we present the results of the first comprehensive survey of the LCT enhancer region in south Asia. Having genotyped 2,284 DNA samples from across the Indian subcontinent, we find that the previously described west Eurasian -13910 C>T mutation accounts for nearly all the genetic variation we observed in the 400- to 700-bp LCT regulatory region that we sequenced. Geography is a significant predictor of -13910*T allele frequency, and consistent with other genomic loci, its distribution in India follows a general northwest to southeast declining pattern, although frequencies among certain neighboring populations vary substantially. We confirm that the mutation is identical by descent to the European allele and is associated with the same>1 Mb extended haplotype in both populations.     

Acid phosphatase, adenosine deaminase and esterase D polymorphisms in the Spanish Basque population.

The 3 red-cell polymorphic systems acid phosphatase (ACP), adenosine deaminase (ADA) and esterase D (ESD) have been studied in a random sample of 1,112 individuals from the Basque country: The allelic frequencies obtained were ACP*A = 0.275, ACP*B = 0.718 and ACP*C = 0.007; ADA*2 = 0.021, and, ESD*2 = 0.066. The allelic frequencies have been compared with those of other Basque and other European populations. In comparison with Basques, significant differences were detected only for ACP, whereas as regards other Europeans significant differences were obtained with practically all the populations compared for the 3 genetic systems studied. The low values of the less frequent alleles, especially that for the ACP*C allele which is the lowest reported in Europe, are noteworthy.     

High Trans-ethnic Replicability of GWAS Results Implies Common Causal Variants

Genome-wide association studies (GWAS) have detected many disease associations. However, the reported variants tend to explain small fractions of risk, and there are doubts about issues such as the portability of findings over different ethnic groups or the relative roles of rare versus common variants in the genetic architecture of complex disease. Studying the degree of sharing of disease-associated variants across populations can help in solving these issues. We present a comprehensive survey of GWAS replicability across 28 diseases. Most loci and SNPs discovered in Europeans for these conditions have been extensively replicated using peoples of European and East Asian ancestry, while the replication with individuals of African ancestry is much less common. We found a strong and significant correlation of Odds Ratios across Europeans and East Asians, indicating that underlying causal variants are common and shared between the two ancestries. Moreover, SNPs that failed to replicate in East Asians map into genomic regions where Linkage Disequilibrium patterns differ significantly between populations. Finally, we observed that GWAS with larger sample sizes have detected variants with weaker effects rather than with lower frequencies. Our results indicate that most GWAS results are due to common variants. In addition, the sharing of disease alleles and the high correlation in their effect sizes suggest that most of the underlying causal variants are shared between Europeans and East Asians and that they tend to map close to the associated marker SNPs.     

Nutrition and health at contact in late prehistoric central Gulf Coast Florida

This paper presents an analysis of human remains from Tatham Mound, a dual-component mortuary site from central Gulf Coast Florida. The human remains from Tatham are significant because they come from a limited time period during the initial contact with Europeans at AD 1525-1550. Dietary reconstruction demonstrates that at the time of European contact, maize was not a predominant dietary item. Low frequencies for several dental and skeletal pathological indicators are consistent with relatively good health as compared to other Southeastern late prehistoric and protohistoric populations. Despite the limited time period represented by the mound population, critical interactions occurred between Native Americans and Spaniards, as indicated by skeletal elements severed by metal weapons. The Tatham population is significant because it is one of the earliest studied populations contacted by Europeans in North America, and the only one with well-documented sharp-force trauma that represents intergroup hostility.     

The LWb blood group as a marker of prehistoric Baltic migrations and admixture.

Archaeological findings and historical records indicate frequent migrations and exchange of genetic material between populations in the Baltic Sea area. However, there have so far been very few attempts to trace migrations in this area using genetic markers. We have studied the Baltic populations with respect to exceptional variations in the frequencies of the Landsteiner-Wiener (LW) blood group. The frequency of the uncommon LWb gene was high in the Balts, around 6% among Latvians and Lithuanians, very low among the other western Europeans (0-0.1%) and apparently absent in Asiatic and African populations. From the Baltic region of peak frequency there was a regular decline of LWb incidence (a descending cline) in the neighboring populations: 4.0% in the Estonians, 2.9% in the Finns, 2. 2% in the Vologda Russians, and 2.0% in the Poles. Thus the distribution of LWb suggests considerable and extensive Baltic admixture, especially in the north and northeast direction. In Southern Sweden with an LWb frequency of 0.3%, the Baltic influence appeared slight, while in the population of the Swedish island Gotland in the middle of the Baltic Sea there was a significantly increased LWb frequency of 1.0% compared with that of Western European countries. The distinction of codominantly inherited LW antigenic forms, LWa and LWb (previously Nea), is known to be due to a single base substitution. Based on our population data, it is plausible that the expansion of this point mutation occurred only once during human history. Furthermore, our data indicate that the expansion of the LWb mutation occurred in Balts and that LWb can be considered a 'Baltic tribal marker', its presence in other populations being an indicator of the degree of Baltic genetic influence.     

Genetic admixture, relatedness, and structure patterns among Mexican populations revealed by the Y-chromosome

Y-linked markers are suitable loci to analyze genetic diversity of human populations, offering knowledge of medical, forensic, and anthropological interest. In a population sample of 206 Mestizo males from western Mexico, we analyzed two binary loci (M3 and YAP) and six Y-STRs, adding to the analysis data of Mexican Mestizos and Amerindians, and relevant worldwide populations. The paternal ancestry estimated in western Mexican-Mestizos was mainly European (60-64%), followed by Amerindian (25-21%), and African ( approximately 15%). Significant genetic heterogeneity was established between Mestizos from western (Jalisco State) and northern Mexico (Chihuahua State) compared with Mexicans from the center of the Mexican Republic (Mexico City), this attributable to higher European ancestry in western and northern than in central and southeast populations, where higher Amerindian ancestry was inferred. This genetic structure has important implications for medical and forensic purposes. Two different Pre-Hispanic evolutionary processes were evident. In Mesoamerican region, populations presented higher migration rate (N(m) = 24.76), promoting genetic homogeneity. Conversely, isolated groups from the mountains and canyons of the Western and Northern Sierra Madre (Huichols and Tarahumaras, respectively) presented a lower migration rate (N(m) = 10.27) and stronger genetic differentiation processes (founder effect and/or genetic drift), constituting a Pre-Hispanic population substructure. Additionally, Tarahumaras presented a higher frequency of Y-chromosomes without Q3 that was explained by paternal European admixture (15%) and, more interestingly, by a distinctive Native-American ancestry. In Purepechas, a special admixture process involving preferential integration of non-Purepecha women in their communities could explain contrary genetic evidences (autosomal vs. Y-chromosome) for this tribe.