Exploring Population Admixture Dynamics via Empirical and Simulated Genome-wide Distribution of Ancestral Chromosomal Segments

The processes of genetic admixture determine the haplotype structure and linkage disequilibrium patterns of the admixed population, which is important for medical and evolutionary studies. However, most previous studies do not consider the inherent complexity of admixture processes. Here we proposed two approaches to explore population admixture dynamics, and we demonstrated, by analyzing genome-wide empirical and simulated data, that the approach based on the distribution of chromosomal segments of distinct ancestry (CSDAs) was more powerful than that based on the distribution of individual ancestry proportions. Analysis of 1,890 African Americans showed that a continuous gene flow model, in which the African American population continuously received gene flow from European populations over about 14 generations, best explained the admixture dynamics of African Americans among several putative models. Interestingly, we observed that some African Americans had much more European ancestry than the simulated samples, indicating substructures of local ancestries in African Americans that could have been caused by individuals from some particular lineages having repeatedly admixed with people of European ancestry. In contrast, the admixture dynamics of Mexicans could be explained by a gradual admixture model in which the Mexican population continuously received gene flow from both European and Amerindian populations over about 24 generations. Our results also indicated that recent gene flows from Sub-Saharan Africans have contributed to the gene pool of Middle Eastern populations such as Mozabite, Bedouin, and Palestinian. In summary, this study not only provides approaches to explore population admixture dynamics, but also advances our understanding on population history of African Americans, Mexicans, and Middle Eastern populations.     

Biohistorical approaches to “race” in the United States: Biological distances among African Americans,European Americans,and their ancestors

Folk taxonomies of race are the categorizations used by people in their everyday judgments concerning the persons around them. As cultural traditions, folk taxonomies may shape gene flow so that it is unequal among groups sharing geography. The history of the United States is one of disparate people being brought together from around the globe, and provides a natural experiment for exploring the relationship between culture and gene flow. The biohistories of African Americans and European Americans were compared to examine whether population histories are shaped by culture when geography and language are shared. Dental morphological data were used to indicate phenotypic similarity, allowing diachronic change through United States history to be considered. Samples represented contemporary and historic African Americans and European Americans and their West African and European ancestral populations (N = 1445). Modified Mahalanobis' D² and Mean Measure of Divergence statistics examined how biological distances change through time among the samples. Results suggest the social acceptance for mating between descendents of Western Europeans and Eastern and Southern European migrants to the United States produced relatively rapid gene flow between the groups. Although African Americans have been in the United States much longer than most Eastern and Southern Europeans, social barriers have been historically stronger between them and European Americans. These results indicate that gene flow is in part shaped by cultural factors such as folk taxonomies of race, and have implications for understanding contemporary human variation, relationships among prehistoric populations, and forensic anthropology. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc.     

Estimating African American admixture proportions by use of population-specific alleles.

We analyzed the European genetic contribution to 10 populations of African descent in the United States (Maywood, Illinois; Detroit; New York; Philadelphia; Pittsburgh; Baltimore; Charleston, South Carolina; New Orleans; and Houston) and in Jamaica, using nine autosomal DNA markers. These markers either are population-specific or show frequency differences >45% between the parental populations and are thus especially informative for admixture. European genetic ancestry ranged from 6.8% (Jamaica) to 22.5% (New Orleans). The unique utility of these markers is reflected in the low variance associated with these admixture estimates (SEM 1.3%-2.7%). We also estimated the male and female European contribution to African Americans, on the basis of informative mtDNA (haplogroups H and L) and Y Alu polymorphic markers. Results indicate a sex-biased gene flow from Europeans, the male contribution being substantially greater than the female contribution. mtDNA haplogroups analysis shows no evidence of a significant maternal Amerindian contribution to any of the 10 populations. We detected significant nonrandom association between two markers located 22 cM apart (FY-null and AT3), most likely due to admixture linkage disequilibrium created in the interbreeding of the two parental populations. The strength of this association and the substantial genetic distance between FY and AT3 emphasize the importance of admixed populations as a useful resource for mapping traits with different prevalence in two parental populations.     

Dental morphology and ancestry in Albuquerque, New Mexico Hispanics

The term “Hispanic” groups people from Central and South America and the Caribbean, combining disparate cultures, languages, and ancestry, and masking biological differences. Historical and current admixture patterns within these populations and with indigenous and European-, African-, and/or Asian- derived populations complicate the biological picture. Although “Hispanic” has little biological meaning, it is used widely in epidemiology, disease management, and forensics as a biologically significant group. An interdisciplinary approach combining historical, cultural, and biological data can characterize regional and temporal differences between Hispanic populations.We examined biological distances with a population of central New Mexico Hispanics, as a case study of the local specificity of population history. We collected dental morphological trait frequencies from samples of recent Albuquerque-area Hispanic Americans and several ancestral and contemporary groups. To explore regional admixture patterns we calculated biological distances using the modified Mahalanobis D² statistic. Our results indicate that Albuquerque Hispanics are more similar to their European and African ancestral groups than to Native Americans in New Mexico. Additionally, their affinity to Native Americans is greater with prehistoric rather than contemporary samples. We argue that these results reflect a local rather than pan-Hispanic admixture pattern; they underscore that populations are better understood at the local and regional levels. It is undesirable to make sweeping biological generalizations for groups known to be geographically and genetically disparate. This research is part of a growing trend in biological research concerning Hispanics and other groups—an emphasis on local samples, informed by historical, cultural, and biological factors.     

Asymmetric male and female genetic histories among Native Americans from Eastern North America

Previous studies have investigated the human population history of eastern North America by examining mitochondrial DNA (mtDNA) variation among Native Americans, but these studies could only reconstruct maternal population history. To evaluate similarities and differences in the maternal and paternal population histories of this region, we obtained DNA samples from 605 individuals, representing 16 indigenous populations. After amplifying the amelogenin locus to identify males, we genotyped 8 binary polymorphisms and 10 microsatellites in the male-specific region of the Y chromosome. This analysis identified 6 haplogroups and 175 haplotypes. We found that sociocultural factors have played a more important role than language or geography in shaping the patterns of Y chromosome variation in eastern North America. Comparisons with previous mtDNA studies of the same samples demonstrate that male and female demographic histories differ substantially in this region. Postmarital residence patterns have strongly influenced genetic structure, with patrilocal and matrilocal populations showing different patterns of male and female gene flow. European contact also had a significant but sex-specific impact due to a high level of male-mediated European admixture. Finally, this study addresses long-standing questions about the history of Iroquoian populations by suggesting that the ancestral Iroquoian population lived in southeastern North America.     

Gene-Based Sequencing Identifies Lipid-Influencing Variants with Ethnicity-Specific Effects in African Americans

Although a considerable proportion of serum lipids loci identified in European ancestry individuals (EA) replicate in African Americans (AA), interethnic differences in the distribution of serum lipids suggest that some genetic determinants differ by ethnicity. We conducted a comprehensive evaluation of five lipid candidate genes to identify variants with ethnicity-specific effects. We sequenced ABCA1, LCAT, LPL, PON1, and SERPINE1 in 48 AA individuals with extreme serum lipid concentrations (high HDLC/low TG or low HDLC/high TG). Identified variants were genotyped in the full population-based sample of AA (n = 1694) and tested for an association with serum lipids. rs328 (LPL) and correlated variants were associated with higher HDLC and lower TG. Interestingly, a stronger effect was observed on a “European” vs. “African” genetic background at this locus. To investigate this effect, we evaluated the region among West Africans (WA). For TG, the effect size among WA was the same in AA with only African local ancestry (2–3% lower TG), while the larger association among AA with local European ancestry matched previous reports in EA (10%). For HDLC, there was no association with rs328 in AA with only African local ancestry or in WA, while the association among AA with European local ancestry was much greater than what has been observed for EA (15 vs. ∼5 mg/dl), suggesting an interaction with an environmental or genetic factor that differs by ethnicity. Beyond this ancestry effect, the importance of African ancestry-focused, sequence-based work was also highlighted by serum lipid associations of variants that were in higher frequency (or present only) among those of African ancestry. By beginning our study with the sequence variation present in AA individuals, investigating local ancestry effects, and seeking replication in WA, we were able to comprehensively evaluate the role of a set of candidate genes in serum lipids in AA.     

Y chromosome lineages in men of west African descent

The early African experience in the Americas is marked by the transatlantic slave trade from ～1619 to 1850 and the rise of the plantation system. The origins of enslaved Africans were largely dependent on European preferences as well as the availability of potential laborers within Africa. Rice production was a key industry of many colonial South Carolina low country plantations. Accordingly, rice plantations owners within South Carolina often requested enslaved Africans from the so-called "Grain Coast" of western Africa (Senegal to Sierra Leone). Studies on the African origins of the enslaved within other regions of the Americas have been limited. To address the issue of origins of people of African descent within the Americas and understand more about the genetic heterogeneity present within Africa and the African Diaspora, we typed Y chromosome specific markers in 1,319 men consisting of 508 west and central Africans (from 12 populations), 188 Caribbeans (from 2 islands), 532 African Americans (AAs from Washington, DC and Columbia, SC), and 91 European Americans. Principal component and admixture analyses provide support for significant Grain Coast ancestry among African American men in South Carolina. AA men from DC and the Caribbean showed a closer affinity to populations from the Bight of Biafra. Furthermore, 30-40% of the paternal lineages in African descent populations in the Americas are of European ancestry. Diverse west African ancestries and sex-biased gene flow from EAs has contributed greatly to the genetic heterogeneity of African populations throughout the Americas and has significant implications for gene mapping efforts in these populations.     

Genetic and morphological differentiation in Populus nigra L.: isolation by colonization or isolation by adaptation?

Identifying processes underlying the genetic and morphological differences among populations is a central question of evolutionary biology. Forest trees typically contain high levels of neutral genetic variation, and genetic differences are often correlated with geographic distance between populations [isolation by distance (IBD)] or are due to historic vicariance events [isolation by colonization (IBC)]. In contrast, morphological differences are largely due to local adaptation. Here, we examined genetic (microsatellite) and morphological (from a common garden experiment) variation in Populus nigra L., European black poplar, collected from 13 sites across western Europe and grown in a common garden in Belgium. Significant genetic differentiation was observed, with populations from France displaying greater admixture than the distinct Spanish and central European gene pools, consistent with previously described glacial refugia (IBC). Many quantitative traits displayed a bimodal distribution, approximately corresponding to small‐leaf and large‐leaf ecotypes. Examination of nine climatic variables revealed the sampling locations to have diverse climates, and although the correlation between morphological and climatic differences was significant, the pattern was not consistent with strict local adaptation. Partial Mantel tests based on multivariate summary statistics identified significant residual correlation in comparisons of small‐leaf to large‐leaf ecotypes, and within the small‐leaf samples, but not within large‐leaf ecotypes, indicating that variation within the small‐leaf morphotype in particular may be adaptive. Some small‐leaf populations experience climates very similar to those in large‐leaf sites. We conclude that adaptive differentiation and persistent IBC acted in combination to produce the genetic and morphological patterns observed in P. nigra.     

Admixture mapping provides evidence of association of the VNN1 gene with hypertension

Migration patterns in modern societies have created the opportunity to use population admixture as a strategy to identify susceptibility genes. To implement this strategy, we genotyped a highly informative ancestry marker panel of 2270 single nucleotide polymorphisms in a random population sample of African Americans (N = 1743), European Americans (N = 1000) and Mexican Americans (N = 581). We then examined the evidence for over-transmission of specific loci to cases from one of the two ancestral populations. Hypertension cases and controls were defined based on standard clinical criteria. Both case-only and case-control analyses were performed among African Americans. With the genome-wide markers we replicated the findings identified in our previous admixture mapping study on chromosomes 6 and 21 [1]. For case-control analysis we then genotyped 51 missense SNPs in 36 genes spaced across an 18.3 Mb region. Further analyses demonstrated that the missense SNP rs2272996 (or N131S) in the VNN1 gene was significantly associated with hypertension in African Americans and the association was replicated in Mexican Americans; a non-significant opposite association was observed in European Americans. This SNP also accounted for most of the evidence observed in the admixture analysis on chromosome 6. Despite these encouraging results, susceptibility loci for hypertension have been exceptionally difficult to localize and confirmation by independent studies will be necessary to establish these findings.     

Origins and spread of agriculture in Italy: a nonmetric dental analysis

Dental morphological traits were employed in this study as direct indicators of biological affinities among the populations that inhabited the Italian peninsula from the Upper Paleolithic-Mesolithic to Medieval times. Our analysis aims at contributing to the ongoing debate regarding the origin and spread of agriculture in the peninsula by contrasting the dental evidence of archaeological and modern molecular samples. It is not possible to generalize given the complex and dynamic nature of these populations. However, the results from the principal component analysis, maximum likelihood, mean measure of divergence, and multidimensional scaling do indicate a net separation of the Paleo-Mesolithic sample from the other groups that is not related to dental reduction. This suggests that the shift in dental morphology was the product of Neolithic populations migrating into the peninsula from other areas. Nonetheless, the Paleo-Mesolithic populations share several discriminative traits with the Neolithic group. The biological relevance of such evidence suggests that, to some minor extent, the spread of agriculture did not occur by total population replacement. Because of regional small sample sizes, this hypothesis cannot be tested on a micro-regional scale. It is, however, feasible to depict a scenario where processes of genetic mixture or replacement probably took place at different rates on a macro-regional level.     

Possible Race and Gender Divergence in Association of Genetic Variations with Plasma von Willebrand Factor: A Study of ARIC and 1000 Genome Cohorts

The synthesis, secretion and clearance of von Willebrand factor (VWF) are regulated by genetic variations in coding and promoter regions of the VWF gene. We have previously identified 19 single nucleotide polymorphisms (SNPs), primarily in introns that are associated with VWF antigen levels in subjects of European descent. In this study, we conducted race by gender analyses to compare the association of VWF SNPs with VWF antigen among 10,434 healthy Americans of European (EA) or African (AA) descent from the Atherosclerosis Risk in Communities (ARIC) study. Among 75 SNPs analyzed, 13 and 10 SNPs were associated with VWF antigen levels in EA male and EA female subjects, respectively. However, only one SNP (RS1063857) was significantly associated with VWF antigen in AA females and none was in AA males. Haplotype analysis of the ARIC samples and studying racial diversities in the VWF gene from the 1000 genomes database suggest a greater degree of variations in the VWF gene in AA subjects as compared to EA subjects. Together, these data suggest potential race and gender divergence in regulating VWF expression by genetic variations.     

Anthropometric variation among Bering Sea natives

Recent research indicates that anthropometrics can be used to study microevolutionary forces acting on humans. We examine the use of morphological traits in reconstructing the population history of Aleuts and Eskimos of the Bering Sea. From 1979 to 1981, W. S. Laughlin measured a sample of St. Lawrence Island Eskimos and Pribilof Island Aleuts. These samples included adult participants from St. George and St. Paul in the Pribilof Islands and from Gambell and Savoonga on St. Lawrence Island. The Relethford-Blangero method was used to examine the phylogenetic relationship between Aleuts and Eskimos. Anthropometric measurements for Native North Americans (measured by Boas and a team of trained anthropometrists in 1890-1904) and Native Mesoamericans (compiled from the literature for 1898-1952) were used for comparison. A principal components analysis of means for measurements and a neighbor-joining tree were constructed using Euclidean distances. All these tests revealed the same strong relationship among the focus populations. The R matrix from the Relethford-Blangero method clusters Aleuts and Eskimos separately and accounts for 97.3% of the variation in the data. Phenotypic variation within the population is minimal and therefore minimum F(ST) values are low. Genetic distances were compared to a Euclidean distance matrix of anthropometric measurements using a Mantel test and gave a high but not significant correlation. Our results provide evidence of a close phylogenetic relationship between Aleut and Eskimo populations in the Bering Sea. However, it is apparent that history has affected the relationship among the populations. Despite previous findings of higher European admixture in Gambell (based on blood group markers) than in Savoonga, Savoonga has greater within-group variation in anthropometric measurements. Anthropometrics reveal a close relationship between Gambell and St. Paul as a result of European admixture. The St. George population was the most divergent of the populations, indicating that it diverged from the Eskimos and St. Paul because of the compounding effects of genetic drift and limited European gene flow. These findings are in agreement with previous anthropometric and genetic studies of the Aleut and Eskimo populations and support the utility of anthropometrics in inferring population history and structure.     

Advances of tooth‐derived stem cells in neural diseases treatments and nerve tissue regeneration

Nerous system diseases, both central and peripheral, bring an incredible burden onto patients and enormously reduce their quality of life. Currently, there are still no effective treatments to repair nerve lesions that do not have side effects. Stem cell–based therapies, especially those using dental stem cells, bring new hope to neural diseases. Dental stem cells, derived from the neural crest, have many characteristics that are similar to neural cells, indicating that they can be an ideal source of cells for neural regeneration and repair. This review summarizes the neural traits of all the dental cell types, including DPSCs, PDLCs, DFCs, APSCs and their potential applications in nervous system diseases. We have summed up the advantages of dental stem cells in neural repair, such as their neurotrophic and neuroprotective traits, easy harvest and low rejective reaction rate, among others. Taken together, dental stem cells are an ideal cell source for neural tissue regeneration and repair.     

河北阳原姜家梁新石器时代人类牙齿形态特征的观察与研究

本文应用牙齿人类学的研究方法,对出自河北阳原姜家梁遗址的新石器时代居民的牙齿形态特征进行了研究。采用“亚利桑那州立大学牙齿人类学系统”进行牙齿形态观察,应用“平均差异度”(MMD)距离公式计算出姜家梁组与其他各对比组的MMD距离系数以估计群体间的相似程度,并根据MMD矩阵对18组人群进行聚类分析和因子分析。本文研究结果表明,姜家梁居民的牙齿形态特征属于中国型牙(Sinodonty),但自身又具有某些独特的特征,如铲形上颌中央门齿和单根上颌第一前臼齿等特征的出现率很高。综合来看,姜家梁组在铲形上颌中央门齿、双铲形上颌中央门齿、单根上颌第一前臼齿和第一臼齿转向皱纹这4项性状上具有很高的出现率;上颌第一臼齿釉质延伸、上颌第三臼齿退化、三根下颌第一臼齿和下颌第二臼齿四尖这四项性状出现率处于中等水平。与同时代的下王岗组和庙子沟组比较而言,姜家梁组与庙子沟组的关系更为密切,有研究表明姜家梁组居民与庙子沟组居民具有较为相近的头骨形态特征,本文研究结果表明两者具有较为接近的牙齿形态特征,这说明在体质特征上相近的人群在头骨形态特征和牙齿形态特征方面的表现可能较为一致,但只通过这两个对比组的比较结果而下此结论还为时过早,尚有待于积累更多的同类型族群的相关牙齿人类学资料验证之。     

A genomewide admixture mapping panel for Hispanic/Latino populations

Admixture mapping (AM) is a promising method for the identification of genetic risk factors for complex traits and diseases showing prevalence differences among populations. Efficient application of this method requires the use of a genomewide panel of ancestry-informative markers (AIMs) to infer the population of origin of chromosomal regions in admixed individuals. Genomewide AM panels with markers showing high frequency differences between West African and European populations are already available for disease-gene discovery in African Americans. However, no such a map is yet available for Hispanic/Latino populations, which are the result of two-way admixture between Native American and European populations or of three-way admixture of Native American, European, and West African populations. Here, we report a genomewide AM panel with 2,120 AIMs showing high frequency differences between Native American and European populations. The average intermarker genetic distance is ~1.7 cM. The panel was identified by genotyping, with the Affymetrix GeneChip Human Mapping 500K array, a population sample with European ancestry, a Mesoamerican sample comprising Maya and Nahua from Mexico, and a South American sample comprising Aymara/Quechua from Bolivia and Quechua from Peru. The main criteria for marker selection were both high information content for Native American/European ancestry (measured as the standardized variance of the allele frequencies, also known as "f value") and small frequency differences between the Mesoamerican and South American samples. This genomewide AM panel will make it possible to apply AM approaches in many admixed populations throughout the Americas.     

Evaluation of Group Genetic Ancestry of Populations from Philadelphia and Dakar in the Context of Sex-Biased Admixture in the Americas

Background

Population history can be reflected in group genetic ancestry, where genomic variation captured by the mitochondrial DNA (mtDNA) and non-recombining portion of the Y chromosome (NRY) can separate female- and male-specific admixture processes. Genetic ancestry may influence genetic association studies due to differences in individual admixture within recently admixed populations like African Americans.

Principal Findings

We evaluated the genetic ancestry of Senegalese as well as European Americans and African Americans from Philadelphia. Senegalese mtDNA consisted of ∼12% U haplotypes (U6 and U5b1b haplotypes, common in North Africa) while the NRY haplotypes belonged solely to haplogroup E. In Philadelphia, we observed varying degrees of admixture. While African Americans have 9–10% mtDNAs and ∼31% NRYs of European origin, these results are not mirrored in the mtDNA/NRY pools of European Americans: they have less than 7% mtDNAs and less than 2% NRYs from non-European sources. Additionally, there is <2% Native American contribution to Philadelphian African American ancestry and the admixture from combined mtDNA/NRY estimates is consistent with the admixture derived from autosomal genetic data. To further dissect these estimates, we have analyzed our samples in the context of different demographic groups in the Americas.

Conclusions

We found that sex-biased admixture in African-derived populations is present throughout the Americas, with continual influence of European males, while Native American females contribute mainly to populations of the Caribbean and South America. The high non-European female contribution to the pool of European-derived populations is consistently characteristic of Iberian colonization. These data suggest that genomic data correlate well with historical records of colonization in the Americas.     

Ancient teeth and modern human origins: an expanded comparison of African Plio-Pleistocene and recent world dental samples

Previous research by the first author revealed that, relative to other modern peoples, sub-Saharan Africans exhibit the highest frequencies of ancestral (or plesiomorphic) dental traits and, thus, appear to be least derived dentally from an ancestral hominin state. This determination, in conjunction with various other lines of dental morphological evidence, was interpreted to be supportive of an African origin for modern humans. The present investigation expands upon this work by using: 1) direct observations of fossil hominin teeth, rather than data gleaned from published sources, 2) a single morphological scoring system (the Arizona State University Dental Anthropology System) with consistent trait breakpoints, and 3) data from larger and more varied modern human comparative samples. As before, a multivariate distance statistic, the mean measure of divergence, was used to assess diachronic phenetic affinities among the Plio-Pleistocene hominins and modern humans. The present study also employed principal components analysis on dental trait frequencies across samples. Both methods yielded similar results, which support the previous findings; that is, of all modern human samples, sub-Saharan Africans again exhibit the closest phenetic similarity to various African Plio-Pleistocene hominins-through their shared prevalence of morphologically complex crown and root traits. The fact that sub-Saharan Africans express these apparently plesiomorphic characters, along with additional information on their affinity to other modern populations, evident intra-population heterogeneity, and a world-wide dental cline emanating from the sub-continent, provides further evidence that is consistent with an African origin model.     

Mitochondrial DNA (mtDNA) haplotypes reveal maternal population genetic affinities of Sea Island Gullah-speaking African Americans

To better understand the population substructure of African Americans living in coastal South Carolina, we used restriction site polymorphisms and an insertion/deletion in mitochondrial DNA (mtDNA) to construct seven-position haplotypes across 1,395 individuals from Sierra Leone, Africa, from U.S. European Americans, and from the New World African-derived populations of Jamaica, Gullah-speaking African Americans of the South Carolina Sea Islands (Gullahs), African Americans living in Charleston, South Carolina, and West Coast African Americans. Analyses showed a high degree of similarity within the New World African-derived populations, where haplotype frequencies and diversities were similar. Phi-statistics indicated that very little genetic differentiation has occurred within New World African-derived populations, but that there has been significant differentiation of these populations from Sierra Leoneans. Genetic distance estimates indicated a close relationship of Gullahs and Jamaicans with Sierra Leoneans, while African Americans living in Charleston and the West Coast were progressively more distantly related to the Sierra Leoneans. We observed low maternal European American admixture in the Jamaican and Gullah samples (m = 0.020 and 0.064, respectively) that increased sharply in a clinal pattern from Charleston African Americans to West Coast African Americans (m = 0.099 and 0.205, respectively). The appreciably reduced maternal European American admixture noted in the Gullah indicates that the Gullah may be uniquely situated to allow genetic epidemiology studies of complex diseases in African Americans with low European American admixture.     

Three novel mtDNA restriction site polymorphisms allow exploration of population affinities of African Americans

To develop informative tools for the study of population affinities in African Americans, we sequenced the hypervariable segments I and II (HVS I and HVS II) of mitochondrial DNA (mtDNA) from 96 Sierra Leoneans; European Americans; rural, Gullah-speaking African Americans; urban African Americans living in Charleston, South Carolina; and Jamaicans. We identified single nucleotide polymorphisms (SNPs) exhibiting ethnic affinities, and developed restriction endonuclease tools to screen these SNPs. Here we show that three HVS restriction site polymorphisms (RSPs), EcoRV, FokI, and MfeI, exhibit appreciable differences in frequency (average delta = 0.4165) between putative African American parental populations (i.e., extant Africans living in Sierra Leone and European Americans). Estimates of European American mtDNA admixture, calculated from haplotypes composed of these three novel RSPs, show a cline of increasing admixture from Gullah-speaking African American (m = 0.0300) to urban Charleston African American (m = 0.0689) to West Coast African American (m = 0.1769) populations. This haplotype admixture in the Gullahs is the lowest recorded to date among African Americans, consistent with previous studies using autosomal markers. These RSPs may become valuable new tools in the study of ancestral affinities and admixture dynamics of African Americans.