Substantial native American female contribution to the population of Tacuarembó, Uruguay,reveals past episodes of sex‐biased gene flow

For many years it has been assumed that the population of Uruguay is almost exclusively European‐derived and that the biological contribution of the native population as well as of individuals of African descent is negligible. Several recent studies based on a variety of genetic markers, mostly morphological and serological markers, have produced quite a different picture of the constitution of the Uruguayan population. The Native American contribution varies from 1–20%, while the African contribution ranges from 7–15%, in different regions of the country. In the present study we examine the way the admixture process took place in Uruguay by analyzing the ancestry of maternal lineages in a sample from the northern city of Tacuarembó. To accomplish this goal we typed mitochondrial DNA (mtDNA) markers of Native American, African, and European origin and estimated the proportions of each parental group in the admixed population. We found that 62% of all mtDNA haplogroups were of Native American descent, a surprising figure considering the “European roots” of the country. Consequently, this result assimilates Uruguay to the rest of Latin American populations where sex‐biased gene flow between European men and Native American women has been the rule. We further analyzed the distribution of the four major founding mitochondrial lineages in Tacuarembó and compared it to other South American populations. We discuss our findings in the light of historical records and assess the need for additional genetic studies. Am. J. Hum. Biol. 16:289–297, 2004. © 2004 Wiley‐Liss, Inc.     

Genetic origins in a South American clefting population

It has been proposed that susceptibility to clefting in South America is related to Amerindian ancestry, where clefting is present at a higher frequency than in the other admixed populations (Caucasian and African) that make up the diverse racial mix of current South Americans. To clarify the genetic origins and establish a method for genetic mapping, mitochondrial DNA variation and Y-chromosome markers were studied in a South American population affected with clefting. Two-hundred and seventeen subjects and matched controls were selected through the Latin-American Collaborative Study of Congenital Malformations (ECLAMC). The case group showed a higher frequency of Native American haplogroups and a lower frequency of African haplogroups (p < 0.00001). In addition, the case group showed a much higher frequency of the specific native American haplogroup D than the control group (p < 0.00001). For the Y-chromosome markers, the case group showed a lower frequency of the African-specific marker, YAP (p = 0.002), and a higher frequency of the Native American-specific marker, DYS199 (p < 0.00001). Even though differences were found in the frequencies of the markers studied, the contribution of each founder population was similar for both groups. Results suggest a strong Native American maternal contribution and a strong Caucasian (Spanish and Portuguese) paternal contribution to the population studied. The implications of this finding include the possibility of using admixture mapping approaches to this population.     

An Asian–Native American paternal lineage identified by RPS4Y resequencing and by microsatellite haplotyping

Human paternal population history was studied in 9 populations [three Native American, three Asian, two Caucasian and one African-derived sample(s)] using sequence and short tandem repeat haplotype diversity within the non-pseudoautosegmal region of the Y chromosome. Complete coding and additional flanking sequences (949 base pairs) of the RPS4Y locus were determined in 59 individuals from three of the populations, revealing a nucleotide diversity of 0.0147%, consistent with previous estimates from Y chromosome resequencing studies. One RPS4Y sequence variant, 711C>T, was polymorphic in Asian and Native American populations, but not in African and Caucasian population samples. The RPS4Y 711C>T variant, a second unique sequence variant at DYS287 and nine Y chromosome short tandem repeat (YSTR) loci were used to analyze the evolution of Y chromosome lineages. Three unambiguous lineages were defined in Asian, Native American and Jamaican populations using sequence variants at RPS4Y and DYS287 . These lineages were independently supported by the haplotypes defined solely by YSTR alleles, demonstrating the haplotypes constructed from YSTRs can evaluate population diversity, admixture and phylogeny.     

Gender bias in the multiethnic genetic composition of central Argentina

A sample of central Argentina (Córdoba) was genotyped for the first hypervariable region (HVS-I) plus a set of coding region mitochondrial DNA (mtDNA) single nucleotide polymorphisms (SNPs) (N = 102) and compared with a data set of Y-chromosome short tandem repeats (Y-STRs; N = 100) previously genotyped in the same individuals. We additionally compiled a database containing more than 4,000, 6,800, and 12,000 HVS-I sequences of Native American, sub-Saharan African, and European origin, respectively. The Y-Chromosome Haplotype Reference Database (YHRD) was used as a reference for the Y-STR profiles from Córdoba. The Native American component is highly prevalent on the maternal side (approximately 41%) in contrast to the Y-chromosome paternal contribution (approximately 2%), indicating a strong gender bias in the colonization and admixture processes that occurred in the recent history of Argentina, in agreement with historical records. The demographic input of African slaves in Córdoba was very high in the eighteenth century (approximately 40% of the total population) but decreased dramatically after a few decades; therefore, the minor traces of sub-Saharan Y-chromosome and mtDNA lineages observed in our sample fit well with these historical records. The European Y-chromosome component of Córdoba (approximately 97%; in contrast to the 57% observed in the mtDNA side) also mirrors the substantial immigration experienced by Argentina during the beginning of the last century, predominantly from Italy and Spain.     

Y-chromosomal short tandem repeat haplotypes in southern Croatian male population defined by 17 loci

Aim

To define the Y-chromosome genetic structure in a sample of men from southern Croatia.

Methods

Blood samples were collected from 166 unrelated healthy men from southern Croatia at the Department of Forensic Medicine and Biochemical Laboratory of University Hospital Split between 2004 and 2007. Genomic DNA was extracted using the standard procedures. Seventeen Y-chromosome short tandem repeat (Y-STR) polymorphic loci (DYS456, DYS389I, DYS390, DYS389II, DYS458, DYS19, DYS385, DYS393, DYS391, DYS439, DYS635, DYS392, GATAH4, DYS437, DYS438, and DYS448) were analyzed using AmpFlSTR Yfiler Polymerase Chain Reaction Amplification Kit.

Results

We observed 152 different haplotypes. Total haplotype diversity was 0.997289 and 141 haplotypes (84.49%) were unique. The most common haplotype was shared by only 4 men in the study sample. The locus diversity ranged between 0.21292 for DYS392 and 0.75546 for DYS439 locus.

Conclusion

The Y-chromosome structure in men from southern Croatia is very diverse. Combination of Y chromosome 17 STR loci may be used as a powerful tool for individual identification and parentage analysis in the southern Croatian male population.Except for occasional mutations, the major part of the male-specific Y chromosome is inherited from father to son unchanged, as a haplotype of physically linked markers, because it is not involved in recombination with X chromosome. Genotyping of this Y-specific non-recombining region (NRY) can be used to track paternal lineage, since all patrilineal relatives share the same NRY haplotype. Thus, NRY multiple marker genotyping is used to infer paternity when the putative father is not available for DNA analysis or to validate biological relationships when one of the relatives is unable to take part in the DNA typing test. NRY multiple marker genotyping is also used in forensic casework to identify a male perpetrator’s DNA in mixed samples with an excess of female victim’s DNA. In such cases, it is a better option than polymerase chain reaction (PCR)-based amplification of female autosomal DNA markers or potential overlap of autosomal DNA marker profiles (1).Genotyping small tandem repeats (STR) or microsatellite repeats or simple sequence repeats represents one of the most reliable and reproducible DNA profiling methods in forensic investigation. Genotyping multiple Y-chromosomal STR (Y-STR) markers is widely used in forensic and population studies in spite of its lower discrimination potential in comparison with autosomal STR genotyping. The constantly growing number of Y-STR markers available for forensic, evolutionary, and population studies increases Y-haplotype differentiation potential in distinct male populations (2).The aim of our study was to use 17 Y-STRs to define the genetic structure of Y chromosome in a sample of men from southern Croatia. Our results may contribute to the development of a population database that may be used to estimate the haplotype frequency, ie, the probability that two or more unrelated men share the same Y-STR haplotype. Furthermore, a Y-STR haplotype database for Croatian population may serve for assigning geographic origin to male individuals, since Y chromosomal markers are more prone to genetic drift than autosomal markers due to smaller effective population size, which enhances geographically-based differentiation of Y lineages.     

Estimates of interethnic admixture in the Brazilian population using a panel of 24 X‐linked insertion/deletion markers

Objectives. In this study, we aimed to identify ancestry informative haplotypes and make interethnic admixture estimates using X‐chromosome markers. Methods. A significant sample (461 individuals) of European, African, and Native American populations was analyzed, and four linkage groups were identified. The data obtained were used to describe the ancestral contribution of populations from four different geographical regions of Brazil (745 individuals). Results. The global interethnic admixture estimates of the four mixed populations under investigation were calculated applying all the 24 insertion/deletion (INDEL) markers. In the North region, a larger Native Americans ancestry was observed (42%). The Northeast and Southeast regions had smaller Native American contribution (27% in both of them). In the South region, there was a large European contribution (46%). Conclusions. The estimates obtained are compatible with expectations for a colonization model with biased admixture between European men (one X chromosome) and Native American and African women (two X chromosomes), so the 24 X‐INDEL panel described here can be a useful to make admixture interethnic estimates in Brazilian populations. Am. J. Hum. Biol., 2010. © 2010 Wiley‐Liss, Inc.     

Maximum likelihood estimates of admixture in northeastern Mexico using 13 short tandem repeat loci

Tetrameric short tandem repeat (STR) polymorphisms are widely used in population genetics, molecular evolution, gene mapping and linkage analysis, paternity tests, forensic analysis, and medical applications. This article provides allelic distributions of the STR loci D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, CSF1PO, TPOX, TH01, and D16S539 in 143 Mestizos from Northeastern Mexico, estimates of contributions of genes of European (Spanish), American Indian and African origin in the gene pool of this admixed Mestizo population (using 10 of these loci); and a comparison of the genetic admixture of this population with the previously reported two polymorphic molecular markers, D1S80 and HLA‐DQA1 (n = 103). Genotype distributions were in agreement with Hardy‐Weinberg expectations (HWE) for almost all 13 STR markers. Maximum likelihood estimates of admixture components yield a trihybrid model with Spanish, Amerindian, and African ancestry with the admixture proportions: 54.99% ± 3.44, 39.99% ± 2.57, and 5.02% ± 2.82, respectively. These estimates were not significantly different from those obtained using D1S80 and HLA‐DQA1 loci (59.99% ± 5.94, 36.99% ± 5.04, and 3.02% ± 2.76). In conclusion, Mestizos of Northeastern Mexico showed a similar ancestral contribution independent of the markers used for evolutionary purposes. Further validation of this database supports the use of the 13 STR loci along with D1S80 and HLA‐DQA1 as a battery of efficient DNA forensic markers in Northeastern Mestizo populations of Mexico. Am. J. Hum. Biol. 14:429–439, 2002. © 2002 Wiley‐Liss, Inc.     

Genetic background of people in the Dominican Republic with or without obese type 2 diabetes revealed by mitochondrial DNA polymorphism

People in the Dominican Republic are considered to be genetically heterogeneous owing to the post-Colombian admixture of Native American, African, and European populations. To characterize their genetic background, nucleotide sequences of the D-loop region of human mitochondrial DNA (mtDNA) were examined in 33 healthy women and 50 gender-matched patients with obese type 2 diabetes (OD) from the Dominican Republic. Phylogenetic analysis of 198 mtDNA lineages including Native Americans, Africans, and Europeans enabled us to assess relative genetic contributions of the three ancestral fractions to the two groups in the Dominican Republic. In the OD group, the majority (64.0%) of the mtDNA lineages were from African ancestry, whereas the Native American fraction was predominant (51.5%) in the healthy group, with both showing smallest amounts (14.0% and 9.1%, respectively) of European contribution. This difference in maternal genetic background between the two groups was similarly demonstrated by phylogenetic analysis at the population level based on net nucleotide diversities between populations. These findings may imply ethnic-specific predisposition to OD, a possible association of an unidentified factor from African ancestry with OD in the Dominican Republic population.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers AB174901–AB174983.     

Ancestral heterogeneity in a biethnic stroke population

To test for and characterize heterogeneity in ancestral contributions to individuals among a population of Mexican American (MA) and non-Hispanic white (NHW) stroke/transient ischemic attack (TIA) cases, data from a community-based stroke surveillance study in south Texas were used. Strokes/TIA cases were identified (2004-2006) with a random sample asked to provide blood. Race-ethnicity was self-reported. Thirty-three ancestry informative markers were genotyped and individual genetic admixture estimated using maximum likelihood methods. Three hypotheses were tested for each MA using likelihood ratio tests: (1) H(0) : μi = 0 (100% Native American), (2) H(0) : μi = 1.00 (100% European), (3) H(0) : μi = 0.59 (average European). Among 154 self-identified MAs, estimated European ancestry varied from 0.26 to 0.98, with an average of 0.59 (SE = 0.014). We rejected hypothesis 1 for every MA and rejected hypothesis 2 for all but two MAs. We rejected hypothesis 3 for 40 MAs (20 < 59%, 20 > 59%). Among 84 self-identified NHWs, the estimated fraction of European ancestry ranged from 0.83 to 1.0, with an average of 0.97 (SE = 0.014). Self-identified MAs, and to a lesser extent NHWs, from an established bi-ethnic community were heterogeneous with respect to genetic admixture. Researchers should not use simple race-ethnic categories as proxies for homogeneous genetic populations when conducting gene mapping and disease association studies in multi-ethnic populations.     

鄂伦春族Y染色体短串联重复序列多态性研究

目的 调查鄂伦春族Y染色体上10个短串联重复序列基因座及单倍型的遗传多态性。方法 应用PCR和变性聚丙烯酰胺凝胶电泳结合银染显色分型技术，检测102名无关系鄂伦春族男性血样。结果 在DYS392、DYS438、DYS439、DYS456、DYS459、DYS460、DYS461、DYS462、DYS389Ⅰ、DYS389Ⅱ等10个基因座中共检出44个等位基因，等位基因频率分布在0．418（DYS461）至0．727（DYS389Ⅰ）之间，除了DYS461（0．418）和DYS462（0．479）以外，其余等位基因频率均大于0．5。由10个基因座组成的Y染色体单倍型系统单倍型有101种，单倍型频率0．99。结论 上述10个Y-短串联重复基因座在鄂伦春族群体中具有较好的多态性，单倍型具有很高的遗传多态性。     

Assessing individual interethnic admixture and population substructure using a 48–insertion‐deletion (INSEL) ancestry‐informative marker (AIM) panel

Estimating the proportions of different ancestries in admixed populations is very important in population genetics studies, and it is particularly important for detecting population substructure effects in case‐control association studies. In this work, a set of 48 ancestry‐informative insertion‐deletion polymorphisms (INDELs) were selected with the goal of efficiently measuring the proportions of three different ancestries (sub‐Saharan African, European, and Native American) in mixed populations. All selected markers can be easily analyzed via multiplex PCR and detected with standard capillary electrophoresis. A total of 593 unrelated individuals representative of European, African, and Native American parental populations were typed, as were 380 individuals from three Brazilian populations with known admixture patterns. As expected, the interethnic admixture estimates show that individuals from southern Brazil present an almost exclusively European ancestry; Afro‐descendant communities in the Amazon region, apart from the major African contribution, present some degree of admixture with Europeans and Native Americans; and a sample from Belém, in the northeastern Amazon, shows a significant contribution of the three ethnic groups, although with a greater European proportion. In summary, a panel of ancestry‐informative INDELs was optimized and proven to be a valuable tool for estimating individual and global ancestry proportions in admixed populations. The ability to accurately infer interethnic admixtures highlights the usefulness of this marker set for assessing population substructure in association studies, particularly those conducted in Brazilian and other Latin American populations sharing trihybrid ancestry patterns. Hum Mutat 31:184–190, 2010. © 2009 Wiley‐Liss, Inc.     

Heterogeneity of Y chromosome markers among Brazilian Amerindians

The allele frequency distribution of DYS19 and DYS199 loci were analyzed in 59 Brazilian Amerindians from five tribes from the Amazon region (Zoé, Awá-Guajá, Urubú-Kaapór, Katuena, and Kayapó, Xikrin of Bacajá village). Three different alleles of the DYS19 microsatellite (182-bp, 186-bp, and 190-bp) were found at average frequencies of 0.08, 0.85, and 0.07, respectively. The DYS199-T allele was identified in 78% of the Amerindians studied (43/55), the frequencies varying from 0.46–0.93. Four different haplotypes were found, the combination DYS19–186/DYS199-T being the most common (average frequency of 0.65), followed by DYS19–186/DYS199-C with an average frequency of 0.22. These four haplotypes have been found in five other Brazilian tribes, and most of them were also identified in Native populations from South, Central and North America. The observed variability at the DYS19 microsatellite is probably due to forward or back mutations from the putative ancestral 186-bp allele, since the mutation rate of this locus is high and the post-Columbian admixture of the Brazilian tribes studied is very low or undetectable to explain these data. On the other hand, the DYS19/DYS199 haplotype distribution may suggest that the two most common haplotypes (186-bp/T and 186-bp/C) were present among the population(s) that peopled the New World. Am. J. Hum. Biol. 11:481–487, 1999. © 1999 Wiley-Liss, Inc.     

African,Native American,and European mitochondrial DNAs in Cubans from Pinar del Rio Province and implications for the recent epidemic neuropathy in Cuba

Genetic predisposition, particularly specific mitochondrial DNA (mtDNA) backgrounds, has been proposed as a contributing factor in the expression of an epidemic of bilateral optic neuropathy that has affected residents of Cuba since 1991. To substantiate or refute the possibility that specific subsets of mtDNAs could participate in disease expression, we took advantage of the heterogeneous ethnic origin of the Cuban population and the recent identification of a number of mtDNA polymorphisms that appear to be specific for Africans, Native Americans, and Europeans. The screening of both carefully selected people with epidemic neuropathy and control subjects from the Pinar del Rio Province for these polymorphisms revealed that African, Native American, and European mtDNA haplotypes were equally represented among case and control subjects, and suggested that ～ 50% of Cuban mtDNAs originated from Europeans, 46% from Africans, and 4% from Native Americans. These findings demonstrate that mutations arising in spic mtDNAs are unlikely to play a role in the epidemic neuropathy and indicate that analysis of mtDNA haplotypes can be a valuable tool for assessing the relative maternal contribution of Africans, Native Americans, and Europeans in a mixed population. © 1995 Wiley-Liss, Inc.     

Mitochondrial and nuclear variants in a U.S. Black population: origins of a hybrid population

The maternal transmission of mitochondria in higher eukaryotes makes it possible to distinguish between reciprocal matings, since offspring possess the mitochondrial DNA variants received from the mother. This possibility can be extended to hybrid populations, the mitochondrial frequencies reflecting the relative maternal contributions from the parental populations. Nuclear variations reflect the relative genetic contributions of the parental populations, irrespective of parental sex. The U.S. Black population is a hybrid of West African and European populations. The African-European matings that contributed to the present Black population are traditionally considered to have been almost exclusively between African females and European males. We have studied nuclear and mitochondrial variants in a sample of U.S. Blacks, comparing them with published frequencies from African and Caucasian groups. Our results suggest that the mitochondria of present-day American Blacks are derived from Caucasians to an extent similar to nuclear genes. In contrast to traditional beliefs, the contribution from Caucasian females is of the same magnitude as that from Caucasian males.     

Haplotype data for 23 Y-chromosome markers in a reference sample from Bosnia and Herzegovina

Aim

To detect polymorphisms of 23 Y-chromosomal short tandem repeat (STR) loci, including 6 new loci, in a reference database of male population of Bosnia and Herzegovina, as well as to assess the importance of increasing the number of Y-STR loci utilized in forensic DNA analysis.

Methods

The reference sample consisted of 100 healthy, unrelated men originating from Bosnia and Herzegovina. Sample collection using buccal swabs was performed in all geographical regions of Bosnia and Herzegovina in the period from 2010 to 2011. DNA samples were typed for 23 Y STR loci, including 6 new loci: DYS576, DYS481, DYS549, DYS533, DYS570, and DYS643, which are included in the new PowerPlex^® Y 23 amplification kit.

Results

The absolute frequency of generated haplotypes was calculated and results showed that 98 samples had unique Y 23 haplotypes, and that only two samples shared the same haplotype. The most polymorphic locus was DYS418, with 14 detected alleles and the least polymorphic loci were DYS389I, DYS391, DYS437, and DYS393.

Conclusion

This study showed that by increasing the number of highly polymorphic Y STR markers, to include those tested in our analysis, leads to a reduction of repeating haplotypes, which is very important in the application of forensic DNA analysis.The highly polymorphic short tandem repeat (STR) loci located on the Y chromosome in the male human genome are widely used for forensic and paternity testing and population genetic studies (1-3). Currently, in response to the requirement for increasing the number of Y-STR markers included in some Y-STR multiplex kits, Promega developed the PowerPlex® Y 23 amplification kit (Promega Corporation, Madison, WI, USA), which we used in this study.Previously, population studies of the male reference sample of Bosnia and Herzegovina were performed by analyzing 12 Y-chromosomal STR loci incorporated in the PowerPlex® Y 12 amplification kit (Promega Corporation) (4), various numbers of Y-SNP markers (5), as well as autosomal (6,7), and X-STR markers (8). All obtained results were included in the reference database of Bosnia and Herzegovina. However, these studies used different referent samples. In order to contribute to the development of this database we decided to analyze 23 Y-STR loci, which included 11 additional loci compared to the previous number of Y-STRs, among which there were 6 new loci incorporated for the first time in the Y-STR multiplex kit (DYS576, DYS481, DYS549, DYS533, DYS570, DYS643).     

Heterogeneity of the genome ancestry of individuals classified as White in the state of Rio Grande do Sul, Brazil.

One hundred nineteen individuals classified as White, living in different localities of the Brazilian state of Rio Grande do Sul, were studied in relation to the HVS-I region of the mitochondrial DNA (mtDNA). The male fraction of the sample (N = 74) was also tested for seven Y-chromosome polymorphisms. In a specific population (Veranópolis), a city characterized by a large influence of the Italian immigration of the 19th century, the results from the maternal and paternal sides indicated almost complete European ancestry. However, another sample identified as White, from different localities of Rio Grande do Sul, presented significant fractions of Native American (36%) and African (16%) mtDNA haplogroups. These results indicate that Brazilian populations are remarkably heterogeneous; while some present an overwhelming majority of transplanted European genomes, with a complete correspondence between physical appearance and ancestry, others reflect a history of extensive admixture with dissociation between physical appearance and ancestry.     

Apparent intrachromosomal exchange on the human Y chromosome explained by population history

The human Y chromosome displays an unusual content of repetitive sequences. Y-chromosomal repeats are potential targets for intrachromosomal recombination, which is thought to be involved in a number of Y-associated defects, such as male infertility. Such rearrangements could potentially be investigated by the use of highly polymorphic DNA markers located within the repeat units, such as microsatellites. Here we analyse the two copies of the Y-chromosomal microsatellite DYS385, which we identified and localized to an approximately 190 kb duplicated and inverted fragment at Yq11.223. We found a highly significant correlation (r=0.853, P&<0.001) and a nonsignificant difference in a chi(2)-test (chi(2)=15.45, P>0.05) between the allele frequency distributions at both copies of the Y-STR in a German population sample (n=70). Such nearly identical allele frequency distribution between two copies of a duplicated highly polymorphic microsatellite cannot be explained by the independent mutational process that creates microsatellite alleles. Instead, this might be interpreted as evidence for a reciprocal intrachromosomal exchange process between the duplicated fragments. However, more detailed analyses using additional human populations as well as additional Y chromosome markers revealed that this phenomenon is highly population-specific and disappears completely when Y-STR diversity is analysed in association with two Y-SNP haplogroups. We found that the diversity of the two DYS385 loci (and other Y-STRs) is highly depending on the haplogroup background, and that equal proportions of both haplogroups in the German sample explains the nearly identical allele frequency distributions at the two DYS385 loci. Thus, we demonstrate here that allele frequency distributions at duplicate loci that are suggestive of intrachromosomal recombination can be explained solely by population history.     

Genetic variation by birth cohorts in Mexican Americans of Starr County,Texas

Mexican Americans residing in Starr County, Texas, were grouped by their year of birth (1896–1925, 1926–1955, and 1956–1985) to determine the extent of birth cohort-related genetic variation within this population and the genetic differences, if any, from the Mexican population residing in the Metropolitan Monterrey Area (MMA), Nuevo León, México. Twenty-one genetic markers were analyzed which indicate that the three birth cohort groups are genetically indistinguishable. Gene diversity analysis suggests that more than 99.8% of the total gene diversity can be attributed to variation between individuals within the birth cohort populations and that the subdivision by birth cohort has only a small contribution (0.18%) to the total gene diversity. Genetic admixture analysis indicates a predominant influence from the Spanish, and that the three birth cohort groups were similar in terms of contributions of this ancestral population. The genetic structure of the Mexican American population of Starr County was also similar to the Mexican population from the State of Nuevo León, México. These findings, together with previous results, suggest that the Mexican Americans of Starr County, Texas, classified by gender, birthplace, and age, are not genetically distinguishable and are similar to the Mexican populations of the State of Nuevo León. © 1994 Wiley-Liss, Inc.     

Genetic population history relationships of the population of Bogotá, Colombia,by using the D1S80, VWA,and TH01 molecular markers

The genetic relationships of the population of Bogotá, Colombia, was comparatively studied with regard to other populations from America, Europe, and Asia, by using the D1S80, VWA, and TH01 molecular loci. From a population history point of view, the population of Bogotá seems to be more related to a European origin, with several differential contributions coming from Amerindians rather than from African and Asian populations, when the D1S80 and TH01 markers were employed. However, the contribution was greater from African populations for the VWA marker. Several explanations are offered to resolve the genetic affiliation of this population. Am. J. Hum. Biol. 13:374–383, 2001. © 2001 Wiley‐Liss, Inc.     

Inferring Continental Ancestry of Argentineans from Autosomal, Y-Chromosomal and Mitochondrial DNA

We investigated the bio-geographic ancestry of Argentineans, and quantified their genetic admixture, analyzing 246 unrelated male individuals from eight provinces of three Argentinean regions using ancestry-sensitive DNA markers (ASDM) from autosomal, Y and mitochondrial chromosomes. Our results demonstrate that European, Native American and African ancestry components were detectable in the contemporary Argentineans, the amounts depending on the genetic system applied, exhibiting large inter-individual heterogeneity. Argentineans carried a large fraction of European genetic heritage in their Y-chromosomal (94.1%) and autosomal (78.5%) DNA, but their mitochondrial gene pool is mostly of Native American ancestry (53.7%); instead, African heritage was small in all three genetic systems (<4%). Population substructure in Argentina considering the eight sampled provinces was very small based on autosomal (0.92% of total variation was between provincial groups, p = 0.005) and mtDNA (1.77%, p = 0.005) data (none with NRY data), and all three genetic systems revealed no substructure when clustering the provinces into the three geographic regions to which they belong. The complex genetic ancestry picture detected in Argentineans underscores the need to apply ASDM from all three genetic systems to infer geographic origins and genetic admixture. This applies to all worldwide areas where people with different continental ancestry live geographically close together.