Verónica Gomes

Continent-Wide Decoupling of Y-Chromosomal Genetic Variation from Language and Geography in Native South Americans

Numerous studies of human populations in Europe and Asia have revealed a concordance between their extant genetic structure and the prevailing regional pattern of geography and language. For native South Americans, however, such evidence has been lacking so far. Therefore, we examined the relationship between Y-chromosomal genotype on the one hand, and male geographic origin and linguistic affiliation on the other, in the largest study of South American natives to date in terms of sampled individuals and populations. A total of 1,011 individuals, representing 50 tribal populations from 81 settlements, were genotyped for up to 17 short tandem repeat (STR) markers and 16 single nucleotide polymorphisms (Y-SNPs), the latter resolving phylogenetic lineages Q and C. Virtually no structure became apparent for the extant Y-chromosomal genetic variation of South American males that could sensibly be related to their inter-tribal geographic and linguistic relationships. This continent-wide decoupling is consistent with a rapid peopling of the continent followed by long periods of isolation in small groups. Furthermore, for the first time, we identified a distinct geographical cluster of Y-SNP lineages C-M217 (C3*) in South America. Such haplotypes are virtually absent from North and Central America, but occur at high frequency in Asia. Together with the locally confined Y-STR autocorrelation observed in our study as a whole, the available data therefore suggest a late introduction of C3* into South America no more than 6,000 years ago, perhaps via coastal or trans-Pacific routes. Extensive simulations revealed that the observed lack of haplogroup C3* among extant North and Central American natives is only compatible with low levels of migration between the ancestor populations of C3* carriers and non-carriers. In summary, our data highlight the fact that a pronounced correlation between genetic and geographic/cultural structure can only be expected under very specific conditions, most of which are likely not to have been met by the ancestors of native South Americans.

Reconstructing the Indian origin and dispersal of the European Roma: a maternal genetic perspective.

Previous genetic, anthropological and linguistic studies have shown that Roma (Gypsies) constitute a founder population dispersed throughout Europe whose origins might be traced to the Indian subcontinent. Linguistic and anthropological evidence point to Indo-Aryan ethnic groups from North-western India as the ancestral parental population of Roma. Recently, a strong genetic hint supporting this theory came from a study of a private mutation causing primary congenital glaucoma. In the present study, complete mitochondrial control sequences of Iberian Roma and previously published maternal lineages of other European Roma were analyzed in order to establish the genetic affinities among Roma groups, determine the degree of admixture with neighbouring populations, infer the migration routes followed since the first arrival to Europe, and survey the origin of Roma within the Indian subcontinent. Our results show that the maternal lineage composition in the Roma groups follows a pattern of different migration routes, with several founder effects, and low effective population sizes along their dispersal. Our data allowed the confirmation of a North/West migration route shared by Polish, Lithuanian and Iberian Roma. Additionally, eleven Roma founder lineages were identified and degrees of admixture with host populations were estimated. Finally, the comparison with an extensive database of Indian sequences allowed us to identify the Punjab state, in North-western India, as the putative ancestral homeland of the European Roma, in agreement with previous linguistic and anthropological studies.

A Perspective on the History of the Iberian Gypsies Provided by Phylogeographic Analysis of Y-Chromosome Lineages

The European Gypsies, commonly referred to as Roma, are represented by a vast number of groups spread across many countries. Although sharing a common origin, the Gypsy groups are highly heterogeneous as a consequence of genetic drift and different levels of admixture with surrounding populations. With this study we aimed at contributing to the knowledge of the Roma history by studying 17 Y‐STR and 34 Y‐SNP loci in a sample of 126 Portuguese Gypsies. Distinct genetic hallmarks of their past and migration route were detected, namely: an ancestral component, shared by all Roma groups, that reflects their origin in India (H1a‐M82; ∼17%); an influence from their long permanence in the Balkans/Middle‐East region (J2a1b‐M67, J2a1b1‐M92, I‐M170, Q‐M242; ∼31%); traces of contacts with European populations preceding the entrance in the Iberian Peninsula (R1b1c‐M269, J2b1a‐M241; ∼10%); and a high proportion of admixture with the non‐Gypsy population from Iberia (R1b1c‐M269, R1‐M173/del.M269, J2a‐M410, I1b1b‐M26, E3b1b‐M81; ∼37%). Among the Portuguese Gypsies the proportion of introgression from host populations is higher than observed in other groups, a fact which is somewhat unexpected since the arrival of the Roma to Portugal is documented to be more recent than in Central or East Europe.

Digging deeper into East African human Y chromosome lineages

The most significant and widely studied remodeling of the African genetic landscape is the Bantu expansion, which led to an almost total replacement of the previous populations from the sub-Saharan region. However, a poor knowledge exists about other population movements, namely, the Nilotic migration, which is a pastoralist dispersal that, contrary to the Bantu expansion, impacted only East African populations. Here, samples from a Ugandan Nilotic-speaking population were studied for 37 Y chromosome-specific SNPs, and the obtained data were compared with those already available for other sub-Saharan population groups. Although Uganda lies on the fringe of both Bantu and Nilotic expansions, a low admixture with Bantu populations was detected, with haplogroups carrying M13, M182 and M75 mutations prevailing in Nilotes together with a low frequency of the main Bantu haplogroups from clade E1b1a-M2. The results of a comparative analysis with data from other population groups allowed a deeper characterization of some lineages in our sample, clarifying some doubts about the origin of some particular Y-SNPs in different ethnic groups, such as M150, M112 and M75. Moreover, it was also possible to identify a new Y-SNP apparently specific to Nilotic groups, as well as the presence of particular haplogroups that characterize Nilotic populations. The detection of a new haplogroup B2a1b defined by G1, could be, therefore, important to differentiate Nilotes from other groups, helping to trace migration and admixture events that occurred in eastern Africa.

Demographic history of Canary Islands male gene-pool: replacement of native lineages by European

BackgroundThe origin and prevalence of the prehispanic settlers of the Canary Islands has attracted great multidisciplinary interest. However, direct ancient DNA genetic studies on indigenous and historical 17th–18th century remains, using mitochondrial DNA as a female marker, have only recently been possible. In the present work, the analysis of Y-chromosome polymorphisms in the same samples, has shed light on the way the European colonization affected male and female Canary Island indigenous genetic pools, from the conquest to present-day times.ResultsAutochthonous (E-M81) and prominent (E-M78 and J-M267) Berber Y-chromosome lineages were detected in the indigenous remains, confirming a North West African origin for their ancestors which confirms previous mitochondrial DNA results. However, in contrast with their female lineages, which have survived in the present-day population since the conquest with only a moderate decline, the male indigenous lineages have dropped constantly being substituted by European lineages. Male and female sub-Saharan African genetic inputs were also detected in the Canary population, but their frequencies were higher during the 17th–18th centuries than today.ConclusionThe European colonization of the Canary Islands introduced a strong sex-biased change in the indigenous population in such a way that indigenous female lineages survived in the extant population in a significantly higher proportion than their male counterparts.

The Karimojong from Uganda: Genetic characterization using an X-STR decaplex system

The Karimojong, an African group from the Karamoja region of Northeast Uganda, were genetically analysed using a decaplex system for X chromosome short tandem repeats (X-STRs). A total of 255 individuals (117 males and 138 females) were genotyped for the following loci: DXS8378, DXS9898, DXS7133, GATA31E08, GATA172D05, DXS7423, DXS6809, DXS7132, DXS9902 and DXS6789. Allele frequencies and parameters for forensic evaluation were calculated for each STR. No association was found between any pairs of loci studied. DXS6789 was the most polymorphic marker in this sample, followed by DXS6809, with gene diversities of 84.79% and 83.94%, respectively. The less discriminating locus observed was DXS7133, with a gene diversity of 39.79%. High overall values of power of discrimination were obtained for female (1 in 1.8 x 10(10)) and male samples (1 in 1.6 x 10(6)), as well as high power of exclusion in father/mother/daughter trios (99.9997%), in father daughter duos (99.9862%) and in half sisters with same father (99.0331%). These results confirm the potential of this 10-plex in parentage testing and in human identification.

Population data defined by 15 autosomal STR loci in Karamoja population (Uganda) using AmpF/STR Identifiler kit

Karamoja is a region located in the northeast edge of Uganda where it borders Kenya and Sudan. The majority of inhabitants of this region belong to Karimojong ethnic groups. In this work, we present allele frequencies for 15 STRs included in the AmpF/STR Identifiler kit (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPO and VWA) in 218 unrelated individuals from Karamoja region. Observed genotype distributions for each locus do not show deviations from Hardy-Weinberg equilibrium expectations. When comparing allele frequencies, for each locus, with other five African samples (Equatorial Guinea, Mozambique, Cabinda (Angola), Rwanda and Tanzania) the only population that did not show significant differences with Karamoja (Uganda) was Rwanda.

Phylogeographic Analysis of Paternal Lineages in NE Portuguese Jewish Communities

The establishment of Jewish communities in the territory of contemporary Portugal is archaeologically documented since the 3rd century CE, but their settlement in Trás-os-Montes (NE Portugal) has not been proved before the 12th century. The Decree of Expulsion followed by the establishment of the Inquisition, both around the beginning of the 16th century, accounted for a significant exodus, as well as the establishment of crypto-Jewish communities. Previous Y chromosome studies have shown that different Jewish communities share a common origin in the Near East, although they can be quite heterogeneous as a consequence of genetic drift and different levels of admixture with their respective host populations. To characterize the genetic composition of the Portuguese Jewish communities from Trás-os-Montes, we have examined 57 unrelated Jewish males, with a high-resolution Y-chromosome typing strategy, comprising 16 STRs and 23 SNPs. A high lineage diversity was found, at both haplotype and haplogroup levels (98.74 and 82.83%, respectively), demonstrating the absence of either strong drift or founder effects. A deeper and more detailed investigation is required to clarify how these communities avoided the expected inbreeding caused by over four centuries of religious repression. Concerning haplogroup lineages, we detected some admixture with the Western European non-Jewish populations (R1b1b2-M269, approximately 28%), along with a strong ancestral component reflecting their origin in the Middle East [J1(xJ1a-M267), approximately 12%; J2-M172, approximately 25%; T-M70, approximately 16%] and in consequence Trás-os-Montes Jews were found to be more closely related with other Jewish groups, rather than with the Portuguese non-Jewish population.

Colombia’s racial crucible: Y chromosome evidence from six admixed communities in the Department of Bolivar

Abstract Objectives: To determine the African, European and Native-American paternal contributions in genetic samples from the Department of Bolivar (Colombia) with the aims of establishing (1) possible population substructures, and (2) the proportion of biological African heritage in admixed populations of European, Amerindian, and African descent. Methods: Y-SNPs were typed in samples from six communities, including Palenque (renowned for its African linguistic and cultural heritage). Results: Findings reveal a high diversity of Y-haplogroups. With the exception of Palenque, the sum of European male lineages uniformly exceeded 57%. In Palenque, African lineages accounted for 57.7% of its chromosomes, with European male lineages constituting a mere 38.5%. In Pinillos, a significant proportion (23.8%) of the chromosomes belongs to the Native American haplogroup Q1a3a*-M3. Genetic differentiation analyses reveal significant divergences in most pairwise comparisons among the Bolivar municipalities, and the same holds between Bolivar and other South American populations. Conclusions: Heterogeneous patterns of admixture reveal a genetic substructure within the Department of Bolivar. On the paternal side, five out of the six communities studied exhibit a predominantly European gene pool. The exception is Palenque, where European input (38%) is more significant than we had expected.

Male lineages in South American native groups: evidence of M19 traveling south.

With this study, we aimed to determine the different male ancestral components of two Native American communities from Argentina, namely Toba and Colla. The analysis of 27 Y-chromosome SNPs allowed us to identify seven different haplogroups in both samples. Chromosomes carrying the M3 mutation, which typically defines the Native American haplogroup Q1a3a, were seen most frequently in the Toba community (90%). Conversely, Q1a3a was represented in 34% of the Colla Y-chromosomes, whereas haplogroup R1b1, the main representative of western European populations, exhibited the highest frequency in this population (41%). Different M3 sublineages in the Toba community could be identified by observing point mutations at both DYS385 and M19 loci. A microvariant at DYS385, named 16.1, has been characterized, which helps to further subdivide Q1a3a. It is the first time the M19 mutated allele is described in a population from Argentina. This finding supports the old age of the lineages carrying the M19 mutation, but it contradicts the previous hypothesis that the M19 mutated allele is confined to only two Equatorial-Tucano population groups from the north region of South America. The detection of M19 further south than previously thought allows questioning of the hypothesis that this lineage serves as an example of isolation after colonization. This observation also affirms the strong genetic drift to which Native Americans have been subjected. Moreover, our study illustrates a heterogeneous contribution of Europeans to these populations and supports previous studies showing that most Native American groups were subjected to European admixture that primarily involved immigrant men.