35 research outputs found
The First Peopling of South America: New Evidence from Y-Chromosome Haplogroup Q
<div><p>Recent progress in the phylogenetic resolution of the Y-chromosome phylogeny permits the male demographic dynamics and migratory events that occurred in Central and Southern America after the initial human spread into the Americas to be investigated at the regional level. To delve further into this issue, we examined more than 400 Native American Y chromosomes (collected in the region ranging from Mexico to South America) belonging to haplogroup Q – virtually the only branch of the Y phylogeny observed in modern-day Amerindians of Central and South America – together with 27 from Mongolia and Kamchatka. Two main founding lineages, Q1a3a1a-M3 and Q1a3a1-L54(xM3), were detected along with novel sub-clades of younger age and more restricted geographic distributions. The first was also observed in Far East Asia while no Q1a3a1-L54(xM3) Y chromosome was found in Asia except the southern Siberian-specific sub-clade Q1a3a1c-L330. Our data not only confirm a southern Siberian origin of ancestral populations that gave rise to Paleo-Indians and the differentiation of both Native American Q founding lineages in Beringia, but support their concomitant arrival in Mesoamerica, where Mexico acted as recipient for the first wave of migration, followed by a rapid southward migration, along the Pacific coast, into the Andean region. Although Q1a3a1a-M3 and Q1a3a1-L54(xM3) display overlapping general distributions, they show different patterns of evolution in the Mexican plateau and the Andean area, which can be explained by local differentiations due to demographic events triggered by the introduction of agriculture and associated with the flourishing of the Great Empires.</p></div
Estimated Ages for Q Sub-Lineages in Native Americans.
<p>SE, Standard Errors.</p>a<p>excluding samples with duplicated loci and micro-variants (partial repeats).</p>b<p>including PV4, 24.3±3.4 without PV4.</p>c<p>including PV4, 23.7±3.7 without PV4.</p>d<p>including or excluding PV2.</p>e<p>one sample from this study and five from the YRHD database.</p>f<p>DYS388 and DYS461 were not genotyped.</p
PCoA plots.
<p>Analyses were performed on 433 Native American haplogroup Q Y chromosomes and based on pairwise, individual-by-individual genetic distances generated from 33 <i>loci</i> Y-STR haplotypes (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071390#pone.0071390.s002" target="_blank">Table S2</a>) represented in their (A) geographic (<u>Andes</u>: Bolivia, Chile, Colombia, Ecuador, Peru; <u>C</u>entral <u>America</u>: Costa Rica, El Salvador, Guatemala, Nicaragua, Panama; <u>S</u>outh <u>E</u>ast <u>America</u>: Argentina, Brazil, Paraguay, Uruguay) and (B) sub-haplogroup Q contexts. Ancient DNA (aDNA) matching haplotypes <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071390#pone.0071390-Baca1" target="_blank">[75]</a> are indicated by arrows. Three separated (Central American, Mexican and Andean) clusters are indicated by ovals.</p
Observed Frequencies of Haplogroup Q and of its Sub-Lineages.
a<p>Marker described here for the first time.</p>b<p>Grouping due to sample size <10 in single populations. <u>C</u>entral <u>American Isthmus</u>: El Salvador, Guatemala and Honduras; <u>N</u>orthern <u>S</u>outh<u> America</u>: Colombia, Ecuador, Venezuela; <u>S</u>outhern <u>S</u>outh <u>America</u>: Argentina and Paraguay; <u>The Caribbeans</u>: Barbados, Bermuda, Cuba, Dominican Rep., French Guiana, Grenada, Haiti, Jamaica, Martinique.</p><p>The following mutations were surveyed in all potential carrier samples but they were not observed: NTW01, M323, L401 and M19. M199 was only typed in a subset of samples.</p><p>In parentheses, % frequencies.</p
Y-Chromosome Diversity in Modern Bulgarians: New Clues about Their Ancestry
<div><p>To better define the structure and origin of the Bulgarian paternal gene pool, we have examined the Y-chromosome variation in 808 Bulgarian males. The analysis was performed by high-resolution genotyping of biallelic markers and by analyzing the STR variation within the most informative haplogroups. We found that the Y-chromosome gene pool in modern Bulgarians is primarily represented by Western Eurasian haplogroups with ∼ 40% belonging to haplogroups E-V13 and I-M423, and 20% to R-M17. Haplogroups common in the Middle East (J and G) and in South Western Asia (R-L23*) occur at frequencies of 19% and 5%, respectively. Haplogroups C, N and Q, distinctive for Altaic and Central Asian Turkic-speaking populations, occur at the negligible frequency of only 1.5%. Principal Component analyses group Bulgarians with European populations, apart from Central Asian Turkic-speaking groups and South Western Asia populations. Within the country, the genetic variation is structured in Western, Central and Eastern Bulgaria indicating that the Balkan Mountains have been permeable to human movements. The lineage analysis provided the following interesting results: (i) R-L23* is present in Eastern Bulgaria since the post glacial period; (ii) haplogroup E-V13 has a Mesolithic age in Bulgaria from where it expanded after the arrival of farming; (iii) haplogroup J-M241 probably reflects the Neolithic westward expansion of farmers from the earliest sites along the Black Sea. On the whole, in light of the most recent historical studies, which indicate a substantial proto-Bulgarian input to the contemporary Bulgarian people, our data suggest that a common paternal ancestry between the proto-Bulgarians and the Altaic and Central Asian Turkic-speaking populations either did not exist or was negligible.</p> </div
Reconstructing the genetic history of Italians: new insights from a male (Y-chromosome) perspective
<p><b>Background:</b> Due to its central and strategic position in Europe and in the Mediterranean Basin, the Italian Peninsula played a pivotal role in the first peopling of the European continent and has been a crossroad of peoples and cultures since then.</p> <p><b>Aim:</b> This study aims to gain more information on the genetic structure of modern Italian populations and to shed light on the migration/expansion events that led to their formation.</p> <p><b>Subjects and methods:</b> High resolution Y-chromosome variation analysis in 817 unrelated males from 10 informative areas of Italy was performed. Haplogroup frequencies and microsatellite haplotypes were used, together with available data from the literature, to evaluate Mediterranean and European inputs and date their arrivals.</p> <p><b>Results:</b> Fifty-three distinct Y-chromosome lineages were identified. Their distribution is in general agreement with geography, southern populations being more differentiated than northern ones.</p> <p><b>Conclusions:</b> A complex genetic structure reflecting the multifaceted peopling pattern of the Peninsula emerged: southern populations show high similarity with those from the Middle East and Southern Balkans, while those from Northern Italy are close to populations of North-Western Europe and the Northern Balkans. Interestingly, the population of Volterra, an ancient town of Etruscan origin in Tuscany, displays a unique Y-chromosomal genetic structure.</p
Phylogenetic relationships and percent frequencies of Y-chromosome haplogroups in each of the former provinces and in Bulgarians as a whole.
<p>The following markers: M2 (within Hg E), M365, M367, M368, M390 (within Hg J), M120, M323 (within Hg Q) and M529 (within Hg R) were typed but not observed.</p
Map of Bulgaria outlining the former administrative provinces within which samples were allocated.
<p>The provinces are indicated as follows: 1. Burgas; 2. Varna; 3. Lovech; 4. Montana; 5. Plovdiv; 6. Razgrad; 7. Sofia City; 8. Sofia Province and 9. Haskovo.</p
Analysis of molecular variance in populations of the former nine provinces of Bulgaria.
*<p>p≈0.05.</p
Principal components plots based on Y-chromosome haplogroup frequencies.
<p>(A) African and Eurasian populations analyzed at the highest level of phylogenetic resolution, (B) Bulgaria in the European context, at a lower level of phylogenetic resolution, and (C) Bulgaria in the Asian context, based only on informative Asian markers. Data and abbreviations are provided in Tables 2–4. Numbers in brackets indicate the proportion of the total genetic information retained by a given PC. Inset plot illustrates the contribution of each haplogroup.</p