A multistep process for the dispersal of a Y chromosomal lineage in the Mediterranean area

Tn this work we focus on a microsatellite-defined Y-chromosomal lineage (network 1.2) identified by us and reported in previous studies, whose geographic distribution and antiquity appear to be compatible with the Neolithic spread of farmers. Here, we set network 1.2 in the Y-chromosomal phylogenetic tree, date it with respect to other lineages associated with the same movements by other authors, examine its diversity by means of tri- and tetranucleotide loci and discuss the implications hi reconstructing the spread of this group of chromosomes in the Mediterranean area. Our results define a tripartite phylogeny wit-bin HG 9 (Rosser et al. 2000) with the deepest branching defined by alleles T (Haplogroup Eu 10) or G (Haplogroup Eu9) at M172 (Semino et al. 2000), and a subsequent branching within Eu9 defined by network 1.2. Population distributions of HG 9 and network 1.2 show that their occurrence in the surveyed area is not due to the spread of people from a single parental population but, rather, to a process punctuated by at least two phases. Our data identify the wide area of the Balkans, Aegean and Anatolia as the possible homeland harbouring the largest variation within network 1.2. The use of recently proposed tests based on the stepwise mutation model suggests that its spread was associated to a population expansion, xvith a high rate of male gene flow in the Turkish Greek area

Clinal patterns of human Y chromosomal diversity in continental Italy and Greece are dominated by drift and founder effects

We explored the spatial distribution of human Y chromosomal diversity on a microgeographic scale, by typing 30 population samples from closely spaced locations in Italy and Greece for 9 haplogroups and their internal microsatellite variation. We confirm a significant difference in the composition of the Y chromosomal gene pools of the two countries. However, within each country, heterogeneity is not organized along the lines of clinal variation deduced from studies on larger spatial scales. Microsatellite data indicate that local increases of haplogroup frequencies can be often explained by a limited number of founders. We conclude that local founder or drift effects are the main determinants in shaping the microgeographic Y chromosomal diversity. (C) 2003 Elsevier Science (USA). All rights reserved

A multistep process for the dispersal of a Y chromosomal lineage in the Mediterranean area

Tn this work we focus on a microsatellite-defined Y-chromosomal lineage (network 1.2) identified by us and reported in previous studies, whose geographic distribution and antiquity appear to be compatible with the Neolithic spread of farmers. Here, we set network 1.2 in the Y-chromosomal phylogenetic tree, date it with respect to other lineages associated with the same movements by other authors, examine its diversity by means of tri- and tetranucleotide loci and discuss the implications hi reconstructing the spread of this group of chromosomes in the Mediterranean area. Our results define a tripartite phylogeny wit-bin HG 9 (Rosser et al. 2000) with the deepest branching defined by alleles T (Haplogroup Eu 10) or G (Haplogroup Eu9) at M172 (Semino et al. 2000), and a subsequent branching within Eu9 defined by network 1.2. Population distributions of HG 9 and network 1.2 show that their occurrence in the surveyed area is not due to the spread of people from a single parental population but, rather, to a process punctuated by at least two phases. Our data identify the wide area of the Balkans, Aegean and Anatolia as the possible homeland harbouring the largest variation within network 1.2. The use of recently proposed tests based on the stepwise mutation model suggests that its spread was associated to a population expansion, xvith a high rate of male gene flow in the Turkish Greek area

Y chromosomal haplogroup J as a signature of the post-neolithic colonization of Europe

In order to attain a finer reconstruction of the peopling of southern and central-eastem Europe from the Levant, we determined the frequencies of eight lineages internal to the Y chromosomal haplogroup J, defined by biallelic markers, in 22 population samples obtained with a fine-grained sampling scheme. Our results partially resolve a major multifurcation of lineages within the haplogroup. Analyses of molecular variance show that the area covered by haplogroup J dispersal is characterized by a significant degree of molecular radiation for unique event polymorphisms within the haplogroup, with a higher incidence of the most derived sub-haplogroups on the northern Mediterranean coast, from Turkey westward; here, J diversity is not simply a subset of that present in the area in which this haplogroup, first originated. Dating estimates, based on simple tandem repeat loci (STR) diversity within each lineage, confirmed the presence of a major population structuring at the time of spread of haplogroup J in Europe and a punctuation in the peopling of this continent in the post-Neolithic, compatible with the expansion of the Greek world. We also present here, for the first time, a novel method for comparative dating of lineages, free of assumptions of STR mutation rates

Disuniting uniformity: A pied cladistic canvas of mtDNA haplogroup H in Eurasia

It has been often stated that the overall pattern of human maternal lineages in Europe is largely uniform. Yet this uniformity may also result from an insufficient depth and width of the phylogenetic analysis, in particular of the predominant western Eurasian haplogroup (Hg) H that comprises nearly a half of the European mitochondrial DNA (mtDNA) pool. Making use of the coding sequence information from 267 mtDNA Hg H sequences, we have analyzed 830 mtDNA genomes, from 11 European, Near and Middle Eastern, Central Asian, and Altaian populations. In addition to the seven previously specified subhaplogroups, we define fifteen novel subclades of Hg H present in the extant human populations of western Eurasia. The refinement of the phylogenetic resolution has allowed us to resolve a large number of homoplasies in phylogenetic trees of Hg H based on the first hypervariable segment (HVS-I) of mtDNA. As many as 50 out of 125 polymorphic positions in HVS-I were found to be mutated in more than one subcluster of Hg H. The phylogeographic analysis revealed that sub-Hgs H1*, H1b, H1f, H2a, H3, H6a, H6b, and H8 demonstrate distinct phylogeographic patterns. The monophyletic subhaplogroups of Hg H provide means for further progress in the understanding of the (pre)historic movements of women in Eurasia and for the understanding of the present-day genetic diversity of western Eurasians in general