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

Abstract

In this work we focus on a microsatellite-defined Y-chromosomal lineage (network 1n2) 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 in reconstructing the spread of this group of chromosomes in the Mediterranean area. Our results define a tripartite phylogeny within HG 9 (Rosser et al. 2000), with the deepest branching defined by alleles T (Haplogroup Eu10) or G (Haplogroup Eu9) at M172 (Semino et al. 2000), and a subsequent branching within Eu9 defined by network 1n2. Population distributions of HG 9 and network 1n2 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 1n2. The use of recently proposed tests based on the stepwise mutation model suggests that its spread was associated to a population expansion, with a high rate of male gene flow in the Turkish-Greek area.

Paleolithic Y-haplogroup heritage predominates in a Cretan highland plateau

“…A prominent frequency of DYS413 (CA)16-(CA)18 chromosomes in Crete, and particularly in the prefecture of Chania, was detected in the past and was attributed to a founder effect in the island. 7 It appears from our results that this founder effect is associated with the introduction or origin in Crete of the J2a1h-M319 mutation.…”

“…As the CA illustrates (Figure 4), these proportions suggest genetic affinity with groups from the Turkish-Greek area, where this marker is believed to have originated. 7 Based on the generally low frequency of J2-DYS413 chromosomes in present mainland Greece, 6 the Turkish region is favored as the origin of these lineages. Furthermore, the high frequencies of DYS413-derived chromosomes in the island of Crete, as well as in a number of coastal locations from both mainland Greece and Italy, together with the moderate frequencies of this mutation in the Aegean islands, 6 can be interpreted as the signals of a maritime demic diffusion from Anatolia.…”

“…6 An analysis of J2 chromosomes from Crete, similarly revealed additional examples of diversity within the island. 7 In the present study, we explore Y chromosomal diversity in the eastern half of Crete by typing a total of 77 markers in two general populations from the prefectures of Heraklion and Lasithi, and in a relatively isolated group from the Lasithi Plateau. The historical importance of the latter region is underscored by the role played by mountain plains, such as the one mentioned above, as natural refuges for late Minoans.…”

Different genetic components in the Norwegian population revealed by the analysis of mtDNA and Y chromosome polymorphisms

“…Thus, the present European populations harbour different genetic components that originated in distant locations. 40 It is important, for addressing genetic research in a given population, to determine these components and evaluate their prevalence in the population.…”

Molecular dissection of the Y chromosome haplogroup E-M78 (E3b1a): a posteriori evaluation of a microsatellite-network-based approach through six new biallelic markers

“…Malaspina et al, 2001;Cruciani et al, 2004;Di Giacomo et al, 2004;Semino et al, 2004;Sanchez et al, 2005).…”