Genetic structure of Mediterranean populations revealed by Y-chromosome haplotype analysis.
The allelic variability at six Y-chromosome-specific polymorphisms (YAP, DYS19, DYS389-I, DYS390, DYS391, and DYS392) was used to generate male-specific haplotypes in 333 males representing 12 population samples from the region around the Mediterranean sea. Extreme interindividual variation was observed, as more than 160 distinct Y-chromosome variants could be defined as six-locus haplotypes. Concomitant with this high variability, low levels of population genetic structure were observed. In particular, a "core" of populations directly facing the north and the east of the Mediterranean basin, from the Middle East to the Italian Peninsula, was found to be genetically undifferentiated. This observation, supported by a reanalysis of Y-specific binary polymorphisms in the same populations, suggests that at least part of the male-specific gene pools of these populations has either a very recent common origin (that could be related with the Neolithic demic diffusion hypothesis), and/or that gene flow has played a significant role in shaping the patterns of genetic variability in this region. In agreement with both hypotheses, we found that the spatial distribution of DYS392 alleles revealed a marked differentiation between the East and the West of the Mediterranean area. Through the analysis of microsatellite variation, the time to the most recent common ancestor (TMRCA) of the YAP(+) sublineage 4 has been estimated. The estimations, based on two different data sets, turn out to be quite recent (7,000-11,000 YBP), suggesting that this lineage may have been first introduced into Southern Europe through Neolithic migrations from the Middle East.
CNRS URA 1961, Institut Pasteur, Paris 75015, France. quintana@pasteur.fr
Lluís
L
Quintana-Murci
Reiner
R
Veitia
Marc
M
Fellous
Ornella
O
Semino
Estella S
ES
Poloni
D041322:Chromosomes, Human, Y / Q000235:genetics*; D004641:Emigration and Immigration; D014644:Genetic Variation / Q000235:genetics; D005828:Genetics, Population / Q000379:methods*; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D008297:Male; D019083:Mediterranean Region; D018895:Microsatellite Repeats / Q000235:genetics; D017720:Molecular Epidemiology; D010375:Pedigree; D044465:White People / Q000235:genetics*