Recent Male-Mediated Gene Flow over a Linguistic Barrier in Iberia,

We have examined the worldwide distribution of a Y-chromosomal base-substitution polymorphism, the T/ C transition at SRY-2627, where the T allele defines haplogroup 22; sequencing of primate homologues shows that the ancestral state cannot be determined un-ambiguously but is probably the C allele. Of 1,191 hu-man Y chromosomes analyzed, 33 belong to haplogroup 22. Twenty-nine come from Iberia, and the highest fre-quencies are in Basques (11%; ) and Catalansn = 117 (22%;). Microsatellite and minisatellite (MSY1)n = 32 diversity analysis shows that non-Iberian haplogroup-22 chromosomes are not significantly different from Ibe-rian ones. The simplest interpretation of these data is that haplogroup 22 arose in Iberia and that non-Iberian cases reflect Iberian emigrants. Several different method