Y chromosomal polymorphisms reveal founding lineages in the Finns and the Saami

Y chromosomal polymorphisms were studied in 502 males from 16 Eurasian ethn ic groups including the Finns, Saami (Inari Lake area and Skolt Saami), Kar elians, Mari, Mokshas, Erzas, Hungarians (Budapest area and Csangos), Khant y, Mansi, Yakuts, Koryaks, Nivkhs, Mongolians, and Latvians. The samples we re analysed for polymorphisms in the Y chromosome specific Alu insertion (Y AP) and six microsatellites (DYS19, DYS389-I and II, DYS390, DYS392, DYS393 ). The populations were also screened for the recently described Tat polymo rphism. The incidence of YAP(+) type was highest in the Csangos and in othe r Hungarians (37.5% and 17.5%, respectively). In the Karelians and the Latv ians it was present at approximately the same level as commonly found in ot her European populations, whilst absent in our further samples of Eurasian populations, including the Finns and the Saami. Aside from the Hungarians, the C allele of the Tat polymorphism was common in all the Finno-Ugric spea king populations (from 8.2% to 63.2%), with highest incidence in the Ob-Ugr ian Khanty. The C allele was also found in the Latvians (29.4%). The haplot ypes found associated with the Tat C allele showed consistently lower densi ty than those associated with the T allele, indicating that the T allele is the original form. The computation of the age of the Tat C suggested that the mutation might be a relatively recent event giving a maximum likelihood estimate of 4440years (95% confidence interval about 3140-6200years). The distribution patterns of the 222 haplotypes found varied considerably among the populations. In the Finns a majority of the haplotypes could be assign ed to two distinct groups, one of which harboured the C allele of the Tat p olymorphism indicating dichotomous primary source of genetic variation amon g Finnish males. The presence of a bottleneck or founding effect in the mal e lineages of some of the populations, namely in the Finns and the Saami, w ould appear to be one likely interpretation for these findings.