The phylogeography of Brazilian Y-chromosome lineages

We examined DNA polymorphisms in the nonrecombining portion of the Y-chromo some to investigate the contribution of distinct patrilineages to the prese nt-day white Brazilian population. Twelve unique-event polymorphisms were t yped in 200 unrelated males from four geographical regions of Brazil and in 93 Portuguese males. In our Brazilian sample, the vast majority of Y-chrom osomes proved to be of European origin. Indeed, there were no significant d ifferences when the haplogroup frequencies in Brazil and Portugal were comp ared by means of an exact test of population differentiation. Y-chromosome typing was quite sensitive in the detection of regional immigration events. Distinct footprints of Italian immigration to southern Brazil, migration o f Moroccan Jews to the Amazon region, and possible relies of the 17th-centu ry Dutch invasion of northeast Brazil could be seen in the data. In sharp c ontrast with our mtDNA data in white Brazilians, which showed that greater than or equal to 60% of the matrilineages were Amerindian or African, only 2.5% of the Y-chromosome lineages were from sub-Saharan Africa, and none we re Amerindian. Together, these results configure a picture of strong direct ional mating between European males and Amerindian and African females, whi ch agrees with the known history of the peopling of Brazil since 1500.