The phylogeography of Brazilian Y-chromosome lineages

Abstract

We examined DNA polymorphisms in the nonrecombining portion of the Y-chromosome to investigate the contribution of distinct patrilineages to the present-day white Brazilian population. Twelve unique-event polymorphisms were typed in 200 unrelated males from four geographical regions of Brazil and in 93 Portuguese males. In our Brazilian sample, the vast majority of Y-chromosomes proved to be of European origin. Indeed, there were no significant differences when the haplogroup frequencies in Brazil and Portugal were compared 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 of Moroccan Jews to the Amazon region, and possible relics of the 17th-century Dutch invasion of northeast Brazil could be seen in the data. In sharp contrast with our mtDNA data in white Brazilians, which showed that > or =60% of the matrilineages were Amerindian or African, only 2.5% of the Y-chromosome lineages were from sub-Saharan Africa, and none were Amerindian. Together, these results configure a picture of strong directional mating between European males and Amerindian and African females, which agrees with the known history of the peopling of Brazil since 1500.

Figure 1

Geographic localization of Brazilian regions selected for study: Amazonas, Acre, Rondônia, Pará (northern region, N), Pernambuco (northeast region, NE), Minas Gerais (southeast region, SE), and Paraná, Santa Catarina, Rio Grande do Sul (south region, S).

Figure 2

Phylogeography of the Y-chromosome haplogroups studied (Hammer et al. ; ; Pandya, ; Hurles et al. ; Shinka et al. ; Zerjal et al. 1999).

Figure 3

Y-chromosome haplotype networks in Brazilians (A) and Portuguese (B). Sampled haplogroups are indicated by circles (with area proportional to the absolute frequency), whereas haplogroups not seen in our sample but essential to drawing the network are indicated by blackened squares. Each link corresponds to one mutational event and is indicated by arrows pointing to the derived state.