The ancestry of Brazilian mtDNA lineages

Abstract

We have analyzed 247 Brazilian mtDNAs for hypervariable segment (HVS)-I and selected restriction fragment-length-polymorphism sites, to assess their ancestry in different continents. The total sample showed nearly equal amounts of Native American, African, and European matrilineal genetic contribution but with regional differences within Brazil. The mtDNA pool of present-day Brazilians clearly reflects the imprints of the early Portuguese colonization process (involving directional mating), as well as the recent immigrant waves (from Europe) of the last century. The subset of 99 mtDNAs from the southeastern region encompasses nearly all mtDNA haplogroups observed in the total Brazilian sample; for this regional subset, HVS-II was analyzed, providing, in particular, some novel details of the African mtDNA phylogeny.

Figure 1

Five major geographic regions of Brazil: N = northern, NE = northeastern, SE = southeastern, S = southern, and CW = central west. Brazilian states from which the mtDNA lineages of the present study have mainly been sampled are indicated by name.

Figure 2

Classification tree highlighting selected diagnostic sites and positions for haplogroups present in the Brazilian sample (see tables 1 andtable 6table 6). Each square represents the root node of the respective haplogroup, with the acronym inscribed; two central/eastern-African haplogroups, represented by circles, are only partially characterized (T. Kisivild, personal communication). “CRS” indicates the revised reference sequence (Andrews et al. 1999). Numbers along links refer to RFLP sites (with arrows pointing to presence of sites) or transitions, unless a single-letter suffix indicates a transversion. Note that some diagnostic sites and positions, especially in the control region, have undergone recurrent mutations. The root of the tree, labeled “mtEve,” is inferred by employing the Neanderthal HVS-I and HVS-II sequences (Krings et al. 1997, 1999) and the coding-region sequences of bonobo and common chimpanzee (Horai et al. 1995) as outgroups; this corroborates the rooting of the Vigilant (1990) tree.