DIVERSITY OF THE HUMAN Y-CHROMOSOME OF SOUTH-AMERICAN AMERINDIANS - ACOMPARISON WITH BLACKS, WHITES, AND JAPANESE FROM BRAZIL

We defined the Y-chromosome haplotypes on the basis of six polymorphic sites: an Alu-element insertion (YAP), a single-base change (C --> T at DYS199), one trinucleotide repeat (DYS392) and three tetranucleotid e repeats (DYS393, DYS390 and DYS19). Among 140 Y chromosomes fr om Wh ites, Blacks, Japanese and Amerindians we identified 67 different hapl otypes, the majority of them population-specific; only seven haplotype s were shared by three different racial groups, mostly owing to admixt ure. Overall, three main lineages can be defined on the basis of the Y AP/DYS199/DYS392 markers: (a) a predominant /-/C/10/13/22 (or) 23/ lin eage, observed among all racial groups; (b) a /+/C/ lineage which pred ominates among Blacks (comprising mainly the sublineage /+/C/10/13/), although it is eventually found among Japanese and Whites; and (c) a / -/T/ lineage observed only among Amerindians (comprising mainly the su blineage /-/T/13/13/). The decreasing haplotype diversity of the three lineages agrees with the idea that the first is the most ancient, whi le the last is the more recent. The data also indicate that the YAP in sertion occurred in a /-/C/10/13/ chromosome and the C --> T mutation occurred in a /-/C/13/13/ chromosome. Finally, the data suggest that a t least two Y-chromosome lineages (/-/C/13/ and /-/T/13/) contributed to the early peopling of the Americas, and supports the hypothesis tha t /-/T/13/ could be derived from /-/C/13/ and that both haplotypes cou ld be present in the ancestral populations that peopled the continent.