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 tetranucleotide repeats (DYS393, DYS390 and DYS19). Among 140 Y chromosomes
from Whites, Blacks, Japanese and Amerindians we identified 67 different
haplotypes, the majority of
them population-specific; only seven haplotypes were shared by three different
racial groups, mostly
owing to admixture. Overall, three main lineages can be defined on the
basis of the
YAP/DYS199/DYS392 markers: (a) a predominant
/−/C/10/13/22
(or)
23/ lineage, observed
among all racial groups; (b) a/+/C/ lineage which
predominates 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 sublineage
/−/T/13/13/). The
decreasing
haplotype diversity of the three lineages agrees with the idea that the
first is the most ancient, while the last is the more recent. The data
also
indicate that the YAP insertion occurred in a
/−/C/10/13/ chromosome
and the
C→T mutation occurred in a
/−/C/13/13/ chromosome.
Finally, the data suggest that at least two Y-chromosome lineages
(/−/C/13/ and
/−/T/13/) contributed to the early
peopling of the Americas, and supports the
hypothesis that /−/T/13/ could
be derived from /−/C/13/ and that
both haplotypes could be
present in the ancestral populations that peopled the continent.