Continent-wide decoupling of Y-chromosomal genetic variation from language and geography in native South Americans

.ROEWER L., ; GUSMAO L; GOMES V; GONZALEZ M; CORACH D; SALA A; ALECHINE E

Innsbruck

Congreso; DNA in Forensics 2012. "DNA in Forensics: Exploring the Phylogenies"; 2012

Y User and EMPOP

   The way of initial habitation creates a primordial spatial pattern of human genetic variation that is subsequently modified by demographic processes. Under the assumption that most such changes follow trajectories set by climate as well as geographic and cultural conditions, some correlation between the genetic structure on the one hand, and the linguistic and geographical structure on the other, is to be expected in extant human populations even a long time after an initial colonization event and has been documented in numerous studies on European and Asian populations. In contrast, there is a notable absence of such descriptions for South America. Here, we examined Y-chromosomal genetic diversity and its relation to geographic location and linguistic classification on a continental scale in the so far largest study on South American natives, involving up to 17 microsatellite markers genotyped in a total sample of 1011 individuals representing 50 tribal populations from 81 settlements as well as single-nucleotide polymorphisms defining the founding native American phylogenetic lineages Q and C and its sub lineages. We observed a large decoupling of Y-chromosomal genetic diversity from geographical habitats and in parts from language groups on a continental scale, which is consistent with a rapid peopling of the continent and subsequent long periods of isolation of relatively small-sized tribal groups. Our results highlight the fact that a pronounced correlation between genetic and geographic/cultural structure can be expected only under very specific conditions, most of which are likely not to have been met by native South Americans