Mitochondrial variation among the Aymara and the signatures of population expansion in the central Andes.
OBJECTIVE
The exploitation of marine resources and intensive agriculture led to a marked population increase early in central Andean prehistory. Constant historic and prehistoric population movements also characterize this region. These features undoubtedly affected regional genetic variation, but the exact nature of these effects remains uncertain.


METHODS
Mitochondrial DNA (mtDNA) hypervariable region I sequence variation in 61 Aymara individuals from La Paz, Bolivia, was analyzed and compared to sequences from 47 other South American populations to test hypotheses of whether increased female effective population size and gene flow influenced the mtDNA variation among central Andean populations.


RESULTS
The Aymara and Quechua were genetically diverse showing evidence of population expansion and large effective population size, and a demographic expansion model fits the mtDNA variation found among central Andean populations well. Estimated migration rates and the results of AMOVA and multidimensional scaling analysis suggest that female gene flow was also an important factor, influencing genetic variation among the central Andeans as well as lowland populations from western South America. mtDNA variation in south central Andes correlated better with geographic proximity than with language, and fit a population continuity model.


CONCLUSIONS
The mtDNA data suggests that the central Andeans experienced population expansion, most likely because of rapid demographic expansion after introduction of intensive agriculture, but roles of female gene flow need to be further explored.
Cancer Education and Career Development Program, Institute for Health Research and Policy, University of Illinois at Chicago (M/C 275), Chicago, Illinois, 60608; Institute of Human Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, 60607.
Ken
K
Batai
Sloan R
SR
Williams
D001838:Bolivia; D004272:DNA, Mitochondrial / Q000235:genetics* / Q000378:metabolism; D005006:Ethnicity / Q000235:genetics; D005260:Female; D051456:Gene Flow; D063426:Human Migration; D006801:Humans; D019901:Locus Control Region; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011158:Population Growth; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial