Understanding early human demography variation and Mt haplogroup distribution in the Americas

J. LANATA, C. DEJEAN, C. CRESPO, R. CARNESE.

oregon

Congreso; EARLY MAN IN SOUTH AMERICA: NEW PARADIGMS IN LATE PLEISTOCENE / EARLY HOLOCENE BIOLOGICAL ANTHROPOLOGY.; 2012

81stAnnual Meeting of the American Association of Physical Anthropologists

The tempo and mode of the initial human dispersal in theAmericas is a key issue for the study of its ulterior variation and diversity through time. We present a demographic model to explore the population dynamic on the base of paleo-environmental reconstructions between the ca. 18 and 10 kybp and different dispersal simulations are presented by considering a fast invasive process and a slow one. The model used Fisher equation plus a term related to carrying capacity; when population density achieved certain threshold, it has to move to the best neighbor environment. Our population dispersal model depends on population growth, diffusion and a minimum population to produce a migration. The equation considers gender differences in the populations and also estimates the reproduction probability for men and women. The results show a relatively similar demographic distribution in both cases, where Mesoamerica and the Amazon were areas with higher population densities since early moments. We consider Mt haplogroups inheritance in the models and its shows a very similar distribution with the actual ancient DNA available data. It seems that Mt haplogroups distribution is probably related to major bottleneck effects during the initial population dispersal in North and South America. The simulations also reveal that a high average annual population growth could be necessary to explain theAmericascolonization by a single population spreading from Beringia toTierra del Fuego. The models show diverse scenarios useful for highlight different aspects of the Pre Clovis-Clovis debate. The evolutionary consequences are discussed.