Neolithic transitions: can genetic data help us understand a major demographic event in human prehistory?

Dissertation presented to obtain the Ph.D degree in BiologyThe Neolithic transition is probably the most important cultural, economic and demographic revolution in human prehistory. It profoundly modified the distribution of human genes, languages and cultures worldwide. However, the study of the transition from hunting and gathering to farming societies has generated major controversies among archaeologists and geneticists alike, with one side favouring demic diffusion models and the other the cultural diffusion models. As a first approximation two alternative demographic scenarios can be considered. Under the cultural diffusion models the transition to agriculture is regarded essentially as a cultural phenomenon, involving the movement of ideas and practices, rather than people. In the demic diffusion models, a movement of people is involved. It can be shown that both models can be seen as special cases of an admixture model between Palaeolithic/ Mesolithic and Neolithic populations. In this thesis, I used nonequilibrium and spatial admixture model approaches to help answer this long-standing controversy. I showed that demic diffusion models better explain the patterns of genetic diversity found in today’s European and Japanese populations, but I do not rule out the role of cultural processes locally. (...)Esta tese obteve o apoio financeiro da FCT e do FSE no âmbito do Quadro Comunitário de Apoio, BD nº SFRH/BD/30821/2006