Scientists use genetics and climate reconstructions to track the global spread of modern humans out of Africa

Research indicates the out-of-Africa spread of humans was dictated by the appearance of favourable climatic windows. The idea that we can reconstruct climate, and estimate food availability and finally figure out the demographic changes and movements of our ancestors all over the world is simply amazing." - —Andrea Manica By integrating genetics with high resolution historical climate reconstructions, scientists have been able to predict the timing and routes taken by modern humans during their expansion out of Africa. Their research reveals that the spread of humans out of Africa was dictated by climate, with their entry into Europe possibly delayed by competition with Neanderthals. The research is published today, 17 September, in the journal PNAS . Anders Eriksson, from the University of Cambridge, the lead author of the paper said: "By combining extensive genetic information with climate and vegetation models, we were able to build the most detailed reconstruction of human history so far." The role of climate change in determining the timing of the expansion of human populations has been long debated. The oldest fossil remains of anatomically modern humans are found in Africa and date back to around 200 thousand years ago, but there is no trace outside Africa until 100 thousand years later. The newly published model provides the first direct link between climate change and the timing of the expansion out of Africa, as well as the routes taken.