Europe

Many aspects of the population history of Europe have been reconstructed from genetic and genomic evidence, drawing inference both from levels and patterns of present genetic diversity and from ancient DNA data. The main events that have been proposed to have shaped the European gene pool are probably as few as four, including: (1) the replacement of Neanderthals by anatomically modern humans around 40,000 years BP, with very limited, but nonzero levels of introgression, (2) the Paleolithic peopling of the continent, followed by a demographic contraction at the last glacial maximum; (3) a large demographic replacement associated with the Neolithic expansion of early farmers, that would have affected the genetic makeup of Europeans more strongly in the Southeast than in the Northwest; and (4) successive migration phenomena, mostly from the East, with a peak in the Bronze age. The relative importance in the present gene pool of the Paleolithic and Neolithic substrates, both having entered Europe from the Southeast, has been a matter of debate, with an important increase of evidence favoring a strong impact of the Neolithic. Several open questions remain to be addressed, including the relative role of cultural and migrational phenomena in causing the Indo-European linguistic expansion. Recent evidence of ancient DNA, with its diversity in time and space, makes the picture more complex and opens the possibility of other, more recent events, having left their signature in the European gene pool.