DNA sequenced from 39 ancient skeletons suggests the foundations of the modern European gene pool were laid down between 4000 and 2000 BCE, in Neolithic times - likely by the rapid growth and movement of some populations.
     Decades of study suggest two major events in prehistory significantly affected the continent's genetic landscape: its initial peopling by hunter-gatherers 35,000 years ago in Palaeolithic times, and a wave of migration by Near Eastern farmers some 6,000 years ago in the early Neolithic.
     Genetic signatures of people from the Early Neolithic were either rare or absent from modern populations. From the Middle Neolithic onwards, mitochondrial DNA patterns more closely resemble those of people living in the area today, pointing to a major and previously unrecognised population upheaval around 4000 BCE.
     Co-author Professor Alan Cooper, from the University of Adelaide in Australia, said: "What is intriguing is that the genetic markers of this first pan-European culture, which was clearly very successful, were then suddenly replaced around 4,500 years ago, and we don't know why."
     A significant contribution appears to have been made in the Late Neolithic, by populations linked to the so-called Bell Beaker culture. The origins of the "Beaker folk" are the subject of much debate - Beaker individuals in this study excavated from the Mittelelbe Saale region of Germany showed close genetic similarities with people from modern Spain and Portugal.
     Other remains belonging to the Late Neolithic Unetice culture attest to links with populations further east.

Edited from BBC News (23 April 2013)