New research by scientists at the University of California, Davis, shows how natural selection has purged all but the smallest bits of that ancient Neanderthal DNA from modern humans.

This picture shows three bones (Vi33.16, Vi33.25, Vi33.26) from Vindija cave, Croatia. Most of the Neandertal genome sequence was retrieved from these bones./ Image courtesy of Max-Planck-Institute EVA A new...