http://www.usatoday.com/tech/science/discoveries/2010-05-06-neanderthal07_ST_N.htm

Neanderthals and humans interbred, fossils indicate

Modern humans, meet the relatives: Neanderthals.
It turns out, based on a new fossil analysis out Thursday, that people of European and Asian descent inherited a small amount, an average 1% to 4% of their genes, from the extinct species.

Humans and Neanderthals likely interbred 50,000 to 80,000 years ago in the Near East, concludes the international genetics team's pair of studies in the new issue of the journal Science. The research was led by German genome researcher Svante Paabo of the Max-Plank Institute for Evolutionary Anthropology. The finding splits the difference in a long-running scholarly debate over whether people are solely African in origin, or spring from "multiregional" interbreeding of early human species.