We're not talkin' Kiwis or sheep here, but ...

Neanderthals and humans interbred, fossils indicate

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.

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. 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.

Stocky, thick-browed and heavy-boned, the Neanderthals last shared a common ancestor with the African precursors to modern humans about 500,000 years ago. The Neanderthals populated the Near East and Europe until they vanished from the fossil record about 30,000 years ago. The gene maps produced by the DNA analysis of the bones found Neanderthal genes scattered randomly among non-Africans, Paabo says, indicating they don't account for any racial differences between modern-day Africans and anyone else. Also, the study finds no sign of human genes intruding into the Neanderthal lineage.

The studies also revealed a few dozen genes altered in humans since they genetically diverged from Neanderthals; some related to skull and brain development. But overall, "they were not very genetically distinct from us," Paabo says.