Scientists who have been studying the DNA of Neanderthals say they can't find evidence that they ever bred with modern humans.

The bones used in the study came from a cave in Croatia. The scientists say they have mapped about 60% of the Neanderthal genome so far.

Although they have found no evidence that Neanderthals are the direct ancestors of modern humans the scientists say Neanderthals and humans share the genes that are responsible for the development of speech and language.