The story of the inter-action and inter-breeding of Modern Man with Neanderthals is an ever changing one. As analytical techniques become more sophisticated and accurate then the picture becomes clearer. The latest technique to be applied uses ultra-filtering of samples, to eliminate any form of contamination, thus making the subsequent analysis more accurate.
     Using this technique on analysis of samples of bone and charcoal from several Russian sites seems to shift the evidence to show that Neanderthals were actually starting to die out, before they inter-acted with Modern Man, who was not therefore, on this evidence, the cause of their extinction.
     The decline started between 41,000 and 39,000 years ago, with Modern Man appearing on the scene only 35,000 years ago. there was an overlapping period of about 2,500 years when both species co-existed and inter-bred. It is now hoped to widen the research to eastern Europe and Eurasia, to corroborate these findings.

Edited from LiveScience (20 August 2014)