Neanderthals, Denisovans and homo sapiens sapiens - and now the Monday Forum post as well

 The mystery of the Neanderthals has long fascinated people. What were they? Why did they vanish? Were they wiped out by homo sapiens? Now we know that human beings carry a proportion of Neanderthal genes that varies but appears to be an average of perhaps 2%. The Neanderthal survives within us.

Given such apparent inter-breeding, the question of when the two groups first had sex exercises a sort of fascination. We can see this in this Guardian headline:
Skull discovery suggests location where humans first had sex with Neanderthals.

The story is by no means as exciting as the headline would suggest. It refers to the discovery of a modern human skull in a cave in Northern Israel dating to perhaps 55,000 year ago, a time when the "region when it was already well populated with Neanderthals. Skeletons of Neanderthals from the same time have been recovered from Amud cave 24 miles (40km) to the east of Manot cave, and from Kebara cave 30 miles to the south."

The Neanderthal are far more ancient than that Johnny come lately homo sapiens sapiens  with a sophisticated tool using culture. Nor, as we now know through the miracles of DNA analysis, were they the only older human species co-existing with and interbreeding with homo sapiens sapiens. 

In March 2010, scientists announced the discovery of a finger bone fragment of a juvenile female who lived about 41,000 years ago, found in the remote Denisova Cave in the Altai Mountains in Siberia, a cave that has also been inhabited by Neanderthals and modern humans.

Analysis of the mitochondrial DNA (mtDNA) of the finger bone showed it to be genetically distinct from the mtDNAs of Neanderthals and modern humans. Subsequent study of the nuclear genome from this specimen suggests that Denisovans shared a common origin with Neanderthals, that they ranged from Siberia to South-East Asia, and that they lived among and interbred with the ancestors of some modern humans, with about 3% to 5% of the DNA of Melanesians and Aboriginal Australians deriving from Denisovans.

DNA discovered in Spain suggests that Denisovans at some point resided in Western Europe, where Neanderthals were previously thought to be the only inhabitants. A comparison with the genome of a Neanderthal from the same cave revealed significant local interbreeding with local Neanderthal DNA representing 17% of the Denisovan genome, while evidence was also detected of interbreeding with an as yet unidentified ancient human lineage. 

In addition to the linked Wikipedia articles, you can find more on the Denisovans (and the Neanderthals too) on John Hawks blog.

Postscript

I had planned to bring up a post last night on the Finnish school system for the Monday Forum but events intervened. Now it seems that the Neanderthal theme has generated its own comments not connected with the post, so go for it in whatever direction you like!