Past posts have described the science of evolution, and the development on Earth over time of its atmosphere and of various life forms. Prior posts have also noted that science is a constantly changing picture as new data and information are developed. Speaking of recent developments, research now appears to suggest that Neanderthals and non-African Homo Sapiens (us) may have interbred.
Previous genetic analysis which examined mitochondria (non-cellular nucleus DNA which passes from mother to child) had indicated that there was no interbreeding between Neanderthals and so-called modern humans. The new assessment, unlike that which was undertaken beforehand, examined the DNA in the cell nucleus. The researchers compared the DNA of Africans (whose ancestors could not have interbred with Neanderthals since they did not have overlapping geographical locations) and various Eurasians (whose ancestors could have interbred with Neanderthals) with DNA derived from bone fragments of Neanderthals. The research indicates that between 1% and 4% of Eurasian nuclear DNA is Neanderthal. However, what is so curious about this result is that no Neanderthal mitochondrial DNA has turned up in modern humans. Normally one would expect to see such DNA because historically invader's males mate with the females of the invaded.
The research also illuminates some of the differences between Neanderthals and modern humans. The researchers compared modern humans, Neanderthals, and chimpanzees in order to highlight genetic changes that arose as the several species of humans evolved away from the great-ape lineage. More than 90% of the "human accelerated regions" that have been identified in modern humans are shared with Neanderthals. Genetic analysis is still rather primitive, but the researchers alleged they found a number of genes associated with cognitive ability that were present in modern humans but not in Neanderthals. Other genetic differences are associated with skull and rib-cage shape. Earlier analysis had shown that modern humans and Neanderthals share a gene called FOXP2, which is involved with the ability to speak, and which is differs in chimpanzees. Thus, Neanderthals may not have been the grunting hulks of recent stereotype.
Some anthropologists have criticized the conclusions drawn, arguing that there is no cultural evidence for the implications drawn. As they say, we shall see.
The report by the researchers can be found at http://www.sciencemag.org/cgi/content/abstract/328/5979/710.