Passage Summary: Scientists used to think we mixed with Neanderthals, but because our DNA looks very different from a Neanderthal's DNA, the author says it never happened.

Conclusion: Prehistoric ancestors of modern humans did not interbreed with Neanderthals.

Reasoning: DNA from a Neanderthal specimen is significantly different from the DNA of people living today.

Analysis: The anthropologist is making a huge leap from 'modern DNA is different' to 'interbreeding never happened.' This argument relies on the assumption that if interbreeding had occurred, we would still see Neanderthal DNA in humans today. It also assumes that the DNA from the specific remains tested is representative of Neanderthals as a whole. If Neanderthal genetic markers could have disappeared over thousands of generations, the author's evidence wouldn't actually prove their conclusion. The necessary assumption will likely bridge the gap between ancient mating and modern genetic evidence.