" And so Mary at last turned her attention to Ponter’s nuclear DNA. She’d thought it would be even more difficult to find a difference there, and indeed, despite much searching, she hadn’t found any sequence of nucleotides that was reliably different between Neanderthals and Homo sapiens sapiens; all her primers matched strings on DNA from both kinds of humans. "

― Robert J. Sawyer , Humans (Neanderthal Parallax, #2)