Ötzi the Iceman died around 3,300 B.C., yet his body was preserved frozen in the Alps until 1991. DNA sequencing of Neandertals (who died out about 35,000 years ago) suggests modern humans with ancestry outside of Africa carry a few percent of Neandertal genes due to interbreeding. Now (in a blog post knocking down a re-interpretation of the Neandertal DNA evidence) paleontologist John Hawkspreviews an upcoming publication of his examining Ötzi's DNA::
If we took as a baseline that Europeans have an average of 3.5 percent Neandertal, Ötzi would have around 5.5 percent (again, the actual percentage would be highly model-dependent). He has substantially greater sharing with Neandertals than any other recent person we have ever examined.Previously (Ötzi), Previously (Neandertals)