You’re not presenting your sources accurately. The full quote from [1]: > No evidence of Neanderthal mitochondrial DNA has been found in modern humans. This s

You’re not presenting your sources accurately. The full quote from [1]: > No evidence of Neanderthal mitochondrial DNA has been found in modern humans. This suggests that successful Neanderthal admixture happened in pairings with Neanderthal males and modern human females. The full quote from [2]: > A 2016 study presented evidence that Neanderthal males might not have had viable male offspring with AMH females. This could explain why no modern man to date has been found with a Neanderthal Y chromosome. Also from [2]: > Positive evidence for admixture was first published in May 2010. Neanderthal-inherited genetic material is found in all non-African populations and was initially reported to comprise 1 to 4 percent of the genome. This fraction was later refined to 1.5 to 2.1 percent.