As I recall, the natives of New Guinea were supposed to have Neanderthal DNA. I know that Melanesians are claimed to have the DNA of the newly discovered, Neanderthal-ish Denisovans.
I guess the question of the origins of the Australian Aborigines is complex. Some investigatprs posit multiple migrations of different human groups.
On a related note, I have recently learned of the Solutrean Hypothesis that North America was partially settled by European immigrants during the latter part of the Wisconsinian glaciation. This seems plausible to me. I have long noted that the Northeastern forest Indians, to judge from the portraits of such notables as Joseph Brant (supposedly an ancestor of mine), Little Turtle and Tecumseh, look much more "Caucasoid" than their Western counterparts. I am aware that DNA analyses supposedly show all the American Indians to be descended from a single Asian, migration. However, as I have said before, I remain profoundly distrustful of a lot of these DNA analyses, even though some might say this puts me in the same league as Flat Earthers, Young Earthers and moon mission deniers.
Coincidentally, a couple of weeks ago I mentioned Julia Pastrana, the Mexican "ape-woman" in this thread. I just noticed on the Net that her remains are finally getting a decent burial.