DNA shows a prehistoric Colombian population that vanished totally

[Duncan Head]

https://www.smithsonianmag.com/smart-news/ancient-dna-reveals-mysterious-new-group-of-humans-in-colombia-with-no-genetic-ties-to-people-today-180986819/

[Nick Harbud]

Abducted by aliens, obviously.   

[Duncan Head]

The stuff of so many SF novels...

Does make me wonder how many times this may have occurred (the disappearance, not necessarily the abductions) without the telltale DNA evidence being found.

[Keraunos]

At least one episode captured on film - The Last of the Mohicans 

[Imperial Dave]

Perhaps they imbibed too much marching powder and marched off somewhere...

[Andreas Johansson]

They were hunter-gatherers in a region later colonized by immigrant agriculturalists, so the possibility raised in the article that they were simply genetically swamped by the newcomers seems highly plausible. There probably never were very many of them.