Inbreeding and population/demographic shifts could have led to Neanderthal extinction
(PHYSorg.com Archaeology & Fossils)

Small populations, inbreeding, and random demographic fluctuations could have been enough to cause Neanderthal extinction, according to a study published November 27, 2019 in the open-access journal PLOS ONE by Krist Vaesen from Eindhoven University of Technology, the Netherlands, and colleagues.