Neanderthals held on for thousands of years after modern humans migrated out of Africa, and then died out. Our understanding of how that happened changes continuously as new research is done. At first we assumed that modern humans killed them off. Then we found Neanderthal DNA in living humans, and began to think that maybe we just absorbed the smaller Neanderthal population. Or maybe it was a combination of the two. Another possibility has emerged: that male Homo sapiens mating with Neanderthal women sabotaged their ability to produce thriving offspring due to genetic differences. Researchers found the culprit is hemolytic disease of the newborn, which includes Rh factor disease and ABO compatibility. From the research paper:
We show that Neanderthal and Denisova were polymorphic for ABO and shared blood group alleles recurrent in modern Sub-Saharan populations. Furthermore, we found ABO-related alleles currently preventing from viral gut infection and Neanderthal RHD and RHCE alleles nowadays associated with a high risk of hemolytic disease of the fetus and newborn. Such a common blood group pattern across time and space is coherent with a Neanderthal population of low genetic diversity exposed to low reproductive success and with their inevitable demise.
In other words, the Neanderthal population wasn't large or genetically diverse enough to withstand the influx of incompatible blood types from the more populous modern humans. Read a layman's translation of the research with lots of links at Metafilter.
(Image credit: Bacon Cph)
#Neanderthal #DNA #bloodtype #hemolyticdisease
