Neanderthals and Denisovans were ancient humans who lived across Eurasia, from Western Europe to Siberia, from about 300,000 to 30,000 years ago.
Your Rh status (positive or negative) is determined by an antigen found on your red blood cells (RBCs). Being Rh-positive or Rh-negative means that either you have the Rhesus D antigen on your RBCs (positive) or you don’t (negative). Rh status is inherited from our parents, separately from our blood type.
While it was long assumed that Neanderthals all possessed blood type O, a new study of previously sequenced genomes of three Neanderthal individuals shows polymorphic variations in their blood, indicating they also carried other blood types found in the ABO blood group system.
We found two Neanderthal variants of the O allele in the Siberian Neanderthals (O1 and O2), one of these variants is shared with an European Neanderthal, who is a heterozygote for this O1 variant and a rare cis-AB variant. The Denisovan individual is heterozygous for two variants of the O1 allele, functionally similar to variants found widely in modern humans. Perhaps more surprisingly, the O2 allele variant found in Siberian Neanderthals can be found at low frequencies in modern Europeans and Southeast Asians, and the O1 allele variant found in Siberian and European Neanderthal is also found at very low frequency in modern East Asians. Our genetic distance analyses suggest both alleles survive in modern humans due to inbreeding with Neanderthals. We find that the sequence backgrounds of the surviving Neanderthal-like O alleles in modern humans retain a higher sequence divergence than other surviving Neanderthal genome fragments, supporting a view of balancing selection operating in the Neanderthal ABO alleles by retaining highly diverse haplotypes compared with portions of the genome evolving neutrally.
