A recent study published in Science has found that interbreeding between ancient human species may have given a survival advantage to groups migrating to the Americas thousands of years ago. The study focused on a gene called MUC19, which is involved in producing proteins for saliva and mucus barriers.
Researchers discovered that a variant of this gene present in modern people with Latin American and Indigenous American ancestry did not come from ancient Homo sapiens but from Denisovans, an archaic human species. Denisovans are most closely related to Neanderthals and diverged from them about 400,000 years ago.
The study found that Denisovan DNA is present in modern people from Papua New Guinea and may have helped strengthen their immune systems. The new study also discovered that ancient Indigenous American populations had high frequencies of the Denisovan MUC19 gene, suggesting it provided a survival advantage.
Statistical analysis revealed that this gene was subject to positive natural selection, indicating it was clearly useful for these populations. Further research is needed to understand how this genetic variation helped ancient modern humans who migrated to the Americas.
Source: https://cosmosmagazine.com/history/archaeology/ancient-human-interbreeding-americas