A new study has found that ancient interbreeding with archaic human species, such as Denisovans, may have provided modern humans with a genetic variant that helped them adapt to new environments. Researchers focused on a gene called MUC19, which is involved in the production of proteins that form saliva and mucosal barriers.
The study showed that a variant of this gene derived from Denisovans is present in high frequencies in modern Latin Americans with Indigenous American ancestry, as well as in DNA collected from individuals excavated at archeological sites across North and South America. This suggests that the gene was under significant natural selection, meaning it provided a survival or reproductive advantage to those who carried it.
The researchers believe that this genetic variant may have helped populations fight off pathogens encountered during their migration into the Americas thousands of years ago. The study’s findings demonstrate the importance of interbreeding in introducing new and potentially useful genetic variation in the human lineage.
According to Emilia Huerta-Sánchez, a professor of ecology, evolution, and organismal biology at Brown University, “From an evolutionary standpoint, this finding shows how ancient interbreeding can have effects that we still see today.” The researchers hope that further study will reveal the function of this gene and its potential biological mechanisms.
Source: https://www.brown.edu/news/2025-08-21/denisovan-genes