Congratulations to current and past CCMB students David Peede, Valeria Añorve-Garibay, Elizabeth T. Chevy and CCMB Faculty Emilia Huerta-Sanchez on their recent publication in Science!
This research explores how genes and traits inherited from ancient human species (Neanderthals and Denisovans) might have helped Indigenous populations adapt to new environments as they populated the Americas.
About the research: 
Modern human genomes contain a small number of archaic variants, the legacy of past interbreeding events with the archaic human species Neanderthals and Denisovans. While most of these variants are believed to be neutral, some archaic variants found in modern humans have been targets of positive natural selection and may have been pivotal for adapting to new environments as humans populated the world. As ancient humans moved into the Americas and encountered a myriad of novel environments, this provided the opportunity for natural selection to favor archaic variants in these new environmental contexts. Indigenous and admixed American populations have historically been understudied in this regard, but they present great potential for studying the underlying evolutionary processes of local adaptation.
In the research team’s recent paper published in Science, they examined patterns of archaic genetic ancestry in the gene MUC19—which codes for a mucin involved in immunity—to determine whether it carries signatures of adaptation in modern human populations from the Americas and to identify the specific regions of the gene involved.
The findings show that archaic variants in MUC19 present in these populations bear clear signs of being beneficial, suggesting they may have helped early populations adapt to the environments of the Americas during their expansion into the continent. The researchers identified point mutations that alter the protein sequence, as well as a unique structural variant that duplicates one of the gene’s exons. Because these changes occur in coding regions, they likely affect the protein’s structure and potentially its function, suggesting that this was likely a game-changing genomic event when it happened. The results point to a complex pattern of multiple introgression events, from Denisovans to Neanderthals and Neanderthals to modern humans, which may have later played a distinct role in the evolutionary history of Indigenous American populations.
Read the full research article: https://doi.org/10.1126/science.adl0882
Fernando A. Villanea et al., “The MUC19 gene: An evolutionary history of recurrent introgression and natural selection.” Science 389, eadl0882 (2025). DOI: 10.1126/science.adl0882