The first humans to reach the Americas didn’t just bring tools and survival skills; they also carried a unique genetic legacy from Neanderthals and Denisovans. This connection may have played a crucial role in helping them adapt to unfamiliar and challenging environments.
A recent study in Science led by researchers from the University of Colorado Boulder and Brown University delved into a specific gene called MUC19. This gene is linked to the production of mucus, which helps protect the body from infections. The study found that many Indigenous Americans carry a version of this gene inherited from Denisovans. This variant seems to have provided a survival advantage, as it became more common over time.
Interestingly, about one in three Mexicans today possesses this Denisovan variant, compared to only 20% of Peruvians and about 1% of individuals from Puerto Rico and Colombia. This variation likely mirrors the amount of Indigenous American ancestry in these populations.
What’s particularly fascinating is how this genetic material was passed down. Scientists discovered that the Denisovan DNA didn’t go directly into modern humans. Instead, it made its way through Neanderthals, creating a unique blend of genetics. This process is likened to an “Oreo”—with the Denisovan DNA as the creamy filling, encapsulated by Neanderthal DNA. This finding represents the first documented case where a Denisovan gene was introduced into humans via Neanderthals.
The researchers analyzed genomes from ancient Indigenous remains as well as modern DNA from populations across the Americas. They identified that the Denisovan variant alters how MUC19 behaves, potentially enhancing immunity. The study suggests a strong selection advantage for this genetic feature, reflecting a significant evolutionary leap.
In terms of broader implications, Villanea noted the gene’s spread hints at remarkable adaptation among Indigenous groups. Despite still having many unanswered questions about Denisovans—who were only recognized as a distinct group in the last 15 years—research shows that their influence can be found in various modern populations. For example, some Oceanians carry up to 5% Denisovan genes.
The research indicates that the MUC19 variant has been crucial for survival, helping early Americans tackle new climates, diets, and pathogens. As time progressed, natural selection favored those who carried this protective gene variant, enhancing their resilience.
The next steps for Villanea and his team involve exploring how different versions of MUC19 affect health today, particularly among Latino and Indigenous populations. This research not only deepens our understanding of human evolution but also sheds light on the health challenges these communities face now.
For more insights into the genetic history and influence of Denisovans and Neanderthals, you can read the full study here.
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Denisovans,DNA analysis,Homo sapiens,Native American civilization,Neanderthals
