Neanderthal extinction reconsidered with recent DNA discoveries suggesting continued survival
In a groundbreaking discovery, an international team of geneticists and AI experts, led by Joshua Akey at Princeton's Lewis-Sigler Institute for Integrative Genomics, have provided new insights into our shared history with Neanderthals and Denisovans.
The research, published in the current issue of the journal Science, has uncovered a history of genetic intermingling between early humans and Neanderthals, challenging previous beliefs about our evolutionary past.
According to Akey, the Neanderthal population was likely on the brink of extinction for a long time. The estimated total Neanderthal population, calculated based on the new genetic studies, is about 70,000 individuals. This is significantly smaller than previously believed.
The first Neanderthal bones were discovered, sparking curiosity about these ancient hominins. Neanderthals, known for their robust body build, better suited for enduring physical stress and retaining heat, were skilled hunters and toolmakers who treated injuries with advanced techniques. They adapted well to cold European climates, with a more prominent brow ridge, wider noses, and a mid-facial projection, adaptations for cold climates.
Modern humans, on the other hand, developed a leaner, more gracile frame better suited for endurance running and heat dissipation. They have flatter faces and smaller noses, reflecting different environmental pressures. Neanderthals had larger brains than early modern humans, but their brain structure was different.
The team mapped genetic flow between these groups over the past 250,000 years using genomes from 2,000 living humans, three Neanderthals, and one Denisovan. They identified three waves of contact: 200-250,000 years ago, 100-120,000 years ago, and the largest around 50-60,000 years ago.
Approximately 1-2% of the genome in people of Eurasian descent comes from Neanderthals, contributing to traits like immunity and skin pigmentation. This finding supports the "assimilation model" proposed by Fred Smith in 1989, which suggests that Neanderthals were steadily overwhelmed and incorporated into modern human populations.
The discovery of the Denisovans added to questions about Neanderthals and early humans. However, these new findings provide a more comprehensive understanding of our shared history with these ancient hominins.
This research not only sheds light on our evolutionary past but also opens up possibilities for understanding the genetic basis of various traits in modern humans. It serves as a reminder of the complex and interconnected nature of human history.
