Looking at habitat overlap for Neanderthals and Denisovans, Pusan National University researcher Jiaoyang Ruan and colleagues found patterns of interbreeding between these two hominins that correlate with climate and environmental change in Eurasia.
“Contemporary humans carry in their cells a small amount of DNA derived from Neanderthals and Denisovans,” Dr. Ruan and co-authors said.
“The 90,000-year-old hominin individual named ‘Denny’ — recently identified as the daughter of a Denisovan father and a Neanderthal mother — bears testimony to the possibility that interbreeding was quite common among early human species.”
“But when, where, and at what frequency did this interbreeding take place?”
Using fossil data, supercomputer simulations of past climate, and insights obtained from genomic evidence, the authors were able to identify habitat overlaps and contact hotspots of these early human species.
“Little is known about when, where, and how frequently Neanderthals and Denisovans interbred throughout their shared history,” Dr. Ruan said.
“As such, we tried to understand the potential for Neanderthal-Denisovan admixture using species distribution models that bring extensive fossil, archeological, and genetic data together with transient Coupled General Circulation Model simulations of global climate and biome.”
The researchers found that Neanderthals and Denisovans had different environmental preferences to start with.
While Denisovans were much more adapted to colder environments, such as the boreal forests and the tundra region in northeastern Eurasia, their Neanderthal cousins preferred the warmer temperate forests and grasslands in the southwest.
However, shifts in the Earth’s orbit led to changes in climatic conditions and hence vegetation patterns.
This triggered the migration of both these hominin species towards geographically overlapping habitats, thus increasing the chance of their interbreeding.
The scientists further…
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