Researchers from Cornell University (Melissa Hubisz and Amy Williams) Cold Spring Harbor Laboratory (Adam Siepel), analyzed genomes from two Neanderthals, a Denisovan, and two African humans to identify segments of DNA that came from other species.
Using a genetic analysis algorithm developed by the scientists it has revealed that today’s humans carry the genes of an unknown ancestor due to hominin species intermingling hundreds of thousands of years ago.
The scientists also found more evidence that ancient humans and related species crossbred various times, thanks to the remnants inside our DNA.
It is known that some humans migrated out of Africa and crossbred with Neanderthals in Eurasia approximately 50,000 years ago. However, this new study shows that that was not the only instance where our human ancestors and their relatives interbred with each other and exchanged DNA.
The surprising result was that it was seen that 3% of the Neanderthal genome could be traced back to ancient humans and that the interbreeding had happened between 200,000 and 300,000 years ago. Additionally, it was found that 1% of the Denisovan genome was determined to have come from an unexpected source – an “archaic human ancestor” that was neither human, nor Neanderthal, nor Denisovan.
The scientists propose that this archaic human ancestor could be Homo Erectus, and writes, “It may be reasonable to assume that genetic exchange was likely whenever two groups overlapped in time and space.”
Read more:
- We Carry DNA From a Mysterious Species, Science Finds
- Mapping gene flow between ancient hominins through demography-aware inference of the ancestral recombination graph; Published: August 6, 2020 PLOS Genetics.