A team of researchers has discovered that modern humans carry genes form an unknown ancestors. The newly-found genes may have been obtained from mating between hominin species more than a million years ago.
It is theorized that the ancestor may have been Homo erectus, but it is hard to say since the genome of the species hasn’t been sequenced. The new study has also revealed that early humans mated with Neanderthals between 200,000 to 300,000 years ago, which is considerably earlier in comparison to similar mating events which took place 50,000 years ago.
Previous research had mentioned that humans and Neanderthals mated when the population interacted in Europe before the latter went extinct. A 2010 study noted that up to 4% of the DNA encountered in people from Europa, Asia, and Oceania can be traced back to the Neaderthalian ancestors.
Advancement in technology has offered the opportunity to sequence sensitive DNA fragments that have been collected from ancestors, revealing that interbreeding has been taking place thousands of years ago. For example, Denisovan genes have been found in the DNA of inhabitants who live on select Pacific Islands
The authors of the new study relied on a computational method to compare genes collected from Neanderthals, a Denisovan, and two persons from Africa, as Africans do not feature the Neanderthal genes which were obtained from recent interbreeding events which took place 50,000 years ago.
The main advantage offered by the method which was chosen by the researchers is that it allows them to trace recombination events found within recombination events. In this case, a gene may have have been incorporated from an unknown source into the Neanderthal genome, and from there into the genome of ancient humans.
More information can be found in the study, which was published recently in a scientific journal.