US researchers have discovered traces of two previously unknown hominin groups in human DNA. Hominins include modern humans, Neanderthals, and other human evolutionary lineages. One of these groups originated in Africa about 50,000 years ago. Its existence had been speculated before, but until now it had not been proven.
Read more Will you answer 10 difficult general knowledge questions?
The other lineage – the so-called “superarchaic” hominins – is much older. It is believed to date back about 1.8 million years. According to researchers, this group interbred with Denisovans – another extinct hominin group, like Neanderthals no longer surviving to this day.
Their DNA mixed in Eurasia, and after thousands of years, the Denisovans passed part of this “superarchaic” DNA to modern humans. It is believed that these “ghostly” genetic traces in the genome of modern humans may be about as much as Neanderthal DNA – about 1 percent.
“We found that about 2 percent of the modern human genome comes from archaic hominins,” said Yulin Zhang, one of the researchers from the University of California, Berkeley.
“Regarding this ‘ghostly’ lineage, both modern Africans and non-African populations inherited a similar amount of its genetic material. Each person has about 0.5 to 1 percent of the genome inherited from this ‘ghostly’ lineage,” he explained.
Arjunas Biddanda, a postdoctoral researcher at Johns Hopkins University and one of the main authors of the study, told the portal “Phys.Org”: “The superarchaic discovery is especially exciting because it reveals a genetic contribution from a human evolutionary lineage that lived more than a million years ago, even though we have no sequenced DNA from that population.”
It was previously thought that “ghost” DNA exists in the genome of modern African populations. However, the new study showed that it is similarly found among both Africans and non-African populations. This suggests that much of the interbreeding occurred before Homo sapiens began spreading beyond Africa.
These data also strengthen theories that modern humans are composed of genetic legacies from various extinct hominins. It shows that different branches of the human family were connected by interbreeding for thousands of years, ultimately contributing to the formation of the humans we are today.
Read more Homecoming for Champions League coach of «Kauno Žalgiris»: «Maybe this will be THAT one time?»
