For millennia, mankind has walked the earth. While homo sapiens are the only existing human species at present, we have not always been alone.
This comes after a new study’s findings which shows a newfound extinct human lineage actually lived in New Guinea, who interbred with modern humans.
While this discovery might be frowned upon by creationists, scientists add this lineage’s genetic differences from other humans, makes it as distinct a group as our closest extinct relatives, the Neanderthals and the Denisovans.
This cannot be possibly true. Or can it?
While Homo Sapiens are currently the only living part of the human family tree, other humans lived among modern man and interbred with them. Actually, leaving behind DNA in the modern human genome.
These ancient lineages don’t only include Neanderthals, which are our closest extinct relatives, but also the Denisovans, who are only known through fossils unearthed in the Denisova Cave located in the Altai Mountains, Siberia.
While previous research found Denisovans shared a common origin with Neanderthals, they were almost as genetically distinct from Neanderthals as Neanderthals are from Homo Sapiens.
Furthermore, prior work estimates the ancestors of Homo Sapiens split from the common ancestors of Neanderthals and Denisovans approximately 700,000 years ago. From there, it is speculated the ancestors of Neanderthals and Denisovans then diverged from one another about 400,000 years ago.
During the course of 2018, scientist discovered Denisovans possessed one more lineage. One which is closely related to the Siberian Denisovan and actually has a genetic legacy found primarily in East Asians. The other was more distantly related to the Siberian Denisovan and has DNA found mostly in Papuans and South Asians these days.
These groups apparently split up approximately 283,000 years ago.
Determined to learn more about Denisovan genetics, scientists embarked on a study of epic proportions. Going out, the scientists analysed 161 homo sapiens genomes, spanning 14 island groups in both Southeast Asia and New Guinea.
During this study, the researchers found large stretches of DNA from this geographic region, which were not consistent with a scenario where homo sapiens interbred with just one specific line of Denisovan.
Rather, researchers found modern Papuans carried hundreds of gene variations from two very different Denisovan groups. The one lineage has been recognised in Papuans and South Asians, while the other has amazingly never been identified before.
What does this mean?
Study senior author Murray Cox, a population geneticist at Massey University in New Zealand explained to Live Science that where it was initially thought there were only one group of Denisovans, it turns out there were actually three different groups. The groups showing more diversity among them than modern mankind.
Researchers suggest that based on the level of genetical differences between the three Denisovan Groups, the newfound lineage separated from the other two groups approximately 363 000 years ago.
With substantial differences in the various lineages, Cox says we should consider giving this new group a name. After all, if we are going to call Neanderthals and Denisovans by special names, this group should be given a new name to.
As interesting as the discovery is, what is the main goal of the study?
The main goal of the researchers was not to learn more about human evolution, but rather to benefit modern human health.
Cox says the research program is focused primarily on improving health for a region which is rather understudied. This region is the tropics and most research on ancient humans has been focused mainly on DNA collected from old bones found in Europe and Northern Eurasia.
Through homo sapiens inheriting numerous genetic variants from prehistoric man, there is still much to learn about fighting off infections and other ailments.
With the researchers focusing on using their findings to improve health care for people in the islands of Southeast Asia, what are your thoughts on the findings? Do you feel learning more about ancient humans will help modern man endure? Or do you feel this is the next step in the evolution of man?