Tuesday, November 1, 2016
Evidence For Possible Unknown Human Relative Found in Modern Human DNA
We all know that the Neanderthals and Denisovans are the closest relatives to the Homo sapiens (Modern Human) species. However, genetic evidence in Melanesians (Aboriginal Australians, and natives in New Guinea and neighboring islands) hint that there is a possible third extinct hominid relative.
While many Neanderthal fossils were found in Europe and Asia, and the Denisovans were discovered from DNA from a finger bone and teeth found in a cave in Siberia, the third possible extinct hominid DNA may been preserved in human DNA, and not in fossil evidence, as reported by statistical geneticist Robert Bohlender on October 20 at the annual American Society of Human Genetics meeting. In 2012, a research team suggested that there were also people in Africa carrying DNA from an extinct hominid ancestor. Less than a decade ago, it was even discovered that early humans mixed with other hominid species. Bohlender and his research team concluded that a third hominid group may have bred with the human ancestors of the Melanesians.
Eske Willerslev and his research team also came to a similar conclusion. They conducted an experiment in which they collected saliva samples from volunteers for DNA sequencing. The DNA examined was from 83 Aboriginal Australians and 25 natives from Papua New Guinea highlands. The researchers found Denisovan-like DNA, but was found to be different and possibly from another hominid species. Willerslev speculates that this DNA can be from Homo erectus or from the extinct Hobbits hominid species, but he is not a hundred percent sure.
According to evolutionary geneticist Mattias Jakobsson, researchers don't know much about the Denisovan's genetic diversity. He believes that it was possible that a different branch of Denisovans could have been the group that mated with the Melanesians' ancestors. There geneticists like Elizabeth Blue, that believe that the genetic evidence found from Neanderthals and Denisovans is limited. Denisovans may have been spread around the world and have had genetic diversity. If they weren't however, then the genetic evidence could have come from another extinct species.
I think that it's fascinating how evolutionary evidence could be found in modern human DNA, and not just in fossils. I hope that after further research, scientists would be able to confirm if this genetic evidence came from another distinct hominid species or just another branch of Denisovans. I also think that this evidence can help us learn more about human evolutionary history, along with that of other hominids.