Sequenced genome of Altai Mountain Neanderthal has modern human DNA

by SchwerdtfegerK on April 9, 2017 - 4:53pm

Kianu Schwerdtfeger

Kristin Muller

Genetics 206

5 March 2017



While it is known that modern humans once coexisted with other species of hominids, such as the Neanderthals and the Denisovans, it is still uncertain how often they may have interacted, or how much they may have even potentially interbred. In a genetic study, published under the name “Ancient gene flow from early modern humans into Eastern Neanderthals,” a team of researchers investigated the genetic makeup of two different prehistoric humans that were found in the Altai Mountains of central Asia, one being a recently discovered species known colloquially as a Denisovan, and the other specimen being a more well-known Neanderthal. Both individuals lived in this region of central Asia about 100,000 years ago.



The genes of the Denisovan were compared to the genes of the Neanderthal. These were then contrasted with the a sequenced 21st chromosome from two European Neanderthals from modern-day Spain and Croatia, respectively. The researchers further compared them with the genes of modern African populations, as those who live in Africa have had the lowest contributions of DNA from other hominids throughout their genetic history. After sequencing, they discovered that the Neanderthal, specifically, had a greater contribution of DNA from modern humans than did the Denisovan or the European Neanderthals, and had specifically inherited modern human alleles dating back to about 100,000 years ago. To elaborate, the genome of the Altai neanderthal shared 5.4% more genetic alleles with modern-day human populations than the Denisovan, 3.5% more than the Spanish Neanderthal, and 4.9% more than the Croatian Neanderthal. As the lineage of modern humans and neanderthals diverged at least 430,000 years ago, this would almost certainly imply that, either the Altai Neanderthal, or a recent ancestor of said Neanderthal, had encountered and interbred with a modern human.



While we known that humans and neanderthals encountered one another, and occasionally mixed (it was estimated by those within this study that modern humans have inherited about 1% of their DNA from Neanderthals on average), we know less about genetic contributions in the other direction. It is not only interesting because it shows what populations of Neanderthals we may have first come into contact with. It also shows where modern humans may have first traveled on their exodus out of Africa, and how we interacted with who and what we encountered.


I always find interest in the historical aspects of our species that have not been conveniently written down for us by our predecessors. The entirety of human history is separated into the written historic accounts and that which we hadn’t recorded, known as “pre-history”. Out of the approximate 200,000 years our species has existed, we only have a few millennia of recorded history that we can study, and what lead up to the transition between hunter-gatherer societies and modern civilization is far harder to determine. It is this enigmatic aspect of our history that I find the most intriguing; whoever existed in prehistoric times never wrote their experiences down for us. Thus, it is up to us to piece together what we can about our own history from the clues our predecessors left behind.

Comments

I also find it interesting to read about the history of human evolution and the dead ends that occurred in the various other species that went extinct. I also read it is very likely interbreeding happened as it happens in other species with interspecies breeding between members of the same taxonomic family. It occurs in bears regularly when several different species live in the same area, making the research on how genes are shared between species interesting to study,

It's always interesting to read about how humans have evolved and become the species that we are today. I've seen a few documentaries that have various different explanations on what happened to the neanderthals. One of those theories I had read was that the neanderthals wound up being unable to migrate and went extinct during the ice age. It would be have been truly interesting to see what would have become of our race genetically if the other species hadn't went extinct.

This is an awesome post because it adds more to the dialogue of where humans beings originate from and further strengthens the argument for the theory of evolution. Yes, maybe the differentiation between the genetic codes of Neanderthals and modern day humans is large, but the similarity between the two is certainly a step towards understanding how humans evolved - perhaps even how we will evolve moving forward.

I really liked your article and it gave a great opening and insight on the question of the origins of our genes themselves. Seeing that we share more of our DNA from the neanderthal than the Denisovan or the European Neanderthals was an interesting subject to get a little grasp of. I suggest to you the following article from the journal Cell that talks about the actual contribution of the Neanderthal to the human gene and more precisely the modern human gene expression. How much did the Neanderthal give us and how close is our gene expression linked to his? What traits could we have inherited from it? Proceed to the following article to know more about the subject.
https://phys.org/news/2017-02-neanderthal-dna-contributes-human-gene.html