Human evolution has been shaken once again as new fossil evidence has been discovered. It reveals ancient human DNA that dates back over 400,000 years, but instead of helping give answers to questions of human evolution, all it has done is cause more mystery.
The research was released in a study in the science journal Nature. It stated that scientists had found the fossil and that this totally shatters the prior relic record which was dated at about 100,000 years.
The fossil, which is of a thigh bone, was discovered in Spain. It was previously believed to have belonged to one of the forerunners of the Neanderthals. However the DNA instead revealed another story. The bone fragment DNA was most similar to a lineage of humans which were known as Denisovans. Up to now, the Denisovans have only been known through DNA that was gathered from remains around 80,000 years old located in Siberia. This was over 4,000 miles to the east of where the newest DNA had been found.
Such discrepancy between both the genetic and the anatomical evidence shocked scientists working on the DNA. It is causing them to look at what they thought was fact before, and reevaluate their standards of what could have been possible in the past hundred thousand years. There might have been numerous different extinct human populations in which researchers have not found yet. These different populations could have bred with one another and interchanged their DNA. Scientists are indeed hopeful that the more they study the tremendously old human DNA, the more it will be able to illuminate its secrets.
Researchers were amazed that they were able to find such ancient human DNA. It has shown to be a major advance in the technological system of things, stated a geneticist who works at Harvard Medical School.
It has been all the way since the 1970’s that various scientists have found numerous amounts of fossils from the cave in which the thigh bone was found. It is considered a very special place of excavation where nearly 30 complete skeletons have been discovered.
When researchers drilled deep inside the femur, they were able to find the prehistoric human DNA just like they hoped was there, but they expected it to be a human from the Neanderthal period.
However, the DNA did not match those types. They took comparisons of it with DNA of the Denisovans. It was a surprise when they discovered that it was a match. At first it was believed to be a mistake, so more testing was done. With the extra research, it showed, without a doubt, that the DNA definitely fitted up on the Denisovan family tree.
Such findings are difficult to merge together with the long thought idea human evolution which has emerged that was based on other DNA and fossils. Denisovans were thought to have been only in eastern Asia.
Scientists had basically agreed that various human ancestors had a common ancestor between them. This shared lineage diverged and spread out from Africa, then ended up splitting even more so into both the Neanderthals and the Denisovans around 300,000 years ago. The evidence which had been found showed that Neanderthals moved toward the west, heading for Europe, where the Denisovans went east.
In the meantime, humans’ ancestors lived on in Africa, and gave rise to the Homo sapiens around 200,000 years ago. Humans stretched out from Africa into Europe and Asia and Europe around 60,000 years ago. They started to interbred with both the Neanderthals, and the Denisovans. This would cause the latter two groups to become extinct. At least that is what was believed.
Now researchers say they must review the entire story. They believe it could be possible that the new DNA was passed to both the Neanderthals and also the Denisovans, but it ultimately vanished from Neanderthals and was replaced with other genes.
It seems that all-in-all, the more that scientists have learned from this DNA, it has just made the story of humans all that more complicated.
Researchers are planning more trips to the particular cave in which the thigh bone was found. They hope to discover more fossils at the site. If they do, maybe the pieces will aid in solving the puzzle which in now in their laps.
One scientist admitted that they all were a bit lost with all the information in front of them. With this new fossil evidence and DNA information, it is not surprising that human evolution ideas have been shaken once more.
By Kimberly Ruble