And analysis of old teeth is giving scientists a rare look at the interactions between human relatives from hundreds of thousands of years ago that left a lasting mark on our species.
a new study reveals genetic clues about a human ancestor called The man stood upwhich emerged in Africa about 2 million years ago and spread to other parts of the world, including Asia and possibly Europe.
Scientists found remains of this early human in several countriesincluding Indonesia, Spain, China and Georgia. But genes and proteins are not well preserved, so information about the internal composition of those early humans proved difficult to obtain.
In new work, researchers extracted ancient proteins from tooth enamel of H. erectus belonging to five men and one womanrecovered from various locations in China, to learn how these early humans may have mixed.
Two key mutations
The teeth, of 400,000 years oldhad two key mutations in a protein present in tooth enamel. A mutation had not been observed before and could be a unique hallmark of members of H. erectus from East Asia.
The second, however, was more complex. The scientists identified a variant that is also present in a small fraction of modern humans, as well as in Denisovansone of our extinct cousins.
This told the scientists that he H. erectus could have mated with the Denisovans and having passed on their genes to them in the past. But how did it reach us? Scientists believe that this could have happened later, when our ancestors mixed with the Denisovans.
“This allows us to trace who we are now back to our ancestors in a really fascinating and exciting way, using new methods.”said the paleoanthropologist Ryan McRaeof the Smithsonian’s National Museum of Natural History, who was not involved in the new research.
However, there is still confusion
The exact relationships between all of these early human relatives remain a bit unclear. It could be that the H. erectus may actually just be an ancestor of the Denisovans, who eventually inherited those genes, McRae said.
It’s a difficult puzzle to unravel with extremely limited data. Finding more fossils and analyzing the limited evidence for traces of DNA can help consolidate the history of human evolution.
“We really need to get more DNA” and fragments of the H. erectus to find out how this predecessor «exactly relates to other humans,» said the author of the study, Qiaomei Fufrom the Institute of Vertebrate Paleontology and Paleoanthropology in China.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation.
With information from AP
