Traces of Neanderthal Virus DNA Found in Modern Human Genomes

IMG_3361

Even though the last common ancestor of Homo sapiens and Neanderthals lived at least 400,000 years ago, traces of our cousins can still be found in our DNA. Fragments of DNA from viruses that affected Neanderthals have been found in modern human genomes according to new research led by Emanuele Marchi from the University of Oxford’s Department of Zoology, which was was published online this month in Current Biology.

Marchi’s results show that humans today have traces of Neanderthal viruses in portions of our DNA that don’t code for protein. DNA from Denisovan bone fragments was compared with genetic samples from Neanderthals and cancer patients today. The results showed that viruses that infected Neanderthals nearly half a million years ago can still be found in our genomes today, and researchers aren’t sure yet what implications that DNA may have for modern diseases like HIV and cancer.

Viral DNA that gets passed down though DNA is known as endogenous retroviruses (ERVs). While ERVs make up almost a tenth of our genomes, it is found in regions that we don’t really understand. There are hints that some of these ERVs can team up to cause disease, but it requires a lot more study. Future research will seek to understand ERVs better to determine if it still has pathogenic properties and if those ancient genetic sequences can possibly be used to target treatments.

As genetic sequencing techniques continue to improve, we will continue to understand our evolutionary history more completely. By learning more about what makes us who we are, we will be able to exploit those processes to improve our quality of life while we’re here and will make it better for those who come after.

Found on: ifl science

Image

Advertisements

Ancient Humans Had Sex With Mystery Species…

… new DNA Study Shows

Was our Earth once a place like the Hobbit’s Middle Earth, hosting many different humanoid species?

 

The ancient genomes, one from a Neanderthal and one from a different archaic human group, the Denisovans, were presented on 18 November at a meeting at the Royal Society in London. They suggest that interbreeding went on between the members of several ancient human-like groups living in Europe and Asia more than 30,000 years ago, including an as-yet unknown human ancestor from Asia.

“What it begins to suggest is that we’re looking at a ‘Lord of the Rings’-type world — that there were many hominid populations,” says Mark Thomas, an evolutionary geneticist at University College London who was at the meeting but was not involved in the work.

The first Neanderthal and the Denisovan genome sequences revolutionized the study of ancient human history, not least because they showed that these groups interbred with anatomically modern humans, contributing to the genetic diversity of many people alive today.

All humans whose ancestry originates outside of Africa owe about 2% of their genome to Neanderthals; and certain populations living in Oceania, such as Papua New Guineans and Australian Aboriginals, got about 4% of their DNA from interbreeding between their ancestors and Denisovans, who are named after the cave in Siberia’s Altai Mountains where they were discovered. The cave contains remains deposited there between 30,000 and 50,000 years ago.

Those conclusions however were based on low-quality genome sequences, riddled with errors and full of gaps, David Reich, an evolutionary geneticist at Harvard Medical School in Boston, Massachusetts said at the meeting. His team, in collaboration with Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have now produced much more complete versions of the Denisovan and Neanderthal genomes — matching the quality of contemporary human genomes. The high-quality Denisovan genome data and new Neanderthal genome both come from bones recovered from Denisova Cave.

The new Denisovan genome indicates that this enigmatic population got around: Reich said at the meeting that they interbred with Neanderthals and with the ancestors of human populations that now live in China and other parts of East Asia, in addition to Oceanic populations, as his team previously reported. Most surprisingly, Reich said, the new genomes indicate that Denisovans interbred with another extinct population of archaic humans that lived in Asia more than 30,000 years ago, which is neither human nor Neanderthal.

The meeting was abuzz with conjecture about the identity of this potentially new population of humans. “We don’t have the faintest idea,” says Chris Stringer, a paleoanthropologist at the London Natural History Museum, who was not involved in the work. He speculates that the population could be related to Homo heidelbergensis, a species that left Africa around half a million years ago and later gave rise to Neanderthals in Europe. “Perhaps it lived on in Asia as well,” Stringer says.

This story originally appeared in Nature News.