April 11 (UPI) – Denisovan's family tree was more diverse than previously thought. Through the analysis of ancient and modern DNA, scientists have discovered a lineage Denisovan not yet identified.
"We compared the genomes of the modern peoples of Indonesia and New Guinea and found pieces corresponding to Denisovan's genome," said Murray Ux, professor of computational biology at Massey University, in New Zealand, at UPI. "However, they did not fit perfectly, which we expected if the Denisovans in the cave and the Denisovans mixed with Papuans belonged to the same group."
Instead, Cox and his research partners found the genetic signatures of two groups related to Denisovan, both different from the original troglodyte dwelling Denisovans.
"One of these groups is as different from the cave Denisovans as the Neanderthals, so it should probably get its own name," Cox said.
The discovery was published Thursday in the journal Cell, just a day after scientists announced the discovery of a new species of hominin in the Philippines.
This new species, found on the island of Luzon, is much older than the Denisovans groups described in Cell, but both discover the importance of Southeast Asia in the history of human evolution .
Until now, most scientists have assumed that hominin diversification is practiced in Europe and Eurasia, but recent findings suggest that researchers have been misled by the old DNA. Since old DNA is degraded in hot climates and is more likely to be stored in cold climates, older DNA has been found in Europe and Eurasia.
"The oldest DNA in the tropics is only 6,000 years old, which is not helpful for questions about archaic hominins," Cox said. "It is unlikely that we will go a step further than that."
However, by comparing what DNA scientists can retrieve with modern human genomes in the remains of the tropical hominin, researchers can gain new insights into the complexity of human evolution by South East Asia.
"If you look at modern human diversity, and biodiversity in general – plants and animals, for example – most of the diversity is in the tropics," said Cox. "This study – and Luzon's hominin – fits into a much larger body of scientific discoveries that shows that this was also true for archaic hominins, their center of gravity was also found in the tropics. "
According to Cox, the latest discoveries would not have been possible without the work of scientists at the Eijkman Institute of Molecular Biology of Indonesia, including Herawati Sudoyo, co-director of the institute . Just as ancient DNA is oriented toward Western sources, so too does deciphering the history of human evolution.
"There has been a lot of criticism lately against Western scientists coming from developing countries without giving back," Cox said. "We are working on very different designs, I have been a real partner with Eijkman for almost 20 years, and Indonesian researchers have played a key role in this project."