"The Neanderthals might have had more inferior genes that their part did not manage to survive," Fu said.

An earlier research published by Nature in December 2013 found that the A gene that increases the risks for Type 2 diabetes was inherited from the Neanderthals.

Other studies suggested that modern Europeans and Asians have taken over the Neanderthals' fair skin and a number of their diseases such as lupus and Crohn's Disease.

David Reich, professor of genetics at Harvard Medical School and co-senior author of the paper, said, "This study raises by about tenfold the number of ice aged hunter-gatherers for which there is ancient DNA, and in so doing, it makes it possible to track genetic change over time."

"It's a great privilege to be able to work on these samples; it's like being an art historian given full access to the treasures of the Louvre."

Co-senior author Svante P??bo said, "Prior to this work, we had a static view of the first 30,000 years of modern human history in Europe. Now we can begin to see how people moved around and mixed with one another during this period."

The second major surprise came when the researchers found another previously unknown population turnover: the Europeans started to show a genetic relationship to present-day Near Easterners during the first major warming period 14,000 years ago, some 6,000 years earlier than the agriculture established connection between the two parts of world.

The authors speculate that it could be the warming weather rather than development of agriculture - as it was previously believed - that drove early Near East residents to Europe and led to the gene fusion.

Fu, from Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences, said,"The goal of our research is to figure out what happened to the human ancestors during the last ice age and its influence to modern people."

The research, as Fu said, is the largest-scale ancient DNA research on ancient humans living 45,000 to 10,000 years ago.

"Previous researches usually include genome-wide data on only one or two Upper Paleolithic individuals. But this research managed to collect valid genome-wide data from 51 individuals from a more than 100 sample bases."