Published on Halloween, a study co-authored by Pontus Skoglund and Martin Jacobsson found that a recently discovered member of the Homo genus' genes are more common than we previously thought.
The Denisovans lived in central and eastern Asia 40,000 years ago, sharing a common ancestor with Neanderthals and humans about 1 million years ago. Previous research has traced the genomes of the Denisovan people to Oceania but not Southeast Asia.
Jacobsson says that the Denisovans interbreeding with other members of their family tree is actually not that uncommon. Jacobsson and Skoglund examined 1,500 human genome scans from every part of the world searching for Denisovan genes while skipping chimpanzee or Neanderthal genes.
There hasn't been too much known about the Denisovans up until this point. What we learned about them came from no more than several bone fragments throughout the years, including a finger bone, a tooth, and what's believed to be a toe bone. We also figured the Denisovans split up from Neanderthals about 300,000 years ago, but very little is known about their physical appearance and behavior.
Different from previous studies and research, Jacobsson says they used low-resolution scans instead of ultra-high-resolution human genome scans. Low-resolutions scans are more readily available to researchers ultimately lead the two to find signals in genomes from Southeast Asia.
The researchers believe that this finding adds a rich aspect to the story of human evolution. We always knew that our human ancestors embarked 100,000 years ago out of Africa. Patterns are understood to be much more complex now. Fossil findings have shown that our ancestor's migratory paths were more than just a straight shot from Africa. In fact, the fossils suggest that Homo sapiens and its neighbor relatives migrated out of Africa multiple times. Throughout, some of these groups died off as others survived, all the while never living too far from each other either.
Now that these preserved ancient genomes, scientists will be able to study interbreeding more in-depth than before. So far, these Denisovan studies are suggesting that interbreeding patterns are evident in more than one period. This could mean that our ancestors evolved for awhile, isolated from each other, and then interbred again, Jacobsson explains.
While Neanderthal genes have been found to boost human immune systems, scientists are still uncovering what is characteristic of Denisovan genes. Jacobsson says it will take them longer to get their hands on better-quality ancient genomes, but is confident that others out there are already investigating this.