Two new studies published in tandem have discovered that modern humans have retained many parts of the Neanderthal genome, but have shed other parts as well.

According to NBC News, the researchers found that many modern day humans have skin and hair traits of the Neanderthal, while other traits are long gone. The studies, published separately Wednesday in the journals Science and Nature, further explore previous work that suggested Neanderthals interbred with humans outside of Africa.

"Our genomes have these amazing stories that we're still learning to how to read, that tell us about our past 50,000 to 100,000 years," Science study co-author Joshua Akey, a geneticist at the University of Washington, told NBC News.

Akey and his colleagues looked at 665 modern-day human genomes found a 20 percent overlap with Neanderthal genomes. However, the Nature study examined 1,004 modern-day genomes and found a 30 percent overlap. Both studies agreed that skin and hair are the most common areas for modern humans to have similarities to their Neanderthal ancestors.

"The idea is that maybe Neanderthals carried versions of alleles [genetic variants] for these genes that were well-adapted to their environment," Nature study lead author Sriram Sankararaman, of Harvard Medical School, told NBC News.

Neanderthals became extinct approximately 30,000 years ago, but their geographic range overlapped and they left genomes in non-African DNA.

University of Washington scientist and Science study co-author Benjamin Vernot said in a press release that he and Akey could not pinpoint how many Neanderthal ancestors modern humans have.

"I think what was most surprising to me is that we found evidence of selection," he said. "Last year, I would have bet that a Neanderthal/human hybrid would have been as fit as a fully modern human. This was mostly because we haven't been separated from them that long, on an evolutionary scale.

"In the future, I think scientists will be able to identify DNA from other extinct hominin, just by analyzing modern human genomes."