The Neanderthal genes make up only about 2 percent to 4 percent of the DNA carried by a given human today, according to a paper published in the journal Science. Even so, it may be linked to the development of our hair and skin, as well as to immune disorders such as Type 2 diabetes, the research found.

New DNA techniques are reshaping knowledge of human evolution just as quickly as they’re sparking the development of medical tests and treatments. That’s allowing scientists to peek into history by comparing modern DNA with the Neanderthal genome, recently reconstructed by scientists using material from the toe bone of a female who lived 50,000 years ago.

“We’re not as beholden to ancient DNA anymore,” said Joshua Akey, an associate professor of genome science at the University of Washington in Seattle, and an author of one of the studies. “Rather than excavating bones, we can now excavate DNA from modern individuals.”