Neanderthals may have been gone for the past 40,000 years, but their role in the lives of humans still persists.

Humans continued to mate with Neanderthals until about 50,000 years ago -- and this practice has the long-extinct species still affecting modern humans' genes such as their health and looks, scientists from the University of Washington revealed in a research paper published in the journal Cell.

According to a report from New Scientist, the study examined the DNA of 214 people in the U.S. with European ancestry. Led by Joshua Akey of the University of Washington in Seattle, the team of researchers compared the participants' DNA to those of the Neanderthals', discovering that there were Neanderthal gene fragments that are active in 52 kinds of human tissue.

Apparently, some of the participants had two copies of the same gene: one human and one Neanderthal. More significantly, there were differences in activity in a quarter of these genes.

For example, the gene ADAMTSL3 is linked to schizophrenia, but the Neanderthal's control of it decreases risk and increases height. Susceptibility to lubus may also be an effect of the presence of Neanderthal genes, a report from The Verge revealed.

"The implication is that these variants that came into the human gene pool around 50,000 years ago are still affecting human biology," Sriram Sankararaman, scientist at the University of California at Los Angeles who wasn't involved in the study, told New Scientist. "This study makes important progress in understanding how Neanderthal genes many of us carry in our genomes affect diverse human traits by dictating how genes are regulated."

Meanwhile, the Neanderthal versions of genes in the brain and testes were hardly ever active. Changes in gene regulation in the brain might account for humans having eventually overtaken Neanderthals intellectually, while the differences in the testes might help scientists understand the way two species develop incompatibility sexually.