This article was originally published on April 17, 2021.
Tens of thousands of years ago, humanity was far more diverse than it is now. Multiple lineages of humans — those in the genus Homo — roamed the Earth, including Neanderthals and Denisovans. Today, Homo sapiens is the last surviving member of that tribe. But remnants of those lost humans live on today in our genomes.
We know that our ancestors mated with both Neanderthals and Denisovans at various points in our history. Those trysts left snippets of DNA from both groups in our genomes today. The amounts vary by ethnicity, but can account for up to a few percent of the human genome. Genes from Neanderthals have been implicated in a number of biological traits today, from our immune systems to our hair and skin.
Our Hominin Ancestors
In recent years, research into the intertwined history of humans and our hominin cousins has painted an increasingly nuanced picture of interrelations between the groups. Humans likely interbred with both lineages at multiple times, hinting at a complex shared history. (Anthropologists don’t yet agree on whether we should call Neanderthals and Denisovans separate species — instead, the term lineages is often used.)
