"Don't be such a Neandertal!" You may have heard the insult tossed around toward someone acting particularly brutish. The idea, of course, is that the Neandertals were a sluggish, unsophisticated, caveman kind of people who died off long ago due in part to the superiority of our own species, Homo sapiens. We endeavor to uncover the story of the past by telling the story of our ancestry. A part of the story of our shared human ancestry lies with the Neandertals, and our other human sibling-species, tens of thousands of years ago.
Once upon a time, the human race did not walk alone on Earth. For millennia, Homo sapiens (or rather, an ancestral species to Homo sapiens) were a part of a broad human family. Dozens of cousin- and sibling-species lived all across the Old World; some were small people like Homo floresiensis, some broad and strong like Homo erectus. And all of them were humans.
Stringer, C. (2012). "What makes a modern human". Nature 485 (7396): 33–35. doi:10.1038/485033a.
Eventually, the environment changed, our cousins faded away into the fossil record, and our human family dwindled to a handful of siblings separated from one another by continents.
Homo sapiens, however, are an adventurous sort. We are explorers by nature, and are not often content to sit idly. We took off across the globe at an explosive pace, considering we were travelling by foot. When we had travelled far enough, we found our human family again.
Genetic research confirms that Homo sapiens admixed (a fancy word for “mated”) with at least two other now-extinct human species: Denisovans in Asia, and the Neandertals in Europe. In addition, ongoing research also shows evidence for admixture with currently-unknown human species in Africa and Asia. Living Homo sapiens, like you and me, carry with us the genetic heritage of the last members of the human species.
Our understanding of Homo sapiens' relationship with extinct human species changed in 2010, with the publication of the Neandertal genome by Dr. Svante Pääbo and his research group. It marked the first time that genetic material was successfully reproduced from a human fossil. The research that followed was explosive; soon admixture between Homo sapiens and Neandertals was confirmed, and shortly thereafter the DNA from the Denisovans and more unidentified human species were found lingering in modern humans DNA. Previously, all research had been limited to the genomes of living humans and the physical fossil record. The barrier to the past had finally been breached and, like a time machine, we could now source DNA from tens of thousands of years ago. In doing so, we discovered our own DNA is not as purely Homo sapiens as we thought.
“Wait,” you might be thinking, “I’m not a Neandertal! I’m not some caveman!” But indeed you are! The only living humans without Neandertal DNA are those with exclusively African lineages, and even they have evidence in their genomes of admixure with archaic, extinct human species. We are all cavemen, but it is not an insult! Our human siblings were sophisticated: there is strong evidence that they could speak, that they created art and clothing, and that they had cultures that were similar in complexity to that of the Homo sapiens who were alive at the same time.
Clemens Vasters / Flickr
If you have ancestry that would indicate Neandertal admixture in your DNA, and you would like to explore your truly ancient heritage, you can visit das Neanderthal Museum in Mettmann, Germany. At the museum you can walk through the history of Neandertal research, see artistic interpretations of our Neandertal siblings, and learn about how the Neandertals lived. You can even walk the Neander Valley, the location of the discovery of the Neandertals.
Some DNA testing services out there will tell you what percentage of your genome comes from your Neandertal ancestry (mine sits at around 2.4%!). There is pride and poetry in the fact that all of us carry our sibling species in our genes. And if that is the case, then they never went extinct; they became a part of us. While Homo sapiens walks the Earth alone today, we are not alone in our DNA.