February 2025 newsletter: I’ve followed Star Trek since the original series. Yes, I fantasized about Spock, not Kirk—don’t judge. What appealed to me most was how Spock handled being the outsider—not entirely human, not entirely Vulcan. This theme of hybrids, caught between worlds, shows up again and again in Star Trek: B’Elanna Torres in Voyager, Deanna Troi in The Next Generation, and so on. But what if I told you that, in a way, we’re all hybrids?
It’s odd to think that really not that long ago, we lived among other kinds of humans, all of us diverging at various points along the evolutionary line. And not only could we interbreed, we did interbreed.
Years ago I took a ’23 and me’ genetic test, and after scratching my head over just who in my great-grandparents generation was Ashkenazi Jewish, I saw that I have more Neanderthal genes than 87% of people tested by the company, a bit less than 2% of my genome.
No, I don’t have hairy knuckles. Behave. But researchers believe Neanderthal DNA may influence traits like immune response, skin, metabolism, and even some aspects of brain function.
Neanderthals lived from roughly 400,000 to 40,000 years ago, overlapping with modern humans. Denisovans were their mysterious cousins, known mostly through DNA. The first Neandertal genome was published in 2010, only seven years after the Human Genome Project completed the first sequencing of our own genome. Readily apparent from that was that many of us have Neandertal genes.
Apparently interbreeding between humans and Neanderthal started when we arrived in Europe just over 50,000 years ago and lasted for about 7,000 years. Denisovan DNA shows up mostly in east Asians. People from Oceania have up to 4% of their DNA from Denisovans. There is evidence of mixing with other, unknown species as well.
It doesn’t stop there. Research suggests we interbred with Homo heidelbergensis in Africa, who lived between 600,000 to 200,000 years ago. Other interbreeding with the so-called ‘ghost hominids’ (inferred species we don’t yet have fossil evidence for) happened over 124,000 years ago, possibly as far back as 200,000–300,000 years.
While much of our knowledge about ancient humans comes from bones and teeth, those are often hard to find. Enter environmental DNA (eDNA), which lets scientists uncover genetic secrets from something as simple as a sample of soil from ancient human habitation. It works with modern DNA too—no body needed.
This kind of testing also works with water and air. Genetic studies of whole populations can be done without any direct contact, raising questions of privacy and consent. You might remember from the pandemic when scientists tested wastewater at sewage treatment plants for COVID-19 and were able to determine the viral load for the communities involved. Imagine what they can do (are doing) with the human DNA found there. Or simply in the air of a city.
Sorry, brain immediately went to them finding evidence of alien-human hybrids. Or were-whatevers. Or lizard-human hybrid overlords. Note that I had ChatGPT review this article and he was a bit worried you’d think I meant these findings were possible. No. At the present time and to the best of my knowledge, pretty sure even, they aren’t.
So, what all this science shows us is that being a hybrid isn’t just a sci-fi concept—it’s baked into who we are.
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Some interesting links:
- “Paleogenomics and the Tangled Web of Human Speciation” (2014). BioLogos. A great introduction to human evolution, if a little dated. Published in 2014, this is one of a twenty-two article series on human evolution. BioLogos, a magazine that reconciles science and religion, was founded by Francis S. Collins, author of The Language of God: A Scientist Presents Evidence for Belief. Collins headed the Human Genome Project from 1993 until 2008.
- “How Neandertal DNA May Affect the Way We Think” (January 21, 2025). Scientific American.
- Two from Smithsonian Magazine. Totally plagued by ads, but the articles do reference recent science behind paywalls. “Researchers Track Down When Neanderthals and Early Modern Humans Interbred Using Ancient Genomes” by Margherita Bassi (December 2024). Smithsonian Magazine. “Scientists Can Now Pull Human DNA From Air and Water, Raising Privacy Questions” by Margaret Osborne (May 2023). Smithsonian Magazine.