What if We Made a Humanzee? (Or Chimphuman?)

Maybe we'd all be better off if we made a chimp-human combo.

Posted Sep 13, 2018

No one has yet cloned a human being, although the barriers to doing so are not so much scientific or biological as primarily ethical and legal. There is every reason to think that given a serious effort, Homo sapiens could be cloned, as has already been done for dogs, cats, sheep, goats, cattle, horses, and so forth. It is a bit more of a stretch–but by no means impossible or even unlikely–that a hybrid or “chimera” (composed of parts derived from two closely related species) combining the genotypes of a human being and a chimpanzee could be produced in a laboratory.

After all, human and chimp (or bonobo) share, by some estimates, roughly 99 percent of their DNA, with the human-gorilla genetic overlap at approximately 98 percent. Granted that the one percent difference in the former case presumably involves some key alleles, the new gene-editing tool CRISPR offers the prospect (for some, the nightmare) of adding and deleting targeted genes as desired. As a result, it is not unreasonable to foresee the possibility–eventually, perhaps, the likelihood–of producing “humanzees” or “chimphumans.”

During the 1920s, a Russian biologist with the marvelously Slavic name Ilya Ivanovich Ivanov appears to have made the first serious, scientifically informed efforts to create a genetic hybrid between chimpanzees and human beings. Ivanov had the perfect qualifications: not only did he possess a special interest in creating interspecific hybrids, he was an early specialist in artificial insemination, who had achieved international renown as a successful pioneer when it came to horse breeding.

Prior to his work, even the most prized stallions and mares were limited to reproducing by “natural cover”–i.e., the old-fashioned way, one mounting at a time. But Ivanov found that by appropriate and careful dilution of stallion semen, combined with adroit use of the equine equivalent of a turkey baster, he could generate as many as 500 foals from a single genetically well endowed stallion. His achievement caused a worldwide sensation, but nothing compared to what he next attempted.

And failed.

It happened initially at the Research Institute of Medical Primatology, the oldest primate research center in the world, located at Sukhumi, the capital of Abkhasia, currently a disputed region in the state of Georgia, along the Black Sea. At one time, the Sukhumi Institute was the largest facility conducting research on primates. Not coincidentally, Stalin is believed to have been interested in such efforts, with an eye toward developing the “new Soviet man” (or half-man, or half-woman).

Nor was Soviet interest in combining human and nonhuman genetic material limited to Russian biologists. The novelist M. Bulgakov, best known–at least in the West–for his fantasy, The Master and Margarita, also wrote Heart of a Dog, a biting satire on early Soviet-era social climbers, in which a pituitary gland from a drunken person is implanted into a stray dog, who subsequently becomes more and more human–although not noticeably more humane as he proceeds to eliminate all “vagrant quadrupeds” (cats) from the city. Maxim Gorky was on board, writing approvingly that Lenin his Bolshevik allies were “producing a most severe scientific experiment on the body of Russia,” which would eventually achieve ‘the modification of human material.’

Similar modification became a staple of Soviet biology, as well, as when S. A. Voronov attempted “rejuvenation therapy,” a series of failed attempts to restore sexual function in rich, elderly men by transplanting slices of ape testes. But it was Ivanov who made the most serious efforts at combining human and nonhuman apes. Earlier in his career, in addition to the successful artificial insemination of horses, Ivanov had created a variety of animal hybrids, including “zeedonks” (zebras + donkeys) and different combinations of small rodents (mice, rats and guinea pigs). For a time in the 1990s a fictional version of Ivanov was the chief character in a Russian-era television show portraying him as the “Red Frankenstein.”

In 1910, Ivanov had announced, at a World Congress of Zoologists in Graz, Austria, that it might be possible to produce a human-ape hybrid via artificial insemination. During the mid-1920s, working at a laboratory in Conakry (then part of French Guinea) under the auspices of France’s highly respected Pasteur Institute, Ivanov attempted just that, seeking without success to inseminate female chimpanzees with human sperm. (We don’t know whose, and we also presume–although don’t know for certain–that the attempted insemination was by artificial rather than natural means.)

Then, in 1929, at the newly established Sukhumi Primate Research Institute, he endeavored to reverse donor and recipient, having obtained consent from five women volunteers to be inseminated–once again, presumably by artificial methods rather than “natural cover”–with sperm from chimpanzees and orangutans. Inconveniently, however, the nonhuman primate donors died before making their “donations,” and for reasons that are unclear, Ivanov himself fell out of political favor and was sent to Siberia in 1930; he died a few years later.

Ilya Ivanov’s story is not especially well known outside Russia, and insofar as Westerners learn of it, they are inclined to ridicule it as an absurd episode of reaching for a would-be “planet of the (communist) apes,” or– paradoxically–to inveigh against the immorality of such at attempt, which is increasingly feasible. To be sure, Ivanov’s crude efforts at cross-species hybridization are at present no closer to fruition, simply because even though human and chimp DNA are overwhelmingly similar, getting sperm from either species to combine with eggs from the other is – to put it literally - inconceivable. However, CRISPR makes it extremely likely that a humanzee could be generated in a laboratory. Such an individual would not be an exact equal-parts, 50-50 hybrid, but would be neither human nor chimp: rather, something in between.

Would this be a good idea? Most people are horrified at the prospect. In my next post, I’ll provide some more background and then argue – controversially, to be sure – that it would probably do more good than harm.

David P. Barash is professor of psychology emeritus at the University of Washington. His most recent book is Through a Glass Brightly: using science to see our species as we really are (2018, Oxford University Press).