Humanzee

If a Human-Chimp hybrid was created, would more people believe we share a common ancestor? I think a few more would.  The DNA evidence is already clear enough regarding our evolution, but a humanzee would make the point viscerally.  Some are worried it will happen soon.

The humanzee (also known as the Chuman, or Manpanzee) is a hypothetical chimpanzee/human hybrid. Chimpanzees and humans are very closely related (95% of their DNA sequence, and 99% of coding DNA sequences are in common^[1]), leading to contested speculation that a hybrid is possible, though no specimen has ever been confirmed.

I previously thought this was impossible because we have different numbers of chromosomes, but it turns out chromosomal polymorphism is possible.

It has also been studied in alfalfa,^[2] shrews,^[3] Brazilian rodents,^[4] and an enormous variety of other animals and plants.^{[5] ...} All forms of chromosomal polymorphism can be viewed as a step towards speciation. Polymorphisms will generally result in a level of reduced fertility, because some gametes from one parent cannot successfully combine with all gametes of the other parent. However, when both parents contain matching chromosomal patterns, this obstacle does not occur. - wiki

Interestingly, one of our chromosomes is two of the smaller ape chromosomes that fused together in our ancestral past.

Humans have one chromosome fewer than other apes, since the ape chromosomes 2p and 2q have fused into a large chromosome (which contains remnants of the centromere and telomeres of the ancestral 2p and 2q) in humans.^[2] Having different numbers of chromosomes is not an absolute barrier to hybridization. Similar mismatches are relatively common in existing species, a phenomenon known as chromosomal polymorphism.

The genetic structure of all the great apes is similar. Chromosomes 6, 13, 19, 21, 22, and X are structurally the same in all great apes. 3, 11, 14, 15, 18, and 20 match between gorillas, chimpanzees, and humans. Chimps and humans match on 1, 2p, 2q, 5, 7 - 10, 12, 16, and Y as well. Some older references will include Y as a match between gorillas, chimps, and humans, but chimpanzees (including bonobos) and humans have recently been found to share a large transposition from chromosome 1 to Y that is not found in other apes.^[3]

Are we genetically similar enough to have a living hybrid?

"Chimpanzees (Pan troglodytes) and human beings (Homo sapiens) are placed taxonomically in different genera, Pan and Homo, respectively. These species are much alike in anatomical and physiological features as well as in DNA and protein composition. Comparisons of chromosomes show basic similarities with a few superimposed structural rearrangements. The overall number of chromosomes is comparable (46 for Homo, 48 for Pan). Homologous pairs can be identified, and general chromosome structure can be matched band for band between the pairs. ...  (Gardner, 1991, p506). - asa3

Even after our species split from early apes, our ancestors interbreed again over a million years later.

Looking back millions of years into early human history, current research into human evolution tends to confirm that in some cases, interspecies sexual activity may have been a key part of human evolution. Analysis of the species' genes in 2006 provides evidence that after humans had started to diverge from chimps, interspecies mating between "proto-human" and "proto-chimps" nonetheless occurred regularly enough to change certain genes in the new gene pool:

"A new comparison of the human and chimp genomes suggests that after the two lineages separated, they may have begun interbreeding... A principal finding is that the X chromosomes of humans and chimps appear to have diverged about 1.2 million years more recently than the other chromosomes."

The research suggests that:

"There were in fact two splits between the human and chimp lineages, with the first being followed by interbreeding between the two populations and then a second split. The suggestion of a hybridization has startled paleoanthropologists, who nonetheless are 'treating the new genetic data seriously.'[1]

At this point we are about 6 million years different from apes, and I don't know anyone who finds apes attractive so I highly doubt there will ever be a natural hybrid.

Would it work in theory? Dr. MacKellar things so.

In an interview with The Scotsman, Dr Calum MacKellar, director of research at the Scottish Council on Human Bioethics, warned the controversial draft Human Fertilisation and Embryology Bill did not prevent human sperm being inseminated into animals. He said if a female chimpanzee was inseminated with human sperm the two species would be closely enough related that a hybrid could be born. He said scientists could possibly try to develop the new species to fill the demand for organ donors. Leading scientists say there is no reason why the two species could not breed, although they question why anyone would want to try such a technique. - scotsman

Has it ever been attempted in a laboratory setting?

Yes. Soviet Professor Ilya Ivanov attempted to create a human-ape hybrid, but there is no evidence of any success.

[Stalin's] weirdest move was to pony up $300,000 and order
artificial insemination pioneer Ilya Ivanov  to produce a human/chimpanzee hybrid: "I want a new invincible human being,  insensitive to pain, resistant and indifferent about the quality of food he  eats." Ivanov had previously studied a zeedonk (zebra plus donkey), a zubron  (European bison plus domestic cow), an antelope/cow, a mouse/guinea pig, and
other novel blendings. Between 1926 and 1930 he made several attempts to  conceive a humanzee which all failed, though it should be noted that many of  his setbacks were circumstantial and sociopolitical (I'll say) rather than  biological.

Rumors of Humanzees

There are various rumors of humanzees in the past, but none have been proven to be true.

Stories of such paradigm-jarring creatures have circulated since at least as  far back as Pope Alexander II in the eleventh century, but so far proof is  elusive. Belgian cryptozoölogist Bernard Heuvelmans co-authored a book in 1974 that contained an account from a Russian Gulag escapee, a doctor, claiming a  slave race of human/gorilla hybrids had been produced. They were supposedly furry and strong but sterile and made indefatigable salt miners. And in 1987 Florence University dean of anthropology Brunetto Chiarelli said that a secret  experiment did conceive a viable humanzee zygote (in vitro, one hopes) but, for ethical reasons, after a number of routine cell divisions the mass was  destroyed.

I once nosed around the small town of Dulce, New Mexico with a reporter from the Sacramento News and Review many years ago. In Dulce, it is rumored that a secret underground lab with many levels houses many different kinds of human-hybrids.

I didn't find a thing, but we were a bit freaked out to be stopped by a group of heavily armed men at a night time roadblock on the way out of town. I'll save that story for another time.




Finally, some evidence:

Some related questions, notes:

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What other hybrids have happened?

in April 2006 a hunter in Canada's North-west Territories shot a polar bear whose fur had an orange tint. Research showed that it had a grizzly bear father, and it became known as a pizzly.  ... Lions and tigers have been bred to create ligers, the world's largest cats.  And there are also zorses (zebra and horse), wholphins (whale and dolphin), tigons (tiger and lion), lepjags (leopard and jaguar) and zonkeys (zebra and donkey). As well as these hybrid mammals, there are also hybrid birds, fish, insects and plants.

Are all hybrids sterile?

Many hybrids, such as mules, are sterile, which prevents the movement of genes from one species to another, keeping both species distinct. However, some can reproduce and there are scientists who believe that grey wolves and coyotes mated thousands of years ago to create a new species, the red wolf.