Wow. A websearch on this turns up a few oddities....
Here, from the Megafoundation ("we pay gifted people to be gifted!") website:
I wanted to know if it was possible to cross a human being with a chimpanzee and obtain a viable offspring. ... I also knew that the DNA sequences of man and chimpanzee were identical at 99 out of 100 base pairs. The possibilities for a viable cross, therefore, looked reasonably good – good enough at any rate to justify spending some time in a library researching the matter.
...The answer came from an article titled "The Striking Resemblance of High-Resolution G-Banded Chromosomes of Man and Chimpanzee," written by Jorge J. Yunis, Jeffrey R. Sawyer and Kelly Dunham [Science, Vol. 208, 6 June 1980, pp. 1145-8]. These investigators applied a new staining agent called giemsa to the chromosome compliments of man and chimpanzee and made a detailed comparison of their banding patterns. Their new stain was able to resolve more than a thousand bands in the chromosomes of each species, revealing a similarity so close that they found it difficult to account for the phenotypic differences. As part of their article, they provided a diagram of the chromosome comparisons, showing not only an astonishing similarity, but a number of interesting differences as well. Among these differences was the revelation of nine pericentric inversions. This observation provided the answer to my question. Chromosome inversions are known to result in semi-sterility when crosses are made to individuals without the inversion. Since there are nine of these, and since a cross with only one inversion results in semi-sterility, the answer must be: No, it’s not possible to cross a human being with a chimpanzee and obtain a viable offspring.
Sometimes, however, when one is looking for an answer to a trivial question, one stumbles across the answer to a much more important one. That’s what happened in this case. The diagram given in the article clearly reveals the exact genetic mechanism responsible for the evolution of genus Homo, and strongly suggests that this did not take place over hundreds of thousands of years, as is generally believed, but occurred within the span of only three generations.
Which is pretty weird.
The guy goes on to suggest that we could pretty easily rear-engineer Lucy from human genetic material, or make a human out of a chimp.
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On the other hand, the Great Apes Project says otherwise:
In fact, we share over 98% of our DNA with chimpanzees; genetically, we may be close enough to produce viable offspring.
But it's a throwaway line in a natural history article, so it's not terribly heavy.
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The River Apes" people have this to say about taxonomy and breeding among ape species:
To cut a long story short it will be argued here that Mayr’s (1969) modified definition of the BSC that “Species are groups of interbreeding populations which are reproductively isolated from other such groups” is still as good a definition as we have and it’s emphasis is the one that will be used in this study.
The BSC seems to have stood the test of time despite some problems and criticisms of it putting too much emphasis on reproductive isolation. Sokal and Crovello (1970) for instance, pointed out that if a hybrid of two ‘species’ is able to successfully backcross with either of the two parental populations then it would imply, if the BSC is applied strictly, that the two parental populations must belong to the same species. Bonobos and chimpanzees have been known to have produced viable offspring in captivity (Sommer 2000 pers. comm.) providing evidence that according to strict adherence to BSC they should not be classified as separate species.
The problem appears to be that reproductive isolation is not a binary condition. There are degrees of isolation and a full range of variability between extremes.
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That last paragraph is a fancy way of saying that sometimes mules are viable.
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As a footnote, I had to share
this bit of filth here:
Male chimpanzees compete by producing vast quantities of sperm. Their testicles make up about three-tenths of a percent of their total body weight - about ten times that of human males. Since female chimpanzees mate with many different males, the male who produces the most sperm has the best statistical chance of fathering her offspring, and an average ejaculation contains about 600 million sperm (compared to 250 million in humans). A male chimpanzee can also sustain his erection for several hours, thus monopolizing the female and preventing her from mating with other males.
So conducting at least one version of the experiment might have some perks for a plucky volunteer.... |
