vac@cs.cmu.edu (Vincent Cate) (06/14/91)
Niklas Grip: >Not long ago someone asked if it is possible to cross-fertilizate a human with >a monkey. Yesterday I read in a scientific magazine that it is impossible. The question is humans and Chimpanzees. The Chimpanzee is closer to humans than it is to any monkey or Ape. Humans and Chimpanzees are closer together than some other species that are able to cross. So even though there are DNA differences (like 1%) there is a good chance that Humans and Chimps can cross. What was this "scientific magazine"? Did they mention Chimps? Had they tried the experiment, even in a testtube? If they did not try the experiment, then I don't see how they can claim it won't work, since DNA is so amazingly resilient. If they did not try any experiment but were able to publish a claim it won't work, I question your claim that this is a "scientific magazine". My expectation is that Humans and Chimps can cross, but I would love to know of any experimental evidence either way. However, I don't think anything has been published on this. Anyone have a chimp with a womb for rent? -- Vince
mtp@allwet.zso.dec.com (Michael T. Peterson) (06/14/91)
There are a host of reasons why Humans and Chimps are unable to cross-breed. Apart from the genetic differences, there are substantial differences in the histocompatibility complexes of each species. Differences in these cell-surface proteins, for example, may preclude the sperm of one species from attaching and/or penetrating the egg of the other. Another potential problem in this scenerio is the specific binding of the protein complexes responsible for DNA unwinding. Chimp complexes may not recognize human DNA or vice versa, or the rates at which the species' DNA was unwound and recombined may be so different as to preclude proper recombination, etc., etc. In point of fact, the specific variation in the sequences of nucleotide bases probably has little to do with the potential for successful breeding -- It's all the housekeeping that occurs before, during, and after that probably exerts the more significant effect. By the way, one of the operational tests of speciation is whether breeding can be successfully accomplished. Said another way, if A can breed with B, then A and B belong to the same species. If A can not, the A and B are of a different species. regards, /mtp
mll@hpfcso.FC.HP.COM (Mark Luce) (06/14/91)
/ hpfcso:sci.bio / mtp@allwet.zso.dec.com (Michael T. Peterson) / 6:22 pm Jun 13, 1991 /
writes:
There are a host of reasons why Humans and Chimps are
unable to cross-breed. Apart from the genetic differences,
there are substantial differences in the histocompatibility
complexes of each species. Differences in these cell-surface
proteins, for example, may preclude the sperm of one species
from attaching and/or penetrating the egg of the other.
Another potential problem in this scenerio is the specific
binding of the protein complexes responsible for DNA
unwinding. Chimp complexes may not recognize human DNA or
vice versa, or the rates at which the species' DNA was
unwound and recombined may be so different as to preclude
proper recombination, etc., etc.
In point of fact, the specific variation in the sequences of
nucleotide bases probably has little to do with the potential
for successful breeding -- It's all the housekeeping that occurs
before, during, and after that probably exerts the more
significant effect.
By the way, one of the operational tests of speciation is
whether breeding can be successfully accomplished. Said another
way, if A can breed with B, then A and B belong to the same
species. If A can not, the A and B are of a different
species.
This last paragraph, at least, is just plain wrong. Tigers and
lions are classified as separate species, yet they can interbreed to
produce 'tiglons' and 'ligers' (depending on whether the mother is a
tiger or a lion, respectively, although I may have this reversed).
Horses and donkeys are classifed as separate species but interbreed
to produce mules. The several species of the genus Canis can all
interbreed to produce fully interfertile offspring. The operational
test of speciation, I believe, is better described by asking whether
A typically can and does interbreed with B in the wild. Whether
chimps and humans can be hybridized is something that, IMO, can only
be answered by experimentation.
regards,
/mtp
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