🚀 go-pugleaf

In article <38212@eerie.acsu.Buffalo.EDU> dmark@acsu.buffalo.edu (David Mark) writes:
>Such data, if they exist, would not be definitive.  I recall (I hope
>correctly) that recent biochemical work suggests that the Homo sapiens
>is the closest living relative of the chimps (Pan), and that human-chimp
>are genetically the closest pair among great apes of different
>genera.
It is, unfortunately, not so simple.  There are some immuno-compatibility
results which, if interpreted naively, suggest that humans and chimps are
the closest pair.  Some other DNA based studies have produced similar results.
However, there are other studies, and other approaches to relatedness which
make the chimp-gorilla pair the closest.  For instance - chimps and gorillas
both use knuckle-walking on the ground, but even the earliest Hominids (such
as Lucy) show *no* trace of knuckle-walking.  This suggests a shared common
ancestor between chimps and gorillas not shared with humanity.

The problem with the DNA distance results is that the most commonly cited
studies fail to indicate the standard error values for the measurements.
When this deficit is corrected, the distinctions amoung chimps, gorillas,
and humans are statistically insignificant.  (That is the branching sequence
is indeterminate).  So, for all proctical purposes gorillas, chimps and humans
are about equally related to one another.

>a lack of successful inter-
>generic hybrids among other pairs of great apes would not really indicate
>that human-chimp hybrids are unlikely.  However, successful hybridization 
>between any other pair would suggest (but not prove) that the viability of 
>chimp-human would be reasonably likely.

Also quite true, though for different reasons.  Hybridization may depend
on other things besides genetic difference, such as physical differences.

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uunet!tdatirv!sarima				(Stanley Friesen)