>Notice the distinction, "Old World monkeys." In other
words, we have genetic markers common to African
monkeys, but not South American monkeys. Why? Well,
the monkey family was separated at the breaking up of
Pangea roughly 200 million years ago. Which in turn
implies that monkeys divided off the primate line, and that
apes and man, dare I say it, branch off the monkey line, not
that monkeys divided off the primate line to go on their
merry way before apes evolved, and then man.<
Actually, the South America-Africa split dates closer to 100
million, as part of the breakup of Gondwana. The New
World-Old World monkey split is rather more recent than
that, however, with the New World monkeys closer to us
than to the lemurs and other primitive Old World primates.
Thus, the South American primates are thought to have
rafted over from Africa in the mid-Cenozoic, and a similar
origin for the South American rodents seems likely.
This does not affect the basic argument that Old World
monkeys appear more closely related to us than to New
World monkeys.
The latest Science has an article on differences between
us and other primates. Patterns of gene expression in
tissues such as the liver correspond well to levels of
genetic similarity, so that our livers are almost identical to
chimps'. However, gene activity in our brains is very
unusual, and the chimp is closer to the Old World monkey
in that regard.
(Incidentially, i do not recall seeing an answer to Allen's
question about gene number in humans. The estimated
number has increased a good deal over 30,000 as closer
study revealed additional genes and found that the two
teams each found several that the other missed.)
Dr. David Campbell
Old Seashells
University of Alabama
Biodiversity & Systematics
Dept. Biological Sciences
Box 870345
Tuscaloosa, AL 35487 USA
bivalve@mail.davidson.alumlink.com
That is Uncle Joe, taken in the masonic regalia of a Grand
Exalted Periwinkle of the Mystic Order of Whelks-P.G.
Wodehouse, Romance at Droigate Spa
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