Re: Spliceosomal introns


"g" <gillawton@xxxxxxxxxxxxx> wrote in message news:dtfh3b$6sa$1@xxxxxxxxxxxxxxxxxxxxxx

"Perplexed in Peoria" <jimmenegay@xxxxxxxxxxxxx> wrote in message
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"g" <gillawton@xxxxxxxxxxxxx> wrote in message
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The MAIN questions I have surround not whether germline cells are
communicated with by somatic cells (adjacent, neuronal...?) or by way of
enzymes in the blood, or by way of lymphatic or other routes...
They HAVE to be triggered to degress, or the kitten eye taping experiment
would not turn out as it does. Also, if the germline cells were not
communicated with in cave creatures and burrowing creatures that live in
dark environments, those creatures would not end up blind.

Sure they would, for the same reason that fruit eating mammals ended
up without the ability to synthesize vitamin C.

So are you saying that the reason fruit eating mammals began to repress
their genes coding for proteins to make ascorbic acid is because those genes
got no stimulus to act?

Nope. Gene repression has nothing to do with it. I'm talking
about standard natural selection. A mutation destroys the ability
to synthesize ascorbate in one individual. Since there is not
selection against this mutated gene, it can rise in frequency to
fixation. But in sibling taxa, where fruit-eating is not the
habit, the same mutation is selected against.

Similarly for the genes for building eyes. If there is not positive
selection for having eyes, the processes of mutation and drift will
result in the loss of functional eyes, and perhaps eventually in the
loss of even non-functional eyes.


.

Relevant Pages

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