[Protein-analysis] Re: Question about enzymes

chris.linthompson from gmail.com via proteins%40net.bio.net (by chris.linthompson from gmail.com)
Tue Oct 17 05:19:13 EST 2006

yubbers9 from yahoo.com wrote:
> chris.linthompson from gmail.com wrote:
> > Do you realize you've just made a case for complex molecules being
> > subject to natural selection, and thus, evolution?
> The 3rd site wasn't being used so it wasn't
> under any evolutionary pressure to improve.

It's bad form to snip out sections of the conversation, especially
without marking them.  It also makes the thread more difficult to
follow. Please leave the threads intact.

Here's your example:

Site 1: useful effect that increases chances of gene being passed on
Site 2: unwanted effect that sligthly decreases chances of gene passing
Site 3: unused effect lacking some coenzyme

The balance of the 3 sites will be chances for the gene continuing
improve, even though Site 2 *creates* a problem rather
than solving one.

So even if the third site is totally neutral, there's still selective
pressure on sites 1 and 2. Look up "balanced polymorphism". This isn't
exactly that situation, but it's close.

I  might also add that even if site 3 is totally nonfunctional, the
entire molecule would (might) be under some selective pressure- to at
least save some energy in production of the enzyme by dropping the
unused portion (if possible).


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