>(not my statement,
> just a paraphrase)
>"there are no examples of beneficial genetic mutations that result in an
>increase of genetic material. Only ones that appear to help exist and are
>in fact harmed information that is a loss of info." (cited examples are
>usually moths in England, and one more that slips my mind)
There was an article in yesterday's New York Times that seems interesting
and possibly relevant (NYT 09-Mar-1999, Science Times section, p. D2:
"Antarctica's frigid waters form evolutionary cauldron"). One thing
that caught my eye: "Fish living nearest to the icy surface have about
twice as much antifreeze in their blood and more copies of antifreeze
genes in their genome than those that live in relatively warmer, deeper
waters". An increase in the number of copies of a gene can produce an
increase in the expression of a gene product (perhaps a useful antifreeze
protein?). There are any number of situations where a simple increase in
a gene's expression might be beneficial in a particular environment (eg.
Growth on a substrate for which some catabolic step is rate limiting, or
growth in the presence of a antibiotic which can be sequestered by binding
harmlessly to some other protein). Gene duplication is by any measure an
increase of genetic material and it can be beneficial...
> Now, my qs: What examples of "positive" mutations are there? If
> there are none, how does the idea still stand or what explanation
> has replaced it?
In this context, what do you mean by a "positive" mutation?
Simply one that is beneficial? They're out there. If you
mean something else, you might want to check out previous
discussions about the metrics of biological information
from last fall (around September).
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