Re: Mutation Rates

Radix2 wrote:

John Harshman wrote:

Radix2 wrote:

<snip>

If so, do we have any information on the ratio of deleterious to
neutral (or beneficial) mutations in functional DNA? Or is this almost
impossible to collate?

It varies wildly. It varies with gene and with selective environment. To
a first approximation, around a third of point mutations in
protein-coding sequences are silent, therefore likely to be neutral. If
a species is well adapted to its current environment, most non-neutral
mutations would be deleterious. That's as close as I can get it.


So with this, are you saying that a well adapted species (to a static
environment) would most likely have only two outcomes of functional
(coding) DNA mutation? i.e. Deleterious or neutral. Not immediately
beneficial in some way?

Sure. That's what "well adapted" means. If there was much room for
improvement, the organism wouldn't be well adapted.

Thus "beneficial mutation" is an accumulation
of neutral mutations and only measurable after success in an altered
environment?

Or it could be a new mutation that happens in the altered environment,
to which the species is, because of that alteration, no longer so well
adapted.

Which leads to fixation. How (apart from sexual or geographic
isolation) does gene fixation occur?

I don't understand the question. Fixation means that a particular allele
has spread to 100% of the genomes in the population, i.e. that it's the
only allele at that locus. This happens by drift and/or selection.

.

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