[Taxacom] Dispersal... again

[Michael Heads]

Hi Curtis,
?
Mutation bias does seem to have a fundamental importance for?evolution.?(Historically, the term 'orthogenesis'?referred to all sorts of different ideas, including mutation bias, but it?is not used in current genetics literature).??
?
For example, Gibson et al. (2005, Molecular Biology and Evolution) analysed the mitochondrial
genomes of 69 mammals. They found that ?Mammalian mitochondria exhibit striking
variations in base composition both within genomes and across species. ...It is now obvious that the
proportions of C and T both change between different species and that changes
are congruent at all sites examined within the genome, consistent with a
directional mutation pressure?.
?
Stoltzfus
and Yampolsky (2009, Journal of Heredity) concluded: ?First,
evolution has tendencies or propensities, an idea that has faced resistance
from those committed to the idea that evolution is unpredictable (see Beatty,
2008, for an analysis of the resistance to the idea of trends or directions)...
Second, these tendencies are predictable...?. Neo-darwinian
authors who accepted random mutation and selection as the basis for evolution
have interpreted evolution as ?climbing Mount Improbable? (Dawkins, 2006). In
contrast, Stoltzfus
and Yampolsky (2009)
saw intrinsic bias in mutation as a cause of non-randomness and so interpreted evolution as ?climbing Mount
Probable?.??

Michael

Wellington, New Zealand.


My papers on biogeography are at: http://tiny.cc/RiUE0


________________________________
From: Curtis Clark <lists at curtisclark.org>
To: taxacom at mailman.nhm.ku.edu
Sent: Friday, 28 October 2011 3:04 PM
Subject: Re: [Taxacom] Dispersal... again

On 10/27/2011 5:15 PM, Michael Heads wrote:
> MH: The genetic forces are not random - that's the point.
Let's cut to the chase. Does accepting panbiogeography require accepting 
orthogenesis? I.e., does panbiogeography only make sense if directed 
mutation is common?

-- 
--
Curtis Clark
Cal Poly Pomona


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