Constraints of evolution

From: Pim van Meurs <pimvanmeurs@yahoo.com>
Date: Sun Aug 07 2005 - 14:11:50 EDT

In my discussions with CH, I mentioned that evolution works under
various constraints, and that these constraints are essential in
understanding evolutionary pathways.

Arthur Wallace has written a book which I intend to read as soon as it
arrives in my mailbox. Until then some quotes and reviews:

[quote]
To epitomize Arthur’s position, there is “a bias in the production of
variant phenotypes or a limitation on phenotypic variability caused by
the structure, character, composition or dynamics of the developmental
system”. The quote isn’t from his book, it is from John Maynard Smith’s
famous position paper (Q. Rev. Biol. 60, 265–287; 1985) defining what
most of us call ‘developmental constraints’ — it’s just that Arthur
doesn’t like the term. Many, perhaps most, evolutionary biologists
accept that developmental constraints exist.
[/quote]

Maynard's 1985 paper is called " Developmental constraints and
evolution" http://wwworm.biology.uh.edu/evodevo/lecture7/msmith85.pdf

"Developmental constraints (defined as biases on the production variant
phenotypes or limitations on phenotypic variability caused by the
structure, character, composition or dynamics of the developmental
system) undoubtably playes a significan role in evolution."

So now we get to convergence

http://www.blackwell-synergy.com/doi/abs/10.1046/j.1525-142x.1999.99022.x

Ralf J. Sommer "Convergence and the interplay of evolution and
development" Evolution & Development Volume 1 Issue 1 Page 8 - July 1999

[quote]
Developmental constraints have been defined as "biases on the production
of variant phenotypes or limitations on phenotypic variability caused by
the structure, character, composition, or dynamics of developmental
systems". The term has been widely discussed, but is far from being
generally accepted. One reason might be that the concept of a constraint
has so far not been possible to test experimentally. Experimental tests
are difficult because the hypothesis is supported only by the failure or
the limitation of seeing phenotypic variation, which can always
hypothetically be explained by stabilizing selection. In the following,
I will suggest an approach to study the potential molecular basis for
developmental constraints.
[/quote]

So what are some of the constraints?
http://wwworm.biology.uh.edu/evodevo/lecture8/lecture8.pdf

*Developmental constraints *Biases in the production of variant
phenotypes or limitations on phenotypic variability caused by the
structure, character, composition, or dynamics of the developmental system1.

*Generative constraints *Constraints that limit or bias the production
of certain phenotypes during development. Therefore, generative
constraints result in the non-random production (or non-production) of
phenotypic variants on which natural selection can act2.

*Selective constraints *Constraints arising from natural selection
during development2; also known as internal selection3. Selective and
generative constraints are dicult to distinguish in practice.

*Genetic constraints *Constraints caused by lack of genetic variation
for a given phenotype. These may result from lack of mutations, lack of
standing variation within a population, or genetic correlations.

See also http://wwworm.biology.uh.edu/evodevo/

Which has notes and links to the many various relevant papers. An
excellent resource.
Received on Sun Aug 7 14:14:39 2005

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