No subject


Sun Apr 10 21:46:03 EST 2005


or two aa's) could change key receptor properties, right? I don't know where
to fit differential RNA processing in, but this I think is another
consideration.

>
> All this is "garbage" in the sense that at the beginning, you
> already had one peptide and one receptor capable of opening potassium
> channels, so why make more?  The standard argument (a favorite of people
> who are in the business of identifying and cloning new receptors) is that
> all these new ones differ from each other in very subtle ways that allow
> for more versatility in fine tuning.
>

I think a lot of this might relate to redundancy. Gibson and Spring's (1998)
article on vertebrate genetic redundancy might apply.

>
> So in that sense, they're not
> garbage, they're highly evolved, highly specialized systems for getting
> the most diversity in the range of neural responses. Maybe this is right.
>
With redundancy, there is a little more freedom.
>
> But maybe it was just evolutionarily cheaper to leave all these extra
> proteins lying around than it would be to get rid of them once they're
> there.
>

An argument based on efficiency might ask why this redundancy isn't plucked
out due to costs, but this probably would assume that selection molds every
square inch of an organism's phenotype.

I raise these issues as a barometer of what people in the neuroscience
community are doing related to evolutionary studies of neurobiology. I have
interests in evolutionary developmental biology and would like to see how
this might overlap with neurobiology. I've got a LONG way to go :-)

refs:

Garcia-Fenandez J and Holland PWH. 1994. Archetypal organization of the
amphioxus *Hox* gene cluster. Nature (370): 563-566

Gerhart J and Kirschner M. 1997. Cells, Embryos, and Evolution. Blackwell
Science. Malden, Massachusetts

Gibson TJ and Spring J. 1998. Genetic redundancy in vertebrates: polyploidy
and persistence of genes encoding multidomain proteins. Trends in Genetics
(14): 46-9

Gould SJ. 1991. Exaptation: a crucial tool for an evolutionary psychology.
Journal of Social Issues (47): 43-65

Slack JMW, Holland PWH, and Graham CF. 1993. The zootype and the phylotypic
stage. Nature (361): 490-2

Scott Chase


-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/       Search, Read, Discuss, or Start Your Own    



More information about the Neur-sci mailing list