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
>> 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
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 :-)
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
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
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