The Serine Shift

Shane McKee shane at reservoir.win-uk.net
Mon Sep 11 12:54:09 EST 1995

Just a little question - I don't know how relevant it is, or
whether it has been studied, but you'll all be familiar with the
amino-acid Serine. In mRNA, it can be coded for by 6 separate
codons, namely AGU, AGC, UCU, UCA, UCC, & UCG. 

There are also several proteins in which serine will be conserved
by selection. I suppose the precursor to mammalian thyroxine,
thyroglobulin, would be one. Now, related species will have
related genes, and I wonder whether all such related genes in this
case will have the same codon group coding for the Serine?

What I mean is that it is simple to point-mutate between the UCx
options, but it requires a bigger jump to get from UCx to AGU, or
vice versa. Does anyone know of examples where Serine is coded by
UCx in one species, and coded for by AGU or AGC at the same locus
in another? 

Sorry if it seems like a bizarre question, but my own feeling is
that the codons ought to be conserved even between widely
differing species.

Any thoughts?


Shane McKee (SHO, RVH, Belfast)  | /      Art becomes science when
Shane at reservoir.win-uk.net     --O--    you start trying to figure
                               / |  out what the heck you're doing

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