RE: [HAPS-L] Mutations - well, maybe

[Ken Saladin <ksaladin@xxxxxxxxxx>]

> If you
> also take a look at the genetic code, there are six codons for arginine
> alone, which suggests that if one of the bases in the middle of the codon
> was erroneous, it wouldn't matter during transcription - arginine is
> still going to become part of the peptide chain.    
> So the redundancy of the code itself for some amino acids may offset some
> of these mutations.    


I also read recently that even if a mutation changes one codon to a
different codon for the same amino acid, it can still affect protein
structure. The reason is that different codons are translated at
different speeds. Changing one arginine codon to a different arginine
codon may speed up or slow down the translation process as rRNA is able
to read one codon more efficiently than another. That change in rate, in
turn, can alter the folding of the protein, and thus alter protein
functionality even when the amino acid sequence remains
unchanged.

I wonder also if mutagens have equal access to euchromatin and
heterochromatin. If not, that might alter the probability of mutation in
different regions of the DNA.

Ken