http://www.bio.net/hypermail/MOLECULAR-EVOLUTION/lost of genes in primate

Shane McKee shane at reservoir.win-uk.net
Mon Mar 4 13:53:27 EST 1996


Stephen Wray (stevew at debretts.Comp.VUW.AC.NZ) writes:

> Shane> Jeff continued:  
> >> The paradox is that the amount of DNA or the number of genes do not
> >> correlate with "complexity."  Genetic complexity and physiological
> >> complexity are not tightly coupled.
>
>What if the function of the non-coding segments were structural, or coded
>"for" higher-level operators...

I think that's entirely plausible, in fact, I think it's probably
*right*. Examples would include telomeres, centromeres,
recombination hot-spots near repeats etc - all of these turn out
to be importants genomic features, despite the simplicity of their
coding DNA sequences. 

>My idea here is that 
>chromosomes are folded & twisted in very complex ways. These are
>not exactly random, but relate to the structure of the chromosome.
>What if these folds & twists were relevant to replication? Or in 
>expression ?

You've hit upon one of my favourite notions here - that repeats
(which are often highly polymorphic) may be able to influence
gene expression, and thus act as a further source of evolutionary
variability without affecting protein structure or expressor
sequences (which are more dangerous things). 

>In that case, they need not be information rich (in an 
>information-theoretic sense) in order to be complex (in a structural
>or functional sense.

The twists and coils and higher structure of the DNA molecule and
chromosome are often quite complex, but in a different sense from
what we're talking about here. For instance, slight changes in
sequence are unlikely to bring about much change in this structure
(correct me if I'm wrong, folks). 

>Bear in mind that I am a computer scientist, not a biologist.

>I'm looking at ways of using "non-coding" sequences to code for
>crossover and mutation operators. This would mean that  these 
>operators could adapt along with the "coding" sequences.

All the best (& good luck)
Shane


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Shane McKee, Belfast, Northern Ireland, United Kingdom
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===========Give us back our ceasefire. Now.===========    



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