Several questions on evolution, and mutation (rate)

[Linnea Ista]

On 27 Aug 1996, Joan Shields wrote:

> Stats haven't always been one of my strong points but there is something I
> think I can add - something I think a lot of people are overlooking.
> 
> Whether or not is would take, on average, X numbers of tries in order to
> form amino acids - you have to remember that all those different
> combinations didn't/don't occur one right after the other - they can
> happen all at once.  In other words, evolution doesn't just happen in a
> straight line - mutations occur everywhere and in every direction.  If you
> look at mutations that have been successful, then it appears that
> evolution is going in a line (or meandering path).  

I also recall something about "exon shuffling". Whole domains of enzymes 
being  encoded on a single exon and then new enzymes or proteins being 
formed by recombiunation between exons.

Recombination in general is a powerful mechanism that most discussions of 
evolution seem to leave out. 

And let's not forget endosymbiosis!
Linnea