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Re: Rapid Lizard Evo
how many organisms don't benefit from recombination?
Bdelloid rotifers... (Prominent in last week's Nature.)
Surely genes can
'cross over' (nothing to do with John Edwards) during asexual cell
division just as
much as during meiosis?
They don't, though. In eukaryotes that only happens during DNA repair and in
meiosis, when special enzymes for making and repairing double-strand breaks
are switched on -- and some do it only in meiosis (there are no knock-out
flies because "*Drosophila*" doesn't do recombination outside of meiosis;
people have to resort to knock-down flies).
I suppose it depends on how you define 'random mutation'. I tend to
it's use to random changes in gene structure due to outside influences
(radiation, mutagenic chemicals, etc), whereby genetic damage is inflicted
that isn't completely repaired by the cell.
Also mistakes in copying, and insertion of transposable stuff and virus
I suppose some people might use
the term more broadly to encompass any process that alters a gene sequence
(which would include recombination).
Recombination is directed mutagenesis: the site at which the mutation
happens is not random.