[Molecular-evolution] Re: ribosomal genes
dazzhiggins at hotmail.com
Tue May 30 06:12:56 EST 2006
"Peter Ellis" <pjie2 at cam.ac.uk> wrote in message
news:mailman.13.1148958920.18505.mol-evol at net.bio.net...
>> "Des Higgins" <dazzhiggins at hotmail.com> wrote:
>> The possible mechanisms that allow concerted evolution include unequal
>> crossing over
>> (you have tandem repeats that match up incorrectly at meiosis; these
>> swap between
>> chromosomes and some are gained and some lost; this repeated sampling
>> uniformity over time) and gene conversion (transcript of one gene
>> "corrects" the sequence
>> of another).
> And how exact are these? Any idea what percentage sequence variance, if
> any, would you expect in the ribosomal sequences within a single
I do not have any exact data on this. The textbooks say that variation
between copies is minimal or zero.
It may depend on the species. Species with just a few copies (e.g.
bacteria) may have significant variation between copies (just a guess).
Plasmodium certainly has variation between the small number (4-8 or so) of
rRNA genes. Humans and fungi can have hundereds opf copies in tandem arrays
and if I had to guess, I would say they were mainly identical copies but
that is a guess.
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