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On Thu, 24 Apr 1997 13:22:49 -0700 (PDT) Susan Richardson <slr@mustelid.biology.yale.edu> writes: > > Well, I haven't been losing sleep over this, but I do think about it >on > occasion. First of all, don't forget that in forams, which have life > cycles of alternating haploid and diploid phases, reproduction by >multiple > fission isn't always strictly "asexual," but may be preceeded by >meiosis. > > Other things to consider are the allozyme studies on Marginopora >vertebralis > (there were a couple of papers by Benzies et al. in JFR and Coral >Reefs) > showed population level differentiation in a group of "larger" >foraminiferans > also known to be capable of successive asexual reproductive events. > > Another interesting thing, which may or may not be related, are the >results > of Maria Holzmann and Jan Pawlowski (Mol. Biol. and Evol.) which >showed > high rates of sequence divergence in rDNA between individuals in the >same > species! > > Obviously, forams have mechanisms for generating genetic diversity, >even if > they are reproducing "asexually" at times. > > Cheers, Susan Richardson > >-- >Susan L. Richardson (e-mail: SLR@PEAPLANT.BIOLOGY.YALE.EDU) > >Dept. Ecology and Evolutionary Biology >OML 327/Wagner Lab >Yale University >P.O. Box 208104 >New Haven, CT 06520-8104 > I have been following this thread.. and I may be misunderstanding the question.. is someone trying to figure out the cause of genetic diversity in asexual reproduction? IF so.. then the answer is obvious.. the backgroud mutation rate for DNA, caused by natural processes.. errors in the copying process and chemical and physical effects on the parent DNA.. Sexual reproduction is a faster method for stirring the gene pool.. but certainly not the only one. Once a genetic mutation "has arrived on the scene" in an asexual reproducing species.. there is little chance of it being "diluted" within the population. The statistical probability of a mutation for "larger" is lower than a mutation for another drastic change.. because "larger", in most instances, can be accomplished by "more of the same" rather than "something different." The only editing process left is the mutations beneficial aspect related to its environment.. Dave O'Neal ONeal1@ Juno.com
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