In article <Pine.3.89.9410132159.A19974-0100000 at biobase.aau.dk> thorup at BIOBASE.AAU.DK (Jan Ulrik Thorup) writes:
>>Has anyone ever before experimentally seen that through evolution two exons
>merged to one exon, say that a intron through evolution has dissappeared ?
I seem to recall reading that there a number of eukaryotes that, like
prokaryotes, have their 5.4S and 28S rDNA complements as a single transcript
(and single gene). For Vairimorpha necatrix, I (J. Protozool. 1992)
argued that this was evidence against Sogin and Peatie's suggestion that
Giardia lamblia was representative of the first divergent eukaryotic lineage.
(G. l. and V. n. were the first 2 of the base but both had long br. ln. and
parsimony said V. n. as well).
Anyway, notwithstanding the situation in microsporidans which I think
is a prokaryotic hold-over, some of the others with this single gne
would have to be the result of reversion since they follow successive
ancestries of having disjunct genes. Thus the splicing out of the
You'll have to share the prize I suppose. :)
Mark E. Siddall "I don't mind a parasite...
mes at vims.edu I object to a cut-rate one"
Virginia Inst. Marine Sci. - Rick
Gloucester Point, VA, 23062