higher ploidy and mitochondrial maintenance hypothesis

Iuval clejan clejan at mindspring.com
Fri Aug 17 15:15:04 EST 2001

Iuval clejan wrote:

> I am also not sure if the uricotelic organisms use glutamine synthetase
> and other mitochondrial enzymes in their mitochondria to get rid of
> ammonia.

I was mistaken once more (those damn details, Aubrey). It seems that GS is
mitochondrial mostly  in uricotelic animals. There are intermediate animals
like the treefrog (which keeps GS mostly in the cytosol but is mostly
uricotelic, cf James W Campbell  et al 1984) and alligator (which keeps GS
mostly in the mitochondria but is mostly amoniatelic cf Darwin D Smith et
al, 1986). At this point I can't see a connection from the pattern of ploidy
across species and mitochondrial maintenance. Maybe I should look at other
enzymes involved in amino acid and purine catabolism which are mitochondrial
in mammals, and fish (although for fish there is the complication of
germline higher ploidies) but not in other (liver-possessing) animals. Maybe
the tetraploidy is not about mitochondrial maintenance.


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