why U instead of T in m-RNA ?

Bold said:

Does anyone know why it is uracil instead of thymine in
the messenger-RNA. I mean why doesn't nature just keep
sticking to T and takes U? (I might have got the spelling
wrong, if that is the cause, sorry :-/ )

mfg Bold

It would be just speculation. If RNA came first, there would
have been a selection for the genetic storage template to
change U to T for the reason that cytosine deamination
constantly occurs spontaneously and changes C to U. There
would be more mutations if repair mechanisms couldn't
distiguish the deamination events. We have repair complexes
that can snip out U from DNA, but they leave T alone.

Ron Okimoto

Ron Okimoto said:

Quoted message said:

Bold said:

Does anyone know why it is uracil instead of thymine in
the messenger-RNA. I mean why doesn't nature just keep
sticking to T and takes U? (I might have got the
spelling wrong, if that is the cause, sorry
:-/ )

mfg Bold

It would be just speculation. If RNA came first, there
would have been a selection for the genetic storage
template to change U to T for the reason that cytosine
deamination constantly occurs spontaneously and changes C
to U. There would be more mutations if repair mechanisms
couldn't distiguish the deamination events. We have
repair complexes that can snip out U from DNA, but they
leave T alone.

Ron Okimoto

See:

madsci.org879354206.Bc.r.hOpen ↗
tml

Thanks for your help!