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Posted by Ramellini on December 01, 1999 at 11:48:21:
In Reply to: The genetic program: creator, demiurge, or neither? (Re: Program God) posted by Ramellini on November 01, 1999 at 04:41:55:
Instruction, selection and genetic program
According to Kupiec and Sonigo (1999, see HBG essays), the correspondance
between DNA and polypeptide sequences can be explained or, better, interpreted
either by instructive or selective models.
The observative data show that more than one aminoacid sequence correspond to
one DNA sequence (seldom, usually or always? This is not clear to me). This
observation is interpreted in a different way by the two alternative models.
The instructive model speaks about errors in protid synthesis: there is one
correct protid and many uncorrect or illegitimate products; the criterion to
distinguish among correct and uncorrect products is the linear correspondence
between certain DNA triplets and certain aminoacids, according to the rules of
the genetic code. The selective model says that all the products of the
synthesis are biologically significant, and that a sort of broad selection
among them takes place; so, according to this model, there are no univocal or
specific instructions.
What about the genetic program, seen as a system of instructions?
This concept is pleasant to the instructive model while it seems rejected by
the second one. Nevertheless, I think that the analogy of instruction could be
accepted by both the models, though in a different way: the instructive model
conceives instructions as iron obligations, the selective one as kindly
suggestions. If it so, the difference between the two models wouldn't be the
presence/absence of instructions, but the compulsoriness of instructions. The
instructive model would be better called a univocal, specific instructive
model, while the selective one would be a equivocal, unspecific instructive
model.