[Haskell-cafe] [Haskell] ANNOUNCE: genprog-0.1

Andrew Coppin andrewcoppin at btinternet.com
Wed Dec 8 18:57:20 CET 2010

On 08/12/2010 02:40 PM, Alberto G. Corona wrote:
> A change to a gene does not make you to have a extra bone. It can make 
> you to have your hand slighltly longer. or shorter. 

Actually I suspect it does - or at least can do. It's just a rather rare 

> In fact there are metalevels of selection that discard abrupt changes. 
> For example, when females ovulate there are a strong selection where 
> thounsands of candidate cell ovules are tested and discarded. This is 
> one of the reasons why anomalous mutations are scarce.

I won't claim to be an expert in genetics, but I was under the 
impression that "big" changes to an organism's genetic code are usually 
fatal. This is the mechanism that "discards" any "abrupt" changes; they 
tend to not work properly.

The situation is a little different with evolving computer programs, 
since it isn't the computer program itself that makes the copies, it's 
some external entity "analysing" the programs and "deciding" which ones 
to copy.

Random example: Most animals can synthesize vitamin C. But humans and a 
handful of other related species can't. We have the whole metabolic 
pathway, it's all there, it's still working, except that the gene for 
the final enzyme in the sequence is busted. The enzyme transcribed from 
it doesn't actually work at all. Now, if you were born with a busted 
rhodopsin gene, you'd be blind, and probably wouldn't remain alive very 
long. However, since the stuff we eat has a fair amount of vitamin C in 
it anyway, apparently being biologically incapable of synthesizing it 
isn't actually a very big deal. (Unless you try to sail across the 
Atlantic Ocean...) Thus, almost nobody inherits a busted rhodopsin gene, 
but the entire human species has inherited a knackered L-gulonolactone 
oxidase enzyme.

Make of that what you will...

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