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Southstar



Posts: 150
Joined: Nov. 2011

(Permalink) Posted: Nov. 16 2011,00:41   

Quote (qetzal @ Nov. 14 2011,20:14)
I was confused by this passage from the penultimate paragraph of Bard's review:

 
Quote
Complex systems have properties that cannot be pre- dicted, albeit that they can be understood with hindsight, and it may well be that the network for some trait (e.g. bone growth or pigmentation pattern) in the offspring has quantitative properties that are very different from those of the parents, not because of new mutations but because the novel mix of the rate constants will yield a trait that is an outlier of the normal distribution (known as a sport in breeding circles). As a result, the offspring may be able to colonise a novel environment far better than its peers. Equally important, this variant will naturally be heritable because it derives from the kinetics of the network (minor variation) rather than additions or losses to the proteins that comprise them.

I understand and agree that a novel combination of existing alleles could result in the offspring having a novel phenotype due to particular network interactions. But how would that novel phenotype be heritable? If it depends on an unlikely combination of alleles, it's not likely to recur in the subsequent generation.

And even if it did result in selective fixation of the relevant combination of alleles, how does that go beyond existing evolutionary theory?

I feel like I must be missing something, but I'm not sure what.

I guess we should really answer this question:

how does mutation-induced variation in a molecular network generate variation in the resulting phenotype? At least in some detail if we are to trash the book review

or am I missing something

Marty

--------------
"Cows who know a moose when they see one will do infinitely better than a cow that pairs with a moose because they cannot see the difference either." Gary Gaulin

  
  366 replies since Nov. 08 2011,06:46 < Next Oldest | Next Newest >  

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