An example that has been known for decades is the eye of the frog species Rana fusca and Rana esculents which determination and differentiation are completely different (in one the lens develops from the epidermis on the optic cup. In the other, the optic cup does not induce the lens to develop).
Interesting claim. Do you have any links for this? It would be interesting to see how different the induction events actually are. I've just had a quick search on pubmed and couldn't find much - possibly because the work was done a while ago. I did find
this abstract though:
quote:
Our data lead us to propose that the optic vesicle in amphibians is not generally sufficient for lens induction. Instead, we argue that lens induction occurs by a multistep process in which an essential phase in lens determination occurs as a result of inductive interactions preceding contact of ectoderm with the optic vesicle.
I'll do a little digging but it does look as though all is not as black and white as it once seemed.
This sort of thing is common, and not surprisingly we often find different genes involved. Evolution predicts that similar structures, in similar species, would be homologous.
Do you have any other examples of molecular mechansims for closely related species being different? I can only think of ones which show how developmental patterning and gene expression are
conserved (a very important prediction of the ToE)- the hox genes being a prime example.
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