Amazing to me is that the gene is conserved across phyla. Between human and mouse, it is 100% identical and between human and drosophilia 94%.
We also know that eyes form whereever they are expressed, i.e. ectopic (eyes on a wing, etc.) Mouse Pax-6 in drosophilia leads to fully formed ectopic eyes – and vice versa!
The assertion was that the Pax-6 in the common ancestor was a factor in survival. I challenged that assertion per se because at that level, the organism had no eyes – thus nothing manifest physically as a factor for survival. The secondary argument was that the Pax-6 gene made the organism more adaptable. But that could be said of any Pax, as you noted – thus I didn’t address it.
No, the Pax-6 gene is seperate from the genes that code for the eye. DNA evidence (as I posted above) indicate that those genes arose independently.
Amazing to me is that the gene is conserved across phyla. Between human and mouse, it is 100% identical and between human and drosophilia 94%.
It makes a lot of sense when you understand the phylogenetic relationship between organisms. Humans and mouse are much more closely related than humans and flies.
We also know that eyes form whereever they are expressed, i.e. ectopic (eyes on a wing, etc.) Mouse Pax-6 in drosophilia leads to fully formed ectopic eyes – and vice versa!
Yes. The genes for eye development are present in all tissues and Pax-6 (highly conserved) is able to activate the developmental pathway in several other tissues.
The assertion was that the Pax-6 in the common ancestor was a factor in survival. I challenged that assertion per se because at that level, the organism had no eyes – thus nothing manifest physically as a factor for survival.
I guess it didn't occur to you that transcription factors can be used for regulation of other genes. Recruitment of genes for different purposes is a common theme in evolution.
Schutzenberger speaks to this:
"If one starts from an evolutionary point of view, it must be acknowledged that in one manner or another, the earliest fish contained the capacity, and the appropriate neural wiring, to bring into existence organs which they did not possess or even need, but which would be the common property of their successors when they left the water for the firm ground, or for the air."
Why would the primaeval fish "naturally select" for functions/capabilities that it didn't need to improve its survival fitness? Did the fish "know" that its "descendents" leaving the water would need such capabilities, and thus "thoughtfully," providentially provided for this exigency via natural selection -- a selection for capabilities that it didn't need and couldn't use anyway?
It appears to me (following Schutzenberger's suggestion) that natural selection is not the "universal key" of biological evolution that turns every lock: It seems there must be other factor(s) at work as well.
In this regard, Wolfram's remark seems on-point:
"...indeed there is every indication that the level of complexity of individual parts of organisms has not changed much in at least several hundred million years. So this suggests that somehow the complexity we see must arise from some straightforward and general mechanism and not, for example, from a mechanism that relies on elaborate refinement through a long process of biological evolution...."