Re: CONTRARY EVIDENCE (WASRe: Evide)nce!

Ernest Major wrote:

On 16/03/2024 22:37, Ron Dean wrote:

Explain how if eyes evolved independently about 40 times, how is it that the same master control gene exist in fruit flies, mice and humans. The eye gene (Pax6 gene) was taken from a mouse and placed into a fruit fly embryo and the mouse gene produced eyes in the fruit fly, but not mouse eyes, but fruit fly eyes. . Furthermore, some of the first complex organisms ie certain species of trilobites had highly complex functioning eyes. Is there reason to think the same Pax6 gene was not involved in the eyes of trilobites with vision?

 One of the functions of DNA binding regulatory proteins is to "specify" parts of the body. For example the Hox proteins divide the bilaterian body into regions along the anterior/posterior axis. Some MADS box genes in plants divide the developing flower along the proximal/distal access into the floral whorls of calyx, corolla, androecium and gynoecium.
 There is an obvious hypothesis for the role of Pax6 genes in independently evolved eye development - that Pax6, among it's other roles, specifies a forward facing region of the head, which is where eyes usually developed, and has been pressed into service as a switch in the early stages of eye development. One possible test for this hypothesis is look at the control of eye development in organisms with non-cephalic eyes - is the claim that Pax6 is a "master control gene" for eye development across all Bilateria an overly hasty generalisation?

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Ok, but the pax6 gene function is a function of eyes and part of the brain. But the fact that a mouse gene function controlling or switching on the downstream fly genes suggest it's the same gene. What seems amazing is that this gene remains "fixed" or unchanged back into deep time,100s of millions of years. I think deliberate and purposeful design is a better explanation than random, unguided blind natural forces for what is observed.
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The most vexing problem I have with evolution is the dogma of a blind, random, unguided process. I'm an engineer. In engineering we never see this, there no chance that a complex program can undergo random changes without dire consequence. There might possibly be on rare occasion where an unguided change might have no effect. Engineering starts out with an objective or goal,  so must evolution. If there's no goal, then what distinguishes a beneficial mutation from a bad mutation. Survival one might say? But no! offspring with bad mutations can do frequently survive, protected by the mother. And they can have offspring; only the worst die out.
The members that usually survival depends largely upon luck, surviving to adulthood without being eaten by other beast while at rest or asleep at night and living long enough to reproduce is real. The fittest is in reality survival of the luckiest. In other cases massive numbers of eggs are laid. Sea turtles for example, lay eggs by thousands and they hatch and rush forwards into the sea, except for the large numbers that become food for birds and other animals. Another consideration is the fact that each cell has it's own DNA proofreading and repair systems, a defective cell can repair itself or it is destroyed.
Another vexing issue for me is the will to survive. In the case of the turtles, it's as if they _know_ they are in danger, and seek the protection of the sea. How do the know. Instinct where did instinct come from. Going back the first living cell. What was the impetuous of dead inorganic chemicals to created a living cell. Did the first living cell have the will to survive? Where did this will come from?

Having conceived of this issue, I identified a group of organisms with non-cephalic eyes, i.e. Pectinidae (scallop), and asked a question of the web. The reply was Wang et al, Scallop genome provides insights into evolution of bilaterian karyotype and development, Nature Ecology and Evolution 1: 0120 (2017), which reports that eye development in Patinopecten yessoensis does not utilise Pax6, nor several other genes involved in eye development in Homo. 

I can accept that there are exceptions, but where commonality exist I think this is valid. According to some sources the homo eye gene is the same as the mouse eye gene. I can accept that there or other genes in addition to the Pax6 gene involvement in the development of the homo eye.