Early embryology; clockwork construction plan (Introduction)

by dhw, Wednesday, October 19, 2011, 12:32 (4567 days ago) @ David Turell

DAVID: Hox genes ( from the word homeobox) are the master planning genes in the genome for various parts of the musculoskeketal body and for organ systems.. They have great power, which is why they are under tight controls and they MUST act in time sequence. Thus the Hox clock, also a new term, and 'cute'.

Now you have made me wonder: could there be a major Hox controlling code that allows for the jumps that result in new species? Random mutations are too dangerous to rely on them for advancement. Not through the clock mechanism but a major coordinated set of changes in the Hox genes.

And you have made me wonder too. Thank you for this explanation, which is a real eye-opener, particularly with your use of the word “coordinated”. So many evolutionists gloss over the implications of “random mutations” as if the words themselves were an explanation, but any mutation would require coordination with the rest of the body if it were to be useful and to survive. If Hox genes control both organ systems and parts of the musculoskeletal structure, it doesn’t seem unreasonable to suppose that they would adjust themselves to accommodate any innovations. Maybe only one in a million such changes might actually work, but that would suffice over time to account for the variety of new organs and new species. It would also account for the general absence of transitional forms (because, as you say, the process would have to work by the “jumps” which Darwin categorically rejected) and even for species explosions like the Cambrian, since a change in atmosphere might make its presence felt on the whole Hox mechanism – perhaps including the clock? (That’s a question, because I’m way out of my depth here.)

It all brings me back to one of my hobbyhorses. Once we strip the word “mutations” of its association with “randomness”, isn’t this a view of evolution that might be acceptable on both sides of the fence? The theist can carry on claiming that the mutations have been coded into the Hox mechanism (or the UI has intervened), while the atheist can carry on claiming that they have come about through chance and/or environmental pressures. I certainly find this scenario immeasurably more convincing than the creationist insistence on separate creation, and Dawkins’ “smooth gradient up Mount Improbable”.

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