Thought Provoker
Posts: 530
Joined: April 2007
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Hi qetzal,
You wrote...
| Quote | Regardless of the above, I don't consider your ideas to be equivalent to front loading. Here's why.
In 'traditional' front loading, all of the 'information' needed to generate every possible future organism was loaded into the first organism. Proponents generally argue that it was all encoded into the DNA, but most of it was repressed. The key point is that it was all inherent in that first organism.
You're arguing (I think) that the information needed to generate every possible organism was loaded not into the first organism, but into the universe itself. That's fundamentally distinct. You may choose to call that front loading, but it's not compatible with front loading as it's commonly understood. |
I understand that MikeGene and Krauze of Telic Thoughts are credited for pushing the Front Loading meme for a long time. I can't speak for them, but I have noticed they have rejected similar characterizations of "traditional front loading" in past comments.
MikeGene has suggested that the recA gene might be a front-loaded evolution gene. Here is a link to a paper (essay?) MikeGene wrote in the subject (it was the one MikeGene offered when SteveStory came by on his visit to Telic Thoughts)...
RecA is truly a remarkable protein. Even though it is only about 350 amino acids in length, it carries out the multiple functions of binding multiple DNA strands, coordinating their exchange, binding ATP and hydrolyzing it, and interacting with other proteins. In fact, according to one review, the functional domains responsible for these activities closely map together and may even overlap. How is all this carried out?
I’ve left out one very important part of the story – RecA is not functional as a monomer, it only becomes functional when it forms protein fibers that wrap around the DNA.
In other words, recombination occurs because tubulin-like proteins stretch the DNA by forming a dynamically lengthening tube around it. In this way, the growing protein tube can hold onto the single stranded DNA with one “hand” while using its other “hands” to unravel double stranded DNA such that the single-stranded DNA can be used to probe the unraveled DNA for regions that are complementary.
You might have noticed I said “tubulin-like.” Is this simply because RecA forms a semi-hollow protein tube? No. There are several other features that have led one reviewer, for example, to note:
The dynamic behavior protein under conditions of ATP hydrolysis is thus conceptually similar to that of other NTP-hydrolyzing, self-assembling proteins, such as actin and tubulin.
Like tubulin, RecA formation starts slowing with a nucleation step, where a small number of monomers must form a seed that can then be extended. Once formed, like tubulin, RecA then grows at one end by the incorporation of RecA monomers bound to ATP (tubulin dimers add to one end and must be bound to GTP). Like tubulin, the NTP hydrolysis is not needed for assembly, but instead is needed for disassembly. This means that RecA, like tubulin, assembles at one end and disassembles at the other end, forming something like a treadmill. According to one team of researchers:
We argue that RecA can “proofread” the ssDNA by its own binding fluctuations. These fluctuations are similar to microtubule dynamic instability. The assembly dynamics constitute a kinetic proofreading cascade that is a “hair-trigger” sensor of DNA length. Enhancing biomolecular precision by fluctuations, which may seem somewhat counter-intuitive in a deterministic world, is presented as a natural design principle in the noisy realm of the living cell.
A microtubule-like structure is thus in charge of genetic recombination.
Finally, if RecA is an evolution gene, this would lead to an obvious prediction - removal of RecA should compromise an organism’s ability to evolve.
Could the RecA protein be another example of life taking advantage of the power of quantum computing for a key function? I haven't found the time or resources to explore that, but MikeGene went out of his way to point out how his and my hypotheses were mutually supportive.
Whether or not the Third Choice is considered part of the rubric called "Front Loading" isn't up to you or me. It is up to those proposing the Front Loading hypothesis.
Labels aren't important, ideas are.
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