Message 53 of 214 (15015)
08-08-2002 4:01 AM
"Maybe we simply do not know the mechanisms of de-differentiation, yet."
Not only do cells have to de-differentiate, they then have to read temporal and spatial cues from their environments, and their axons have to read chemotaxic cues to synapse with the correct dendrites. These temporal and spatial cues are specific to the developmental period, they aren't present in adult brain.
"The reason lower organisms have the ability to regenerate is primarily most likely because they don't have the problem of regenerating the complexity which higher animals have to."
"I notice a bit of a contradiction here. Since higher organisms are able to regenerate bones and liver it is not restricted to lower organisms. So, this is not an argument, let alone a reason."
Liver and bone are made out of fairly simple (in comparison to other organs, appendages etc.) arrangements of relatively few cell types, arms and legs are not. (an arm requires epidermal, muscle, blood vessels, nerve etc. to regenerate in precise locations.)
"That experiment is not that hard to carry out. One only needs to compare the fitness of far-soared offspring and direct-neighborhood-of-the-parent-tree offspring. I predict that there will no difference in fitness."
This doesn't test fitness, because you've assumed the only purpose of the flaps is to carry them long distances. Gene knockout is the only way to be certain.
"Loss of the gene doesn't show any obvious myopathy for the same reason that differences in muscle fibre composition are not treated as myopathies."
... and that makes it a redundant gene, isn't it?
No, because it can give the organism an advantage, muscle fibre compositions between sprinters and endurance runners are usually different, they do different tasks. If the gene in question affects muscle fibre types then it has a function and will be subject to selection.
Furthermore, you did not respond to my reply in the previous letter, where you say that:
"you haven't done anything of the sort borger (about the falsification of NDT), and if you think you have then you don't understand science very well"
The reason I don't think you have is because the gene is the result of Mutation and Selection. You've assumed something about the selection pressure on certain base pairs to deduce that mutation is non-random. You actually don't know the value of the variable "selection" for any of the bases. So its an assumption, and assumptions do not falsify scientific paradigms. Your assumption might be reasonable, but until you can actually isolate the variable of mutation in the absence of selection pressure, you can't "falsify" random mutation.