MarioNovak wrote:I don't want you to tell me what the first mutation in intron was and then the 2nd, and then the 3rd and so on.
No? We'll see about that.
MarioNovak wrote:I want you to tell me just one thing: how did evolution find "the right way" in the space of infinite number of possible ways
The space of possibilities needed to be searched to alight on functional self-splicing intron RNA
is nowhere near infinite. Probably not even particularly large.
In fact I suspect that RNA that can get copied and subsequently inserted is probably close in sequence space to RNA can that cut itself out (because we know that this is actually true for transposons), otherwise there's a good chance the two capabilities would not be realizable in the same RNA molecule. But it is, so we have good reasons for thinking it does not require many mutations to gain the splicing function from the situation where it only has insertion functionality.
MarioNovak wrote:I want you to tell me just one thing: how did evolution find "the right way"...
Mutation. The "right way" was alighted upon by mutating the string of nucleotides until it functioned in "the right way" that was useful. Yes, it was chance mutations. Random variation accumulated until the "solution" popped up.
That means mutations accumulated until the intron could cut itself out. For all we know, the first intron might even be able to do this to begin with. But that is not a necessary precondition. They might not have been able to do so at the beginning, so they would just be mutating over many generations
until they could.
So here's your problem: You imagine evolution has to search a near-infinite space of irrelevant function, or non-function, to find self-splicing capacity from the position of insertion capacity. This is the same basic fallacy I spoke about earlier in this thread: You imagine, because you've been swallowing IDcreationist propaganda, that sequence space is a vast sea of non functionality, that mutations will be degrading, or destroying, or be just plain neutral, in their thousands upon thousands of combinations, until by some miracle "the right function" is found in this desert. Like finding a single specific grain of sand on a beach.
That view is in your mind because religious propagandists have been installing it there, because they have polluted your understanding of RNA and protein sequence space. So I must again insist that you come to terms with the fact that these functions you think are so hard to find and so unimaginably rare and well hidden from each other, that mutations just cannot ever be expected to find them,
are in fact not. And we know this because we can use comparative genetics to track the evolutionary histories of these functions, and see through this that these functional polymers are actually quite close in sequence space. They have commonalities in structure, function and sequence. So we know that it is not a problem for evolution, we know that the IDcreationists LIE when they make up these stories about insurmountable barriers "infinite possibilities" that need to be searched through.
MarioNovak wrote:Or in other words, what
selection criteria evolution used in choosing the right combination of molecules, a combination that solves a
particular cellular problem.
The selection criteria was: Is the function (self-splice) carried out? If yes, those cells had higher fitness and the mutations were retained by selection. If not, then they just mutated further
until they could.
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