taylor_31 writes:
But I thought that the probability rates of different mutations happening are different.
Well, strictly speaking they are. As already mentioned, transitions (eg purine to purine) are more common than transversions (purine to pyrimidine).
taylor_31 writes:
If that's true, then why can't you predict which mutation would occur?
Mostly just because there are so many nucleotides in any given gene. I mean, we could give a probability for every single nucleotide substitution, but then we also need to consider insertions, deletions, transposons etc...it just gets too complicated.
In this way, it much like the toss of the coin or die that was mentioned. Strictly speaking, we could indeed predict which face/number will be up just by looking at the dice or coin as it falls - it is governed by well-understood physical laws (gravity, friction, inertia, elasticity etc). But, I don't know any computer (yet) that can analyse a falling dice and predict the result, even though it is predetermined by the hand that tossed it (there might be one that can for a coin...not sure). So, because we humans just can't compute all the data we have when we see a die or coin fall, it is considered random by those who operate casinos and so on. It's not
intrinsically random, but we can't predict it with any accuracy either.
It is much the same with a gene. It's just too much to consider.
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