27th March 2003 at 06:27 PM DNAunion said this in Post #88
Only a small fraction of the beneficial mutants are lucky enough to escape accidental loss in the first few generations of their existence. The fortunate few eventually attain a frequency high enough to protect them from further risk of chance extinction
(Kimura and Ohta, 1971, p3)
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Let s be the selection coefficient of a beneficial mutation. For small values of s (said to be typical of evolution) the chance of the mutant eventually reaching fixation is 2s. For example, a mutant with a one-percent advantage (s = 0.01) has only one chance in fifty that it will eventually
spread to the entire population[/I]
This formula applies only to large populations, where N is too large for genetic drift. Care to give us the formula for small populations?
"In a smaller population the outlook is less hopeful. The smaller the population, the smaller is the chance of receiving a beneficial mutation in the first place. A population one tenth as large must wait ten times longer for a beneficial mutation."
This does not follow. This assumes that "beneficial mutations" are rate limiting.
I don't see any references to
observations yet, DNAunion. And that is what you promised.
You are also ignoring that Kimura is promoting a falsified theory here: that speciation occurs by mutation first followed by natural selection. That has been disproved. Speciation is the result of natural selection.
"It is often tacitly assumed that every advantageous mutation that appears in the population is inevitably incorporated. Also, it is not generally recognized that this fact can set an upper limit to the speed of adaptive evolution, because the frequency of
occurrence of advantageous mutations must be much lower than that of deleterious mutations."
This one has actually been refuted by data on studying the rate of "deleterious mutations". The rate of such mutations is actually about 2.6 per thousand mutations. PD Keightley and A Caballero, Genomic mutation rates for lifetime reproductive output and lifespan in Caenorhabditis elegans. Proc. Natl. Acad. Sci. USA 94: 3823-3827, 1997
Note that the data comes 28 years
after Kimura's paper and replaces the statements.
DNAunion, when quote mining, you have to be sure that the quotes are addressing the topic at hand. Kimura and Ohta's paper addressed a different issue.
Finally, the quotes weren't long. Most of it seems to be your words outside the quotation marks but included in the quote box.