Posted: Jan 06, 2015 3:31 pm
MarioNovak wrote:Ok, models. Check this out: this "model" show that the appearance of only two coordinated mutations in humans would have an expected time of appearance of 216 million years.
Waiting for Two Mutations: With Applications to Regulatory Sequence Evolution and the Limits of Darwinian Evolution, http://www.genetics.org/content/180/3/1501.full
Did you even read that paper? Here is what they say near the end:The edge of evolution?
Our final example of waiting for two mutations concerns the emergence of chloroquine resistance in P. falciparum. Genetic studies have shown, see Wooton et al. (2002), that this is due to changes in a protein PfCRT and that in the mutant strains two amino acid changes are almost always present—one switch at position 76 and another at position 220. This example plays a key role in the chapter titled “The mathematical limits of Darwinism” in Michael Behe's book, The Edge of Evolution (Behe 2007).
Arguing that (i) there are 1 trillion parasitic cells in an infected person, (ii) there are 1 billion infected persons on the planet, and (ii) chloroquine resistance has arisen only 10 times in the past 50 years, he concludes that the odds of one parasite developing resistance to chloroquine, an event he calls a chloroquine complexity cluster (CCC), are ∼1 in 1020. Ignoring the fact that humans and P. falciparum have different mutation rates, he then concludes that “On the average, for humans to achieve a mutation like this by chance, we would have to wait a hundred million times ten million years” (Behe 2007, p. 61), which is 5 million times larger than the calculation we have just given.
Indeed his error is much worse. To further sensationalize his conclusion, he argues that “There are 5000 species of modern mammals. If each species had an average of a million members, and if a new generation appeared each year, and if this went on for two hundred million years, the likelihood of a single CCC appearing in the whole bunch over that entire time would only be about 1 in 100” (Behe 2007, p. 61). Taking 2N = 106 and μ1 = μ2 = 10−9, Theorem 1 predicts a waiting time of 31.6 million generations for one prespecified pair of mutations in one species, with (Formula) having reduced the answer by a factor of 31,600.
We are certainly not the first to have criticized Behe's work. Lynch (2005) has written a rebuttal to Behe and Snoke (2004), which is widely cited by proponents of intelligent design (see the Wikipedia entry on Michael Behe). Behe and Snoke (2004) consider evolutionary steps that require changes in two amino acids and argue that to become fixed in 108 generations would require a population size of 109. One obvious problem with their analysis is that they do their calculations for N = 1 individual, ignoring the population genetic effects that produce the factor of (Formula). Lynch (2005) also raises other objections.
(Some of the mathematical symbols are not reproduced, and replaced by the term Formula.)
This paper says the exact opposite of what you think it says. It shows that the emergence of novel genes thru normal evolutionary mechanisms is common place, and provides the math to prove it. The 216 million year figure you quote is the odds of a specific pair of mutations occurring. Not of any pair of mutations.
Own goal!