Provine is an atheist, philosopher, and critic of intelligent design. He has engaged in prominent debates with theist philosophers and scientists about the existence of God and the viability of intelligent design. He has debated the founder of the intelligent design movement Phillip E. Johnson and the two have a friendly relationship. Provine has stated that he starts his course on evolutionary biology by having his students read Johnson's book "Darwin on Trial."When someone likes that publishes a book with the title, The 'Random Genetic Drift' Fallacy, I pay attention.
Provine is a determinist in biology, but not a determinist in physics or chemistry, thus rejecting the idea of free will in humans. Provine believes that there is no evidence for God, there is no life after death, there is no absolute foundation for right and wrong, there is no ultimate meaning for life, and that humans don't have free will.
Let's begin by reminding ourselves that random genetic drift is one of the mechanisms causing changes in allele frequencies in a population [Random Genetic Drift]. It's covered in all the genetics and evolution textbooks. The one I like to quote is by David Suzuki et al. from 1989.
If a population is finite in size (as all populations are) and if a given pair of parents have only a small number of offspring, then even in the absence of all selective forces, the frequency of a gene will not be exactly reproduced in the next generation because of sampling error. If in a population of 1000 individuals the frequency of "a" is 0.5 in one generation, then it may by chance be 0.493 or 0.505 in the next generation because of the chance production of a few more or less progeny of each genotype. In the second generation, there is another sampling error based on the new gene frequency, so the frequency of "a" may go from 0.505 to 0.501 or back to 0.498. This process of random fluctuation continues generation after generation, with no force pushing the frequency back to its initial state because the population has no "genetic memory" of its state many generations ago. Each generation is an independent event. The final result of this random change in allele frequency is that the population eventually drifts to p=1 or p=0. After this point, no further change is possible; the population has become homozygous. A different population, isolated from the first, also undergoes this random genetic drift, but it may become homozygous for allele "A", whereas the first population has become homozygous for allele "a". As time goes on, isolated populations diverge from each other, each losing heterozygosity. The variation originally present within populations now appears as variation between populations.
Suzuki, D.T., Griffiths, A.J.F., Miller, J.H. and Lewontin, R.C.
in An Introduction to Genetic Analysis 4th ed. W.H. Freeman (1989 p.704)
Provine thinks there's also some confusion between the segregation of single loci and whole chromosomes. Both of these misconceptions invalidate random genetic drift according to Provine. Here's part of what he says on page 46.
Fisher and Haldane agreed that "random genetic drift," on a single locus on a chromosome, was a measure of inbreeding in Mendelian populations, Both used the same models and did not understand meiosis, and made a biological mistake. They did not realize their mistake when meiosis, with no "random genetic drift," was understood by 1940. Population geneticists are taught now by other population geneticists, so they still today do not understand the problems with "random genetic drift."I've read these chapters several times and I still don't understand Provine's problem with random genetic drift. It's possibly just historical quibbling but I'm not sure.
I'm hoping that some Sandwalk readers will help me out.
With the development of Neutral Theory in the late 1960s, you'd think that random genetic drift was firmly entrenched in population genetics. After all, how else do allele frequencies change if alleles are neutral with respect to natural selection? How else do you explain all the differences between chimpanzee and human genomes in junk DNA?
The neutral theory and nearly neutral theory missed the supposed biological origin of the "random genetic drift." Neither Kimura nor Ohta saw where "random genetic drift" originated in population genetics. They inherited the theories of Fisher, Haldane, and Wright. Kimura often used the phrase "random sampling of gametes" as the source of "random genetic drift." This process produced maximum genetic variation fro recombination in meiosis in large populations, and minimum in small populations, and no "random genetic drift." Both thought of evolution over speciation; 10,000,000 generations are not much to either theory.Michael Lynch isn't going to like that!
Having no "random genetic drift" in evolution harms the neutral theories, No matter how we approach the neutral theories, "random genetic drift" is the crucial variable, and does not exist. I can see no way to preserve the neutral theory in population genetics."
Is Provine an adaptationist? Is that why he dismisses Neutral Theory and random genetic drift? I don't know. I can't decipher his argument in this book. I think he's arguing that fixation of apparently neutral alleles is always due to hitchhiking on selected loci but I get part of that idea from reading other things he's said over the years.
Here's a passage that causes me to think that there's more to his rejection of Neutral Theory than meets the eye. It's from pages 158-159.
In his last years Kimura had gained the highest honors of an evolutionist. His neutral theory of evolution seemed to have huge support, and he spent most time pointing how neutral evolution could lead to adaptive evolution, even in the 10% of DNA that seemed to code for something. Kimura was at the top of his profession until his death in 1994.Anyone guilty of this kind of fuzzy thinking in one area is probably guilty of the same kind of thinking in another.
Kimura believed that 90% of the DNA was neutral, but concerning percentages, beliefs with time have changed. Most biologists now believe that 70% of DNA codes for RNA, of so many kinds. For sexually breeding populations, mRNA is edited by an RNA editor that can make many different changes into ten or hundreds of different kinds of proteins. Many of those who study RNA think it existed prior to DNA and possibly evolved into using DNA for evolutionary history. The amount of neutral DNA has not decreased by a huge amount; perhaps 20% of neutral DNA is left, probably less. More than 80% of DNA is occupied by coding at various times in life. Kimura's thesis, neutral DNA, is getting smaller than he thought possible.