Quotes on Evolutionary Genetics

Touting of mutations as the ultimate source of genetic variabiltiy....

1. Genetic changes underlie the evolution of organisms; mutations are the ultimate source of the genetic variation that makes possible the evolutionary process. {Is a new evolutionary synthesis necessary? Science 213: p967-971. Francisco Ayala & G.L. Stebbins}
    
2. Mutation is the ultimate source of all genetic variation found in natural populations and the only new material available for natural selection to work on. {Ernst Mayr, POPULATIONS, SPECIES, & EVOLUTION, 1970, p.102}
    
3.  Mutations are, indeed, the ultimate source of all new genetic materials . . . In the final analysis, all evolutionary change depends on mutations . . . all organic evolution is contingent on it. {George Gaylord Simpson & W.S. Beck, LIFE: AN INTRODUCTION TO BIOLOGY, Shorter ed., 1969, p.143}
    
4. We know of no way other than random mutation by which new hereditary variation comes into being. {C.H. Waddington, THE NATURE OF LIFE, 1962, p.98}
    
5. The process of mutation is the only known source of the new materials of genetic variability, and hence of evolution. {T. Dobzhansky, AMERICAN SCIENTIST, v. 45, 1957, p.385}
    
6. "The faithful duplication and repair exhibited by the double-stranded DNA structure would seem to be incompatible with the process of evolution. Thus, evolution has been explained by the occurrence of "errors" during DNA replication and repair." Homologous genetic recombination as an intrinsic dynamic property of a DNA structure induced by RecA/Rad51-family proteins: a possible advantage of DNA over RNA as genomic material. Shibata, T., Nishinaka, T., Mikawa, T., Aihara, H., Kurumizaka, H., Yokoyama, S. & Ito, Y. Proc. Natl. Acad. Sci. U.S.A. 98(15) 8425-8432 (2001)

Mutations are un-credible sources of variability for evolution....

1.  "Adaptive evolution has long been regarded as the result of postmutational sorting by the process of natural selection. Mutations have been postulated to occur at random, producing genetically different individuals that then compete for resources, the result being selection of better adapted genotypes. Molecular biology has demonstrated, however, that the rate and spectrum of mutations is in large part under the control of genetic factors. Because genetic factors are themselves the subject of adaptive evolution, this discovery has brought into question the random nature of mutagenesis. It would be highly adaptive for organisms inhabiting variable environments to modulate mutational dynamics in ways likely to produce necessary adaptive mutations in a timely fashion while limiting the generation of other, probably deleterious, mutations." Evidence for the Adaptive Evolution of Mutation Rates. Minireview by David Metzgar, Christopher Wills (2000) Cell 101, p581
    
2. "The ability to induce homologous recombination in response to unfavorable environmental changes would be adaptive for each species, as it would increase genetic diversity and would help to avoid species' extinction. Homologous recombination would be more efficient for evolution than random mutagenesis or nonhomologous recombination. Although the latter two will mostly disrupt previously existing genes rather than creating new ones, homologous recombination can use previously existing genes as building blocks, thus enabling the creation of new proteins with more complex functions in a step-by-step manner." Proc. Natl. Acad. Sci. U.S.A. 98(15):8425-8432 (2001)
    
3. Just as in a book misprints are more likely to produce nonsense than better sense, so mutations will almost always be deleterious, almost always, in fact, they will kill the organism or the cell, often at so early a stage in its existence that we do not even realize it ever came into being at all. {John C. Kendrew,the Cambridge scientist who is a Nobel laureate for his discovery of the structure of the protein myoglobin, THE THREAD OF LIFE, 1966, pp.106-107}
    
4. Natural selection has used mutations for building up well-integrated organisms. New mutations are likely to upset this balance and are therefore mostly harmful or lethal. (ENCYCLOPEDIA BRITANNICA, 1967 ed., s.v. "Mutations"}
    
5. It is a considerable strain on one's credulity to assume that finely balanced systems such as certain sense organs (the eye of vertebrates, or the bird's feather) could be improved by random mutations. This is even more true of some ecological chain relationships. However, objectors to random mutations have so far been unable to advance any alternative explanation that was supported by substantial evidence. {Harvard biologist Ernst Mayr, SYSTEMATICS & THE ORIGIN OF SPECIES, 1942, p.296}
    
6. The real difficulty of Darwinism is the well-known problem of explaining an evolution which prima facie may look goal-directed, such as that of our eyes, by an incredibly large number of very small steps; for according to Darwinism, each of these steps is the result of a purely accidental mutation. That all these independent accidental mutations should have had survival value is difficult to explain. {Sir Karl Popper, widely regarded as the foremost philosopher of science, OBJECTIVE KNOWLEDGE, rev. ed., 1979, pp.269-270}
    
7. A fact that has been obvious for many years is that Mendelian mutations deal only with changes in existing characters . . . No experiment has produced progeny that show entirely new functioning organs. And yet it is the appearance of new characters in organisms which marks the boundaries of the major steps in the evolutionary scale. {H. Graham Cannon, THE EVOLUTION OF LIVING THINGS, 1958, page unknown}
    
8. Nobody has produced even a species by the selection of micromutations. {Richard B. Goldschmidt, AMERICAN SCIENTIST, v. 40, 1952, p.94}
    
9. To postulate that the development and survival of the fittest is entirely a consequence of chance mutations seems to me a hypothesis based on no evidence and irreconcilable with the facts. These classical evolutionary theories are a gross oversimplification of an immensely complex and intricate mass of facts, and it amazes me that they are swallowed so uncritically and readily, and for such a long time, by so many scientists without a murmur of protest. {Ernst Chain, biologist who won a Nobel Prize for penicillin research, cited in "Was Darwin Wrong?," Francis Hitching, LIFE, April 1982, p.50}

Other Quotes

• Function of meiotic recombination from Dr. Melcher's Molecular Genetic's course at OSU "Many argue that meiotic recombination must serve a purpose. Some point out that recombination speeds evolution. "