a . “Most mutants which arise in any organism are more or less disadvantageous to their possessors. The classical mutants obtained in Drosophila [the fruit fly] usually show deterioration, breakdown, or disappearance of some organs. Mutants are known which diminish the quantity or destroy the pigment in the eyes, and in the body reduce the wings, eyes, bristles, legs. Many mutants are, in fact, lethal to their possessors. Mutants which equal the normal fly in vigor are a minority, and mutants that would make a major improvement of the normal organization in the normal environments are unknown.” Theodosius Dobzhansky, Evolution, Genetics, and Man (New York: John Wiley & Sons, 1955), p. 105.
u “A review of known facts about their [mutated fruit flies’] ability to survive has led to no other conclusion than that they are always constitutionally weaker than their parent form or species, and in a population with free competition they are eliminated. Therefore they are never found in nature (e.g., not a single one of the several hundreds of Drosophila mutations), and therefore they are able to appear only in the favourable environment of the experimental field or laboratory ...” Nilsson, p. 1186.
u “In the best-known organisms, like Drosophila, innumerable mutants are known. If we were able to combine a thousand or more of such mutants in a single individual, this still would have no resemblance whatsoever to any type known as a [new] species in nature. ” Goldschmidt, p. 94.
u “It is a striking, but not much mentioned fact that, though geneticists have been breeding fruit-flies for sixty years or more in labs all round the world—flies which produce a new generation every eleven days—they have never yet seen the emergence of a new species or even a new enzyme.” Gordon Rattray Taylor (former Chief Science Advisor, BBC Television), The Great Evolution Mystery (New York: Harper & Row, 1983), p. 48.
u “Fruit flies refuse to become anything but fruit flies under any circumstances yet devised.” Hitching, p. 61.
u “The fruitfly (Drosophila melanogaster), the favorite pet insect of the geneticists, whose geographical, biotopical, urban, and rural genotypes are now known inside out, seems not to have changed since the remotest times.” Grassé, p. 130.