The Fruit Fly Experiments Few mutation experiments can equal the extensive ones conducted on the common fruit fly, Drosophila melanogaster. Since the early 1900’s, scientists have exposed millions of these flies to X rays. This increased the frequency of mutations to more than a hundred times what was normal. After all those decades, what did the experiments show? Dobzhansky revealed one result: “The clear-cut mutants of Drosophila, with which so much of the classical research in genetics was done, are almost without exception inferior to wild-type flies in viability, fertility, longevity.” Another result was that the mutations never produced anything new. The fruit flies had malformed wings, legs and bodies, and other distortions, but they always remained fruit flies. And when mutated flies were mated with each other, it was found that after a number of generations, some normal fruit flies began to hatch. If left in their natural state, these normal flies would eventually have been the survivors over the weaker mutants, preserving the fruit fly in the form in which it had originally existed. The hereditary code, the DNA, has a remarkable ability to repair genetic damage to itself. This helps to preserve the kind of organism it is coded for. Scientific American relates how “the life of every organism and its continuity from generation to generation” are preserved “by enzymes that continually repair” genetic damage. The journal states: “In particular, significant damage to DNA molecules can induce an emergency response in which increased quantities of the repair enzymes are synthesized.” Thus, in the book Darwin Retried the author relates the following about the respected geneticist, the late Richard Goldschmidt: “After observing mutations in fruit flies for many years, Goldschmidt fell into despair. The changes, he lamented, were so hopelessly micro [small] that if a thousand mutations were combined in one specimen, there would still be no new species.”
