Re: Pasteur and nature of science

From: bivalve (
Date: Tue Jan 08 2002 - 14:33:29 EST

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    >Induced mutations in fruit flies produce only malformed fruit flies - no improvements. <

    How do you tell if one organism is an improvement over another? Each kind is better at some things and worse at others. With regard to the fruit flies in my kitchen, fatal mutations would be an improvement from my point of view, whereas I would have considered fatal mutations detrimental in my genetics lab experiment. Many of the weird mutations in fruit flies have been very useful in improving our understanding of genetics, molecular biology, developmental biology, evolution, and other fields, thus functioning as a great improvement over boring old ordinary fruit flies from the viewpoint of experimental biologists. However, no one wants to make an improved fruit fly defined as one that would be especially successful in the wild. It is not of interest to most fruit fly workers, who are mainly concerned with experimenting on the genes. Those who might be academically interested in the prospect of such an improved fruit fly hopefully realize that existing flies, notably !
    the Medfly, are bad enough from the agricultural perspective.

    The vast majority of mutations have little or no effect; small effects are about equally divided between increasing and decreasing the efficiency of the product. Large mutations are often good in evolving new functions, but significant increase in efficiency for existing functions is rare, because most existing functions have already been subject to a long period of evolutionary optimization.

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