Maintenance of genetic variation - 17.4

Maintenance of genetic variation - 17.4 - Maintenance of...

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Preadaptation: - a trait becomes exploited for another role; - new role increases org's fitness How variation is maintained in a pop'n (in the face of nat seln): Many forms of nat seln reduce variation in a popn, then how do we always have variation? A 1 is mutated - produces diseased state A 2 is normal phenotype If A 1 is dom , then this means that nat seln can identify diseased state in both hom and het indvs (if the trait reduces fitness, then nat seln) can eliminate diseased hom and het invs from a popn, it decreases their contribution in next generation By doing that, decreased in freq of diseased allele Diploid organisms: If A1 recc Nat seln acts on phenotype ---Nat sel`n will act on it and their contribution in next gen is lessened Bc then diseased phenotype only shows up in homozygous state Harder for Nat Seln to act on (bad) recesssive mutations: Normal phenotype will show up on both hom dominate and heterozygous In terms of phenotypes: Since disease doesnt show up in the heterozygous phenotype
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This note was uploaded on 03/15/2011 for the course BIOL 1010 taught by Professor Anafi/quinlan during the Spring '08 term at York University.

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Maintenance of genetic variation - 17.4 - Maintenance of...

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