Selection-Competition and Predation

Selection-Competition and Predation - SELECTION ??? How do...

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Unformatted text preview: SELECTION ??? How do measure such a concept Based on non-random breeding and on fitness Fitness = W = ability of some genotypes to leave more offspring to the next generation When W = 1 indicates best fit genotype (all offspring ) When W = 0 lethal genotype ( 0 offspring) When W = 0.5 genotype leaves offspring for next generation SELECTION COEFFICIENT(S) Measure of the intensity of selection S = 1-W Calculation of fitness W = Reproductive rate of unfavored alleles reproductive rate of favored alleles Consider the condition that for normals W = 1 A. Selection against dominant allele Genotypes AA Aa aa Dominant genes can be good, bad or neutral Most disadvantageous dominant lethal time of lethal events effects W Environmental event may change fitness of dominantcould disappear in single generation Partial selection against dominants A case of Dwarfism Achondroplastic dwarfs produce 19.6% offspring as normal population (no differences in survival) Dwarfism is a dominant allele W = 19.6/100 = 0.196 fitness value Since S = 1-W S = 0.804 selection coefficient against dwarfs i.e. 80.4% of the expected offspring are removed solely by selection % A...
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This note was uploaded on 12/09/2009 for the course BIO 200 taught by Professor Herreid during the Spring '07 term at SUNY Buffalo.

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Selection-Competition and Predation - SELECTION ??? How do...

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