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Unformatted text preview: 19 1.5 Genes, the environment, and the organism changed by environmental effects. Most phenotypes change continually throughout the life of an organism as its genes interact with a sequence of environments. Fix- ity of genotype does not imply fixity of phenotype. Norm of reaction How can we quantify the relation between the geno- type, the environment, and the phenotype? For a partic- ular genotype, we could prepare a table showing the phenotype that would result from the development of that genotype in each possible environment. Such a set of environment-phenotype relations for a given geno- type is called the norm of reaction of the genotype. In practice, we can make such a tabulation only for a par- tial genotype, a partial phenotype, and some particular aspects of the environment. For example, we might specify the eye sizes that fruit flies would have after de- veloping at various constant temperatures; we could do this for several different eye-size genotypes to get the norms of reaction of the species.norms of reaction of the species....
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.
- Spring '08