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Unformatted text preview: Thus, many different genotypes may have the same av- erage phenotype. At the same time, because of environ- mental variation, two individuals of the same genotype may not have the same phenotype. This lack of a one-to- one correspondence between genotype and phenotype obscures the underlying Mendelian mechanism. If we cannot study the behavior of the Mendelian factors controlling such traits directly, then what can we learn about their genetics? Clearly, the methods used to analyze qualitative traitssuch as examining the ratios of offspring in a genetic crosswill not work for quanti- tative traits. Instead, we have to use statistical methods to make predictions about the inheritance of phenotypes in the absence of knowledge about underlying geno- types. This approach is known as quantitative genetics. Quantitative genetics the study of the genetics of con- tinuously varying charactersis concerned with answer- ing the following questions: 1. Is the observed variation in a character influenced at all by genetic variation? Is all the variation simply the result of environmental variation and developmental noise (see Chapter 1)? Or, are there alleles segregating in the population that produce some differential effect on the character?...
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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