BIOA01H3 Lecture 21: Lec 21 - l1
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BIOA01H3 Full Course Notes
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The genetic and environmental basis of complex traits. Complex traits such as height and blood pressure are called quantitative traits = measure along a continuum with only small intervals between similar individuals. Many types of genes and polymorphisms causing these traits and how the environment affects this. Environmental factors can affect the variation in phenotype between individuals. Environmental risk factors exist for several common human diseases e. g. high salt intake for high blood pressure. Looking at colouration of wheat seeds, 3 genes contribute to this colouration. Different genotypes can lead to the same phenotype. Normal distribution of phenotype of complex traits. Relative roles of the environment versus genotype in the expression of a complex trait are impossible to determine. The relative contribution of each to variation among individuals can be determined: Human height variation: 80% genetic differences and 20% nutrition/environmental differences. The environment can influence different genotypes in different ways.
