Biology 1001A Lecture Notes - Lecture 11: Heritability, Phenotype, Twin Study
15 Mar 2015
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4 postulates: variation in trait, at least partly heritable (genotype, variation in survival or reproduction (struggle for reproduction, variation in fitness has to be related to variation in the trait. If all four postulates are met population will evolve by means of natural selection: exception, variation in trait. There has to be a difference in phenotype: heritability in a trait. Not all variation in phenotype is due to genetic variation between individuals: can be due to environment, ex. Many traits are influenced by both genotype and environment. Proportion of variation in phenotype (vp) is due to variation in genotype (vg) rather than environment (ve: vp = vg + ve. Heritability = vg / (vg + ve: heritability can vary between 0 1. Zero all of the variation in phenotype is attributed in environmental differences. One none of the variation in phenotype is attributed in genotype differences. Majority combination - both components: heritability describes population, not individual.
