BIOB51H3 Lecture Notes - Lecture 19: Phenotypic Trait, Population And Environment, Allele Frequency
10 Apr 2016
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Simpliicaion: assume phenotypes fall into discrete categories, determined strictly by genotypes. Internal & external environment important for development of most traits. Phenotypes of individuals may be diferent even if they have idenical genotypes e. g. , yarrow (achillea) colon. Take plants with the same genotype and rear in diferent environments. Dramaic diferences in height & form due to environmental diferences. Efect on mean phenotype; efect on trait variaion. Problem: we usually do not know which loci control quanitaive traits. Tools for measuring: heritable variaion in traits (heritability, diferences in lifeime reproducive success (intensity of selecion) Tools for predicing: efect of selecion on phenotypic trait value (evoluionary response to selecion) Heritability = extent to which phenotypic diferences are due to diferences in genes underlying those traits. Populaion level:what fracion of the variaion in height is due to variaion in genes? (& what fracion is due to variaion in environment)
