BIOL 2400 Study Guide - Final Guide: Phenotypic Plasticity, Genetic Drift, Allele Frequency
28 May 2016
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Document Summary
Gene flow, genetic drift, and natural selection alter a population"s genetic composition, but only natural selection makes a population better adapted to its environment. Most fit genotype depends on its environment. Genetic drift results in divergence in allele frequencies at neutral loci. Population structure inversely related to migration rates between populations. Polygenic trait: influenced by many genetic loci interaction between alleles (epistasis) Quantitative genetics: study of the genetic mechanisms of continuous phenotypic traits. The selection differential, or how intense selection is, is quantified by s=x b - xp where xp is the trait mean in the population before selection and xb is the mean after. The standardized selection differential is i = s/vp. Phenotypic variance (vp): dispersion of measurable trait resulting from an interaction between its genotype and its environment. Vp = vg + ve vg=variance due to genetic differences ve=due to environmental differences. Heritability (h^2): the proportion of phenotypic variation in a quantitative trait that is inherited.
