BIOL 2400 Lecture 7: Quantitative genetics
8 Mar 2017
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Document Summary
Quantitative genetics: deals with traits whose genotypes are nearly continuous in their expression, continuous traits can take on any value (e. g. height, weight) Continuous traits have a complex genetic basis. Polygenic trait: influenced by many genetic loci. Interaction with environment (phenotypic plasticity: merisitc traits can only take on whole integer values (e. g. litter size, appendage number) All the offspring with be heterozygotes of intermediate phenotype. Interbreed offspring of the f1 generation to produce an f2. All possible genotypes and phenotypes will be produced. If the trait is controlled by 1 locus, there are 3 genotypes and 3 phenotypes in the f2 generation. If the trait is controlled by 2 loci, there are 9 genotypes and 5 phenotypes. Vg = phenotypic variance due to genetic variation in the population. Ve = phenotypic variance due to environmental variation: vg can further subdivided into additive, va dominance vd epistasis, vi components.
