GENE20001 Lecture Notes - Lecture 23: Overdominance, Quantitative Trait Locus, Heritability
Document Summary
Overdominance: heterozygote is superior to either of the parents. Considering the contribution of a single locus to phenotype contribution additive. e. g. if phenotype of a1a1 is 2 and phenotype of a2a2 is 4, then a1a2 has a phenotype of 3. Can reliably select to change phenotypic distribution e. g. selection altered bristle number. Note that you reach a plateau since eventually all selected individuals are homozygous at contributing loci. The statistical variance is made of several components. By calculating variance we can determine how large the genetic component is. Narrow sense heritability (heritability) (the portion of the total phenotypic variation that can be explained by the variance of additive variance). Note this is not h squared. h2 is just the symbol of heritability h2 is known as narrow sense heritability. Here you"re comparing the mean phenotype of offspring and the midparent value which is the average of the contribution of father and mother.
