ANT203H5 Lecture Notes - Lecture 8: Genotype Frequency, List Of Compositions By Anton Bruckner, Population Genetics
Document Summary
Natural selection can also affect allele frequencies over time. Natural selection happens when there are differences among genotypes in their ability to survive and reproduce. This differential ability is usually referred to as fitness (normally represented as w). W11, w12, w22 are the fitness coefficients. Fitness is usually expressed as relative fitness. The genotype with the highest fitness is assigned a fitness of 1. Relative fitness ranges from 1 (highest fitness) to 0 (genotypes don"t survive or reproduce). Another way to describe the role of selection is using the selection coefficient (s). The selection coefficient can be described as the proportional reduction in fitness of a genotype with respect to the genotype with the maximum fitness (w=1). Thus, by definition w=1-s: s=portion being eliminated, w=fitness s ranges from 0 (genotype with the maximum fitness) to 1 (genotypes don"t survive or reproduce). The effect of selection on allele frequencies will depend, among other things, on.
