Introduction to Population and Evolutionary Genetics

Factors that Affect Stability of Gene Frequencies (cont.)

Selection

• Mutation causes new functions for the individual.
• These new forms may or may not add to the fitness of the individual.
• If the fitness of the individual leads to a reproductive advantage, then the alleles present in that individual will be more prevalent in the next generation of the population.
• A population undergoes selection when certain alleles are preferentially found in a new generation because of the increased fitness of the parent.
• The alleles in the individual with increased fitness will increase in frequency in the population.
• In a Darwinian context, mutation, migration and selection lead to changes in gene frequencies, and the population evolves by natural selection.