Principles of Genetics and Breeding

10.1.8 Mutation

Mutation is a rare event in nature. It can occur in both the directions, i.e. forward and backward. If mutation is recurrent, it can change the gene and genotype frequency of the population.

• When mutation occurs continuously in a gene it is called recurrent mutation.
• Mutations do not have to be bad; some increase fitness or lead to the evolution of new species by creating new or improved phenotypes.
• But most mutations lower fitness, because they cause random changes in a phenotype that works and that works well as a result of natural selection.
• Many mutant alleles produce phenotypes that are so abnormal that they either cause death or reduce viability severely. Other cause only small reductions in viability.