Principles of Genetics and Breeding

10.1.1 Population genetics

Mendelian principles explain genetic mechanisms in individuals. As fish breeders, however, our task is not to change individuals, but population. So, the knowledge of Mendelian inheritance is extended from the level of individual to the level of population.

• The population genetics may be regarded as the genetics of a population dealing principally with gene and genotype frequencies through time and space.
• Estimation of gene frequencies is the primary requirement for studying the genetics of a population.
• The assessment of the causes of observed frequency changes for which estimates of the rate of mutation, selection coefficients, effective population size, etc. are important.

Population is a collection of individuals or data.

• It may be static or dynamic.
• A static population is one that existed at a particular time only.
• A dynamic population is one that existed over time and is maintained from generation to generation through procreation of new individuals, i.e. progeny.
• Geneticists are concerned with respect to genetic properties. For any improvement programmed of a permanent nature, the genetic properties of the population need to be described.