Principles of Genetics and Breeding

10.1.11 Small populations

In a large population the gene frequencies are inherently stable in the absence of mutation, migration and selection. This property of stability does not hold good in small populations and the gene frequencies show random fluctuation arising from sampling of gametes.

The gametes that transmit genes to the next generation carry a sample of genes in the parent generation and, if the sample is not large, the frequencies are liable to change can be predicted, the direction of change cannot be predicted.

This results in dispersion of gene frequencies and is called the dispersive process (random genetic drift).