Principles of Genetics and Breeding

10.1.14 Change of gene frequency due to sampling

Let us assume that a large population is subdivided into many sub-populations.

• The gene frequency in each sub population is the same in the beginning.
• A sub-population is a small population.
• Breeding within the sub-population causes change in gene frequency,and new frequencies are formed.
• The variance of the change in gene frequency in the progeny generation after one generation of random mating is

pq/2N

where, p and q are the frequencies of the two alleles and

N is the first progeny generation.

The sub population have different gene frequencies, which go on changing from generation to generation. This chance is predictable only in magnitude but not in any direction and is erratic in nature. This is known as random drift or random, genetic drift.