Author:
Kristi Prohm

Date of Publication:
April 19, 2019

Publication:
The Better Breeding Blog

Excerpt:
Selecting animals for breeding is a process by which those deemed ‘best’ are allowed to be parents, and those deemed not, aren’t. The next generation is similarly assessed, and the next, and the next, with the population expected to improve incrementally each time.

This gradual improvement over time is due to the frequency of desirable genes increasing in the population and the frequency of undesirable genes decreasing in the population. This results in a group of animals with increased breeding value, as they have a higher concentration of ‘best’ genes more likely to be passed onto the next generation. That next generation, with its higher concentration of ‘best’ genes will perform* at a higher level than earlier generations did.

(* ‘Performance’ here is a breeding term that doesn’t necessarily refer to athletic performance such as speed. Rather, it refers to the resulting phenotype, as determined by the genotype. ‘Performance’ could be how fine a sheep’s wool is, for example.)

Gene frequencies, breeding values and performance are all intertwined. Increasing breeding values and performance in a population increases the frequencies of desirable genes. Increasing the frequencies of desirable genes increases breeding values and performance.

Read the rest of the article: https://betterbreeding.solutions/index.php/blog/the-effect-of-selection-on-gene-and-genotypic-frequencies