AGB 121: Principles of Animal Genetics and Population Genetics (2+1)

EFFECTIVE POPULATION SIZE

• In domestic animals, the sexes are often unequally represented among breeding individuals and, in general, fewer males than females are used.

Genetically Effective Population Size: "The number of breeding individuals in an idealized population that would show the same amount of dispersion of allele frequencies under random genetic drift or the same amount of inbreeding as the population under consideration"

• The effective population size is based on the number of genes in the population that can be passed on to the next generation. The symbol is N_e (N-effective)
• N_e the harmonic mean of the two sexes

• Rate of inbreeding is inversely proportional to the effective population size.
• That is, the smaller the effective population size, the greater the increase in inbreeding per generation.
• Thus increase in the number of homozygote in the smaller population.