Final answer:
The increase in homozygote individuals can happen very quickly in small populations, typically those with fewer than 50 individuals, due to the effects of genetic drift. Small populations are more susceptible to fluctuations in allele frequencies, which can lead to alleles being rapidly lost or fixed by chance.
Step-by-step explanation:
Genetic Drift and Population Size
The increase in homozygote individuals occurs rapidly in small populations, typically those with fewer than 50 individuals. The primary reason for this is a phenomenon known as genetic drift, which is the random fluctuation in allele frequencies from one generation to the next. In small populations, rare alleles can be lost or become fixed, purely by chance, since there are fewer individuals to buffer the effects of random breeding events and mortality.
Consider genetic drift in a hypothetical rabbit population where brown coat color (B) is dominant over white coat color (b). If a small population begins with equal allele frequencies and only a few individuals reproduce, the allele frequencies can change dramatically in just one or two generations, potentially leading to the loss of the white coat color allele.
When addressing population genetics, it is important to understand that small populations are much more susceptible to these random changes. For instance, if one individual carrying a unique allele in a population of 10 dies before reproducing, 10% of the genetic diversity is lost. However, in a population of 100, the loss would be just 1%. Thus, genetic drift has a more significant influence on small populations.