At what level is the rate of increasing a gene frequency greatest in a closed herd?

At what level is the rate of increasing a gene frequency greatest in a closed herd?

• A. Low level
• B. High level
• C. Intermediate level
• D. Constant level

Answer: (C)

The rate of increasing gene frequency in a closed herd is greatest at an intermediate level due to the balance it strikes between genetic variation and selection pressure. At a low level of gene frequency, there may be insufficient genetic variation to see significant changes, as the traits may not be prominent enough to ensure selection can act effectively. Conversely, at a high level, the gene might become saturated in the population, leading to a plateau in frequency changes because there is less variability for selection to act upon.

Therefore, the intermediate level allows for a dynamic environment where there is enough presence of the gene for effective selection, yet still a level of genetic variation that enables the benefits of selection or breeding for desirable traits to manifest clearly. This optimal stage is characterized by a significant impact of selection and genetic drift, leading to the most rapid increases in gene frequency over time.