Question

Inbreeding had more effect on the traits, which have

• A. low association with fitness
• B. high association with fitness
• C. no association with fitness
• D. medium association with fitness

Hint:

To minimize inbreeding depression in closed herds, breeders should implement structured mating plans such as rotational crossbreeding to maintain heterozygosity.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Inbreeding is the mating of individuals that are more closely related than the average of the population.
The primary genetic effect of inbreeding is the increase in homozygosity across the genome.
This increase in homozygosity exposes recessive deleterious alleles that were previously masked in heterozygous states.
This genetic phenomenon leads to a reduction in the mean phenotypic value of various traits, commonly referred to as inbreeding depression.

Step 2: Detailed Explanation:
Inbreeding depression does not affect all biological traits to the same degree.
Traits are classified based on their evolutionary history and their association with biological fitness and survival.
Fitness traits, such as reproductive performance, fertility, viability, and disease resistance, are highly associated with the overall survival and reproductive success of an organism.
These traits have been under intense directional natural selection over evolutionary history.
This selection tends to fix dominant favorable alleles, leaving deleterious alleles as rare recessives.
When inbreeding occurs, these rare recessive deleterious alleles become homozygous, leading to a marked decline in fitness.
In contrast, production traits like milk yield or fiber diameter often have lower direct associations with natural biological fitness and exhibit lower inbreeding depression.
Therefore, inbreeding has a much more pronounced and deleterious effect on traits that have a high association with biological fitness.

Step 3: Final Answer:
Hence, inbreeding has a more significant effect on traits that possess a high association with fitness.