Question

Mutations in the GDF9 gene in sheep have been linked to changes in female fecundity. The following are the relative fitnesses of different genotypes in the population:

+/- relative fitness: 1
+/+ relative fitness: 0.7
-/- relative fitness: 0.1
a. What is the relative fitness of the +/+ genotype?
b. How does the +/- genotype affect female fecundity?
c. What is the selective advantage of the -/- genotype?
d. What is the overall impact of the GDF9 mutations on female fecundity?

Answer 1

The relative fitness of the +/+ genotype in sheep is 0.7. The +/- genotype increases fecundity, while the -/- genotype has a very low selective advantage. GDF9 mutations affect female fecundity differently depending on the genotype.

Step-by-step explanation:

The question pertains to the impact of mutations in the GDF9 gene on female fecundity in sheep and involves the concept of relative fitness of different genotypes within a population.

The relative fitness of the +/+ genotype is 0.7, which means individuals with this genotype have 70% of the reproductive success compared to the most fit genotype in the population.

The +/- genotype is associated with a relative fitness of 1, indicating that individuals with this genotype have the highest reproductive success and consequently the highest fecundity, within this population.

The -/- genotype has a relative fitness of 0.1, which suggests it has a very low selective advantage. However, the continued existence of this genotype could be due to heterozygote advantage or frequency-dependent selection, where the rare genotype is favored.

The overall impact of the GDF9 mutations on female fecundity in sheep is variable, depending on the genotype. The +/- genotype enhances fecundity, while the +/+ and especially the -/- genotypes decrease fecundity. These mutations reflect a balance of genetic diversity and the result of sexual selection.