A sample of 500 field mice contains 225 individuals that are D₁D₁, 175 that are D₁D₂, and 100 that are D₂D₂. Is inbreeding a possible genetic explanation for the observed distribution of genotypes? Why or why not?

Key Concepts

Genotype Frequencies

Genotype frequencies refer to the proportion of different genotypes within a population. In this case, the frequencies of D₁D₁, D₁D₂, and D₂D₂ genotypes can be calculated to understand the genetic structure of the field mice population. Analyzing these frequencies helps determine if the distribution aligns with expected ratios under Hardy-Weinberg equilibrium or suggests deviations due to factors like inbreeding.

Inbreeding Depression

Inbreeding depression occurs when closely related individuals mate, leading to a higher probability of offspring inheriting deleterious alleles. This can reduce genetic diversity and fitness in a population. If inbreeding is present in the field mice, it may explain the observed genotype distribution, particularly if there is a higher frequency of homozygous genotypes (D₁D₁ and D₂D₂) compared to heterozygous (D₁D₂).

Hardy-Weinberg Equilibrium

Hardy-Weinberg equilibrium is a principle that describes the genetic variation in a population that is not evolving. It provides a baseline expectation for genotype frequencies based on allele frequencies. If the observed genotype distribution significantly deviates from these expectations, it may indicate factors such as selection, mutation, migration, or inbreeding affecting the population's genetic structure.