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?

Verified step by step guidance

1. Step 1: Calculate the allele frequencies in the population. The frequency of allele D₁ (p) can be calculated as: p = (2 * number of D₁D₁ individuals + number of D₁D₂ individuals) / (2 * total number of individuals). Similarly, the frequency of allele D₂ (q) can be calculated as: q = (2 * number of D₂D₂ individuals + number of D₁D₂ individuals) / (2 * total number of individuals). Ensure that p + q = 1.
2. Step 2: Use the Hardy-Weinberg equilibrium principle to predict the expected genotype frequencies in the population. The expected frequencies are: D₁D₁ = p², D₁D₂ = 2pq, and D₂D₂ = q². Multiply these frequencies by the total number of individuals (500) to calculate the expected number of individuals for each genotype.
3. Step 3: Compare the observed genotype frequencies (225 D₁D₁, 175 D₁D₂, 100 D₂D₂) with the expected genotype frequencies calculated in Step 2. If the observed frequencies deviate significantly from the expected frequencies, it may indicate a departure from Hardy-Weinberg equilibrium.
4. Step 4: Consider the potential impact of inbreeding on genotype frequencies. Inbreeding increases the proportion of homozygous individuals (D₁D₁ and D₂D₂) and decreases the proportion of heterozygous individuals (D₁D₂). Check if the observed distribution aligns with this pattern.
5. Step 5: Evaluate whether the observed deviation from Hardy-Weinberg equilibrium can be explained by inbreeding or other factors such as selection, genetic drift, or population structure. Provide reasoning based on the comparison of observed and expected frequencies and the known effects of inbreeding.

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 assess whether the distribution aligns with expected ratios under Hardy-Weinberg equilibrium, which assumes random mating and no evolutionary influences.

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. Deviations from this equilibrium can indicate factors such as inbreeding, selection, or genetic drift affecting the population.

Inbreeding Depression

Inbreeding depression occurs when closely related individuals breed, leading to a higher probability of offspring inheriting deleterious alleles. This can reduce genetic diversity and affect the fitness of the population. In the context of the field mice, a skewed genotype distribution may suggest inbreeding if certain genotypes are overrepresented compared to expected frequencies.