Question

You are studying a population of milkweeds and you find the following allele frequencies: f(A1A1) = 0.36 f(A1A2) = 0.48 f(A2A2) = 0.16 If the fitness of the homozygote (w11) is 0.9 and the average fitness of the population is 0.916, what do we expect the new frequency of the A1A1 homozygote genotype to be in the next generation?

1) 0.35
2) 0.40
3) 0.50
4) 0.60
5) 0.91

Answer 1

The new frequency of the A1A1 homozygote genotype in the next generation, after selection based on its given fitness relative to the average population fitness, is expected to be approximately 0.35.

Step-by-step explanation:

To determine the new frequency of the A1A1 homozygote genotype, we must apply the principles of the Hardy-Weinberg equilibrium and selection. Using the given allele frequencies and fitness values, we first need to calculate the new frequency of the A1 allele after selection, before we can determine the new genotype frequency.

To calculate this, we use the formula for the change in allele frequency under selection, which is:

pf = (pi × wi) / W

where pf is the frequency after selection, pi is the initial frequency, wi is the fitness of the genotype, and W is the average fitness of the population.

For the A1A1 genotype, pi = 0.36 (current frequency) and wi = 0.9 (fitness). The average fitness W is given as 0.916. Thus:

pf(A1A1) = (0.36 × 0.9) / 0.916

The calculation gives:

pf(A1A1) = 0.3541

This would be the expected frequency of the A1A1 genotype in the next generation after selection.

The new frequency of the A1A1 homozygote genotype is expected to be approximately 0.35 in the next generation after selection.

This reflects a slight decrease from the initial frequency due to the selection against this genotype, given its fitness is less than the average fitness of the population.