In a certain population of mice, a single gene controls fur color There are two possible alleles: B, which leads to a black fur, and W, which leads to white fur. Individuals with the genotype BB will have a black fur, individuals with the genotype WW will have white fur, and individuals with the genotype BW will have gray fur. Scientists recorded the fur color of 1,000 mice from the population They found that 200 mice nave black fur, 400 have gray fur, and 400 have white fur. Ten years later, the measurements are repeated Again, they recorded the fur color of 1,000 that 400 have black fur, 400 have gray fur, and 200 have white fur. mice. They found

Question

In a certain population of mice, a single gene controls fur color There are two possible alleles: B, which leads to a black fur, and W, which leads to white fur. Individuals with the genotype BB will have a black fur, individuals with the genotype WW will have white fur, and individuals with the genotype BW will have gray fur. Scientists recorded the fur color of 1,000 mice from the population They found that 200 mice nave black fur, 400 have gray fur, and 400 have white fur. Ten years later, the measurements are repeated Again, they recorded the fur color of 1,000 that 400 have black fur, 400 have gray fur, and 200 have white fur. mice. They found

Part A: Show the Hardy-Weinberg calculations for the beginning and ending populations. Include the values for the equation as well as the p and q values. Show your work.

Part B: Use the Hardy-Weinberg calculation to explain if this population is evolving or not. Then propose a hypothesis about the environment of these mice that would lead to these observations

Answer 1

Part A:

Beginning Population:
- Total number of mice = 1,000
- Number of mice with black fur (BB) = 200
- Number of mice with gray fur (BW) = 400
- Number of mice with white fur (WW) = 400

Calculations for allele frequencies:
- Calculating the total number of alleles: 200(2) + 400(2) + 400(2) = 2,000
- Calculating the frequency of the B allele (p): (200(2) + 400)/2,000 = 0.30
- Calculating the frequency of the W allele (q): (400(2) + 400)/2,000 = 0.70

Equation: p^2 + 2pq + q^2 = 1
Calculating genotype frequencies:
- frequency of BB: p^2 = (0.30)^2 = 0.09
- frequency of BW: 2pq = 2(0.30)(0.70) = 0.42
- frequency of WW: q^2 = (0.70)^2 = 0.49

Ending Population:
- Total number of mice = 1,000
- Number of mice with black fur (BB) = 400
- Number of mice with gray fur (BW) = 400
- Number of mice with white fur (WW) = 200

Calculations for allele frequencies:
- Calculating the total number of alleles: 400(2) + 400(2) + 200(2) = 2,000
- Calculating the frequency of the B allele (p): (400(2) + 400)/2,000 = 0.50
- Calculating the frequency of the W allele (q): (200(2) + 200)/2,000 = 0.50

Equation: p^2 + 2pq + q^2 = 1
Calculating genotype frequencies:
- frequency of BB: p^2 = (0.50)^2 = 0.25
- frequency of BW: 2pq = 2(0.50)(0.50) = 0.50
- frequency of WW: q^2 = (0.50)^2 = 0.25

Part B:

The Hardy-Weinberg principle states that allele frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. In this case, the allele frequencies have changed from the beginning to the ending population. The frequency of the B allele increased from 0.30 to 0.50, and the frequency of the W allele decreased from 0.70 to 0.50. This suggests that the population is evolving.

One hypothesis about the environment of these mice that would lead to these observations is a change in predation pressure. For example, if predators have a preference for black fur mice, they would selectively prey on those individuals, leading to a decrease in the frequency of the B allele. In contrast, white fur mice may be better camouflaged in their environment, resulting in an increase in the frequency of the W allele. This could explain the shift in allele frequencies observed in the population over time.