A)
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
(8 points)
Part A:
Beginning population:
- 200 black mice
- 400 gray mice
- 400 white mice
Total number of mice = 1000
Calculate the frequency of each allele:
- Number of black mice (BB) = 200
- Number of gray mice (BW) = 400
- Number of white mice (WW) = 400
p = frequency of allele B
q = frequency of allele W
p^2 = frequency of BB = 200/1000 = 0.2
2pq = frequency of BW = 400/1000 = 0.4
q^2 = frequency of WW = 400/1000 = 0.4
Ending population:
- 400 black mice
- 400 gray mice
- 200 white mice
Total number of mice = 1000
Calculate the frequency of each allele:
- Number of black mice (BB) = 400
- Number of gray mice (BW) = 400
- Number of white mice (WW) = 200
p = frequency of allele B
q = frequency of allele W
p^2 = frequency of BB = 400/1000 = 0.4
2pq = frequency of BW = 400/1000 = 0.4
q^2 = frequency of WW = 200/1000 = 0.2
Part B:
Based on the Hardy-Weinberg calculations, the allele frequencies in the population remain constant over time. This indicates that the population is not evolving.
Hypothesis:
A possible hypothesis for the observations could be that the environment of these mice does not favor any particular fur color. There is no selective pressure acting on the fur color genes, so all alleles are maintained at stable frequencies in the population. This lack of selection leads to no significant changes in allele frequencies over time, resulting in a stable population with no evolution occurring.