Questions 4 to 10 are based on the following scenario Question 4: The barn owl i
ID: 134605 • Letter: Q
Question
Questions 4 to 10 are based on the following scenario
Question 4:
The barn owl is listed as an endangered bird here in Ontario. You are attempting to revive this population at your small owl rescue facility.
The population at your aviary originated from a pair of sibling owls. Today, the population consists of 143 owls, with an abnormally high percentage possessing extremely dark feathers. Since this phenotype is very rare in wild barn owl populations, you learn (with some research) that a recessive allele has caused the expression of this extreme dark colouration.
Light-coloured owls have the genotype DD or Dd, and the dark-coloured homozygote recessive owls have the genotype dd. The following is the breakdown of phenotypes and genotypes of this owl population.
Phenotype
Genotype
Number of owls
Light
DD
20
Light
Dd
49
Dark
dd
74
Over the next several questions, we will work our way through the process to determine if this owl population is in Hardy-Weinberg equilibrium (this will include applying the Chi-square goodness-of-fit test).
(Before beginning this question, you may find it helpful to review the worked problem on page 475 in your textbook).
Round your answer to three decimal places and submit your answer in the correct format (e.g. 0.062).
(a) What is the frequency of the D allele in this population?
(b) What is the frequency of the d allele in this population?
2 points
QUESTION 5
Question 5:
Calculate the genotype frequencies that you would expect if the population is in Hardy-Weinberg equilibrium.
Round your answer to three decimal places and submit your answer in the correct format (e.g. 0.062).
(a) The frequency of the DD genotype is:
(b) The frequency of the Dd genotype is:
(c) The frequency of the dd genotype is:
Hint: you will need the allele frequencies you calculated in the above question along with the Hardy-Weinberg equation (i.e. the p2, 2pq and q2 terms!)
3 points
QUESTION 6
Question 6:
Using the genotype frequencies you calculated above in Question 5, determine the expected number of owls with each of the following genotypes:
Round your answers to the nearest whole number (because you cannot have part of an owl!).
(a) Expected number of owls with genotype DD =
(b) Expected number of owls with genotype Dd =
(c) Expected number of owls with genotype dd =
Phenotype
Genotype
Number of owls
Light
DD
20
Light
Dd
49
Dark
dd
74
Explanation / Answer
1) The total number of owls is,
= 20 + 49 + 74
= 143
a) Frequency of D allele is
= (20 + (49/2))/ 143
= 44.5/143
= 0.311
b) Frequency of d allele is,
= (74 + (49/2))/ 143
= 98.5/143
= 0.689
5) If the population is in Hardy Weinberg's equilibrium,
Frequency of DD genotype is (0.311)(0.311) = 0.097
Frequency of Dd genotype is 2(0.311)(0.689) = 0.428
Frequency of dd genotype is (0.689)(0.689) = 0.475
6) Expected number of owls with genotype DD = 0.097 × 143 = 14
Expected number of owls with genotype Dd = 0.428 x 143 = 61
Expected number of owls with genotype dd = 0.475 × 143 = 68
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