University:
The University Of Western Ontario
Course:
Biology 2290F | Scientific Method in Biology
Academic year:

2022
Views:

283

Pages:

3
Author:

Kyuwon J.

Name: Hardy-Weinberg Lab Worksheet Hardy-Weinberg Equilibrium (HWE) Practice Worksheet Name: Instructor: Br . Section Code: Date: Simotly OO Part 1: Assumptions of Hardy-Weinberg Equilibrium Fill in the blanks with the correct conditions required for Hardy-Weinberg equilibrium: infinitely 1. The population must be 2. Mating must be completely 3. There is no immigration 4. There are no 5. No large . rundom emmigration or mutation in size. of individuals. (random changes in DNA). natural selection (all individuals are equally likely to survive and reproduce). When all of these conditions are met, the population is not evolving — allele frequencies stay the same across generations. Part 2: Observed Genotype Data You are studying a population of beetles. Their shell color is controlled by two alleles: • B = brown shell (dominant) • b = green shell (recessive) You sample 1,000 beetles and find the following genotypes: • BB: 360 individuals • Bb: 480 individuals • bb: 160 individuals Step 1: Calculate total number of alleles • Total beetles = 1000 • Total alleles = 1000X2 = 2000 Page 1 Name: Hardy-Weinberg Lab Worksheet Step 2: Count total B and b alleles • BB: 360 ×2= 120 B alleles • Bb: 488 ×1= 480 B and • bb: 168 ×2= 320 b alleles • Total B alleles = 480 b alleles 1200 800 • Total b alleles = Step 3: Calculate allele frequencies % 120 • p = frequency of B = 00 800/2000 • q = frequency of b = Check: p + q = 0 6+ 0 4 . . = = 0 = 0 . . 6 4 / Part 3: Expected Genotype Frequencies Under HWE Use the Hardy-Weinberg equation: p2 + 2pq + q 2 = 1 2 • p2 = expected frequency of BB = (0 6) • 2pq = expected frequency of Bb = 2(0 • q 2 = expected frequency of bb = 10 = . . 472 0 36 6) (0 4) · . = 0 = . . 16 = 0 = - BB 48 = BP bb Step 4: Convert expected frequencies to expected individual counts (population size = 1000) • Expected BB = 0 36 x 1000 . • Expected Bb = 0 • Expected bb = 0 - . 48 16 x 1000 x 1000 360 = = = 480 160 Part 4: Compare Observed vs Expected Genotype BB Bb bb Observed Count 360 480 160 Expected Count Match (Yes/No) > Yes - Yes - Yes Page 2 HWE is seen in this population Name: Hardy-Weinberg Lab Worksheet Part 5: Analysis and Conclusion Yes O 1. Is this population in Hardy-Weinberg Equilibrium? Why or why not? The observed Therefore , we genotype frequency conclude this can is identical populations to in HuE, calculated expected no active HWE natural selection No frepency genotype . present. 2. List two possible biological reasons for deviation (if any): - Non-random Mating. - Small population size 3. What would it mean if the frequency of allele b increased significantly over the next 10 generations? The selective pressure muting patterns will furor green shell. migration will introduce moreb alleles . + mutation + non-random . Page 3