Lab 3 Population Genetics

Assignment 3 Pages

Texas State University

Organismal Biology Laboratory

Contributed by

Kenzie Jones

BIO 1131 Fall 2024 Lab 3 Assignment
Make a copy of this document, fill in your answers during and after your lab in google docs, and then
download as a .docx or .pdf file to submit to Canvas by your lab section’s due date
Experiment 1: Bead Sampling
1. Insert your observed counts for each genotype in generations 1-3 from Table 1 of your lab
manual as well as the allele frequency for each generation.
Observed Next Generation
Generation
# of Individuals with each
Genotype
Allele Frequency
#
AA
Aa
aa
A
a
1
5
14
5
0.544
0.456
2
5
14
5
0.544
0.456
3
5
13
6
0.5
0.5
2. Insert your expected counts found in Table 2 of your lab manual.
Parent Population
Expected Next Generation
Allele Frequency
# of Individuals with each
Genotype
Allele Frequency
A
a
AA
Aa
aa
A
a
0.5
0.5
6
12
6
0.5
0.5
3. Do your observed genotype frequencies differ significantly from the expected genotype
frequencies? (Show Chi-square for both your group and whole class)
(0.5-0.5)^2/0.5 = 0
4. Did the allele frequencies change from the start to the end? yes the frequencies changed as we
continued to pull
5. Did your results differ between your group vs. the whole class? no, we stayed in equilibrium.
6. What do you think would account for any differences in the observed vs expected genotype
frequencies? (HINT: think about what the conditions are for Hardy-Weinberg equilibrium to be
met). The frequencies had the possibility of not being completely even
Experiment 2: Allele and phenotype frequencies in rock pocket mouse populations
From Table 4 on page 17 of your lab manual: Calculate the frequencies (number of mice of one
color/total number of mice) of light- and dark-colored mice caught on light-colored substrates.
Page 1
1. Frequency of light-colored mice: 0.298 Frequency of dark-colored mice: 0.912
Calculate the frequencies of dark- and light-colored mice caught on dark-colored substrates.
2. Frequency of dark-colored mice: 0.9 Frequency of light-colored mice: 0.09
Assuming that the populations are currently in Hardy-Weinberg equilibrium, determine the number of
mice with the dd, DD and Dd genotypes on the light, rocky, granite substrate.
3. Frequency of mice with the dd genotype on light-colored substrate 0.70
4. Frequency of mice with the DD genotype on light-colored substrate 0.03
5. Frequency of mice with the Dd genotype on light-colored substrate 0.27
6. What is the frequency of d in this population? 0.84 What about D? 0.16
Assuming that the populations are currently in Hardy-Weinberg equilibrium, determine the number of
mice with the dd, DD, and Dd genotypes on the dark, rocky lava substrate.
7. Frequency of mice with the dd genotype on dark-colored substrate 0.09
8. Frequency of mice with the DD genotype on dark-colored substrate 0.49
9. Frequency of mice with the Dd genotype on dark-colored substrate 0.42
10. What is the frequency of d in this population? 0.3 What about D? 0.7
11. In your own words, describe how this data informs us about hypotheses and predictions of the
selective advantages of different fur colors. (2-3 sentences)
The data stayed at equilibrium for most of the experiment. However, when you factor in the owls we
see the light colored mice are more likely to be eaten. The data provides conclusive evidence
supporting fur color as a selective advantage.
Experiment 3: Natural Selection and Evolution
Page 2
12. Use this google sheets document to fill out the table below using formulas. Tips for entering
these formulas are found in the tutorial boxes in the document. You can copy/paste the
completed table below.
Generation
Allele Frequency
Genotype Frequency
# Mice out of 50
After Predation

p (D)
q (d)
p
2
2pq
q
2
Dark
Light
Dark
Light
0
0.1
0.9
0.01
0.18
0.81
9.5
40.5
8.55
20.25
1
0.161
0.839
0.026
0.271
0.703
14.84
35.16
13.36
17.58
2
0.246
0.754
0.061
0.371
0.568
21.59
28.41
19.43
14.20
3
0.350
0.650
0.123
0.455
0.422
28.89
21.11
26.00
10.56
4
0.463
0.537
0.214
0.497
0.289
35.56
14.44
32.00
7.22
5
0.571
0.429
0.326
0.490
0.184
40.80
9.20
36.72
4.60
6
0.666
0.334
0.444
0.445
0.111
44.43
5.57
39.99
2.78
7
0.745
0.255
0.555
0.380
0.065
46.74
3.26
42.07
1.63
8
0.807
0.193
0.651
0.311
0.037
48.14
1.86
43.32
0.93
9
0.855
0.145
0.731
0.248
0.021
48.95
1.05
44.05
0.53
10
0.891
0.109
0.795
0.194
0.012
49.41
0.59
44.47
0.29
13. As you completed the table on the google sheets document, it should have automatically filled
out figures showing changes in the allele and genotype frequencies over time. Paste these two
figures below.
Page 3