Population Genetics

Student Name: Click here to enter text. Access Code (located on the lid of your lab kit):

Pre-Lab Questions

Assumptions:

· There are approximately 3,000,000,000 base pairs in the mammalian genome (genes constitute only a portion of this total).

· There are approximately 10,000 genes in the mammalian genome.

· A single gene averages 10,000 base pairs in size.

· Only 1 out of 3 mutations that occur in a gene result in a change to the protein structure.

In the mammalian genome:

1. How many total base-pairs are in all the mammalian genes?

Click here to enter text.

2. What proportion (%) of the total genome does this represent?

3. What is the probability that a random mutation will occur in any given gene?

4. What is the probability that a random mutation will change the structure of a protein?

Note: In the following experiments on gene pool, gene frequency, and genetic diversity; assume there are four alleles for color and that they are all homologous.

Experiment 1: Genetic Variation

Post-Lab Questions

1.

Beaker #1 Population Composition
# of Individuals% of Population
Red BeadsBlue BeadsTotalRed BeadsBlue BeadsTotal
Click here to enter text.Click here to enter text.50Click here to enter text.Click here to enter text.100

2.

Beaker #2 Population Composition
# of Individuals% of Population
Yellow BeadsGreen BeadsTotalYellow BeadsGreen BeadsTotal
Click here to enter text.Click here to enter text.20Click here to enter text.Click here to enter text.100

3. What can you say about the genetic variation between these populations?

Experiment 2: Genetic Drift

Beaker #3 Population Composition
# of Individuals% of Population
Yellow BeadsGreen BeadsTotalYellow BeadsGreen BeadsTotal
Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
Beaker #1 Survivors
Trial# of Survivors% of Population
Red BeadsBlue BeadsTotalRed BeadsBlue BeadsTotal
1Click here to enter text.Click here to enter text.25Click here to enter text.Click here to enter text.100
2Click here to enter text.Click here to enter text.25Click here to enter text.Click here to enter text.100
3Click here to enter text.Click here to enter text.25Click here to enter text.Click here to enter text.100
4Click here to enter text.Click here to enter text.25Click here to enter text.Click here to enter text.100
5Click here to enter text.Click here to enter text.25Click here to enter text.Click here to enter text.100
Beaker #2 Survivors
Trial# of Survivors% of Population
Yellow BeadsGreen BeadsTotalYellow BeadsGreen BeadsTotal
1Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
2Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
3Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
4Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
5Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
Beaker #3 Survivors
Trial# of Survivors% of Population
Yellow BeadsGreen BeadsTotalYellow BeadsGreen BeadsTotal
1Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
2Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
3Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
4Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
5Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100

Post-Lab Questions

1. What observations can you make regarding the gene pool and gene frequency of the surviving individuals?

2. Do the results vary between the populations represented by beakers #1, #2 and #3? Why or why not?

3. What observations can you make about the genetic variation between the parent and surviving populations?

Experiment 3: Stochastic Events

Post-Lab Questions

Beaker #1 Founders
Trial# of Founders% of Population
Red BeadsBlue BeadsTotalRed BeadsBlue BeadsTotal
1Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
2Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
3Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
4Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
5Click here to enter text.Click here to enter text.10Click here to enter text.Click here to enter text.100
Beaker #2 Founders
Trial# of Founders% of Population
Yellow BeadsGreen BeadsTotalYellow BeadsGreen BeadsTotal
1Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
2Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
3Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
4Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
5Click here to enter text.Click here to enter text.5Click here to enter text.Click here to enter text.100
Beaker #3 Founders
Trial# of Founders% of Population
Yellow BeadsGreen BeadsTotalYellow BeadsGreen BeadsTotal
1Click here to enter text.Click here to enter text.2Click here to enter text.Click here to enter text.100
2Click here to enter text.Click here to enter text.2Click here to enter text.Click here to enter text.100
3Click here to enter text.Click here to enter text.2Click here to enter text.Click here to enter text.100
4Click here to enter text.Click here to enter text.2Click here to enter text.Click here to enter text.100
5Click here to enter text.Click here to enter text.2Click here to enter text.Click here to enter text.100

1. What observations can you make regarding the gene pool and gene frequency of the founding individuals?

2. Do these results vary between the populations founded by beakers #1, #2 and #3? Why or why not?

3. What observations can you make about the genetic variation between the parent and founding populations?

4. Suppose you have a population of 300 butterflies. If the population experiences a net growth of 12% in the following year, how many butterflies do you have?

5. Now suppose you have 300 eggs, but only 70% of those eggs progress to become a caterpillar, and only 80% of the caterpillar progress to become an adult butterfly. How many butterflies do you have?

6. Suppose you have a population of 150 butterflies, but a wildfire devastates the population and only 24 butterflies survive. What percent does the colony decrease by?

Experiment 4: Natural Selection

1. Record the remaining colors from the “Red Habitat.”

Blue –

Red –

2. Record the remaining colors from the “Blue Habitat.”

Blue –

Red –

Post-Lab Questions

3. How did the distribution of phenotypes change over time?

4. Is there a selective advantage or disadvantage for the red and/or blue phenotypes?

5. What phenotypic results would you predict if starting with the following population sizes?

A. 1000:

B. 100:

C. 10:

6. Assume that you live in a country with 85 million people that consistently experiences an annual growth rate of 4.2%. If this population continues to grow at the same rate for the next 5 years, how many people will live in the country (round to the nearest whole number)?

Experiment 5: Sickle Cell Anemia Inheritance Patterns

Generation 1Generation 2Generation 3Generation 4
#Genotype#Genotype#Genotype#Genotype
1Click here to enter text.1Click here to enter text.1Click here to enter text.1Click here to enter text.
2Click here to enter text.2Click here to enter text.2Click here to enter text.2Click here to enter text.
3Click here to enter text.3Click here to enter text.3Click here to enter text.3Click here to enter text.
4Click here to enter text.4Click here to enter text.4Click here to enter text.4Click here to enter text.
5Click here to enter text.5Click here to enter text.5Click here to enter text.5Click here to enter text.
6Click here to enter text.6Click here to enter text.6Click here to enter text.6Click here to enter text.
7Click here to enter text.7Click here to enter text.7Click here to enter text.7Click here to enter text.
8Click here to enter text.8Click here to enter text.8Click here to enter text.8Click here to enter text.
9Click here to enter text.9Click here to enter text.9Click here to enter text.9Click here to enter text.
10Click here to enter text.10Click here to enter text.10Click here to enter text.10Click here to enter text.
Generation 5Generation 6Generation 7
#Genotype#Genotype#Genotype
1Click here to enter text.1Click here to enter text.1Click here to enter text.
2Click here to enter text.2Click here to enter text.2Click here to enter text.
3Click here to enter text.3Click here to enter text.3Click here to enter text.
4Click here to enter text.4Click here to enter text.4Click here to enter text.
5Click here to enter text.5Click here to enter text.5Click here to enter text.
6Click here to enter text.6Click here to enter text.6Click here to enter text.
7Click here to enter text.7Click here to enter text.7Click here to enter text.
8Click here to enter text.8Click here to enter text.8Click here to enter text.
9Click here to enter text.9Click here to enter text.9Click here to enter text.
10Click here to enter text.10Click here to enter text.10Click here to enter text.
Starting PopulationAfter 7 Generations
# of S alleles (red beads) in population25Click here to enter text.
# of s alleles (blue beads) in population25Click here to enter text.
Total Alleles50Click here to enter text.
% of S allele in population50Click here to enter text.
% of s allele in population50Click here to enter text.

Post-Lab Questions

1. What is the remaining ratio of alleles?

2. Have any been selected against?

3. Given enough generations, would you expect one of these alleles to completely disappear from the population? Why or why not?

4. Would this be different if you started with a larger population? Smaller?

5. After hundreds or even thousands of generations both alleles are still common in those of African ancestry. How would you explain this?

6. The worldwide distribution of sickle gene matches very closely to the worldwide distribution of malaria (Figure 7). What is the significance of this?

Figure 7: Distribution of Malaria (top) and Sickle Cell trait (bottom).
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