Lab 8 Population Genetics BIO101L

Population Genetics

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 the 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 Beads	Blue Beads	Total		Red Beads	Blue Beads	Total
Click here to enter text.	Click here to enter text.	50		Click here to enter text.	Click here to enter text.	100

2.

Beaker #2 Population Composition
# of Individuals		% of Population
Yellow Beads	Green Beads	Total		Yellow Beads	Green Beads	Total
Click here to enter text.	Click here to enter text.	20		Click 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 Beads	Green Beads	Total		Yellow Beads	Green Beads	Total
Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100

 

Beaker #1 Survivors
Trial	# of Survivors		% of Population
	Red Beads	Blue Beads	Total		Red Beads	Blue Beads	Total
1	Click here to enter text.	Click here to enter text.	25		Click here to enter text.	Click here to enter text.	100
2	Click here to enter text.	Click here to enter text.	25		Click here to enter text.	Click here to enter text.	100
3	Click here to enter text.	Click here to enter text.	25		Click here to enter text.	Click here to enter text.	100
4	Click here to enter text.	Click here to enter text.	25		Click here to enter text.	Click here to enter text.	100
5	Click here to enter text.	Click here to enter text.	25		Click here to enter text.	Click here to enter text.	100

 

Beaker #2 Survivors
Trial	# of Survivors		% of Population
	Yellow Beads	Green Beads	Total		Yellow Beads	Green Beads	Total
1	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100
2	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100
3	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100
4	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100
5	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100

 

Beaker #3 Survivors
Trial	# of Survivors		% of Population
	Yellow Beads	Green Beads	Total		Yellow Beads	Green Beads	Total
1	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100
2	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100
3	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100
4	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100
5	Click here to enter text.	Click here to enter text.	5		Click 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 Beads	Blue Beads	Total		Red Beads	Blue Beads	Total
1	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100
2	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100
3	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100
4	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100
5	Click here to enter text.	Click here to enter text.	10		Click here to enter text.	Click here to enter text.	100

 

Beaker #2 Founders
Trial	# of Founders		% of Population
	Yellow Beads	Green Beads	Total		Yellow Beads	Green Beads	Total
1	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100
2	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100
3	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100
4	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100
5	Click here to enter text.	Click here to enter text.	5		Click here to enter text.	Click here to enter text.	100

 

Beaker #3 Founders
Trial	# of Founders		% of Population
	Yellow Beads	Green Beads	Total		Yellow Beads	Green Beads	Total
1	Click here to enter text.	Click here to enter text.	2		Click here to enter text.	Click here to enter text.	100
2	Click here to enter text.	Click here to enter text.	2		Click here to enter text.	Click here to enter text.	100
3	Click here to enter text.	Click here to enter text.	2		Click here to enter text.	Click here to enter text.	100
4	Click here to enter text.	Click here to enter text.	2		Click here to enter text.	Click here to enter text.	100
5	Click here to enter text.	Click here to enter text.	2		Click 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?
6. 1000:
7. 100:
8. 10:
9. 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 1		Generation 2		Generation 3		Generation 4
#	Genotype		#	Genotype		#	Genotype		#	Genotype
1	Click here to enter text.		1	Click here to enter text.		1	Click here to enter text.		1	Click here to enter text.
2	Click here to enter text.		2	Click here to enter text.		2	Click here to enter text.		2	Click here to enter text.
3	Click here to enter text.		3	Click here to enter text.		3	Click here to enter text.		3	Click here to enter text.
4	Click here to enter text.		4	Click here to enter text.		4	Click here to enter text.		4	Click here to enter text.
5	Click here to enter text.		5	Click here to enter text.		5	Click here to enter text.		5	Click here to enter text.
6	Click here to enter text.		6	Click here to enter text.		6	Click here to enter text.		6	Click here to enter text.
7	Click here to enter text.		7	Click here to enter text.		7	Click here to enter text.		7	Click here to enter text.
8	Click here to enter text.		8	Click here to enter text.		8	Click here to enter text.		8	Click here to enter text.
9	Click here to enter text.		9	Click here to enter text.		9	Click here to enter text.		9	Click here to enter text.
10	Click here to enter text.		10	Click here to enter text.		10	Click here to enter text.		10	Click here to enter text.

 

Generation 5		Generation 6		Generation 7
#	Genotype		#	Genotype		#	Genotype
1	Click here to enter text.		1	Click here to enter text.		1	Click here to enter text.
2	Click here to enter text.		2	Click here to enter text.		2	Click here to enter text.
3	Click here to enter text.		3	Click here to enter text.		3	Click here to enter text.
4	Click here to enter text.		4	Click here to enter text.		4	Click here to enter text.
5	Click here to enter text.		5	Click here to enter text.		5	Click here to enter text.
6	Click here to enter text.		6	Click here to enter text.		6	Click here to enter text.
7	Click here to enter text.		7	Click here to enter text.		7	Click here to enter text.
8	Click here to enter text.		8	Click here to enter text.		8	Click here to enter text.
9	Click here to enter text.		9	Click here to enter text.		9	Click here to enter text.
10	Click here to enter text.		10	Click here to enter text.		10	Click here to enter text.

 

	Starting Population	After 7 Generations
# of S alleles (red beads) in population	25	Click here to enter text.
# of s alleles (blue beads) in population	25	Click here to enter text.
Total Alleles	50	Click here to enter text.
% of S allele in population	50	Click here to enter text.
% of s allele in population	50	Click 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 the sickle gene matches very closely to the worldwide distribution of malaria (Figure 7). What is the significance of this?