Solved by a verified expert:Drosophila Genetics Lab Activities and Report
1. Please log on to the Internet and go to
cgslabs.com/getstarted/

2. Launch CGS- located on the left. This opens in a new window.

3. Click on Study a Practice Population.
The page is now
titled “Investigate a Practice Population.”
Practice Population 1 (Tetrapter vs. wildtype) is in the center of the
page.
4. Click on continue, in the lower right part of the
screen.The next screen view is below:

5. Practice hovering over several of the flies pictured in
the center of the screen. At the bottom
of the screen, their assigned number, their body type and their sex will
appear.
All of the offspring on the screen have both parents as wild
type.
What is the dominant phenotype? _______________________
What is the recessive phenotype? ________________________

6. Choose a female fly that is homozygous for wild
type. Click and drag the fly over to the
crossing vial on the right side of the screen.
The screen should look like this:

7. Choose a male fly that is tetrapter. Click and drag the
fly over to the crossing vial on the right side of the screen.

8. Click on button
“Cross Flies”

9. Click on button
“View All Data” it is on the lower right.
10.Fill in the data for Vial 1 found on the screen at the
bottom half of the data sheet.
Body Female Male Total
Tetrapter
Wild type

Do any of the offspring have “aa” as their genotypes? __________
11. Close the Data window.
Screen now shows Vial 1 population, the offspring of the two individuals
you chose in the first cross.
We will now do a second cross, using the offspring of the
first cross.
12. Choose a female
who is heterozygous and place in the crossing vial.
Choose a male who is heterozygous and place in the crossing
vial.
13. Click on “cross flies”.
14. Click on “view all data”
15. Fill in the box below with Vial 2 data:
Body Female Male Total
Tetrapter
Wild type

What is the % of wild types of the Vial 2 population? (# wild/total # of flies) ___________
What is the % of tetrapters of the Vial 2 population? (# tetrapters/total # of flies) __________

Exit the page by clicking on exit. It returns you to the “Investigate a Practice
Population” Page.
We will choose a new population to explore sex linked
traits.
1. Click forward to practice population #3. This represents
a trait that is sex linked. Gull refers
to wide angled wings, and wild type to wings closer to the thorax, or body.
What does sex linked mean?
____________________________________
What is the dominant phenotype? ______________________
What is the recessive phenotype? _______________________
2. Click continue.
3. Choose a male gulland a female wild type. Place in the crossing vial.
4. Click on “cross flies.”
5. Click on “view all data”.

Fill in the box below with the data for Vial 1.
Wing Angle Female Male Total
Gull
Wild type

What is the genotype for the male parent, in question 3
above? _________
How many alleles does a male receive for a sex linked trait?
_____
What is the genotype for the female parent, in question 3
above? _______
What is the genotype of the female offspring, to create all
of them with Gull wings? ________

6. Let’ s do a second population. Choose a female Gull and a
male wild type. Place in the crossing
vial.
7. Click on “cross flies.”
8. Click on “view all data”.
Fill in the box below with the data for Vial 2.
Wing Angle Female Male Total
Gull
Wild type

What is the genotype for the male parent, in question 6
above? _________
What is the genotype for the female parent, in question 6
above? _______
What is the genotype of the female offspring, to create all
of them with Gull wings? ________
What is the genotype of the male offspring, to create all of
them with Gull wings? ________