BSC 1005l Drosophila Genetics Lab Activities and Report

12 Jun BSC 1005l Drosophila Genetics Lab Activities and Report

Question
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? ________