Portfolio: The Study of Fruit Fly Genetics at City High School

Investigation

the ultimate show down of flies!

fivegreen2, fivegreen1, and fivegreen4

Introduction

Our class is doing a lab which focuses on the genetic mutations in fruit flies. We are using fruit flies because they are easy to breed and it is easier to tell which genetic mutation that they have. Our group is focusing on the mutation Vestigial, which is a mutation of the wings. The mutation causes the flys wings to shrivle and become useless.

ClassificationKingdom- Animalia

Phenotypes

+: Have red eyes, their wings are normal, and they can fly and are bacically normal flies.

Vg: They have red eyes, their wings are shrivled and useless, they cant fly at all. Our group fondly calls these "walks" insted of flies. 

Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window

© 2006 fivegreen2

Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window

Fly log

3/16, vial 1, there are 2 females 5 males active vial 2, one dead fly active 4 males zero females.


3/17, vial 1, no larva vial 2, 1 dead fly pretty much the same as the day before.

3/21, vial 1, they all died, vial 2, they all died.

3/24, vial 1, not using vial 1 any more because all the flies keep dying in this vial., vial 2, 6 males are still alive. Everyone is lively and the medium looks good.

3/27, all flies are still alive. no larva yet, medium looks brown

3/30, there is larvae, all the flies are still alive.

3/31, lots more larvae. flies are starting to die, no pupa.

4/3, Lots of pupae. no pupae have hatched yet. There is still larvae.  

4/7, the medium was a little dry, still some pupae.

4/17, lots of flies in vial 2. only 3 flies in vial 1. Lots of pupae in vial 1.

4/21, lots of flys hatched. some F3 larva. Some unhatched pupae still. 

How to Sex Flies

When were learning how to sex the flies we used Fly-nap to put the flies asleep. We waiting for them to fall to the bottom of the vial and then we dumped them out onto a notecard and distinguished male from female. We found out if they were male or female by looking at their abdomens to see if there was a black dot on the bottom. If there was a black dot on the abdomen they were male, if there wasn't they were female.

Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window

The one on the left is female, the one on the right is male 

© 2006 fivegreen2

F1 Predictions

In our F1 cross we crossed Vistigual (VG) and wild (+) fruit flys, we calculated all the outcomes possible, including if VG is dominant, and + is recessive, if + is dominant, and VG is recessive, if Vg is sex linked, dominant, and the mutation is on the male, if VG is sex linked, dominant, and the mutation is on the female, if + is sex linked, dominant, and on the male, and if + is sex linked, dominant, and on the female. Below are three of the possible outcomes, the first is not sex-linked and VG is dominant, the second is not sex linked, and if , is dominant, and the third is sex-linked, and the male is wild.

Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window

© 2006

Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window

© 2006

 

If VG Dominant
  VG VG
+ VG+ VG+
+
VG+ VG+
If WILD (+) dominant
  vg vg
+
+vg +vg
+
+vg +vg

If WILD (+) is sex-linked and the male is wild

F1 outcome

For our F1 outcome all of our flies had the wild phenotype, which shows that wild is dominant and not sex-linked. Our mutation (vestigual wing) is autosomal recessive.

F2 predictions

For our F2 predictions, after gathering our F1 conclusion data, we figured out that there was only one way the fruit flies could cross, since it was not sex-linked, 25% of all F2's should all be VG and 75% should all be WILD

 Punnet sqaure for F2 cross

   VG
VG
VGVG
VG+
+
VG+
++

Fly Final Counts

Vial 1: Female Wild:3  Male Wild:0  Female Vg:0  Male Vg:0

Vial 2: Female Wild:39  Male Wild:49  Female Vg:26  Male Vg:11 

 

Percent error

Vial 1- vial 1 was unusable, the only flies that came out of it were 3 wild females

vial 2

 Phenotype observed
expected
(O-E)
(O-E)/E
X 100
% Error
Wild  88
93.75
5.75
.06133333...
6.1333333...
6.1
VG
37
31.25
5.75
.184
18.4
18.4

 

Conclusion

Our hypothesis was supported by our data: vestigial wing in fruit flies is an autosomal recessive trait, and Wild wings is a dominant one, our percent error was very small, only 6.1 percent, showing we were very accurate. One of our vials was contaminated somehow, and we ended up with a very small amount of offspring. Next time we may take more precautions to make sure a vial is not contaminated, have more vials, and/or take more time outside of the classroom to work on it because we did run into some time issues.

Learning Information

About This Page

Author: fivegreen2, fivegreen1, and fivegreen4
Classroom Project: fivegreen
city high school
Tucson, AZ USA

License: Tree of Life & Partners uses only - Version 1.0

Correspondence regarding this page should be directed to , city high school

 Treehouses are authored by students, teachers, science enthusiasts, or professional scientists. Anyone can sign up as a treehouse contributor and share their knowledge and enthusiasm about organisms. Treehouse contributions are checked for general accuracy and quality by teachers and ToL editors, but they are not usually reviewed by expert scientists. If you spot an error, please get in touch with the author or the teacher. For more information about quality control of Tree of Life content, see Status of Tree of Life Pages.

About This Portfolio

Molly Renner
city high school


University of Arizona

Lisa Schwartz
University of Arizona

Correspondence regarding this page should be directed to Molly Renner at , Kathryn Orzech at , and Lisa Schwartz at

All Rights Reserved.

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