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


Fruit Fly Genetics

fruitflyyellow2, fruitflyyellow1, fruitflyyellow3, and fruitflyyellow4


In my science class, we did a very interesting project on fruit flies.  The reason why we picked fruit flies to work with is because they are the easiest species to use fly nap on.  Our ideas and understandings were based on Mendel's experiments and principles on Genetics. Therefore the main idea is pretty much how characteristics are transmitted from parents to offspring. During the lab we kept track of mutations, vestigial wings and the wild. During class we gathered up in partners to nap the flies in a certain order. First we separated the females and the males, then we separated the ones with vestigial wings and separate those as females and males as well. Basically this project was about learning how scientists predict the genetics of fruit flies and other animals. The key for this data was Genotype and Phenotype. The genetic make-up of the fruit fly is the genotype and it's appearance is the phenotype. 


The fruit fly is a member of the phylum Arthropoda and are arthropods. Like annelids, arthropods are segmented animals. The class is Insecta. They have one pair of wings (hind pair reduced to knobs) they have piercing, sucking, or rapping mouthparts.


During our experiment with the fruit flies, we had to learn three different Phenotypes.  There are three different Phenotypes.  Wild type Drosophila, Recessive sex-linked white eyes, and Red eye vestigial wings.

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 fruitflyyellow3

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 fruitflyyellow1

Group Life Cycle Log


3/16/06- one in each container died (a female and a male)
3/17/06- two are dead in the female Wild Type vial
3/20/06- in female vestigial larva have appeared and three new flies
3/21/06- in vestigial male vial the larvae have tunneled through the medium
              in vestigial female vial the larvae are all over the walls of the vial but didn't tunnel                           through medium
3/23/06- In the female vestigial vial there are lots of pupae and a lot of larvae. Two flies have died
              In the male vestigial vial there more larvae than pupae and one died.
3/24/06- Lots of pupae, three larvae in vestigial female vial
3/31/06- vial one- there are half and half of vestigial and Wild type offspring
             vial two- there was contamination


Vial one- none dead
vial two- none dead but slightly dried medium
4/7/06- vial one- lots of pupae and larvae, cleared vial
vial two- lots of pupae and larvae, cleared
4/21/06 larvae hatched in both vials
4/24/06 vial two- 15 female vestigial, 15 male vestigial

Sexing the Flies

The first step that we took was we used fly nap to anesthetize them so they would be easier to handle. When we were sexing the flies we had to look at the flies while they were on their backs so we could see if they had a darker abdomen or a lighter. When we found the males we put them on one side of a piece of paper and we put the females on the other.


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 fruitflyyellow2


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 fruitflyyellow1


F1 Predictions

We worked with four hypotheses that had either vestigial as dominant or as recessive. The first hypothesis was vestigial dominant and wild recessive. Our second hypothesis was wild dominant and vestigial recessive. We also had hypothesis that were sex-linked like our third, which was vestigial sex-linked and dominant and wild was recessive. The last one was wild type sex-linked and dominant and vestigial recessive.

Autosomal Hypothesis # 1 vestigial dominant

  vg vg
vg+ vg+
+ vg+ vg+

Sex-linked Hypothesis #3 vestigial sex-inked and dominant

  x+ y
xvg xvgx+ xvgy
xvg xvgx xvgy

We first predicted that the phenotype was 100% vestigial and the genotype was vg+, but in vial 1 there were no vestigial flies and in vial 2 there was a contamination. So our conclusion for the F1's were autosomal recessive.

F2 Predictions

For our F2 predictions we had two vials. In vial 1 we had wild males and females.

++  +vg 
vg  +vg   vgvg

Vial 2

 vgvg  vg+
vg  vg+  ++

Fly Counts

Vial One

 Date F2 Counted
 Female Wild
Male Wild
Female vg
Male vg
 9 8
 4/24/06 53 39 16
 4/25/06 18

Overall Total

Total Female +

Total Male +

Total Female vg

Total Male vg

Total WIld

Total vestigial

Vial Two

 Date F2 Counted
Female Wild  Male Wild  Female vg  Male vg 
 4/9/06 36  34 22 22 
32  30  

Overall Total

Total Female +

Total male+

Total Female vg

Total Male vg

Total vestigial

Total Wild

Percent Error

Vial 1

 Phenotype  observed expected   O-E  O-E/E  X100  %ERROR
 vestigial  45  53.75  8.75  .1628  16.28  16.28%
 wild  170  161.25  8.75  .0543  5.43  5.43%

Vial 2

 Phenotype  observed  expected  O-E  O-E/E X100   %ERROR
 vestigial  81  57  25  .4211  42.11  42.11%
 wild  147  171  24  .1404  14.09  14.09&


Our hypothesis was that, if the mutation vestigial is autosomal recessive in the P generation, then by the F2 generation the expected Phenotype Ratio is 75% wild : 25% vestigial. The Hypothesis was supported based on data and percent error. The only problem we had was that we had contamination in vial two which probably messed up some of our data. If we were to repeat this we would probably double check all of our work, like our punnett squares and our tables.


Life never ends, it just takes a left turn, R.I.P fruit flies

Learning Information

About This Page

Author: fruitflyyellow2, fruitflyyellow1, fruitflyyellow3, and fruitflyyellow4
Classroom Project: fruitflyyellow
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

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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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