Introduction
The reason for our project was to try and figure out how the white eye mutation is passed down in flies. The other phenotype of fly (other than white eyed) was the wild fruit fly(red eyed). The reason we used fruit flies was because they breed fast and they are seen as pests to our human supremacy. Overall we are hoping to find out how white eyes are passed from one generation to another.
Characteristics
Kingdom-Animalia
Phylum-Arthropoda
appendages, compound eyes, segmented antennae,open circulatory systems, exoskeleton
Class-Insecta
segmented body, usually small, wings
Order-Diptera
one pair of wings, may sting, make honey
Family-Drosophilidae
Genus-Drosophila
Species-melanogaster
Phenotypes
There are two main phenotypes (phenotype is just a big word for the type of fly) that were involved in our experiments were wild (red eyed) and white (white eyed). So the description for each is very similar in almost all aspects of physical characteristics except for the color eyes. As you can assume the white have white eyes and the wild have red eyes.
OBSERVATION LOG
Date Observation2-27 Flies expand to new cultures
3-2 No sign of larva medium dry-added water
3-3 Larva is alive and is eating and borrowing
3-6 Pupas forming, larva moving
3-7 Pupas turn into flies, cocoons higher up
3-8 More pupa & cocoons still a good number of flies
3-10 we see all stages
3-13 35 of larva ready to hatch, still flies
3-16 p1 cross vial1 5 female 6 male vial2 6 male 6 female no larva
3-17 cocoons, all flies alive vial1 napped vial2 a few deaths most part good
3-20 larva some flies die in both vials
3-21 more larva, moved higher more dead flies
3-22 more larva mostly red some white
3-23 more dead flies only a few still alive vial 2 more larva higher up.
4-3 vial2 four flies died vial1 one fly dies
4-8 saw pupa saw larva killed removed f1 adults
4-17 vial1 many red eyes vial2 lots of flies majority red
4-24 vial1 new flies some larva vial2 many new flies
Sexing
- fruit fly's that are males have black abdomens
- fruit fly's that are females have tan abdomens
- Fruit fly's sometimes have no obvious color to their abdomen.... those are the ones that have semi black but mostly tan abdomens.... its difficult to identify these fly's We had to be careful not to put too many of one sex
F1 predictions
| + | + | |
| W | W+ | W+ |
| W | W+ | W+ |
(key: += wild W=White)
If white eyes are dominant, then all F1 offspring will be heterozygous white eye.
| + | + | |
| w | +w | +w |
| w | +w | +w |
If wild is dominant then the offspring will be all wild eyed and heterozygous.
F1 outcomes
vial 1 P cross= female white X male wild
f1 female Phenotype=white
likely genotypes for f1 Males= XwY
Vial 1 P Cross=female wild X white male
f1 Male Phenotype=wild eye (all)
likely genotypes for f1 females=X+Xw hetro
Vial 2 P cross=female wild X white male
f1 male Phenotype=wild eye (all)
likely genotypes for f1 males=X+Y
Vial 2 P Cross=wild female X white male
f1 female Phenotype= all wild
likely genotypes for f1 females=X+Xw hetro
F2 Predictions
These tables show the expected outcomes for the second generation of flies.
Vial 1
| Xw | Y | |
| X+ | X+Xw | X+Y |
| Xw | XwXw | XwY |
50% wild (25% male,25% female)
50% white(25% male, 25% female)
Vial 2
| X+ | Y | |
| Xw | XwX+ | XwY |
| X+ | Xw+ | X+Y |
25% Male white
50% Wild female
25% Wild Male
Fly Count
Vial 1
The lack of flies is because of a problem during transferring when the medium covered all of the larva and killing of most of the generation.
| Date | Female Wild | Male Wild | Female White | Male White |
| 2-21-06 | 22 | 22 | 15 | 11 |
| 2-24-06 | 2 | 0 | 0 | 0 |
| 2-25-06 | 3 | 7 | 2 | 1 |
| Total= 85 | 27 | 29 | 17 | 12 |
Vial 2
| Date | Female Wild | Male Wild | Female White | Male White |
| 4-21-06 | 17 | 6 | 0 | 12 |
| 4-24-06 | 10 | 2 | 0 | 3 |
| 4-25-06 | 2 | 1 | 0 | 0 |
| Total=53 | 29 | 9 | 0 | 15 |
Percent Error Analysis
vial 1!
| phenotype | observed | expected | (O-E) | (O-E)/E | X 100 | %error |
| Wild Male | 29 | 21 | 8 | .38 | 38 | 38% |
| Wild Female | 27 | 21 | 6 | .28 | 28 | 28% |
| White Male | 12 | 21 | 9 | .42 | 42 | 42% |
| White Female | 17 | 21 | 5 | .23 | 23 | 23% |
Vial 2
| phenotype | observed | expected | (o-e) | (O-E)/E | X100 | %Error |
| Wild male | 9 | 13 | 4 | .30 | 30 | 30% |
| Wild female | 29 | 26 | 3 | .06 | 6 | 6% |
| White male | 15 | 13 | 2 | .15 | 15 | 15% |
Conclusion
Overall, I think that we learned how to work together to complete our fly assignment. We all put in time and work. The only thing that we would want to do differently would be to start working sooner rather than later. We would also take better notes and pay more attention to produce better results. Even though we never would have thought about fruit flies outside of the science room, we did learn a lot about the different types of mutations and the life cycle of the flies. We learned about almost every aspect of the flies life and we also got the chance to participate in the breeding of the flies. Our hypothesis was that white eyes were a sex linked recessive trait. For the most part, our data followed our hypothesis. Our range of error went from a low 6% to a high 42%. Although our percent error was high in some places it was due to transferring mistakes. The only times that we had any difficulty with our flies was, as I mentioned earlier, a transferring mistake. We didn't really have many questions, and the ones we did have were answered.
Eulogy
To all the flies that we brutally massacred in the name of science we're sorry.... kinda.
