Vg+ & +Se
(female)
DARCY
AND
EMMA
(male)
Background: Fruit Fly History
Our Cross:
Vg+ (male) & +Se (female)
Fruit Flies, or Drosophilia Melonogaster, have a small number of Chromosomes (four pairs) making this species easily used for genetic monitoring. Recognizing the short life cycle, is another factor of this ?lies’ monitoring ability. Their very short lifetime is determined by many factors, but usually results in a complete cycle of ten to twelve days. The eggs produced by Drosophilia Melonogaster are small and usually laid on the surface of the food medium, and about after one day produce into larvae. The larvae, constantly eating, move throughout the food medium and growth culture. As the larvae increases in size, the larvae shed its outer layers (usually about 2 times). The Salivary glands produce giant chromosomes at the very end of the larvae stage. From this stage, the larvae move into the pupal stage. In this stage under laboratory monitoring, the pupas move up the side of the canister. Within this stage the features, such as eye, wings,and body, can be determined, and normally are readily visible. Finally the pupas, move into the adult stage, when metamorphosis is complete the adult ?lies emerge. Once this has occurred the pupas have of?icially become adult ?lies. The ?lies we are testing are called drosophila melonogaster and they can either have white, red, or sepia eyes; regular or vestigial wings; and brown or black bodies. Wild, or red, eyes are dominant and sepia and white are recessive. Regular wings are dominant over vestigial, and brown bodies are dominant over black bodies.
Wild
Wings
Vestigial
F1 Cross:
Phenotype:
Vestigial Wing, Wild Eye Male: Sepia Eye, Wild Wing Female
Nomenclature:
Genotype:
Vg+ Male: +Se Female
+ = wild eyes or wings
se = sepia eyes
vg = vestigial wings
F2 Cross:
VgSe
Vg+
+Se ++
VgSe
VgVgSeSe
VgVg+Se
+VgSeSe
+Vg+Se
Vg+
VgVg+Se
VgVg++
+Vg+Se
+Vg++
+Se
+VgSeSe
+Vg+Se
++SeSe
+++Se
++
+Vg+Se
+Vg++
+++Se
++++
Terminology:
Sepia Eyes: Brown like eyes in color
Wild Eyes: Red eyes in color
Wild Wings: Large, full grown wings
Vestigial Wings: Small, ingrown wings
(does not allow the insects to fly)
Phenotype:
1:2:1:2:4:2:1:2:1
1 VgVgSeSe: 2 VgVg+Se: 1 VgVg++: 2 +VgSeSe: 4 +Vg+Se: 2 +Vg++: 1 ++SeSe: 2 +++Se: 1 ++++
Collected Data:
Genotype:
9:3:3:1
9 Wild Wing, Wild Eye : 3 Vestigial Wing, Wild Eye: 3 Wild Wing, Sepia Eye: 1 Vestigial Wing, Sepia Eye
Wild Wing, Wild
Eyes
8
Vestigual Wings,
Wild Eyes
2
Wild Wing, Sepia
Eyes
0
Vestigual Wing,
Sepia Eyes
2
How to
Sex
Fruit
Flies
males:
Have
rounded
ends
Have
small
indents on
underside
Our Cross:
Male:
Vestigial Wings
with Wild Eyes
females:
have
pointed
ends
Female:
Wild Wings with
Sepia Eyes
Eye Pigment: Chromatography Lab
Eye pigment in fruit flies is genetically
controlled. These Flies have genes that
encode pigment-forming enzymes that
make the pigments from pigment
molecules.Specific mutants will be missing
a pigment or a group of pigments. From
analyzing the different pigments under
Ultra-Violet Light. Wild type, or flies
recognized with red eyes had all the
enzymes avialable. This is do to the fact
that they produce violet-blue, green-blue,
yellow-green, blue, and orange on the
chromatography enzyme prodection
graph, and as demonstrated in the lab
under UV light. Sepia type, or flies with
brown looking eyes, don’t produce all enzymes
possible because of the recognized violet-blue,
green-blue, and yellow-greendemonstrated in the
lab under UV light.White Type, or flies with white
eyes, don’t produce enzymes 2 and 7. This means
that the fly does not see a majority of the spectrum
and does not produce most enzymes bythe fly’s
ability to only see blue and green-blue as
demonstrated in the lab under the UV light.
Graph representing how fruit fly colors are made
(http://www.associatedcontent.com/article/
1228243/
eye_pigments_in_drosophila_common_fruit.html)
9:3:3:1
Chi Square
.2315
.0278
2.25
2.0833
80%-95% due to genetics-chance has bigger influence with small number
Phenotype
Wild Wing, Wild
Eye
Observed
698
Expected
685.6875
Chi Square
.0179
Vestigual Wing,
Wild Eye
Wild Wing, Sepia
Eye
Vestigual Wing,
Sepia Eye
219
228.5625
.4001
226
228.5625
.2087
76
76.1875
.0004
Total: 1219 flies tested
Chi
Squares
Phenotype
Observed
Expected
Wild Wing, Wild 8
6.75
Eye
Vestigual Wing,
2
2.25
Wild Eye
Wild Wing, Sepia 0
2.25
Eye
Vestigual Wing,
2
.75
Sepia Eye
Chi square value: .6271
{(o-e)^2}/expected
Chi square value: 4.5926
20%-50% chance due to genetics
analysis
For this lab we tested the cross of sepia eyes and vestigial wings while hypothesizing that the wild wings and wild eyes are dominant. We also hypothesized that the F1 would have a 1:0 ratio of being wild winged and wild eyed, and that is what we got for our cross. However for the F2, we hypothesized a 9:3:3:1 ratio (9 wild wing wild eye: 3 vestigual wing wild eye: 3 wild wing sepia eye: 1 vestigual wing sepia eye) and didn’t get that exactly. Our results of 8:2:0:2 helped us conclude that there was a 20%-­‐50% chance the results were due to genetics based on our Chi-­‐
square. Once we made a Chi Square of all the results from our cross in all the classes, our results proved to be 80%-­‐95% due to genetics. These results were signi?icant because they proved our hypothesis correct and demonstrated the existence of heredity of traits. Because of these results, we would accept the whole groups data as opposed to just our individual groups data, which we would reject based on the low Chi square critical value. This much higher percentage from the Chi Square of all the classes’ data indicates that the more tests that are performed, (1219 as opposed to 12) the least likely chance is to play a role in the results. One improvement in this lab would probably be testing even more fruit ?lies, because the more tested would give us most thorough and accurate results as explained by the elimination of chance as a large factor.