Lab 2
Problem: How can we determine the Mode of Inheritance of a mutant trait in fruit flies?
Information: We know...
a. there are four basic modes of inheritance. AR, AD, XLD, XLR. (Autosomal Recessive, Autosomal Dominant, X-Linked Dominant, and X-Linked Recessive)
b. our mutant fruit flies are caused by a single mutation (1 gene).
c. mendel's laws and how to analyze simple crosses.
d. our wild fruit flies are inbred for homozygous.
e. how to raise fruit flies and how to collect virgin females.
- Observations: 10/11 - Today we put 8 male wilds and put them with 9 or 10 female sepia into vial #1. Then 8 male sepia with 8 female wild into vial #2.
- Hypothesis: If we perform reciprocal crosses on our fruit flies, we will be able to determine the Mode of Inheritance of the sepia trait.
| 8 wild female |
X |
8 males sepia
|
| 9 or 10 sepia female |
X |
8 males wild
|
- Observation: 10/11/07 - Thursday - We performed reciprocal crosses today between the sepia and wild flies.
Experimental Design
We will set up two genetic crosses.
Vial 1 = Male wild X Female sepia
Vial 2 = Female wild X Male sepia
(Phenotypes)
| Expected results
|
Vial 1
|
Vial 2
|
| AR |
100% Wild |
100% Wild
|
| AD |
100% Sepia |
100% Sepia
|
| SLR |
All male sepia, All female wild |
100% Wild
|
| SLD |
100% Sepia |
All female sepia, All male wild
|
Punnett Squares
- I forgot to include the Punnett Squares in my original lab, but they are pretty important. Try not to forget these when you record your data!
| AR
|
r
|
r
|
| R |
100% Wild |
100% Wild
|
| R |
100% Wild |
100% Wild
|
| AD
|
R
|
R
|
| r |
100% Sepia |
100% Sepia
|
| r |
100% Sepia |
100% Sepia
|
| SLR (sepia females)
|
x
|
x
|
| X |
wild |
wild
|
| Y |
sepia |
sepia
|
| SLR (sepia males)
|
X
|
X
|
| x |
wild |
wild
|
| Y |
wild |
wild
|
| SLD (sepia females)
|
X
|
X
|
| x |
sepia |
sepia
|
| Y |
sepia |
sepia
|
| SLD (sepia males)
|
x
|
x
|
| X |
sepia |
sepia
|
| Y |
wild |
wild
|
| 
Project name
Main project page
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