Name__________________ Lab Section (circle one) M-12, M-2-, T-8, T-10, T-2
1. Review your relevant notes from the instructors in class presentation.
2. Access the remote FlyLab Simulation by clicking on the link above.
3. Carefully read the Introduction, Goals and Objectives, Before You Begin, Procedures
(You will be completing this worksheet as you do part of the assignments listed on
the FlyLab webpage), Technical Requirements and Background Information.
4. Get the assignment for the day by going to
http://bio.winona.msus.edu/berg/241f01/Labs/Lab6.htm and clicking on
5. Print a copy of “Worksheet” for in class reference.
6. Read the complete text of the printed assignments found on the “Worksheet”.
7. Once you have read the assignments, scroll down the left hand menu and click on the
"Start Lab" button.
8. Refer to the section "Getting to Know FlyLab" in your printed "Worksheet".
9. Do the Monhybrid and the Dihybrid Crosses as detailed in the "Worksheet" [sections
1 (a-j), 2 & 3]. DO NOT DO THE TRIHYBRID CROSS in section 4. Make sure
that you can answer all of the questions posed in the "Assignments".
Do a "Testcross" as detailed in the "Assignments"
What was the phenotypic ratio for the offspring resulting from this testcross?
Based on this phenotypic ratio, determine whether the F1 wild-type female male was
double homozygous or double heterozygous for the wild-type alleles for eye color and
wing angle. Explain your answer.
If your answer was double homozygous, describe an expected phenotypic ratio for the
offspring produced from a testcross with a double heterozygous fly.
If your answer was double heterozygous, describe an expected phenotypic ratio for the
offspring produced from a testcross with a homozygous fly.
Do the "Lethal Mutations" cross as indicated in the "Assignments"
What phenotypic ratio did you observe in the F1 generation?
What were the phenotypes?
What phenotypic ratio did you observe in the F2 generation?
How do these ratios and phenotypes explain that the aristapedia mutation functions as a
What results did you observe when you performed a cross between a wild-type fly and a
fly with the aristapedia mutation?
State the hypothesis that you developed to predict the phenotypic ratio for the F1
After mating the flies, what phenotypic ratio did you observe in the F1 generation?
What was your chi-square p value when you tested your hypothesis?
What did your chi-square p value tell you?
State the hypothesis that you developed to predict the phenotypic ratio for the F2
Are the phenotypic ratios that you observed in the F2 generation consistent with what you
would expect for a lethal mutation?
Why or why not?
Explain your answers.
Do the "Epitasis" cross as indicated in the "Assignments"
In your cross between a female fly with vestigial wing size and a male fly with an
incomplete wing vein mutation, what did you observe in the F1 generation?
Was this what you expected? Why or why not?
In your F2 generation, which mutation was epistatic?
Was the vestigial mutation dominant or recessive?
What did chi-square analysis tell you about the expected dihybrid phenotypic ratios?
Do the "Sex Linkage" cross as indicated in the "Assignments"
What phenotypes and ratios did you observe in the F1 generation when you crossed a
female fly with a tan body with a wild-type male?
After you mated two F1 flies you observed the results of the F2 generation. Based on
what you know about Mendelian genetics, did the F2 generation demonstrate the
phenotypic ratio that you expected?
If not, what phenotypic ratio was obtained with this cross?
You performed a second experiment by crossing a female fly with the vestigial wing size
mutation and a white-eyed male. Describe the phenotypes obtained in the F2 generation.
Examine the phenotypes and sexes of each fly. Is there a sex and phenotype combination
that is absent or underrepresented? If so, which one?
What does this result tell you about the sex chromosome location of the white eye allele?
Do the "Recombination" crosses as detailed in the "Assignments"
What is the map distance in centimorgans between the eyeless mutation and the shaven
What is the phenotype with the lowest frequency?
What is true of the phenotype with the lowest frequency?
What does this tell you about the position of the purple eye allele compared with the
black body and vestigial wing alleles?
Sketch a genetic map indicating the relative loci for each of these three alleles, and
indicate the approximate map distance between each locus.
For each dihybrid cross:
Which traits are dominant?
Which traits are recessive?
Are any of these mutations lethal in a homozygous fly? Which ones?
Are any of the alleles that you followed sex-linked? How do you know this?
Which alleles appear to be inherited on autosomes?
Attempt to perform one of your crosses on the Punnett square below.