LAB: Virtual Fruit Fly Genetics – ANALYSIS SHEET
PARENT ONE-GENE CROSS: Record the appropriate information in the data table provided.
Cross / Parent (sex/ phenotype) / Sex of Offspring / Phenotype of Offspring / Number with PhenotypeEXAMPLE:
Parent cross
(P cross F1) / Female (wild) x Male (vestigial) / Female / wild-type (+)
Male / wild-type (+)
MONOHYBRID CROSS
(F1 F2) / (use the offspring from the F1 generation to produce the F2!) / Female / wild-type(+)
Male / wild-type(+)
Female / vestigial
Male / vestigial
CHECKPOINT / “Check for Understanding”:
1) What does an incubator do?
2) What is used to anesthetize the flies?
3) Why would a scientist want to do this to the flies?
4) What does the notation “+” mean?
5) What does the notation “VG” mean?
6) What is meant by “monohybrid” cross?
7) For this first cross, what was the “wild-type” phenotype?
8) For this first cross, what was the “vestigial” phenotype?
9) Identify the dominant trait and the recessive trait. Explain how you figured this out.
> DOMINANT TRAIT:
> RECESSIVE TRAIT:
> How do you know?
10) Identify the genotype and phenotypes of the parents for the next cross. (Symbols: “+” for wild-type; “VG” for vestigial.)
> Parent genotypes for next cross:x
> Parent phenotypes for next cross:x
11) Predict the outcome of the next cross and the ratio you expect to find in the F2 generation.
PREDICTION:
Do the cross to get the F2 generation! Record results in data table.
12) How many wild-type offspring resulted from the F1 cross? ______How many vestigial?______
13) What is the ratio of wild-type:vestigial flies (to the tenths place)? ______
TWO-GENE CROSS: Record the appropriate information in the data table provided.
PARENT CROSS
DIHYBRID CROSS
(F1 F2)
CHECKPOINT / “Check for Understanding”:
1) What is a TWO-GENE CROSS?
2) What does the notation “SE” mean?
3) What does the notation SE:VG mean (read as “SE & VG”)?
4) Identify the dominant traits and the recessive traits. Explain how you figured this out.
> DOMINANT TRAITS:
> RECESSIVE TRAITS:
> How do you know?
5) Identify the genotype and phenotypes of the parents for the next cross.
> Parent genotypes for next cross:x
> Parent phenotypes for next cross:x
6) Predict the outcome of the next cross and the ratio you expect to find in the F2 generation.
PREDICTION:
Do the cross to get the F2 generation! Record results in the data table above.
7a) Write the total number of flies that are wild-type for both wing shape & eye color: ______
(example genotype: +VG+SE or ++ ++)
7b) Write the total number of flies that are wild-type for wing shape & sepia for eye color: ______
7c) Write the total number of flies that have vestigial wing shape & are wild-type for eye color: ______
7d) Write the total number of flies that have vestigial wing shape & have sepia for eye color: ______
7e) What is the ratio for the traits above (to the tenths place)? ______:______:______:______
(HINT: use the complete recessive for “1”)
8) What is the genotype for a fly in 7c? ______or ______