Name: ______Date:______

Procedure:

  1. Go to
  2. Select "Body Color" as your trait of choice
  3. As you go through the lab, answer the questions below!

Studying Inheritance of Body Color in Flies

  1. Recessive traits are represented by which type of letters?

a. Capital.

b. Lowercase.

c. Vowels.

d. Consonants.

  1. According to the work of other scientists, the ebony trait is recessive. Therefore, what should we predict the genotype of an ebony fly to be?

a. Ee.

b. EE.

c. ee.

d. eE.

  1. If the wildtype fly we use in our cross is homozygous, what is its genotype?

a. Ee.

b. EE.

c. ee.

d. eE.

  1. Show the cross of the wildtype female to the ebony male using a Punnett square (shown below). What percentage of the offspring in the F1 (first generation) will be ebony?

a. 50%.

b. 75%.

c. 100%.

d. 0%.

  1. According to your Punnett square, what percentage will be wildtype?

a. 50%.

b. 75%.

c. 100%.

d. 0%.

  1. All the offspring that are wildtype will have what genotype?

a. Ee.

b. EE.

c. ee.

d. GG.

  1. On your Punnett square, you wrote letters above each space. What does each single letter represent?

a. A complete genotype.

b. A gamete that contains one allele of the gene from the parent.

c. A gamete that contains a gene from the parent.

d. A body cell that contains a gene from the parent.

  1. A heterozygous fly (Ee) has the same phenotype as a homozygous dominant fly (EE). Why is this so?

a. Since the E allele causes the fly to have at least half its proteins for body color be normal, this is enough for the

fly to have a normal body color.

b. This is false; since a heterozygous fly has only half the proteins for normal body color it will be ebony (and

therefore have a different phenotype from the EE fly).

c. The big E is capital and therefore stronger than the little e, so the heterozygous fly will be wildtype just like the

homozygous dominant fly.

Data Analysis

  1. Overall, did your results support your hypothesis?

a. Yes, because we hypothesized that the ebony trait was dominant and the results show it was not

covered up by the recessive wildtype phenotype.

b. Yes, because we hypothesized that the ebony trait was recessive and the results show it was covered

up by the dominant wildtype phenotype.

c. No, because we hypothesized that the ebony trait was dominant and the results show it was not

covered up by the recessive wildtype phenotype.

d. No, because one ebony fly was produced and we cannot account for it.

  1. Based on the results from this cross, is it likely that the ebony trait is sex-linked recessive rather than merely recessive?

a. No, because the ratio of males to females was equal.

b. Yes, because there was one male with the ebony trait.

c. It cannot be determined from this cross alone.

  1. Suppose the ebony trait is not sex-linked. If we crossed two of our heterozygous wildtype flies, what would be the resulting offspring ratio?

a. 3wildtype to 1 ebony.

b. 1wildtype to 1 ebony.

c. All ebony.

d. Allwildtype.

  1. Why is it important to cross the flies from question 10?

a. A second cross will provide us with more evidence that the ebony trait is inherited in a purely recessive manner.

b. We can be more sure that we did not cross the wrong flies (as may be suggested by the one ebony male fly we found in our results).

c. Both a and b.

  1. What should you do after this experiment has been completed?

a. Record your results in your lab journal.

b. Repeat the experiment.

c. Share your results with other scientists (publish).

d. All of the above.