Use this complementation chart to answer the questions about

Use this complementation chart to answer the questions about these mutant true breeders, with regards to petal pattern.

mut #1

mut #2

mut #3

mut #4

mut #5

mut #1

-

+

-

+

+

mut #2

-

+

-

-

mut #3

-

+

+

mut #4

-

-

mut #5

-

a) If you mated mut #1 and mut #3, would the offspring display the wildtype or mutant phenotype?

b) Are mut #2 and mut #5 allelic? Explain your answer?

c) Lets say that you’ve mated mut #1 and mut #2. Then, you decided to perform a self cross with those F1 offspring… what would be your expected phenotypic ratios?

Solution

A complementation test is a method used in genetics, in which a cross is performed to determine whether mutations are located within the same genes or different genes. If two mutant strains are crossed with one another and t complements each other, then the wild-type phenotype is reverted back.

a) If mutant 1 and mutant 3 are mated, the F1 offspring will have a mutant phenotype. As indicated by the complementation table, the cross between mutant 1 and mutant 3 shows a negative (-) outcome, which in this case is the mutant phenotype.

b) When mutant 1 is mated to mutant 2 and 5, the F1 offspring is wild type. But when mutant 2 and mutant 5 are mated, they produce offspring with mutant phenotype. Thus mut #2 and mut #5 do not complement each other. Hence they are allelic.

c) Phenotypic ratio would be 1:1 (wild type:mutant)