You identify mutations in a separate gene, gene R. Homozygous rr mutant females form a partial vulva because the mutant r allele produces only 15% as much R protein as the WT allele.
You decide to take advantage of this partial loss of function mutation to isolate mutations in other genes that affect vulva development.
Starting with the rr mutant, you screen for mutations that, in combination with rr, result in complete loss of vulva. You isolate a dominant, gain of function, mutation in a different gene (gene E) that in combination with rr result in a complete loss of vulva. You call the dominant allele E*.
Worms of genotype rr E*E do not form vulvas whereas rr single mutants form partial vulvas and E*E single mutants form normal vulvas.
Which of the following terms is the best description of E* in relation to rr?
a. E* is a suppressor mutation
b. E* is an epistatic mutation
c. E* is an enhancer mutation
d. E* is a resistant mutation
e. E* is a dominant mutation
f. both B and E
What does gene E's specific interaction with gene R suggest about what gene E normally does in wild-type worms?
a. Gene E's normal wild-type function is to inhibit vulva formation.
b. Gene E's normal wild-type function is to promote vulva formation.
c. Gene E can’t have any function in vulva formation because we didn’t look at complete loss of function alleles.
Starting with the rr mutant, you screen for mutations that, in combination with rr, result in normal vulvas. You isolate a dominant, gain of function, mutation in a different gene (gene S) that in combination with rr result in a completely normal vulva. You call the dominant allele S*.
Worms of genotype rr S*S form normal vulvas, whereas rr single mutants form partial vulvas and S*S single mutants form normal vulvas.
Which of the following terms is the best description of S* in relation to rr?
a. S* is a suppressor mutation
b. S* is an epistatic mutation
c. S* is an enhancer mutation
d. S* is a resistant mutation
e. S* is a dominant mutation
f. both A and B
What does gene S's specific interaction with gene R suggest about what gene S normally does in wild-type worms?
a. Gene S's normal wild-type function is to inhibit vulva formation.
b. Gene S's normal wild-type function is to promote vulva formation.
c. Gene S can’t have any function in vulva formation because we didn’t look at complete loss of function alleles
