Homework SourseA powerful approach to identifying genes of a developmental
A powerful approach to identifying genes of a developmental pathway is to screen for mutations that suppress or enhance the phenotype of interest. This approach was undertaken to elucidate the genetic pathway controlling C. elegans vulval development.
Part A
A lin-3 loss-of-function mutant with a vulva-less phenotype was mutagenized. Based on your knowledge of the genetic pathway, what types of mutations will suppress the vulva-less phenotype?
SELECT all that apply:
Part B
In a complementary experiment, a gain-of-function let-23 mutant with a multi-vulva phenotype was also mutagenized. What types of mutations will suppress the multi-vulva phenotype?
SELECT all that apply:
PLEASE SELECT ALL THAT APPLY TO THE 2 PART OF THIS QUESTION. THANK YOU!
| a. gain-of-function intracellular signal molecule (LET-60) activated by lin-3 mutants |
| b. loss-of-function intracellular signal molecule (LET-60) activated by lin-3 mutants |
| c. loss-of-function lin-3 mutants |
| d. gain-of-function lin-3 receptor mutants |
| e. loss-of-function lin-3 receptor mutants |
Solution
Please find the answers below:
Answer 1: Choices a, d (in order to obtain a phenotype opposite to vulva-less phenotype, mutations which cause a reverese effect are necessary to take place. Since loss-of-function causes a vulva-less phenotype, a mutation which retains gene lin3 will induce vulva appearance)
Answer 2: Choices b, c (since presence of vulva phenotype is associated with the presence of lin-3 gene, every gain-of-function mutation causing it to over-express would tend to demonstrate a multi-vulvar phenotype)
