Vulval development in C. elegans is dependent on the response of some of the central epidermal progenitor cells in the region of the developing vulva to a chemical signal from the gonad. Signaling from the gonad is blocked by action of the vulvaless mutant let-23 so that none of the central progenitor cells form vulval structures. In the vulvaless mutant, n300, the central progenitor cells do not form.

What phenotype (vulva formed or vulvaless) would you expect from the double mutant? Why?

Key Concepts

Vulval Development in C. elegans

Vulval development in C. elegans involves a series of signaling events between the gonad and epidermal progenitor cells. The gonad releases signals that instruct specific progenitor cells to differentiate into vulval structures. Understanding this process is crucial for analyzing how mutations affect the formation of the vulva.

Mutations and Phenotypes

Mutations like let-23 and n300 can disrupt normal signaling pathways, leading to specific phenotypes. The let-23 mutation prevents the response to gonadal signals, resulting in a vulvaless phenotype. Analyzing the effects of these mutations helps predict the phenotype of double mutants based on their combined genetic influences.

Genetic Interaction and Epistasis

Genetic interaction refers to how different genes influence each other's expression and the resulting phenotype. In the context of double mutants, epistasis can determine which mutation has a dominant effect on the phenotype. Understanding these interactions is essential for predicting the outcome of combining mutations like let-23 and n300.