In gain-of-function let-23 and let-60 C. elegans mutants, all of the vulval precursor cells differentiate with 1° or 2° fates. Do you expect adjacent cells to differentiate with 1° fates or with 2° fates? Explain.

Verified step by step guidance

1. Understand the role of let-23 and let-60 in C. elegans vulval development. These genes are part of the signaling pathway that determines cell fate.
2. Recognize that gain-of-function mutations in these genes lead to overactive signaling, causing all vulval precursor cells to adopt 1° or 2° fates.
3. Recall that in normal development, the primary (1°) fate is typically adopted by the cell closest to the anchor cell, while secondary (2°) fates are adopted by adjacent cells.
4. Consider that in gain-of-function mutants, the signaling is enhanced, potentially leading to more cells adopting the 1° fate due to increased signaling strength.
5. Conclude that in these mutants, adjacent cells are more likely to differentiate with 1° fates due to the overactive signaling pathway, although some may still adopt 2° fates depending on the strength and reach of the signal.

Key Concepts

Vulval Development in C. elegans

In C. elegans, vulval development is a well-studied process involving a specific pattern of cell differentiation. The vulval precursor cells (VPCs) are influenced by signaling pathways that determine their fates as either primary (1°) or secondary (2°) vulval cells. Understanding this process is crucial for predicting how adjacent cells will differentiate in response to mutations.

Gain-of-Function Mutations

Gain-of-function mutations result in a gene product with enhanced or new functions. In the context of let-23 and let-60 mutations in C. elegans, these mutations lead to increased signaling that promotes the differentiation of VPCs into vulval fates. This altered signaling can affect neighboring cells, potentially leading to a uniform differentiation pattern among adjacent cells.

Cell Signaling and Fate Specification

Cell signaling plays a critical role in determining cell fate during development. In C. elegans, the interaction between VPCs and surrounding cells through signaling pathways influences whether they adopt 1° or 2° fates. In gain-of-function mutants, the enhanced signaling may lead to adjacent cells adopting similar fates, which is essential for understanding the expected outcomes in the given scenario.