Question

How many somatic cells are present in {C. elegans?}

• A. 969
• B. 859
• C. 959
• D. 979

Hint:

The number 959 is a classic factoid in molecular and developmental biology related to {C. elegans}. It's one of those specific numbers worth memorizing for competitive exams, as it highlights the concept of eutely and the precision of developmental programs.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
{Caenorhabditis elegans} is a nematode (roundworm) that is a powerful model organism in developmental biology. One of its key features is eutely, which means it has a fixed number of somatic cells in the adult stage. The question asks for this specific number.

Step 2: Detailed Explanation:
The cell lineage of {C. elegans} has been completely mapped from the zygote to the adult.
- During the development of a hermaphrodite {C. elegans}, a total of 1090 somatic cells are generated.
- However, a precisely defined set of 131 of these cells undergoes programmed cell death, or apoptosis.
- This results in an adult hermaphrodite with a constant, invariant number of somatic cells.
- The final count is \(1090 - 131 = 959\) somatic cells.
The adult male has a different number (1031), but 959 is the standard, widely cited number for the hermaphrodite.

Step 3: Final Answer:
The adult hermaphrodite of {C. elegans} has exactly 959 somatic cells. Therefore, option (C) is the correct answer.