Question

Why would a mutation in a somatic cell of a multicellular organism escape detection?

a) Most somatic mutations are recessive and do not cause a phenotypic change in the cell. As a result, it is highly unlikely that the organism will be sufficiently altered to respond to a screen.
b) When conducting genetic screens, it is assumed that all the cells are genetically identical. Since a somatic mutation first appears in a single cell, it is highly unlikely that the organism will be sufficiently altered to respond to a screen because none of the other cells will have the mutation.
c) Most somatic mutations are dominant and do not cause a phenotypic change in the cell. As a result, it is highly unlikely that the organism will be sufficiently altered to respond to a screen.
d) A somatic mutation is a type of mutation that can be easily repaired. Therefore, the mutation is often corrected before the genetic screen takes place.

Answer 1

A somatic cell mutation might escape detection because it often doesn't lead to phenotypic changes, is confined to one cell and unnoticed in genetic screenings, and may be repaired by DNA repair mechanisms. Somatic mutations also cannot be passed on to offspring, limiting their visibility in genetic studies.

Step-by-step explanation:

A mutation in a somatic cell of a multicellular organism might escape detection for several reasons. Firstly, most somatic mutations do not have an observable phenotypic effect because they are either recessive or not in a gene that alters cell function significantly. This means that the mutation may not cause noticeable changes in the organism, so it remains undetected if the cell does not have a critical function or the change doesn't affect the overall phenotype.

Secondly, genetic screens typically assume genetic uniformity among cells, but a somatic mutation occurs in one cell and its descendant cells. Therefore, the chances of detecting a single mutated cell among many normal ones are low unless that cell's genetic change leads to a significant functional or structural change in the organism, such as in the case of cancer. Also, somatic mutations cannot be passed on to offspring, limiting their evolutionary impact.

Lastly, in some contexts, cells have mechanisms for DNA repair, which can fix mutations before they cause any harm or are detected on screens. However, it's important to note that the ability to repair mutations varies greatly across different types of cells and organisms, and not all mutations can be effectively repaired.