Question

Classify each definition or example as a somatic mutation, gametic (germline) mutation, or both.

Answer 1

Somatic mutation 

This happens in a single cell of a developing somatic tissue. This cell is the progenitor of a population of identical mutant cells, all of which have descended from the cell that mutated. Additionally, they do not occur in cells that give rise to gametes; therefore, the mutation cannot be passed on to descendants by sexual means. Somatic mutation are often called acquired mutation because the change in genetic structure is not inherited from a parent for they do not affect the germline. Thus, to maintain the mutation, the individual containing the mutation must be clone.

Example: In red delicious apple, the mutant allele that determine the golden color of an apple arose in a flower’s ovary wall, which eventually developed into a fleshy part of the apple. The seeds are not mutant so it will still give rise to red apple tree. Therefore, the golden delicious apple originally arose from a mutant branch of a red delicious apple tree.

Germline mutation

If a gene is altered in a germ cell, the mutation is called germinal mutation. Germline tissue is set aside in the course of development to form sex cells. Germ cells gives rise to gametes, so if a mutant sex cell participates in the fertilization, then the mutation will be passed on to the next generation. Moreover, germinal mutations will not be expressed in the individual containing the mutation.

Example: A hereditary case of albinism are often link to germline mutation where individual of this disorder are more prone to many types of cancers and may have impaired visions.