Which statement best differentiates germline mutations from somatic mutations?

Which statement best differentiates germline mutations from somatic mutations?

• A. Germline mutations occur only in germ cells and are not present in all cells
• B. Germline mutations are inherited and present in every cell; somatic mutations occur in non-germline tissues and are not inherited
• C. Somatic mutations are inherited and present in every cell
• D. Germline mutations occur only in somatic tissues

Answer: (B)

The key idea is where the mutation happens and whether it’s passed to offspring. Germline mutations occur in the cells that form gametes, so when fertilization happens, the mutation is present in every cell of the resulting organism and can be inherited by future generations. Somatic mutations arise after fertilization in non-germline tissues, affecting only a subset of cells descended from the mutated cell and are not passed on to offspring. That’s why the statement describing germline mutations as inherited and present in every cell, while somatic mutations occur in non-germline tissues and are not inherited, is the best description. The other options misstate either the distribution across cells or the inheritance pattern.

The key idea is where the mutation happens and whether it’s passed to offspring. Germline mutations occur in the cells that form gametes, so when fertilization happens, the mutation is present in every cell of the resulting organism and can be inherited by future generations. Somatic mutations arise after fertilization in non-germline tissues, affecting only a subset of cells descended from the mutated cell and are not passed on to offspring. That’s why the statement describing germline mutations as inherited and present in every cell, while somatic mutations occur in non-germline tissues and are not inherited, is the best description. The other options misstate either the distribution across cells or the inheritance pattern.