Question

Mutations occur when DNA is not properly copied. There are multiple types of mutations that cause changes to DNA sequences. Most mutations go unnoticed and undetected. However, when a change in DNA affects the resulting amino acid, a change in phenotype can occur. Two main categories of mutations that can cause phenotypic variation are germ-line mutations and somatic mutations. The diagram illustrates the differences between the two types of mutations. For each mutation described, classify it as a germ-line mutation or a somatic mutation.

Germ-line mutation
Somatic mutation
A mutation occurs before fertilization.
A virus alters the DNA of an infected individual's body cells.
A mutation occurs in a group of skin cells in a developing embryo.
A genetic disorder caused from a mutation is present in 1 of 4 offspring.

Answer 1

- A mutation occurs before fertilization. — Germ-line mutation
(It affects a gamete and can be passed to offspring.)

- A virus alters the DNA of an infected individual's body cells. — Somatic mutation
(It changes somatic/body cells and is not inherited.)

- A mutation occurs in a group of skin cells in a developing embryo. — Somatic mutation
(It affects somatic tissue (skin) in the embryo, producing a mosaic but not a heritable change.)

- A genetic disorder caused from a mutation is present in 1 of 4 offspring. — Germ-line mutation
(The inheritance among offspring indicates the mutation is in the parental germ line.)