Explain how harmful genes are created. Define and describe germline and somatic mutation

Question

What will be an ideal response?

Answer 1

Harmful genes are created by a sudden but permanent change in a segment of DNA. This mutation may affect only one or two genes, or it may involve many genes. Some mutations occur spontaneously, simply by chance. Others are caused by hazardous environmental agents.
Germline mutation takes place in the cells that give rise to gametes. When an affected individual mates, the defective DNA is passed on to the next generation. In somatic mutation, normal body cells mutate, an event that can occur at any time of life. The DNA defect appears in every cell derived from the affected body cell, eventually becoming widespread enough to cause disease (such as cancer) or disability. Some people harbor a genetic susceptibility that causes certain body cells to mutate easily in the presence of triggering events. This helps explain why some individuals develop serious illnesses as a result of smoking, exposure to pollutants, or psychological stress, while others do not. Somatic mutation shows that each individual does not have a single, permanent genotype. Rather, the genetic makeup of each cell can change over time. Somatic mutation increases with age.