DNA serves as the intricate instruction manual for our bodies, containing all the information needed for cells to grow, function, and repair. Changes can occur within this manual, known as mutations, which affect how cells behave. Somatic mutations are a specific type of genetic change arising in body cells after conception.
What Are Somatic Mutations?
Somatic mutations are genetic alterations that develop in any cell of the body, excluding reproductive cells. They occur after conception and are confined to the individual in whom they arise. When a somatic mutation occurs in a cell, all subsequent cells that divide from that mutated cell will also carry the same genetic alteration.
How Somatic Mutations Develop
Somatic mutations can arise through several mechanisms. One common way is through spontaneous errors during normal cellular processes, such as DNA replication and cell division. Mistakes can happen as DNA is copied, leading to insertions, deletions, or switches in the genetic code.
Environmental factors also contribute. Exposure to elements like ultraviolet (UV) radiation or chemicals in tobacco smoke can damage DNA. This damage, if not properly repaired, can result in mutations. Intracellular processes generating free radicals, a type of unstable molecule, can also stress cells, contributing to DNA damage and subsequent mutations.
Somatic Mutations and Body Health
Somatic mutations play a role in an individual’s health, particularly as they accumulate over time. The gradual buildup of these mutations contributes to cellular aging. As cells divide and are exposed to various factors, more mutations can occur, potentially affecting cellular function.
The most widely studied impact of somatic mutations is their connection to cancer. Cancer develops when multiple somatic mutations accumulate in a cell, leading to uncontrolled cell growth and division. These mutations can affect genes that regulate cell growth, such as proto-oncogenes and tumor suppressor genes. Not all somatic mutations are harmful; many are harmless or effectively repaired by the body’s natural DNA repair mechanisms.
Somatic Versus Inherited Mutations
Somatic mutations differ from germline (inherited) mutations. Germline mutations are present in reproductive cells (sperm and egg) and are passed down from parent to offspring. If present in a fertilized egg, every cell in the resulting individual will carry that mutation.
In contrast, somatic mutations are not present in the germ cells and cannot be transmitted to future generations. These mutations are acquired during an individual’s lifetime in non-reproductive body cells. While an inherited mutation affects every cell in an individual, a somatic mutation is confined to the specific cell where it originated and its descendant cells within that individual.