Back mutation

Back mutation or reversion is a genetic mutation that restores the original sequence of DNA or RNA. It is a type of mutation where the function of a gene is restored by a second mutation. This can occur in various ways, such as through the exact reversal of the original mutation or through a suppressor mutation that compensates for the original mutation.

Overview

Back mutations are a critical aspect of genetic variation and evolution. They can occur in any organism with a genetic code, including bacteria, plants, animals, and humans. Back mutations can have significant effects on an organism's phenotype, or physical characteristics, depending on the nature of the original mutation and the specific gene involved.

Mechanisms

Back mutations can occur through several mechanisms. The simplest form of back mutation is an exact reversal of the original mutation, where the altered nucleotide is changed back to its original state. This is known as a "true reversion."

Another form of back mutation is a suppressor mutation, which does not reverse the original mutation but compensates for it. A suppressor mutation can occur in the same gene as the original mutation (intragenic suppression) or in a different gene (intergenic suppression).

Role in Evolution

Back mutations play a significant role in evolution by contributing to genetic variation. They can restore function to a gene that has been inactivated by a mutation, allowing the organism to survive and reproduce. This can lead to the spread of the back mutation in a population, a process known as natural selection.

Role in Disease

In humans, back mutations can have significant implications for genetic disease. For example, they can restore function to a gene that has been inactivated by a mutation, potentially curing or alleviating the disease. However, back mutations can also have negative effects, such as when a suppressor mutation causes a new disease or exacerbates an existing one.

See Also

• Mutation
• Genetic variation
• Evolution
• Genetic disease