Deleterious

Deleterious refers to something that has a harmful effect, often in a subtle or unexpected way. In the context of genetics, a deleterious mutation has a negative effect on the phenotype, and is therefore subject to purifying selection.

Definition

The term "deleterious" is derived from the Latin word "deleterius", meaning destructive or harmful. In a biological context, it is often used to describe the effect of a mutation on the fitness of an organism. A deleterious mutation decreases the fitness of the organism, making it less likely to survive and reproduce.

Deleterious Mutations

Deleterious mutations can occur in any organism and can affect any part of the organism's genome. They can be caused by a variety of factors, including exposure to radiation or chemicals, errors in DNA replication, or the random incorporation of incorrect nucleotides during DNA synthesis.

Deleterious mutations can be classified into two main types:

• Loss-of-function mutations: These mutations result in the loss of functional activity of a gene. They can be caused by deletions, insertions, or substitutions that disrupt the reading frame of a gene.
• Gain-of-function mutations: These mutations result in a new or enhanced function of a gene. They can be caused by duplications, insertions, or substitutions that change the reading frame of a gene.

Effects of Deleterious Mutations

The effects of deleterious mutations can range from minor to severe, depending on the function of the affected gene and the nature of the mutation. Some deleterious mutations can lead to genetic disorders, while others may have no noticeable effect on the organism's phenotype.

Deleterious mutations can also have an impact on population genetics. They can decrease the overall fitness of a population, leading to a decrease in population size and potentially contributing to the extinction of a species.

See Also

• Beneficial mutation
• Neutral mutation
• Genetic drift
• Natural selection

References

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