Missense mutation

Definition

A missense mutation is a type of genetic alteration where a single nucleotide change results in the substitution of one amino acid for another in a protein. This alteration can affect the protein's function, potentially leading to various diseases or conditions. Missense mutations occur during DNA replication and can be corrected by specific DNA repair mechanisms, highlighting their significance in the context of maintaining genetic stability.

5 Must Know Facts For Your Next Test

1. Missense mutations can lead to changes in protein structure and function, which may result in diseases such as sickle cell anemia.
2. Not all missense mutations are detrimental; some can be neutral or even beneficial, contributing to evolutionary diversity.
3. These mutations are often classified as conservative or non-conservative based on whether the substituted amino acid has similar or different properties than the original one.
4. Missense mutations can be identified using various molecular techniques such as DNA sequencing and bioinformatics tools.
5. The role of DNA repair systems is crucial because if missense mutations go uncorrected, they can propagate through cell divisions, potentially leading to cancer.

Review Questions

• How do missense mutations affect protein function and what implications might this have for an organism?
  • Missense mutations can lead to a change in a single amino acid within a protein, which may disrupt the protein's normal function. This alteration can impact the protein's ability to perform its specific role in cellular processes, potentially leading to diseases or dysfunctions. For example, a missense mutation in the hemoglobin gene can cause sickle cell anemia, illustrating how these mutations can have significant physiological consequences for an organism.
• Discuss the mechanisms by which DNA repair systems can correct missense mutations and why this is important for genetic stability.
  • DNA repair systems are essential for correcting missense mutations to ensure genetic stability. These mechanisms, such as base excision repair and mismatch repair, identify and rectify errors that occur during DNA replication. By correcting these alterations, the body prevents the propagation of faulty genes that could lead to diseases like cancer. If left uncorrected, missense mutations could accumulate over generations, undermining the integrity of an organism's genetic information.
• Evaluate the potential consequences of accumulating missense mutations in an organism's genome over time and how this might influence evolutionary processes.
  • Accumulating missense mutations over time can have varied consequences on an organism's genome. While some mutations may be neutral or beneficial, contributing to adaptation and evolution, others can be harmful and lead to disease or reduced fitness. In a changing environment, beneficial missense mutations may become advantageous for survival, influencing natural selection. However, if harmful mutations accumulate unchecked due to ineffective DNA repair mechanisms, they could result in genetic diseases or extinction events, significantly impacting evolutionary trajectories.

Related terms

Nucleotide: The basic building block of DNA and RNA, composed of a sugar, a phosphate group, and a nitrogenous base.

Point mutation: A type of mutation that involves a change in a single nucleotide base pair in DNA.

DNA repair mechanisms: The biological processes that identify and correct damage to the DNA molecules that encode the genome.