Deciphering the mysteries of missense mutations

The Takeaway: DNA makes up the fundamental code that determines our genetic makeup. Every living organism is basically a product of its genetic information. But what happens when that information has an error? There are many kinds of genetic mutations, and missense mutations are among the most interesting. This blog takes a look at the world of missense mutations, what they are and how they occur, the impact they have on organisms, and their significance in genetics.

What are missense mutations?

Missense mutations are a type of point mutation. They involve a single base pair change in the DNA sequence. However, what sets missense mutations apart is that they result in the substitution of one amino acid for another in the protein that is encoded by the gene. Proteins are the workers that do all the heavy lifting in the cell—they are tasked with performing all of the functions vital for life, such as producing enzymes, structural components, and transport molecules. A missense mutation occurs when a single nucleotide change in the DNA sequence leads to the incorporation of an incorrect amino acid in the protein, and this can potentially alter its structure and function.

Causes of missense mutations

A number of factors can cause a missense mutation, including:

• Spontaneous mutations: Spontaneous mutations can happen naturally during DNA replication because of DNA’s natural chemical instability. Errors made by DNA polymerases, exposure to radiation, or chemical damage can lead to missense mutations.
• Induced mutations: External factors like exposure to chemicals or radiation can induce missense mutations. For example, some carcinogens can introduce changes in the DNA sequence that may result in missense mutations and potentially cause cancer.
• Inherited mutations: Some people inherit missense mutations from their parents, which can lead to genetic disorders.
• Tautomeric shifts: A rare cause of missense mutations is tautomeric shifts. This occurs when the normal base pairs of DNA change their structure temporarily, leading to incorrect base pairing during DNA replication. This can result in the incorporation of the wrong nucleotide and, subsequently, the wrong amino acid in the protein.

Impact on organisms

Missense mutations can have a wide variety of impacts on organisms, with those impacts varying based on the specific mutation, the gene that is involved, and the protein it encodes. The impact can be classified into three main categories:

• Neutral or silent: Sometimes, missense mutations might have no significant effect on the function of the protein. This can happen when the substituted amino acid has similar properties to the original one or when the change is in a non-critical region of the protein. In these cases, the organism may remain healthy and functional.
• Beneficial missense mutations: Although rare, missense mutations can wind up having beneficial changes in a protein's function. These mutations can enhance an organism's survival and reproduction and contribute to adaptation and evolution.
• Harmful missense mutations: Most missense mutations are neither beneficial nor silent. They disrupt the structure and function of a protein and result in health problems. Diseases such as sickle cell anemia and cystic fibrosis result from missense mutations that affect critical proteins in the body. The severity of the consequences depends on the specific mutation and the role of the protein in the cell or organism.

Significance in of missense mutations in genetics and medicine

Missense mutations are a big deal in genetics and medicine. Here’s why:

• Disease genetics: Many genetic disorders are caused by missense mutations. These mutations can provide valuable insights into the genetic basis of disease and serve as targets for potential treatments. Understanding the specific missense mutations responsible for diseases allows for more targeted therapies and genetic counseling.
• Personalized medicine: Missense mutations are key in the field of personalized medicine. By analyzing an individual's genetic makeup and identifying missense mutations, healthcare providers can tailor treatments to a patient's unique genetic profile. This can lead to more effective and personalized healthcare while minimizing side effects and improving outcomes.
• Evolutionary biology: Missense mutations play a crucial role in the process of evolution. They introduce genetic diversity into populations, which can be acted upon by natural selection. Beneficial missense mutations can be favored and become fixed in a population, driving evolutionary changes over time.
• Research and drug development: Researchers study missense mutations to gain insights into protein function and dysfunction, which in turn can allow them to develop targeted therapies for various diseases.

Missense mutations showcase the complexity of the genetic code and how it impacts living organisms. These single-nucleotide changes can have profound effects, from causing genetic diseases to driving evolutionary adaptations. As our understanding of missense mutations continues to grow, it opens doors to personalized medicine, novel drug development, and a deeper understanding of our genetic heritage. While they may be small in scale, missense mutations loom large in the world of genetics, offering both challenges and opportunities for researchers and healthcare providers alike.

How IDT helps

IDT sells a number of solutions for researchers seeking to understand and identify missense mutations. These fall into two general categories:

• Genotyping solutions: Genotyping is the process of determining differences in a person’s genetic makeup. This occurs by examining a person’s DNA sequence using assays, then comparing that sequence to the sequence of another person. 

The rhAmp™ Genotyping Master Mix and Reporter Mixes are amplification and reporter mixes optimized for rhAmp SNP genotyping. They deliver signal-to-noise ratios for high-confidence genotype calls. 

• SNP solutions: SNPs are single-nucleotide polymorphisms, which are a germline substitute of a single nucleotide at a precise point in the genome and that is large enough to be considered a population. SNPs are biological markers and can relate to genes that are associated with diseases like cancer, blood pressure, and others. The genotyping master mix and reporter mixes are part of IDT’s rhAmp™ SNP Genotyping System, which feature flexible design and consistent quality. The rhAmp™ SNP Assays are a collection of predesigned sequences containing more than 10 million human SNPs.