Definition of sense and nonsense mutations

The information that is carried by the genetic code provides a set of “instructions“ for “building“ and “maintaining“ a living organism. A useful analogy might be to think of the genetic code being likened to the alphabet. In the alphabet, different letters can be combined to produce useful and meaningful words – but only if the letters are put together in the “correct“ way. The same goes for DNA. Certain nucleotides (the base units of DNA), be it adenine (A), thymine (T), cytosine (C) or guanine (G), can be arranged in a specific manner to form a certain gene, which in turn, encodes a specific protein. But sometimes biology doesn’t stick to the “blueprint plan“ when organizing the letters and genetic mutations occur. A genetic mutation is a permanent change to the nucleotide sequence of a gene. More often than not, such genetic mutations are advantageous – they enable evolution and produce new desirable traits in organisms. However, genetic mutations can also be problematic if they result in a disease. In humans, genetic disorders are often life-limiting and incredibly tricky to treat. Not all mutations impact the function of the resulting protein. If you want to build a foundational understanding of genomics in both health and disease, it’s important to be able to distinguish between the different type of genetic mutations that can occur. Here, we take a look at some of the mutations that can be encountered and the impact they have on the genome. What is a missense mutation? A missense mutation occurs when there is a mistake in the DNA code and one of the DNA base pairs is changed, for example, A is swapped for C. This single change means that the DNA now encodes for a different amino acid, known as a substitution. Sometimes a change in the amino acid has no effect on the resulting protein’s function at all. On some occasions, the change in amino acid actually enhances the protein’s function, but in other cases it can ultimately render the protein as “faulty“. What is a nonsense mutation? Like a missense mutation, a nonsense mutation also involves a single alteration to the DNA base pair. However, in the case of a nonsense mutation, this single change results in the production of a stop codon, thereby terminating protein synthesis prematurely. The result? A shortened protein that may function, but also may not. #MutationDiseaseCause #nonsenseMutation #HealthIndustry #genetics #DNA #RNA #missenseMutation