21/09/2020
Continuing on my previous post on , let's talk about the types of DNA mutations today. It's broadly classified into 2: point and frameshift. Point mutations can be sub classified into 3: nonsense, missense and mutations.
Before we delve into this, a quick recap of some basics about codons. They exist in triplets, a mixture of A, U, G and C, and they for different amino acids. In nonsense mutations, a codon is formed because of the DNA mutation. When the DNA gets transcribed into RNA, that codon is called a stop codon. These are of three permutations: UAG, UAA and UGA. A nonsense mutation essentially stops further translation. In missense mutations, there is a change in the amino acid formed. The most example for this is Sickle cell , where in hemoglobin, GUG is the mutated version while GAG is the normal version. In silent mutations, a change in the DNA will not affect the amino acid to be formed after transcription and translation.
A frameshift mutation shifts the of the bases and changes the code for amino acids. The resulting protein is usually . It is caused by indels (insertions/ deletions of nucleotide(s)).
