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Transversion is a type of genetic mutation that changes one base in a sequence to a base from the other group of bases. This can result in a nonsense, silent, or missense mutation. The double-stranded nature of DNA is important for binding specificity. Point mutations, including transversions and transitions, can affect the protein product. Transversions cause more disruptions to amino acid sequences than transitions.
Transversion is a term used in genetics that indicates a particular type of mutation. Genetic material uses sequences of single molecules, called bases, to code for particular proteins. A mutation occurs when the sequence changes. Transversions are a type of mutation that changes one base in the sequence to another base. A distinguishing feature of transversions is that the original base is a member of one of two groups of bases, called purines and pyrimidines, and the new base is a member of the other group.
The genetic material can be deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). Some viruses use RNA, but most other life forms use DNA. An organism’s genetic material is organized into sequences that contain the blueprint for proteins, necessary for life. The four bases of DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).
These sequences, in discrete sections known as genes, make sense to the body. The body translates each sequence into a particular protein. It does this by reading blocks of three bases, called codons, like an amino acid. Each gene contains many sections of three bases, which read for one row of amino acids. These amino acids together form a protein.
The DNA bases of A, T, G and C are divided into two groups. Purines are A and G. Pyrimidines are C and T. Base A binds only to T and base G binds only to C.
The double-stranded nature of DNA, this binding specificity, is important. Where an A exists on one wire, it binds to a T on the other wire. Each strand is complementary to each other and a simple double helix results.
There are various types of mutations, but one type is a simple base substitution, also known as a point mutation. A point mutation is a situation where only one base in the sequence is changed. Thus, for each amino acid, only one of the three bases that code for it is altered. For example, a codon AAA transforms into TAA.
The effect of a point mutation depends on what the new codon encodes. This could be the same amino acid, in which case the protein product is not affected. This is called silent mutation.
If a new codon could code for a different amino acid, then the protein product is different. This case is a missense mutation. Alternatively, the new codon may not make sense and the body cannot make any proteins. This is a meaningless mutation.
A transversion is a special type of point mutation. The term refers to the exchange of a purine for a pyrimidine in the sequence or vice versa. This can result in a nonsense mutation, a silent mutation, or a missense mutation.
For example, the body usually reads an AAA codon as instructions for an amino acid of lysine. If a transversion occurs and AAA turns into a TAA, the body does not recognize TAA as any amino acid. So, it can’t make the right protein, and the transversion is a nonsense mutation.
Another form of point mutation is transition, which replaces a purine with a purine or a pyrimidine with a pyrimidine. Pyrimidines, as a group, are more similar to each other than to purines. The dissimilarity between the two groups means that transversions cause more disruptions to amino acid sequences than transitions.
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