Synonymous/Nonsynonymous Mutations (Ks/Ka): Difference between revisions
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'''Non-synonymous mutations (Ka)''' | '''Non-synonymous mutations (Ka) or (Kn)''' | ||
Mutations/substitutions of DNA base pairs that result in a single amino acid change on a given polypeptide. Also known as a substitution mutation. | Mutations/substitutions of DNA base pairs that result in a single amino acid change on a given polypeptide. Also known as a substitution mutation. | ||
Revision as of 20:43, 15 January 2015
Synonymous Mutations (Ks) Mutations/substitutions of DNA base pairs that do not result in a change of amino acid sequence. Also known as a silent mutation.
Non-synonymous mutations (Ka) or (Kn)
Mutations/substitutions of DNA base pairs that result in a single amino acid change on a given polypeptide. Also known as a substitution mutation.
Non-synonymous/Synonymous mutation ratio (Ka/Ks)
Ratio of mutations that change a specific protein structure (non-synonymous, Ka) to mutations that do not change a specific protein. This ratio is used to estimate the selection pressure a given protein or section of DNA experiences. This ratio has been used in several ways: 1) to enhance gene predictions as areas of coding sequence will have a lower Ka/Ks ratio than non-coding areas; 2) determine differences in natural selection pressure on proteins.
- Neutral selection (Ka/Ks = 1) occurs when coding sequences
- Positive selection (Ka/Ks > 1)
- Purifying selection (Ka/Ks < 1)