Term
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Definition
Base changes from one purine (A/G) to another purine.
Or one pyrimidine (C/T) to another pyrimidine |
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Term
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Definition
Base changes from a purine (A/G) to a pyrimidine (C/T)
or vice versa |
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Term
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Definition
Base change in the open reading frame of a protein coding gene that does not lead to a change in the amino acid sequence. These are often (but not always) in the 3rd codon position because of the degeneracy of the genetic code
EX: TTT->TTC both encode phenylalanine |
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Term
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Definition
Base change in the open reading frame of a protein coding gene that leads to a change in the amino acid sequence that does not affect function of protein. Therefore, if there is no phenotype, the mutation is said to be neutral.
EX: AAA->AGA, changes a lysine to an arginine. These are both basic amino acids and in a lot of proteins this change will have no functional consequences (but this is not always the case!) |
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Term
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Definition
Base change that leads to an amino acid change in the encoded protein which affects function of the protein. Therefore, there is a phenotype.
EX: AAA-> AAT changes a lysine to an asparagine. This is a change from a basic amino acid to a polar amino acid. Depending on the position this may result in a change in the functioning of the protein |
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Term
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Definition
Base change that leads to a stop codon
EX: TAC-> TAA changes a tyrosine residue to a stop codon. This will result in a truncated protein and therefore, will most likely be nonfunctional. |
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Term
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Definition
| Addition or subtraction of one or a few bases (but not a multiple of 3), that completely scrambles the genetic code downstream of the mutation. Most likely this will result in a nonfunctional protein |
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Term
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Definition
Total loss of function, either no gene product is made or the product is nonfunctional. These are usually recessive, unless it is haplo-insufficiency (cant survive with only one copy)
EX: Knockouts because these remove the whole open reading frame. However, a single missense mutation can have the same affect if it changes a critical amino acid for function |
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Term
| Leaky or Hypomorphic Mutation |
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Definition
A mutation that results in a protein product that is partially functionl
EX: Mutations of the white gene in Drosophila that result in different amount of red pigments |
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Term
| Gain of Function Mutation |
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Definition
Mutation that confers a new property onto the protein. These are usually dominant mutations
EX: tRNA nonsense suppressor |
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Term
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Definition
A mutation that results in a protein that functions under one environmental condition but not under another
EX: temperature sensitive mutations, at the permissive temperature the protein functions, at the temperatire the protein if nonfunctional |
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Term
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Definition
| The exact reversal of the initial mutation |
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Term
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Definition
A compensatory mutation in the same gene, that leads to a wild-type phenotype, although the gene contains two mutations
EX: Original mutation is a +1 frameshift an intragenic suppressor is an adjacent -1 frameshift |
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Term
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Definition
A mutation in a second gene, that suppresses the mutation in the first gene.
EX: Original mutation is a nonsense mutation, a secondary mutation in the anticodon portion of a tRNA can suppress the mutation |
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