BIOL 039 Lecture Notes - Lecture 17: Trinucleotide Repeat Disorder, Tandem Repeat, High Fidelity
Document Summary
Missense mutation: a base-pair change that alters a single amino acid for another one in the protein. Nonsense mutation: a base-pair change that creates a stop codon in place of a codon specifying an amino acid. Silent mutation: a base-pair change that does not alter the resulting amino acid sequence due to the redundancy of the genetic code. Forward mutation wild type to mutant type. Reverse mutation mutant type to wild type. Neutral mutation a single aa change (missense mutation) that does not alter protein activity/function. Base-pair substitutions can cause (a) missense, (b) nonsense, and (c) silent mutations. Effects of mutations (base-pair insertion and deletion mutations) Insertion or deletion of one or more base pairs in the coding sequence leads to addition or deletion of mrna nucleotides, altering the orf of the message. The wrong amino acid sequence and premature stop codons are produced downstream of the altered nucleotides. Forward mutation: converts a wild-type to a mutant phenotype.