Lecture 9: Gene mutations Flashcards
Somatic mutations
mutations in non-reproductive cells
Germ-line mutations
mutations in cells that form gametes
Point mutations
Mutations on one or a few basepairs
Base substitution
alternation of a single nucleotide
transition
purine into purine, pyrimidine into pyrimidine
transversion
purine into pyrimidine, pyrimidine into purine
base insertion
addition of a single nucleotide
base deletion
removal of a single nucleotide
nucleotide repeat expansions
mutations in which the copy number of a set of nucleotides increases
missense mutation
mutation produces different amino acid
conservative/neutral missense mutation
Altered codon produces a chemically similar amino acid
nonconservative missense mutation
Altered codon produces a chemically dissimilar amino acid
nonsense mutation
Mutation produces a stop codon
Silent/synonymous mutation
mutation doesn’t change amino acid
frameshifting mutations
mutations that alter reading frames and produce very different proteins
in-frame mutations
Mutations that don’t alter the reading frame
Splice-site mutations
mutations produce alternatively spliced protein, new splice site is formed or eliminated
regulatory mutations
mutations in untranslated region that produce altered protein expression
loss-of-function mutations
mutations that produce non functioning protein
Gain-of-function mutations
mutation produces a protein causing a new trait
conditional mutations
expressed under specific conditions
lethal mutations
cause premature death
