Lecture 18 - Effects of mutations Flashcards
What is a point mutation?
When one base pair is replaced with another
What is a transition point mutation?
When the base replaced is the same group, eg purine to purine
What is a transversion point mutation?
When the base replaced is in a different group, eg purine to pyramidine
What is a synonymous mutation?
When the point mutation has no effect on the amino acid sequence
What is a non-synonymous mutation ?
When the mutation changes the amino acid sequence
What is a non-sense mutation?
When the codon for an amino acid is changed into a stop codon
What is a readthrough mutation?
When a stop codon is changed into an amino acid codon
What is a frameshift mutation?
When a mutation means all codons downstream of it are changed
What is an insertion mutation?
One or more base pairs are added to the sequence
What is a deletion mutation?
One or more base pairs are deleted from the sequence
What is an inversion mutation?
Two or more base pairs are excised and reinserted in the opposite orientation
How do we reverse the effect of a mutation?
Through second site reversion
A second mutation restores the correct amino acid sequence
But the nucleotide sequence is still altered
