Unit 1 KA4 - Mutations
What are mutations?
Mutations are changes in the DNA that can result in no protein or an altered protein being synthesised.
What do single gene mutations involve?
The alteration of a DNA nucleotide sequence as a result of the substitution insertion and deletion of nucleotides.
What is substitution
Where one nucleotide is replaced for another.
ATGTCCATG
ATGTCGATG
What is this?
Substitution
What are the 3 types if nucleotide substitutions?
Missense, nonesense and splice-site mutations
What is a missense mutation?
They result in one amino acid being changed for another.
What does a missense mutation result in?
A non-functional protein or having little effect on the protein.
What is a nonsense mutation?
They result in a premature stop codon being produced
What dodes a nonsense mutation result in?
A shorter protein
What do splice-site mutations result in?
Some introns being retained and/or exons not being included in the mature transcript
What is insertion?
There is an addition of one or more nucleotides into the DNA