Point mutation: a single point in the sequence is changed. For instance a G is changed to an A.
Compare this to reading a sentence
Cats eat big rat. --> point mutation --> Cats eat big hat
The sentence is still almost recognizeable, the protein changed in this case might still function.
FRAMESHIFT MUTATION - a point mutation that involves a substitution or deletion, which results in a a shift in the reading frame.
Cats eat big rat --> add an additional letter A, and the reading frame changes
Aca tse atb igr at - this protein does not resemble the original and will probably not be functional
The Scottish Fold cat is a breed created from a single mutation that controls ear shape in cats.