In: Biology
Mostly the mutation is of two types: (A) Spontaneous and (B)Induced
Spontaneous mutations occur without exposure to external agents. This class of mutations may result from errors in DNA replication, or even from the action of transposons.
Virtually any agent that directly damages DNA, alters its chemistry, or interferes with repair mechanisms will induce mutations.
The types of mutations and its effect on protein are described in figure below: