A mutation is a change or alteration of the sequence of nucleotides in the DNA.
Mutations are of various types. Two of the major types are:
Point mutations
Chromosomal aberrations.
Point mutations are changes in one or two or a few nucleotides of DNA. Point mutations are further of various types:
Substitutions are exchanges of one nucleotide with another. Substitutions are also of three types: nonsense (codon changes to stop codon), missense (codon codes for a different amino acid) and silent mutations (codon codes for the same amino acid).
Insertions/deletions are the addition or removal of one or a few nucleotides. Frameshift mutations alter the DNA reading frame, changing all the consequent amino acids.
Chromosomal aberrations constitute translocations (part of one chromosome attaches to another), inversions (the orientation of the chromosome is altered), insertions (duplication or insertion of multiple copies of a chromosomal segment) and deletions (deletion of a chromosomal segment).
