Mutation: A change in the nucleotide sequence of genetic material, whether by substitution, duplication, insertion, deletion or inversion. Chromosomal mutations: rearrangements of segments into the same chromosome or interchange between more than one. Deletion Inversion Translocation Gene mutations (Point mutations): individual changes in the sequence of nucleotides that may cause the appearance of new alleles of a gene. Substitution Insertion or addition Deletion or removal