Mutations Diagram

Two Types of Gene Mutations

  1. Replacement of one nucleotide by another (also called Point Mutation) may lead to:
    • No change in the protein formed
    • Change in an amino acid and protein
    • Non-functional protein or incomplete protein if a stop codon is formed
  2. Addition or deletion of a nucleotide will probably cause a non-functional protein.

Types of Chromosome Mutations

  1. Changes in the Number of Chromosomes can be of two types:
    • Polyploidy - is a condition of having extra sets of chromosomes to make organisms such as plants tetraploid (4n). This is an advantage in plants as cells are larger.
    • Aneuploidy - is a condition of the gain or loss of individual chromosomes. Examples include Downs' Syndrome (extra No. 21 chromosome), Turner Syndrome (extra X chromosome in a female), and Klinefelter Syndrome (extra X chromosome in a male).
  2. Change in the Structure of Chromosomes