Mutation: Sudden Heritable Change

A sudden heritable change in genetic material is known as:

Correct Answer: Mutation

Mutation is a sudden, heritable change in genetic material. The term was coined by Hugo de Vries, who proposed the mutation theory of evolution after studying Oenothera lamarckiana (Evening primrose).

Types of Mutation

• A) Chromosomal mutation:
  • Heteroploidy (Euploidy + Aneuploidy)
  • Chromosomal aberration
• B) Gene mutation:
  • Substitution: Transition (purine→purine or pyrimidine→pyrimidine) OR Transversion (purine→pyrimidine or vice versa)
  • Frame shift mutation

Key Points

• Mutation is the ultimate source of all new genetic variation
• Mutation rate is very low (~10⁻⁵ per locus per generation) — hence the slowest force to change gene frequency
• Multiple alleles are produced by mutation (e.g., ABO blood groups — 3 alleles; coat colour in rabbit — 4 alleles; eye colour in Drosophila — 15 alleles)