Lecture 15: Molecular evolution

Tree of life:
  • Three major branches: bacteria, archaea, eukaryotes
  • Inferred from available data
  • Assumes a common ancestor
  • Based on homologous proteins
Accepted point mutation: one animo acid replaced by another and then it survives by natural selection

Molecular clock: The rate of evolution of a protein (animo acid changes/year) or a gene (nucleotides/year) is constant.
(Allows estimation of time scale of speciation events.)