Strings 2008 2 7

Evolutionary changes

• DNA sequences typically change very slowly
  • e.g. 2*10^-9 /base/year

• changes are not equally likely to persist everywhere
  • some genomic regions may be mutated repeatedly while others remain unchanged.

• nucleotide changes are not equal likely
  • Transitions (interchanges of purines (A⇔G) or of pyrimdines (C⇔T)) are more likely
  • Transversions (interchanges between purines and pyrimdines) are less likely

(Image from: Mimicking Affinity Maturation

--ThomasHuber 15:29, 10 January 2008 (EST)