     IUPAC-IUB SYMBOLS FOR NUCLEOTIDE NOMENCLATURE

     [Cornish-Bowden (1985) Nucl. Acids Res. 13: 3021-3030.]

     Symbol         Meaning              | Symbol         Meaning
     ------------------------------------+---------------------------------
     G              Guanine              | K              G or T
     A              Adenine              | S              G or C
     C              Cytosine             | W              A or T
     T              Thymine              | H              A or C or T
     U              Uracil               | B              G or T or C
     R              Purine (A or G)      | V              G or C or A
     Y              Pyrimidine (C or T)  | D              G or T or A
     M              A or C               | N              G or A or T or C
