Nucleotide definition by IUPAC

CharATGCNomenclature of nucleobase
G GGuanine
A AAdenine
T TThymine
C CCytosine
U UUracil
R G or ApuRine
Y T or CpYrimidine
M A or CaMino
at 6-purine on 2-pyrimidine
K G or TKeto
at 6-purine / 2-pyrimidine
S G or CStrong interaction(H-bonds x 3)
W A or TWeak interaction(H-bonds x 2)
H A or C or Tnot-G, H follows G in the alphabet
B G or T or Cnot-A, B follows A
V G or C or Anot-T(not-U), V follows U
D G or A or Tnot-C, D follows C
N G or A or T or CaNy