The IUPAC code

The International Union of Pure and Applied Chemistry (IUPAC) defined the standard code for representing protein or DNA sequences.

Nucleic IUPAC Code

Code

Nucleotide

A

Adenine

C

Cytosine

G

Guanine

T

Thymine

U

Uracil

R

Purine (A or G)

Y

Pyrimidine (C, T, or U)

M

C or A

K

T, U, or G

W

T, U, or A

S

C or G

B

C, T, U, or G (not A)

D

A, T, U, or G (not C)

H

A, T, U, or C (not G)

V

A, C, or G (not T, not U)

N

Any base (A, C, G, T, or U)