Ambiguous nucleotide

Ambiguous nucleotides are used when the true nucleotide is unknown. The most popular one seen with high-throughput genome sequences is "N" which represents any possible nucleotide.

Ambiguous

• Any nucleotide (A or C or G or T or U) N
• Purine (A or G) R
• Pyrimidine (T or C) Y
• Keto (G or T) K
• Amino (A or C) M
• Strong interaction (3 H bonds) (G or C) S
• Weak interaction (2 H bonds) (A or T) W
• Not A (C or G or T) B
• Not C (A or G or T) D
• Not G (A or C or T) H
• Not T or U (A or C or G) V

Not ambiguous

• Adenosine A
• Cytidine C
• Guanine G
• Thymidine T
• Uridine (if 'Alphabet' set to 'RNA') U