ambiguity.py

# List of nucleotide symbols used in FASTA files:

Nucleotides = {
 'A': 'A',      # Adenosine
 'C': 'C',      # Cytidine
 'G': 'G',      # Guanine
 'T': 'T',      # Thymidine
 'U': 'U',      # Uridine
 'R': 'AG',     # Purine
 'Y': 'TC',     # Pyrimidine
 'K': 'GT',     # Keto
 'M': 'AC',     # Amino
 'S': 'GC',     # Strong Interaction (3H)
 'W': 'AT',     # Weak Interaction (2H)
 'B': 'CGT',    # Not Adenine
 'D': 'ATG',    # Not Cytosine
 'H': 'ACT',    # Not Guanine
 'V': 'ACG',    # Neither Thymidine nor Uridine
 'N': 'GATCU',  # Any nucleotide
}