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Ambiguity codes

Ambiquity codes are codes that mean any of the two or any of the three nucleotides. Normally, purine (R, A or G) is complemented into pyrimidine (Y, C or T) and amino (M, C or A) is complemented into keto (K, T or G). Differently, weak (W, A or T, pairs with the two hydrogen bonds) and strong (S, G or C, pairs with three hydrogen bonds) are normally not swapped during complementation, leaving the S and W codes unchanged instead. This is logical as both a nucleotide and its complement use the same number of bonds to make a complementing pair. See this, for instance. Here is the complete table of our converter:

RA or G, purineY, pyrimidine
YC or T, pyrimidineR, purine
SC or G, strong pairingS, unchanged
WA or T, weak pairingW, unchanged
KG or T, ketoM, amino
MA or C, aminoK, keto
BC or G or T, not AV, not T
VA or C or G, not TB, not A
DA or G or T, not CH, not G
HA or C or T, not GD, not C
any otherany or unknownunchanged

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