Single Letter Codes for Nucleotides
Nucleotide(s) Code Acceptable by Treated as
(in alignment)
 
makeblastdb/formatdb BLAST
AA++A
CC++C
GG++G
TT++T
UU++T
A, CM (amino)-+N
A, GR (purine)-+N
A, TW (weak)-+N
C, GS (strong)-+N
C, TY (pyrimidine)-+N
G, TK (keto)-+N
A,C,GV (not T)-+N
A,C,TH (not G)-+N
A,G,TD (not C)-+N
C,G,TB (not A)-+N
A,C,G,TN (any nucleotide)++N
Universal Genetic Code
1st Pos Second Position 3rd Pos
TCAG
TTTT (Phe, F)TCT (Ser, S) TAT (Tyr, Y)TGT (Cys, C)T
TTC (Phe, F)TCC (Ser, S) TAC (Tyr, Y)TGC (Cys, C)C
TTA (Leu, L)TCA (Ser, S) TAA (Ter, *)TGA (Ter, *)A
TTG (Leu, L)TCG (Ser, S) TAG (Ter, *)TGG (Trp, W)G
CCTT (Leu, L)CCT (Pro, P) CAT (His, H)CGT (Arg, R)T
CTC (Leu, L)CCC (Pro, P) CAC (His, H)CGC (Arg, R)C
CTA (Leu, L)CCA (Pro, P) CAA (Gln, Q)CGA (Arg, R)A
CTG (Leu, L)CCG (Pro, P) CAG (Gln, Q)CGG (Arg, R)G
AATT (Ile, I)ACT (Thr, T) AAT (Asn, N)AGT (Ser, S)T
ATC (Ile, I)ACC (Thr, T) AAC (Asn, N)AGC (Ser, S)C
ATA (Ile, I)ACA (Thr, T) AAA (Lys, K)AGA (Arg, R)A
ATG (Met, M)ACG (Thr, T) AAG (Lys, K)AGG (Arg, R)G
GGTT (Val, V)GCT (Ala, A) GAT (Asp, D)GGT (Gly, G)T
GTC (Val, V)GCC (Ala, A) GAC (Asp, D)GCC (Gly, G)C
GTA (Val, V)GCA (Ala, A) GAA (Glu, E)GGA (Gly, G)A
GTG (Val, V)GCG (Ala, A) GAG (Glu, E)GGG (Gly, G)G
NOTEMany organisms use alternative initiation and termination codons. The information is summarized in different translation tables and is available at this page.


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