IUPAC Single Letter Codes

Nucleotide or amino acid sequences should be written in IUPAC single-letter codes. The single-letter codes supported in MEGA are as follows.

 

    

Symbols

Name

Remarks

DNA/RNA

 

 

A

Adenine

Purine

G

Guanine

Purine

C

Cytosine

Pyrimidine

T

Thymine

Pyrimidine

U

Uracil

Pyrimidine

R

Purine

A or G

Y

Pyrimidine

C or T/U

M

 

A or C

K

 

G or T

S

Strong

C or G

W

Weak

A or T

H

Not G

A or C or T

B

Not A

C or G or T

V

Not U/T

A or C or G

D

Not C

A or G or T

N

Ambiguous

A or C or G or T

 

 

 

Protein

 

 

A

Alanine

Ala

C

Cysteine

Cys

D

Aspartic Acid

Asp

E

Glutamic Acid

Glu

F

Phenylalanine

Phe

G

Glycine

Gly

H

Histidine

His

I

Isoleucine

Ile

K

Lysine

Lys

L

Leucine

Leu

M

Methionine

Met

N

Asparagine

Asn

P

Proline

Pro

Q

Glutamine

Gln

R

Arginine

Arg

S

Serine

Ser

T

Threonine

Thr

V

Valine

Val

W

Tryptophan

Trp

Y

Tyrosine

Tyr

*

Termination

*