Table 1.

Shotgun-scanning codons

	Serine scanb			Homolog scanc
Wild typea	Codond	m2	m3	Codond	Homo
D	KMC	A	Y	GAM	E
E	KMG	A	*	GAM	D
F	TYC			TWC	Y
H	MRC	N	R	MAC	N
I	AKC			RTT	V
K	ARM	N	R	ARG	R
L	TYG			MTC	I
M	AKS	I	R	MTG	L
N	ARC			RAC	D
P	YCT			SCA	A
Q	YMG	P	*	SAA	E
R	MGT			ARG	K
S				KCC	A
T	WCG			ASC	S
W	TSG			TKG	L
Y	TMC			TWC	F

^aAmino acids are represented by the single-letter amino acid code.

^bThe serine-scanning codon for each amino acid ideally encodes only for the wild type or serine, but the degeneracy of the genetic code necessitates the occurrence of two other amino acids (m2 and m3) for some substitutions. Asterisks (*) indicate a stop codon.

^c For homolog scanning, binary shotgun codons were designed to encode the wild type and a similar amino acid (Homo).

^dEquimolar DNA degeneracies in shotgun codons are represented by the IUB code (K=G/T; M=A/C; R=A/G; S=G/C; W=A/T; Y=C/T).