Table 1
		Maize		Soybean		Arabidopsis
AA	CODON	N	RSCU	N	RSCU	N	RSCU
Ala	GCU	841	0.92	606	1.5*	1572	1.87*
	GOC	1319	1.45*	376	0.93	653	0.78
	GCA	511	0.56	492	1.22	728	0.87
	GOC	955	1.05	142	0.35	403	0.48
Leu	UUA	102	0.19	215	0.65	338	0.62
	UUG	407	0.75	474	1.44	860	1.36
	CUU	527	0.97	531	1.62*	1024	1.62*
	CUC	993	1.83*	362	1.1	794	1.26
	CUA	220	0.41	161	0.49	359	0.57
	CUG	1000	1.85*	229	0.7	359	0.57
Gly	GGU	640	0.83	508	1.29*	1287	1.5*
	GGC	1417	1.83*	293	0.75	458	0.53
	GGA	476	0.61	498	1.27*	1287	1.5*
	GGG	566	0.73	274	0.7	396	0.46
Val	GUU	512	0.77	634	1.56*	1172	1.58*
	GUC	883	1.33	243	0.6	712	0.96
	GUA	199	0.30	182	0.45	269	0.36
	GUG	1062	1.6*	568	1.4	805	1.09
Ser	AGU	182	0.43	420	1.38*	487	0.93
	AGC	640	1.54*	254	0.84	480	0.92
	UCU	353	0.85	354	0.65	835	1.6*
	UCC	647	1.55*	114	0.38	459	0.88
	UCA	300	0.72	337	1.11	576	1.1
	UOG	376	0.90	345	1.13	296	0.57
Pro	OCU	459	0.84	586	1.21	730	1.44*
	OOC	581	1.06	325	0.7	278	0.55
	CCA	455	0.83	899	1.85*	707	1.40*
	OOG	701	1.28*	131	0.27	311	0.61
Glu	GAA	555	0.49	854	1.00*	1219	0.91*
	GAG	1724	1.51*	875	1.01*	1465	1.09*
Arg	OGU	231	0.66	178	0.98	433	1.22
	OGC	643	1.85*	153	0.84	152	0.43
	OGA	125	0.36	108	0.59	195	0.55
	OGG	314	0.90	51	0.28	139	0.39
	AGA	207	0.59	320	1.76*	663	1.87*
	AGG	569	1.63*	284	1.56*	544	1.54*
Thr	ACU	369	0.76	421	1.4*	827	1.39*
	ACC	777	1.61*	330	1.1	599	1.01
	ACA	328	0.68	351	1.17	645	1.08
	ACG	459	0.95	101	0.34	310	0.52
Lys	AAA	370	0.39	629	0.8	1043	0.78
	AAG	1540	1.61*	952	1.20*	1635	1.22*
Asp	GAU	645	0.68	716	1.22*	716	1.22*
	GAC	1240	1.31*	453	0.78	453	0.78
lle	AUU	442	0.81	571	1.43*	998	1.24*
	AUC	1013	1.86*	353	0.88	1035	1.29*
	AUA	181	0.33	278	0.69	382	0.47
Gln	CAA	465	0.61	586	1.16*	763	0.98*
	CAG	1066	1.39*	422	0.84	789	1.02*
Phe	UUU	332	0.50	470	0.98*	682	0.79
	UUC	1006	1.5*	486	1.02*	1039	1.21*
Asn	AAU	353	0.55	497	0.91	719	0.82
	AAC	923	1.44*	599	1.09*	1043	1.18*
Tyr	UAU	236	0.45	421	0.94*	455	0.76
	UAC	808	1.55*	473	1.06*	745	1.24*
His	CAU
265	0.63	301	1.11*	413	1.00*
	CAC	572	1.37*	243	0.89	411	1.00*
Met	AUG	891	1.00	505	1.00	1106	1.00
Cys	UGU	151	0.49	133	0.81	332	1.04*
	UGC	470	1.51*	197	1.19*	307	0.96
Trp	UGG	420	1.00	262	1.00	471	1.00
TER	UGA	45	1.35*	23	0.99	43	1.15*
	UAA	23	0.69	31	1.29*	43	1.15*
	UAG	32	0.96	17	0.72	26	0.7

Summary of relative synonymous codon usage in three plant species. Codon usage was tabulated (N) for maize (100 genes), soybean (71 genes), and Arabidopsis (112 genes). The relative synonymous codon usage (RSCU) is the observed frequency divided by the expected frequency assuming random codon usage. The most frequently used synonym for each amino acid of each plant is marked by an asterisk.