Table 1.

Codon usage observed in Escherichia coli (EC), Saccharomyces cerevisiae (SC) and Homo sapiens (HS) ORFeomes (23). Representative examples showing substantial differences in usage of codons between the three ORFeomes are boxed. Frequency per thousand codons is shown

		EC	SC	HS			EC	SC	HS			EC	SC	HS			EC	SC	HS
UUU	Phe	24.4	26.1	17.6	UCU	Ser	13.1	23.5	15.2	UAU	Tyr	21.6	18.8	12.2	UGU	Cys	5.9	8.1	10.6
UUC	Phe	13.9	18.4	20.3	UCC	Ser	9.7	14.2	17.7	UAC	Tyr	11.7	14.8	15.3	UGC	Cys	5.5	4.8	12.6
UUA	Leu	17.4	26.2	7.7	UCA	Ser	13.1	18.7	12.2	UAA	Stop	2.0	1.1	1.0	UGA	Stop	1.1	0.7	1.6
UUG	Leu	12.9	27.2	12.9	UCG	Ser	8.2	8.6	4.4	UAG	Stop	0.3	0.5	0.8	UGG	Trp	13.4	10.4	13.2
CUU	Leu	14.5	12.3	13.2	CCU	Pro	9.5	13.5	17.5	CAU	His	12.4	13.6	10.9	CGU	Arg	15.9	6.4	4.5
CUC	Leu	9.5	5.4	19.6	CCC	Pro	6.2	6.8	19.8	CAC	His	7.3	7.8	15.1	CGC	Arg	14.0	2.6	10.4
CUA	Leu	5.6	13.4	7.2	CCA	Pro	9.1	18.3	16.9	CAA	Gln	14.4	27.3	12.3	CGA	Arg	4.8	3.0	6.2
CUG	Leu	37.4	10.5	39.6	CCG	Pro	14.5	5.3	6.9	CAG	Gln	26.7	12.1	34.2	CGG	Arg	7.9	1.7	11.4
AUU	Ile	29.6	30.1	16.0	ACU	Thr	13.1	20.3	13.1	AAU	Asn	29.3	35.7	17.0	AGU	Ser	13.2	14.2	12.1
AUC	Ile	19.4	17.2	20.8	ACC	Thr	18.9	12.7	18.9	AAC	Asn	20.3	24.8	19.1	AGC	Ser	14.3	9.8	19.5
AUA	Ile	13.3	17.8	7.5	ACA	Thr	15.1	17.8	15.1	AAA	Lys	37.2	41.9	24.4	AGA	Arg	7.1	21.3	12.2
AUG	Met	23.7	20.9	22.0	ACG	Thr	13.6	8.0	6.1	AAG	Lys	15.3	30.8	31.9	AGG	Arg	4.0	9.2	12.0
GUU	Val	21.6	22.1	11.0	GCU	Ala	18.9	21.2	18.4	GAU	Asp	33.7	37.6	21.8	GGU	Gly	23.7	23.9	10.8
GUC	Val	13.1	11.8	14.5	GCC	Ala	21.6	12.6	27.7	GAC	Asp	17.9	20.2	25.1	GGC	Gly	20.6	9.8	22.2
GUA	Val	13.1	11.8	7.1	GCA	Ala	23.0	16.2	15.8	GAA	Glu	35.1	45.6	29.0	GGA	Gly	13.6	10.9	16.5
GUG	Val	19.9	10.8	28.1	GCG	Ala	21.1	6.2	7.4	GAG	Glu	19.4	19.2	39.6	GGG	Gly	12.3	6.0	16.5