41.1%GC3 content

55.2Effective codons (Nc)

248Coding sequences

26/26GC3 rank here

Scope: nuclear genes only

NCBI table 1 (Standard). Do not apply these frequencies to mitochondrial genes, where AGA, AGG, ATA and TGA carry different meanings. The four reassignments.

What distinguishes this table

The most constrained choice in Ferret is proline: of its 4 synonymous codons, CCA takes 37% of the family. Lysine sits at the other end, spread almost evenly across its options (evenness 0.98 against 0.92 for proline). Those two families are where a codon-optimizer has the most and the least room to move.

Measured across all 59 sense codons, this table correlates most closely with Asian elephant (r = 0.995) and least with M. tuberculosis (r = 0.442). A sequence tuned for the first would need little adjustment to move here; one tuned for the second would need a great deal.

Relative to the average across the 26 organisms on this site, Ferret leans hardest on TTT (+0.169 against the mean) and avoids ATC most (-0.176). Those two are the codons that most distinguish this table from the others.

Preferred and avoided codons

Amino acid	Preferred	Freq	RSCU	Avoided	Freq	RSCU
Alanine A	GCT	0.343	1.37	GCG	0.091	0.36
Arginine R	AGA	0.345	2.07	CGT	0.093	0.56
Asparagine N	AAT	0.596	1.19	AAC	0.404	0.81
Aspartate D	GAT	0.635	1.27	GAC	0.365	0.73
Cysteine C	TGT	0.597	1.19	TGC	0.403	0.81
Glutamate E	GAA	0.611	1.22	GAG	0.389	0.78
Glutamine Q	CAG	0.601	1.20	CAA	0.400	0.80
Glycine G	GGA	0.363	1.45	GGG	0.196	0.78
Histidine H	CAT	0.589	1.18	CAC	0.411	0.82
Isoleucine I	ATT	0.455	1.36	ATA	0.244	0.73
Leucine L	CTG	0.255	1.53	CTA	0.091	0.55
Lysine K	AAA	0.572	1.14	AAG	0.428	0.86
Phenylalanine F	TTT	0.624	1.25	TTC	0.376	0.75
Proline P	CCA	0.367	1.47	CCG	0.085	0.34
Serine S	TCT	0.245	1.47	TCG	0.042	0.25
Threonine T	ACA	0.368	1.47	ACG	0.088	0.35
Tyrosine Y	TAT	0.583	1.17	TAC	0.417	0.83
Valine V	GTG	0.329	1.31	GTA	0.196	0.78

Full codon usage table

Amino acid	Codon	Frequency	RSCU
Alanine A	GCT	0.3429	1.372
	GCA	0.2952	1.181
	GCC	0.2707	1.083
	GCG	0.0911	0.364
Arginine R	AGA	0.3451	2.071
	AGG	0.2129	1.277
	CGG	0.1258	0.755
	CGA	0.1253	0.752
	CGC	0.0983	0.590
	CGT	0.0926	0.556
Asparagine N	AAT	0.5964	1.193
Asparagine N	AAC	0.4036	0.807
Aspartate D	GAT	0.6351	1.270
Aspartate D	GAC	0.3649	0.730
Cysteine C	TGT	0.5974	1.195
Cysteine C	TGC	0.4026	0.805
Glutamate E	GAA	0.6109	1.222
Glutamate E	GAG	0.3891	0.778
Glutamine Q	CAG	0.6005	1.201
Glutamine Q	CAA	0.3995	0.799
Glycine G	GGA	0.3628	1.451
	GGC	0.2326	0.930
	GGT	0.2084	0.834
	GGG	0.1962	0.785
Histidine H	CAT	0.5893	1.179
Histidine H	CAC	0.4107	0.821
Isoleucine I	ATT	0.4549	1.365
	ATC	0.3008	0.902
	ATA	0.2443	0.733
Leucine L	CTG	0.2545	1.527
	CTT	0.1877	1.126
	TTG	0.1671	1.003
	TTA	0.1609	0.965
	CTC	0.1386	0.832
	CTA	0.0911	0.547
Lysine K	AAA	0.5721	1.144
Lysine K	AAG	0.4279	0.856
Methionine M	ATG	1.0000	1.000
Phenylalanine F	TTT	0.6244	1.249
Phenylalanine F	TTC	0.3756	0.751
Proline P	CCA	0.3670	1.468
	CCT	0.3310	1.324
	CCC	0.2168	0.867
	CCG	0.0852	0.341
Serine S	TCT	0.2452	1.471
	AGT	0.2017	1.210
	TCA	0.1886	1.132
	AGC	0.1645	0.987
	TCC	0.1582	0.949
	TCG	0.0417	0.250
Threonine T	ACA	0.3684	1.474
	ACT	0.3007	1.203
	ACC	0.2425	0.970
	ACG	0.0883	0.353
Tryptophan W	TGG	1.0000	1.000
Tyrosine Y	TAT	0.5827	1.165
Tyrosine Y	TAC	0.4173	0.835
Valine V	GTG	0.3286	1.314
	GTT	0.2775	1.110
	GTC	0.1982	0.793
	GTA	0.1958	0.783

Provenance

Computed from 248 RefSeq coding sequences for Mustela putorius furo, sampled and counted codon by codon. Frequencies are relative within each amino acid family. Page generated 2026-08-09.

The full derivation of GC3, RSCU and the effective number of codons, along with the limits of each, is set out once in the methods note rather than repeated on every page.

Use this table

Nucleora codon-optimizes a coding sequence against this table directly, then folds the result and reports where structure would interfere with expression.

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