def test_codons(self):
"""AminoAcidUsage codons should return most likely codon freqs"""
a = AminoAcidUsage('GGG')
c = CodonUsage('GGUGGCGGAGGG')
c.normalize()
self.assertEqual(a.codons(), c)
a = AminoAcidUsage('D')
c = CodonUsage('GAUGAC')
c.normalize()
self.assertEqual(a.codons(), c)
a = AminoAcidUsage('GDDFMM')
c = CodonUsage('GGUGGCGGAGGG'+'GAUGAC'*4+'UUUUUC'*2+'AUG'*8)
c.normalize()
self.assertEqual(a.codons(), c)
a = AminoAcidUsage('II*')
c = CodonUsage('AUUAUCAUA'*2+'UAAUAGUGA')
c.normalize()
self.assertEqual(a.codons(), c)
#check that it works with a nonstandard code
code = GeneticCode('A'*4+'C'*28+'G'*32)
a = AminoAcidUsage('AAA')
c = CodonUsage('UUUUUCUUAUUG')
c.normalize()
self.assertEqual(a.codons(code), c)
#check that it works with unequal codon frequencies
unequal = CodonUsage({'GGU':5,'GGC':2,'GGA':2,'GGG':1,'UUU':3,'UUC':1})
a = AminoAcidUsage('GFFF')
exp = {
'GGU':0.5*0.25,
'GGC':0.2*0.25,
'GGA':0.2*0.25,
'GGG':0.1*0.25,
'UUU':0.75*0.75,
'UUC':0.25*0.75
}
obs = a.codons(codon_usage=unequal)
for codon, freq in obs.items():
self.assertFloatEqual(freq, exp.get(codon, 0))
def test_init_string(self):
"""CodonUsage should count codons in string"""
u = CodonUsage('UUUCCCUUUUUUGA')
self.assertEqual(u, CodonUsage({'UUU':3, 'CCC':1, 'GA':1}))
u.normalize()
self.assertEqual(u, CodonUsage({'UUU':0.75, 'CCC':0.25}))