['Genetic code alterations have been reported in mitochondrial, prokaryotic, and eukaryotic cytoplasmic translation systems, but their evolution and how organisms cope and survive such dramatic genetic events are not understood.', 'Here we used an unusual decoding of leucine CUG codons as serine in the main human fungal pathogen Candida albicans to elucidate the global impact of genetic code alterations on the proteome. We show that C. albicans decodes CUG codons ambiguously and tolerates partial reversion of their identity from serine back to leucine on a genome-wide scale.'] Does a genetic code alteration generate a proteome of high diversity in the human pathogen Candida albicans?