“…Various factors related to CUB are G+C% composition, GC skew, protein hydropathy, transcriptional selection (McInerney, ), gene length (Lawrence & Ochman, ), expression level (Gouy & Gautier, ; Sharp & Li, ), protein structure (D'Onofrio, Ghosh, & Bernardi, ), and dietary nitrogen (Seward & Kelly, ). However the influence of these factors in codon usage is still debated (Zhou, Weems, & Wilke, ).…”