Codon Bias of ω-3 Fatty Acid Desaturase Gene (FAD7) in Musa itinerans

The codon bias of ω-3 fatty acid desaturase gene, FAD7, of Musa itinerans was analyzed using CodonW, SPSS19.0, MEGA5.0, and the EMBOSS online program. It was also compared with the FAD7s from different plants and genomes of model organisms. The results showed the codon bias of FAD7 in M. itinerans to be low and leaning toward the synonymous codons with G or C. And, it appeared that the codons CUC, CAG and AGG received a high usage frequency in the gene. In comparison with the FAD7s of different plants, the components of its monocotyledons were bias toward the use G or C, while dicotyledons the opposite. A cluster analysis on the FAD7s based on codon usage bias and CDS showed a same result. Hence, the dicotyledons and monocotyledons in the gene could be satisfactorily differentiated. Based on the frequency of codon usage, the prokaryotic expression system seemed to be suitable for heterologous expression of the FAD7 in M. itinerans.