Figure 2. ENC versus GC3 plots for RVFV segments; (a) L segment, (b) M segment, (c) S (np) segment, (d) S (ns) segment ENC plotted against GC3 of the CDS regions in the L, M and S (NS) segments are distributed below the curve, which means that codon usage is biased. In the S (NP) segment, the ENC values are distributed above the curve, showing that codon usage is more variable.