Figure 1

Principal component analysis of the % GC contents on the 1st, 2nd and 3rd codon position. The first two factors from the principal component analysis (PRIN1 and PRIN2) were presented with each eigenvalue proportion. Nucleocapsid (A) and spike (B) coding genes of Coronavirus genus were compared with CTLD genes of human (homo sapiens) and mouse (mus musculus) species (C, D). Family names of CTLDs were also presented with each plot. G1, Group 1 CoV; G2, Group 2 CoV; G3, Group 3 CoV; N, nucleocapsid gene of CoV; S, spike gene of CoV; homo, homo sapiens; mus, mus musculus.