Path analysis of the relationships among codon bias (ENC), gene position, nonsynonymous substitution rate ( dN ), dN / dS ratio ( ω ), protein length, PPI, the number of regulatory miRNAs, and the length of the 3′-UTR. Continuous and broken lines represent significant and nonsignificant relationships, respectively. Double-headed and single-headed arrows indicate the correlations and causal models assumed in the path analysis, respectively. Numbers on the arrows represent the standardized path coefficients (β). dN and ω were considered endogenous variables, while the other variables were considered exogenous.