Table 3. Linear model results of log₂OR ~ GC content + TFBS frequency + GC content × TFBS frequency + ε.

Dataset	Region	Variable	Estimate	Standard error	P-value	SSR
Human	Enhancer (n = 4321, R2 = 0.127)	GC contents	0.56	0.024	< 1×10−15	0.11
		TFBS frequency	0.44	0.11	0.00012	0.003
		GC × TFBS	NS
	Promoter (n = 1342, R2 = 0.360)	GC contents	6.40	0.30	< 1×10−15	0.21
		TFBS frequency	22.65	2.74	< 1×10−15	0.03
		GC × TFBS	-41.84	4.61	< 1×10−15	0.04
Mouse	Enhancer (n = 4423, R2 = 0.0287)	GC contents	0.25	0.026	< 1×10−15	0.020
		TFBS frequency	0.87	0.097	< 1×10−15	0.018
		GC × TFBS	NS
	Promoter (n = 1615, R2 = 0.372)	GC contents	5.23	0.23	< 1×10−15	0.21
		TFBS frequency	18.79	1.89	< 1×10−15	0.038
		GC × TFBS	-37.82	3.09	< 1×10−15	0.059

We used LASSO-selected species sequence determinants for these analyses. NS indicates that the interaction terms were not statistically significant at P = 0.05. In such cases we conducted log₂OR ~ GC content + TFBS frequency + ε model instead of the original model. Numbers of sequence determinants, R² values of the models, and Type III partial sum of square in regression (SSR) for each variable are also provided.