Table 2. Features of miRNA regulatory system in O. sativa and A. thaliana.

	O. sativa				A. thaliana
	de novo a	Conservedb	All genes	P-valuec	de novo	Conserved	All genes	P-value
Copy numberd(#)	4.31	3.64	4.67	<10−3	11.84	3.82	6.08	<10−3
Splicing numbere (#)	1.77	1.48	1.27	<10−3	1.21	1.43	1.17	<10−3
Segmental duplicationf	27.96%	39.55%	22.13%	<10−3	84.26%	89.86%	65.00%	<10−3
Tandem duplicationg	12.01%	12.63%	11.33%	0.313	31.36%	9.38%	13.86%	0.004

^aTarget genes of de novo generated miRNA genes.

^bTarget genes of conserved miRNA genes.

^ct-test between target genes of conserved miRNA genes and all genes.

^dAverage level of all (target) genes.

^eAverage level of all (target) genes.

^fPercentage of (target) genes in segmental duplication blocks.

^gPercentage of (target) genes in tandem duplication arrays.