The number of the DEAD-box, DEAH-box and DExD/H-box RNA helicase genes in <i>Arabidopsis</i>, <i>Oryza sativa</i>, <i>Zea mays</i>, <i>Glycine max</i>.

<p>Note: In front of diagonal not include the number of alternative splicing; in the back of diagonal include the number of alternative splicing.</p>*<p>In <i>Zea mays</i>, there are two especial genes with different alternative splicing belongs to different RNA helicase subfamilies.