Drum timing/rythm guitar timing important characteristic of reggae. Likewise bass guitar sound (eighteen inch speaker, not multiple tens).

I'd have said ska predated blue beat, and blue beat probably almost two tone in the implication of the white boy in the pork pie hat.

And before anyone asks why I think so, about 40 years ago I used to make a few quid with the eighteen inch speakers playing a disco to a skinhead audience in a very sleazy drinking den (now long gone) colloquially known as "Arry's" in Rochester, Kent. Just down from the river where the small merchant boats tied up.