dont really see how it could be, for a start, DnB hasnt featured massivly in the Pop charts, which is probly the best way of working out definitive genres, even if its a bit of a painful way of doing it. Trance for eg, features massivly thruout the world, both in underground dance, commercial clubs and the pop charts, same goes for house and techno.
I think you need to narrow your question down a bit, more like, what defined drum and bass in the noughties? DnB is a fairly small genre if you look at it on the grand scale of all things musical, even classical music has a bigger following.....perhaps is DnB the definitive EDM (electronic dance music) genre of the naughties...that could be quite interesting, although I dont think its true, DnB certainly has influences from across the whole EDM spectrum, and has influenced everything else at the same time