Lugia have a brother/sister?
That aside, interesting name, some many ways to look at it but foreshadows genetic a bit, which pokemon is all about.
since when is pokemon all about genetic besides the little sidestory part about mew and mewtwo? and a few other gen one pokemon like eevee and ditto
It's probably more likely it's not about chromosomes, which might be a little too high concept for some of the six year olds playing this game, and instead be another reminder that its all about 3D now.
Kinda like every super nintendo game used to have "Super" in its name, or every N64 be "'Game' 64"