What's the Name of That Book??? discussion

I believe there were 2 protagonists in alternating and eventually colliding plots. The girl (and maybe the boy as well) somehow had genes from the other 2 species and was able to interact with them and control(?) them. Something about a floating city, underground (mine?), and at the end a destructive force was released on the world by the girl protagonist. All of this is really vague so expect some inaccurate information, but I think most of it is correct. Thanks

The Sky Village by Chris Rettstatt seems to match your description.

Jack, around what year did you read this book?
Is it part of a series? Young adult?

The Sky Village was exactly it! Thanks so much!

That was it thanks a lot!

Great! Glad you found your book. :)