Which type of dragonborn? The 4E dragonborn and the 3.x dragonborn are entirely different, save for some superficial physical similarities.
And honestly, the same applies to genasi. 2E and 3E genasi were different from 4E genasi... Though, for my personal preference, I really liked how Races of Faerūn handled and described the 3E genasi.
There was a fantastic genasi site online which sought to compile/summarise most of the [then] current source material from 2e and 3e sources.
I can't recall the URL at the moment, though. If you perform a search here at Candlekeep for previous genasi and/or planetouched discussions scrolls, I'm certain you'll find that I've posted the link in one of them.