Where did the Chipettes of Alvin and the Chipmunks come from?

The Chipettes were born in Australia and abandoned as babies. They were adopted by an Australian girl named Olivia, also an orphan. The orphanage's owner took notice of their musical talent and wished to exploit them; they escaped aboard a cargo ship to New York City. Under the professional name "The Chipettes", the girls moved to Los Angeles, where they met The Chipmunks.