That's AMAZING!!! 8D
I wonder if it's dominant genes, or how complex the regrowth mechanism is...
I was just talking with a marine biologist that studies the DNA of oysters and works with hybrid oysters too. He said if its anything like them, its going to come down to the parents......sometimes it could have the fathers gene to regrow it tail, or sometimes its going to be the mother.... He did ask if the crested geckos have ever had the ability to regrown tails...if so, it could be crossing them triggers a dormant gene.