you might be able to reveg her. you say it has a leaf? can you post a picture?
ive had some fun with the revegged "monsters". they look and act crazy and monsterish!
if you have the time, you might get the harvested plant to reveg (maybe... id need to see where and how the leaf looks.) but im not grasping the concept of a root turning into a plant.
there are plants you can do that with, most things that propagate with runners - like spider plants or hydrangea, can grow from roots. but that is in the programming of the plant. cannabis doesnt have runners.
some root plants can grow a new plant when only roots are left, but in actuality it is the veggie growing it with its own new roots, just comes from the root with nothing up top.
if they had a complete genetic sequence for cannabis, those questions would be answered in the absolute.