From the nic 29 patent application:

The inventor of the subject plant, Rene Nicolai, was the owner of Rene Nicolai Nursery, which propagated and sold Malling Nine (M9) apple tree rootstock. Rootstock are propagated by placing plants in a stoolbed which encourages root growth and then dividing the resulting roots into individual plants. Over the years Mr. Nicolai searched the M9 stoolbeds for M9 mutants which were superior to the parent variety in those characteristics which are desirable for apple tree rootstock.

Makes me want to avoid pruning funny looking branches, in case they have special mutant powers.