When I first saw this adult pair of corn snakes for sale in 2004 on Kingsnake.com, they were advertised as Hypo Motleys. Some had overt white blotch margins and the eye color threw me. Not knowing what they actually were, I snagged them immediately, hoping that they could be the illusive T positive (aka T+) Albinos. The T+ is short for Tyrosinase positive. Tyrosinase is an enzyme necessary for the production of melanin.
Upon physical inspection, I was convinced they were not just Hypo Motleys, if HYPOmelanistic at all. After some dialogue on one of the popular corn snake chat forms of that time, it was generally thought that they were a new gene some breeders were working with in Florida that they called ULTRA HYPO. That's what they were, and they were later officially called Ultramels.
The ULTRA mutated gene is recessive to non-Amels and co-dominant to Amels.