The Original Immortal Genes were an aspect that appears in the Clash of the Shape-shifters series and the genes relate to the Original Werewolf and Kanima over four millennium ago, an Alchemist and his Co-Worker desired to learn everything they could about the Universe and so they experimented with different animal and human genetics, they were successful and through a chain of events the first Werewolf and Kanima were created stronger than any species since.
The Immortal Gene was created originally by the Alchemist Amsel, and his Co-Worker, Alchemist Rizzo. Through their dabbling and research they had believed to successfully created this Immortal gene and tested the completed concoction upon their sons, it was successful however their sons were contaminated by being bitten by two of their rabid animal samples: a Wolf and a Jaguar. The gene was corrupted before it had time to settle, creating the first Werewolf and Were-Jaguar.
Annoyed by the alterations made to their search for Immortality, Alchemist Amsel and Rizzo attempted to contain their sons' animal sides through the use of Alchemy, what they did instead was trap William Amsel in an uncontrollable Werewolf and enhanced Mikael Rizzo's Kanima form into that of a reptile, William uncontrollably killed their parents and fled out into the world biting humans to create the first Alpha Werewolves.
Mikael, meanwhile, took their parents research and burned their lab to the ground so that no weakness could be researched for them. Fleeing on his own path, he set out a way to cure and save William from what their parents had done to him.