Progenitor Virus

From Resident Evil - Wiki on Neoseeker

Also known as the Founder virus and the Mother virus, the Progenitor virus was the very first mutagenic virus ever discovered, and would serve as a base for most of Umbrella’s later viruses. It was discovered by James Marcus, Edward Ashford and Oswell E. Spencer on December 4th 1967. Further research on it was carried out by Dr. Marcus, William Birkin and Albert Wesker. Infection causes violent uncontrolled cellular changes through the mutation of the subject’s genes. Like the T-virus this will cause most animals low down the evolutionary ladder to simply increase in size and aggressiveness, but the mutations were not coordinated enough to produce effective B.O.Ws. In order to enhance its mutagenic properties a variant of it was created by combining it with the Ebola virus. Unfortunately the new virus had inherited Ebola’s photosensitive properties. When it was combined with leech DNA to form the T-Virus this property mutated into pyrosensistivity, which can be seen to affect every single B.O.W ever created.