Don't want to report this as a bug incase I'm been an blind idiot and can't figure out what I need to do, basically my main populaiton is being swamped by minor populations and having the FABULOUS Horatio tech tree I just unlocked the Genetic Alteration Lab technology. However for the life of me cannot figure out how to use it so I can keep my main faction population in the higher number ratios compared to minors.

I am using a modded/created new faction with the Horation appearence with the omniscience boost so not sure if this is a custom faction bug or something.

Once you've researched this, you can access it in your production queue.  Add the project, on completion one non-horatio population is replaced by a Horatio.

If hes using omni he isn't using the gene pool special.