Procedural generation seed that can be manipulated

Hello, I'm trying to create a procedural dungeon generator that sort of uses a 'genetic algorithm'. The aim is to generate a map -> rank its 'fitness' -> slightly change the map -> rank fitness again and compare -> proceed with the better map and repeat until a good map has been generated.

However, I am having trouble figuring out how to generate a seed from the generated map that can be manipulated. I've tried using Random.InitState but it doesn't seem to be suitable for what I'm trying to achieve and I am quite lost.

Any help would be really appreciated, thanks.