Re-code your DNA at a Cooling Tower Biopool
There are multiple places these achievement can be obtained, always in a nuclear power plant. It is not labelled as a Cooling Tower Biopool, it is called a mutation spot.
One of the mutation spots is found is in the west of the Fnackyleaves Biome, at the Bio Nucleus 10D power plant. You will need the biohazard suit to enter this area.
On the northeast side of the plant you can find a way underground, follow the path until you come across a green glowing waterfall. Interact with this and you will be able to adjust your character structure. After you exit you get the achievement.