Mutation
From Lexicanum
A mutation is a deviance in the genetic structure of a being.
In Warhammer 40,000 an individual can be born a mutant, or may suffer more spontaneous mutation through the influence of the warp and Chaos, whether by worshiping it or being exposed to its energies. Mutation among humanity is common: as mankind undergoes a long process of evolution into a new, psychic race, the birth of mutant humans accompanies it.
The Imperium considers mutation a crime and a physical sign of spiritual corruption. Mutation is becoming more and more common, threatening to turn humanity into a degenerated race of tentacled and degenerated monstrosities. The only response is to root out and destroy those manifesting mutation. Space Marine chapters are closely monitored for genetic deviance by both the Adepta Sororitas and the Adeptus Mechanicus, but some Chapter gene-seed has undergone mutation over the millennia.
The position of mutants within the Imperium varies from world to world. On primitive worlds they are often slain at birth. On more advanced worlds they may be allowed to live, but rarely enjoy the benefits of other humans and are usually segregated from the normal population. In general terms, mutants form a huge downtrodden portion of the Imperium's population. Their dissatisfaction sometimes erupts into rebellion, sometimes allowing the mutants to take temporary control of an entire world. Retaliation, however, is usually swift and effective.
Navigators are considered mutants, but were actually intentionally created in the distant past. Because they are a vital part of the Imperium, they are the only tolerated form of mutant.
Chaos and mutation also effects other alien species, but mutation is especially prevalent among mankind. The Kroot have the ability to evolve through controlled mutation by consumption of their enemies.
