The regulations concerning the creation of ‘Mules’ are complex and a specialized field of legal expertise. Early trials require that new models are sterile, so that escaping mules can not begin to proliferate. With the inevitable advances and upgrades in new models contrasting with the natural deterioration of the old models’ DNA, wholesale replacement of communities of mules often become necessary. These communities can eventually number in the billions, and so there are a number of genetic preconditions to their replacement. There are quick and slow programs for euthanasia of a breed. All mules must be bred with standard fertility scripts in the DNA chain. This ensures that airborne ‘keys’ can be released into the work environment to switch off the fertility code. This ensures the mules are extinct within a generation. For quicker solutions, a two step process is used. mRNA or messenger retroviruses are used to unlock key chains at the blood brain barrier. This biological key, the endothelial tight junction which protects the brain from being flooded with virus rich blood, is unlocked in a first stage approach to the euthanasia. The ‘coup de grace’ is delivered by a second aerosol release that triggers a chronic histamine-induced shutdown of electric resistance at the junctions, flooding the brain with blood. Death follows in minutes. While mule right activists have lobbied the Soma authorities to halt this practise, the fact that it occurs on remote colonies, has generally kept the practise out of the news and minds of the citizens.