Burton K Wheeler
Moderator
I thought about this as part of a dystopian setting once. The way it would have to work is by having a slave population very phenotypically distinct from the ruling class, whether indigenous or imported, who are kept strictly segregated by something very much like slave codes in the U.S. South. Probably something more like the Spanish rancheria system, where the slaves are a sort of church/state property who live in their own villages and have their labor leased out, would work better than private ownership.
However...
And this was the stumbling block I kept running into. It's basically impossible to keep two human populations living together genetically distinct. There are a few genes, like those that make pygmies, that are visually distinct binary switches between "us" and "those people", but they have the small problem that slaves will occasionally give birth to real people or vice versa, depending on whether they're recessives. Neither is an acceptable situation.
There is, in fact, a genetic engineering trick that can solve this problem, but it wouldn't be possible until early 21st century technology becomes available.
As to how behaviorally distinct you really can make people through breeding, it's hard to say, but I lean towards it being an insurmountable challenge.
I think if you're going to do this, having the slaves live in walled villages, only allowed out under supervision of trained professionals, and breeding them for phenotypical distinctiveness from the free population is the only way you'll maintain a distinct population. It goes without saying there would have to be strict taboos about sexual contact, which will probably still be broken. If slaves live with free people, even as domestic servants, they'll inevitably be submerged into the population.
However...
Humans live too long. You'd probably need about twenty generations. Assuming 15 to 20 years, that's 300 to 400 years, minimum.
The problem, however, is that you'd have wild humans continually breeding back into the slaves. Because the first thing that a 'master' race does to its slaves is rape and impregnate them.
And this was the stumbling block I kept running into. It's basically impossible to keep two human populations living together genetically distinct. There are a few genes, like those that make pygmies, that are visually distinct binary switches between "us" and "those people", but they have the small problem that slaves will occasionally give birth to real people or vice versa, depending on whether they're recessives. Neither is an acceptable situation.
There is, in fact, a genetic engineering trick that can solve this problem, but it wouldn't be possible until early 21st century technology becomes available.
As to how behaviorally distinct you really can make people through breeding, it's hard to say, but I lean towards it being an insurmountable challenge.
I think if you're going to do this, having the slaves live in walled villages, only allowed out under supervision of trained professionals, and breeding them for phenotypical distinctiveness from the free population is the only way you'll maintain a distinct population. It goes without saying there would have to be strict taboos about sexual contact, which will probably still be broken. If slaves live with free people, even as domestic servants, they'll inevitably be submerged into the population.