Originally Posted by $5 submissions

Slave breeding didn't go on a large scale for 400 years. Maybe on a small, regional, localized basis. In fact, up until the British banned Slave transatlanctic transport in the 1820s it was cheaper to supplement their slave force by buying new additions instead of breeding replacements. After 1820s, it became profitable to breed slaves because of lack of steady inputs of new imported slaves.

So, it's not exactly 400 years of mass scale genetic tampering and breeding.