There was another post about inbreeding, and reptiles, and I put forth the possibility of weak snakes not being removed from the breeding program with natural selection.
I'm not saying inbreeding doesn't have it's affects - it might, and we do not intend to inbreed reptiles ourselves but....
Look at how many generations of corn snakes can be bred in 20 years. Many current captive are probably close to 10, and in some cases even 20 generations removed from any wild ancestry.
Look at all the faulty genetics that can be passed on, because often the most prettiest go on to breed, not the most healthy or thrifty.
In the wild, runts, poor feeders - etc, usually are the first animals that are killed.
People usually mention australian species, and how they must be so inbred because no new blood has been available. Some of those pythons weren't bred until they were close to 10 years old, in many cases one could have a baby blackhead or diamond that is only 3 generations from a wild ancestor.
And then, don't forget, that just because it may be illegal, doesn't mean that "new blood" hasn't been introduced to some countries in the past.