Boy, somebody spent a lot of time typing. All I disputed was the contention that there was no mechanism to avoid inbreeding in wild populations. There is. It is sometimes more successful than others. As pointed out, "island" animals and others in isolated conditions have less choice in the matter. I had referenced in my reply to Patty the studies that show humans seem to be inhibited from sexual attraction to those they are raised with. It is interesting that some studies appear to indicate the children must be together from before the age of five.
@eeeefarm:
Interestingly, studies have found that unrelated human children raised from an early age in the same family and meant to marry (arranged marriages) are inhibited sexually and such relationships often fail for this reason. Nature does have its ways of protecting the species.
I have also noted that in my own experience horses are inhibited from breeding with their offspring. A very interesting study "The Behaviour of Horses" by Dr. Marthe Kiley-Worthington notes the same thing. Key seems to be a herd situation where they are not separated artificially and do grow up in the group.
As far as using inbreeding/linebreeding to fix type, of course. The danger of "overdoing it" has become apparent in many species, but appears to be less risky in others. Whether the way in which we choose to recognize our dogs as belonging to a specific breed…...i.e. closed registries.......is a good idea is an interesting question. In the past (before registries) and in working breeds or perhaps more accurately types, incorporating new blood to improve the line is used rather frequently. In horses, many breeds went "outside" e.g.Thoroughbreds & Quarterhorses were a recognized outcross for Paints, but solids produced were relegated to "breeding stock" status, Quarterhorses had "appendix" registry for outcrosses to Thorougbred, etc.
An interesting approach is to register on "type" rather than bloodlines. Warmblood registries are more inclined to follow this route.
I think inbreeding is fine if the breeder is willing to cull anything produced if necessary. COI is a useful tool to recognize just how inbred your line is becoming, and it's too bad the AKC isn't offering this service as the UK registry does. I threw out my original query "does the AKC register pups from close matings? (e.g. brother/sister, father/daughter)" to see whether there was any restriction or plans to have one. It was a serious question, and I was a bit disappointed to receive this reply:
@DebraDownSouth:
And eeeeefarm, lol, yeah, you can breed any dogs. Incest is a human morality/religious issue, not animal.
I don't recall framing my question as a "morality/religious issue", but never mind.
The current direction breeders are taken is called into question by this interesting article:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1950109/
A bit long, but worthy of a read, IMHO.