Shallow gene pools.

[Brian]

How much do you feel the harem setup is responsible for shallow gene pools?

I don't mean to critique it in other ways, but feel free too. For instance it may be responsible for some species being popular and available in the first place. I'm also not trying to draw attention away from the fact that a lot of captive gene pools are not exactly deep to start with.

[Smashtoad]

My Hilljack take on it would be that higher animals (mammals and birds) seem to be negatively affected quicker by inbreeding than herps and fish (though I don't know why)...but even though, there are definately consequences. The question is whether or not it is really that bigga deal...I'd say no unless one just does it for many, many generations.

But you've nailed it when you say it is responsible for quick availability of albinos, leucistics, hypomels, etc....every purebred dog we have owes it's existence to inbreeding...except the wolf and other wild breeds...and even they exist due to "natural" inbreeding. The wolf, coyote, and fox all came from the same ancestor and natural forces eventually shaped them differently just like we shaped the Great Dane and the Chihuahua...selectively, from the same DNA.

This post could be a lot of fun...

[Brian]

Well I mean not just inbreeding. For instance if I keep one male to service 50 females then all offspring are somewhat related through the father. However, by pairing I'd get numerous somewhat unrelated animals in theory.
Then there's all the inbetween stuff.

Although it may not matter much after the animals are farther down the line because maybe the cb male and cb female you bought a year apart are actually products of related animals anyway.

[Mark Baumann]

Oh to be a male with a fifty woman harem. It would probably kill me, I have enough trouble dealing with one. Back to the question at hand. When I breed harem herps I usually keep 1 male to 4 females. I usually try to have at least 2 groups of wild caught to use to infuse new blood every so often. On some animals the gene pool is going to be shallow no matter what you do because they are rare and can't be collected in the wild any more, extinct in the wild and only exist in captivity or a very resessive gene that gets suppressed if outcrossed.

[sciteacher]

Well I mean not just inbreeding. For instance if I keep one male to service 50 females then all offspring are somewhat related through the father. However, by pairing I'd get numerous somewhat unrelated animals in theory.
Then there's all the inbetween stuff.

Although it may not matter much after the animals are farther down the line because maybe the cb male and cb female you bought a year apart are actually products of related animals anyway.

I think there's both good and bad possibilities in the harem setups you describe and the effects those might have on genetic diversity. I come from a horse breeding background and I will draw some parallels with that world.

First, the potential benefits of harem groupings in which one male services multiple females... this setup allows you to use the very best male(s) on your females. For example if I have 12 females and I want to pair them up, each with their own male, I have to find 12 top quality males. There's probably a higher probability in this example that I might settle for using some "average" or even "poor" quality males, which are likely to produce "average" or even "poor" quality offspring. If I have a harem setup, and I have only 1 or 2 high quality males, then those superior genes get passed on to a larger percentage of offspring. With this harem setup, my chances of producing higher quality offspring is enhanced. To draw the parallel to the horse world... if everyone who had a mare or 2 that they wanted to breed had to own a stallion to pair up with that mare, there would be a lot of inferior stallions in use. Having a much higher mare to stallion ratio in this case is a good thing, as hopefully only the stallions with the best genetic characteristics are used as breeding animals (great in theory, but unfortunately not always in practice).

Can this uneven ratio of males : females have drawbacks and make the gene pool too "shallow"? Yes it can. Since many breeds of horses have begun to allow artificial insemination by use of frozen or cooled semen, it has become commonplace for a very small number of "high profile" horses to breed large numbers of mares... a situation that would have been nearly impossible previously. For someone like myself who works with a rather rare strain and a limited gene pool to begin with, this ability to breed to stallions anywhere in the country has opened up exciting new possibilities. For breeders who simply jump on the highly advertised "flavor of the month", it can result in overuse of a single animal.

In the case of geckos in which each breeder uses his / her own breeder male(s), I think the benefits of using a limited number of top quality males on a group of females outweighs the benefits of pairing up animals for greatest genetic diversity. It's somewhat of a balancing act to not go too far in either direction, but that's what responsible breeders do, whether its with horses or with geckos.

Gary

[Brian]

Another thing I think that gets overlooked a lot is superior genes are relative. Typically it deals with color or size or some desireable trait to people which may not actually be superior in other ways people don't care about to the alternatives.