I'm struck by the degree of hyperbole in some of the posts above, especially given the degree of understanding of genetics and inbreeding depression expressed in those same posts.
First things first: *all* members of a species are related (as are members of different species). Whenever two inviduals of any species breed there is a chance that they will both be carriers of one or more nasty, recessive alleles. In that case, we'd expect about 1/4 of their offspring to get two copies of a nasty allele, and incur whatever sort of problems result. No matter how closely or distantly related the individuals, this is always a possibility.
The chances that two individuals will both be carriers for the same nasty allele increases as their relatedness increases. However, it's a crap shoot. It's possible for two essentially unrelated individuals to both be carriers for a nasty allele whereas two siblings have no particularly problematic alleles in common. Regardless of the parentage, however, sometimes individual offspring will be born 'not quite right' or clearly deformed and the only sensible thing is to cull such individuals.
In cases where the option to outbreed exists (and for Panthers there are lots, and lots of individuals, so outbreeding is no problem) I sure as heck would do it. Breeding closely related individuals (e.g., siblings, parent-offspring, etc.) takes the unnecessary risk of producing a proportion of the unviable or less vigorous offspring.
However, in the case with the K. matschiei mentioned above, there is no other option. What do we have, two known pairs of this species in captivity in this country? Inbreeding is going to be required to establish this species, at least until additional broodstock can be brought in. We'd definitely expect reduced genetic diversity of this species in captivity and, if a wild population were reduced to only four individuals, the chances of survival would be grim. However, in captivity we can baby our animals and phenotypes that might be deleterious in nature (e.g., slow predator avoidance response) are irrelevant in captivity. It's absolutely feasible that a viable captive population could be produced from these four animals, especially if effort is placed on breeding the most distantly related individuals, and much more so if some unrelated individuals can be brought into the captive breeding pool in the future. A smaller but still very useful tactic to enhance the viability of the captive population would be to get the size of the breeding population as large as possible. If we have a few hundred animals, even if they are all descended from four, the population will be much more viable than if we have eight breeding animals all descended from four.
The entire Jackson's chameleon population in the Hawaiian Islands, and most of the ones in the U.S. mainland are descendents from a single group of ~12 individuals. Those few expanded to much larger populations of many thousands, but nonetheless they're still doing fine after 30 odd generations. I'm sure they have much lower genetic diversity than the ones back on Mt. Kenya, and would probably be more vulnerable to problems such as disease outbreaks, but nonetheless, 30+ generations is hard to snub ones nose at, especially when our concern is simply having viable captive populations.
Hope that helps,
Chris
p.s. And guys, please for the love, breed those K. matschiei! They are at the top of my list of species I hope to work with one day, and it's going to be at least a couple of years before I move back to the mainland
At least not without a ton of time and money!
