Inbreeding depression

[mike]

As most of the axolotls currently in laboratories and aquaria around the world are descended from 34 animals sent to the Museum of Natural History in Paris in 1863, inbreeding depression in captive bloodlines, initiated by by a small number of founders could be a problem.
With captive colonies having a lesser degree of genetic variation than the wild population. I personally feel that they are not as fecund as when I first bred them 40 years ago. Have other breeders noticed an escalation of infertility problems, deformed or inferior larvae, i.e. don't regrow limbs and gills easily?

 

[brian]

This happens with a lot of captive bred animals, and has been particularly problematic in recent years with reptiles and amphibians. Breeding these animals has become a popular hobby, but unfortunately, many people don't know enough about breeding animals to vary their bloodlines. Deformities are starting to show up frequently in animals like Leopard Geckos and Bearded Dragons, and it doesn't surprise me that it's happening with axolotls. I had a Bearded Dragon that had a genetic inability to process calcium properly, which my vet and I eventually attributed to inbreeding. The result was a very sick little Dragon, who had to be put to sleep at 10 months old.

I would urge every breeder on this board to vary their bloodlines as much as possible, too keep this from happening. A simple solution is to trade babies with other breeders, and keep from breeding offspring back to their parents. Try not to buy pairs or breeding groups from the same place if possible, unless you know that they have a large, varied breeding group (I applaud Indiana University's approach to this).

Sorry if this sounds a little preachy, but I've dealt with inbred animals first hand, and it was very hard on my little Dragon, and on me, and I don't want to see it happen to anyone else.

 

[sarah]

I have a sexually mature pair, I believe they are siblings...do I need to separate them to avoid them breeding? (Maybe that's a stupid question.)

 

[brian]

You can either separate them, or cull the eggs after they are laid.

 

[mike]

If you want to breed them Sarah, I would give it a go.
In the unlikely event that the eggs are non-viable or produce deformed larvae, then cull them as Brian suggests.
Most colour morphs are inbred to fix their colour genes, (parent x sibling, sibling x sibling), and eventually out-crossed.
I would get "new blood" if continuing the line to the next generation tho.

 

[sarah]

Mike, my only experience with breeding things mainly comes from plainly observing groups of domestic cats. I've seen (yuck) sibling to sibling and parent to child breeding, (farm cats and the like) with virtually no problems, i.e. deformities, sickness, etc. Sorry for the redundancy, but are you saying I could breed the male and female I have, even though they are siblings...dispose of the eggs if non-viable or deformed, but possibly hatch the viable embryos...and keep or swap those, just don't breed those offspring with one another or with either parent? Wouldn't that be bad for anyone else to breed even with new bloodlines, as the offspring would already be produced from the parents which are siblings? I really hope my rambling made sense. Also, I'm having trouble determining what type of axolotls I have. I've narrowed it down to some type of albino, maybe golden, but I can't decide between golden albino & white albino. The reason I don't know is that they aren't really really yellow, like th pics I've seen on all the axolotls sites, but they have the iridescence around their eyes.

 

[brian]

What we're saying is that you shouldn't inbreed for too many generations. Keep the inbreeding to a minimum, ideally no more than one generation.

 

[michael]

They aren't all decended from those 34 animals. Their has been new blood added to c.b. axolotls many times. C.B. axolotls are inbred and their are lots of lethal and unhealthy mutations. If you have a line free of these "bad" mutations a few generations of line breeding shouldn't hurt. Many of the "inbreeding" problems in c.b. amphibians turn out to be husbandry problems and are not genetic problems at all.
My breeders are producing mostly healthy offspring. I do have one line that throws some pinheads. The few that produce pinheads have a few less viable offspring than the other lines.

 

[sarah]

Thanks so much, that info really helps!