It may be a dumb question, but, can you mate siblings with each other?
No, this is definitely not a dumb question, as the rabbit community has no consistent answer for it.
We think *Yes* ... maybe! Here's the genetics of our opinion, and see our Rabbit Genetics page for a refresher on the basics, if needed:
For every trait, the rabbit inherits two copies of a gene. These traits can be dominant or recessive. If the dominant gene copy is a healthy normal gene, but the recessive copy is flawed or damaged, you have no way of knowing about the presence of the flawed gene, because the normal dominant gene will completely override the flaw, and keep the animal healthy.
The more related the animal, the greater the chance that two flawed genes for a trait, already present recessively in both siblings, will match up and be unable to prevent an outwardly flawed or damaged offspring. A pairing of recessives is what causes albinism and various other recessive traits like color and size. No problem there. But it's very bad if that flaw is structural or metabolic, like buck teeth, a propensity to cancer or cataracts, or polycystic kidneys.
The inbreeding itself doesn't 'cause' these problems -- it is the pairing of already pre-existing genetic flaws that creates the problems, and inbreeding is the fastest way to reveal IF there are flaws hiding in the genetic code.
So... If you breed siblings together that are excellent genetically, you'll be pleased with the results. If you get 'freaks of nature,' well, now you know that you better not match that set of siblings again. :-)
--Breeding siblings results in offspring that carry 50% of the genetic material of each of the original parents.
--Breeding offspring with a parent results in a 75% - 25% split in genetic material of the original parents, and is a much closer pairing.
That was probably way more than you hoped to hear, but we at least hope it helps.