Reptile & Amphibian Forums

Can you breed brothers and sisters or will they result in unhealthy or infertile babies? Also, if you bred a tiger 100% for albino to a regular phase albino, what would the clutch produce? Thanks a lot!

I would never advise breeding siblings if at all avoidable. Most especially with the already-inbred morphs. In most cases most simple recessive based morphs are established or "created" by breeding offspring back to the homozygous parent (the parent that displays the visible morph trait). This short-cut method of breeding the parent back to its own offspring is much less severe inbreeding than breeding siblings together since each parent only shares half the genes with their offspring. But siblings share 100% of the same genes and breeding them together may lead to deformities or abnormalicies. Now, if you were asking about breeding siblings of a non-morph I would say it's less dangerous since they don't likely come from an already-inbred line. But virtually all morphs are already inbred and all possible routes/means to outbreed them should be practiced.

That pairing would result in 25% albino tigers, 25% albinos, 25% tigers het albino and 25% normals het albino.
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David Beauchemin
High End Herps.Inc
http://HighEndHerps.com

>> This short-cut method of breeding the parent back to its own offspring is much less severe inbreeding than breeding siblings together since each parent only shares half the genes with their offspring. But siblings share 100% of the same genes and breeding them together may lead to deformities or abnormalicies. >>

...but I don't think this is actually true. In fact, I think the opposite (breeding offspring to parent) is statistically more dangerous. When outbreeding, you're trying to prevent "deleterious receissive alleles" from becoming expressed in the offspring. If one of the parents is a heterozygote for that deleterious trait, all of their offspring have a 50% chance of carrying it. When breeding back to a parent, that means you have a 100% het for deleterious trait breeding to a 50% het. Statistically, there is less of a chance of a sibling (50% chance for sib vs. 100% for parent) to be carrying that trait than the parent.

If you're trying to make albinos, one obviously would rather breed a 100% het to a 50% poss het than two 50% poss hets together. Same holds true for the undesirable traits as well...
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~Brian Ott

www.squamations.com

right.

actually, technically, the offspring snake could have gotten a "bad" allele from either parent. This means that there is an equal chance of a snake that is het for the defect crossing with a snake that is completely wild-type for that gene (no defective offspring) or a het crossing with another het (1/4 defective) the final result is that if we're assuming that this theoretical harmful mutation is independent of the trait actually being bred for (not "linked" on the same chromosome) then the numbers work out identically for a sib/sib cross as they do for an offspring/parent cross. A given baby snake shares 50% of its genes with either parent and 50% of its genes with a full sibling (same mother and father) Sorry for the long-winded post, I kinda got carried away.
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1.1 Red Bloods (Cartman and Bebe)
0.1 Boa Constrictor (Victoria)
0.1 Albino Burm (Butters)
0.0.1 Desert King (Miles)

So your saying brother and sister "relations" are good???

Where are you from again???

>>So your saying brother and sister "relations" are good???
>>
>>Where are you from again???

Absolutely!! Alabama teaches good values...

On a serious note, no, I'm not saying that. I'm saying that statistically, there is less of a chance of a hidden deleterious recessive trait being expressed when breeding sibling to sibling than offspring to parent.
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~Brian Ott

www.squamations.com

It depends on the nature of the deleterious mutation. If you know for sure that either the mom or the dad is carrying some particular gene that you don't want expressed, then mating to a sibling rather than that parent is better odds for not getting a mutant offsprign, however, if you're just worried about the general tendency of inbreeding to double up the mutant alleles and bring out recessive mutations, then you have the same odds breeding to either sibling or parent.
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1.1 Red Bloods (Cartman and Bebe)
0.1 Boa Constrictor (Victoria)
0.1 Albino Burm (Butters)
0.0.1 Desert King (Miles)

Since we're talking about heterozygotes of recessive mutations, we have no idea who is carrying the trait. However, if one of the parents IS hiding a negative trait, you have better odds of not expressing it by breeding siblings together. If the parents are NOT carrying any deleterious traits, then it doesn't matter who breeds who. However, since we're trying to prevent any occurrences of this happening, and we don't know if any deleterious mutations are hiding in any of the snakes in question, statistically you have a better chance avoiding the expression of deleterious traits by breeding siblings.
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~Brian Ott

www.squamations.com

ok, let's assume that one of the parents is het for a potentially harmful mutation. We don't know if it's the mother or the father. Now let's assume that the other parent is normal/normal for that same gene, otherwise it is probable that we would see at least one mutant in the orignal clutch. That means that a given offspring is 50% het for that mutation as you said. Any sibling to that particular animal would also be 50% het so a cross between two siblings would be a 50% het X 50% het meaning that there is a 25% chance that you would produce a clutch with 25% mutant animals.
Now, if we crossed that first offspring snake back to one of its parents it would be the 50% het offspring like before, and the parent would also be 50% het since we didn't know if it was the mother or the father that was carrying the mutation in the first place. So it still ends up being a 50% het to a 50% het by odds. Now if you knew for some reason which parent was the carrier (although I can't think of an instance offhand where you would), it would actually be better odds to cross the offspring back to the parent that wasn't the carrier than to a sibling.
Now, if someone has some emperical data that shows they've had better luck crossing siblings or parent/child, I can't really argue with that, but if you're looking purely at the numbers, they are the same.
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1.1 Red Bloods (Cartman and Bebe)
0.1 Boa Constrictor (Victoria)
0.1 Albino Burm (Butters)
0.0.1 Desert King (Miles)

I want to thank you all for your responses, they are more than I could have hoped for. Forgive me, I am familiar with different morphs, but not breeding and genetics - what is meant by "harmful mutations" and "negative traits"? Also, could you elaborate and comment on this . . . "But virtually all morphs are already inbred and all possible routes/means to outbreed them should be practiced." Thank you all so much!

"Also, could you elaborate and comment on this . . . "But virtually all morphs are already inbred and all possible routes/means to outbreed them should be practiced.""

What he means is that nearly every snake morph not commonly found in the wild is somewhat imbred, and that if you get one, it would be for the best not to breed it to siblings or parents, but an animal of a different bloodline.

For example, albino retics/burms. These both came along when ONE specimen of each was discovered in the wild. Well both parents need to be hets (albino gene carriers), and those being the first albinos, there were obviously no (known) hets to breed them to. So they were bred to normals to make 100% hets, and then the siblings bred together to make the first CB albinos. Most morphs are already the result of imbreeding like this, so thats why they should be bred to seperate bloodlines.

Hope that helps.