# Brother & Sister



## TAXI (Apr 5, 2008)

Can you use siblings for breeding, i assume not but not sure.


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## AuntyLizard (Feb 7, 2007)

In snakes or lizards ?

Liz


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## DeanThorpe (Apr 9, 2006)

I think a in depth explanation is prolly required...

however im not capable so the short version is that its best not too, but generally speaking no ill effects coem from in breeding a generation or 2, its once you get passed that that the genes are weakened and problems can occur.

It defo puts buyers off thats for sure, and may shorten lifespan.
Sometimes it is necesary a little, like with endangered species... but then once established you out breed as much as possible to re-strengthen the genetics.

Atleast I think thats it.


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## AuntyLizard (Feb 7, 2007)

agree dean.. I would not in breed my lizards but I know you can inbreed snakes thats why I asked the question.. Well at least for a generation or 2

Liz


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## TAXI (Apr 5, 2008)

*Reply*

I was inquering about snakes.


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## NBLADE (Apr 11, 2007)

siblings can be bred together with no probs, both snakes and lizards, i only go to 3 generations then outcross, 
however a lot of breeders go more, it is often vital in proving out genes, and morphs.


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## al_mcc (Aug 21, 2007)

You _can _interbreed any animals, it just increases the risk of recessive deleterious alleles popping up and so you having 'disabled' animals etc, and it will also mean that it will be likely that all the young are more similar, genetically, potentially putting them at greater risk to disease/parasitism.
there wouldn't be any of the 'fancy' corn/leo/royal morphs around today if people hadn't bred siblings, so it's obviously possible and not (too) detrimental in many cases.: victory:


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## Mason (Jan 21, 2008)

absolutely no problem breeding siblings be it snakes or lizards.


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## sinderman (Aug 19, 2007)

ive just put mother to son no probs thats boas

roger


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## stephenie191 (May 29, 2007)

i think this member may be a troll? not sure on that but with all the really odd questions:whistling2:


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## Mujician (Mar 7, 2007)

When you say up to three generations - what does that entail? - You breed the offspring together up to three generations? You breed up to 3 gens back to the parents? Not sure I understand. Thanks, Ben


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## NBLADE (Apr 11, 2007)

Mujician said:


> When you say up to three generations - what does that entail? - You breed the offspring together up to three generations? You breed up to 3 gens back to the parents? Not sure I understand. Thanks, Ben


 
in that i ment i will breed grandchildren for example back to grandparents, but i don't generally go great grandchildren to great grandparents etc,


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## Mujician (Mar 7, 2007)

Gotcha - thanks, Ben


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## TAXI (Apr 5, 2008)

*Innocent*

JUST FOUND OUT WHAT TROLL IS AIN'T ONE.:whistling2::whistling2:TO TALL TO HANDSOME I FORGIVE YOU ONCE.: victory:


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## eeji (Feb 22, 2006)

stephenie191 said:


> i think this member may be a troll? not sure on that but with all the really odd questions:whistling2:


????????? this is a perfectly sensible question to ask, not the slightest bit odd :bash:


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## stephenie191 (May 29, 2007)

eeji said:


> ????????? this is a perfectly sensible question to ask, not the slightest bit odd :bash:


with the can my snake eat frogs and with this one i was thinking to myself possibly a troll, but like i said, i wasn't sure.

But no he isn't, just needs alot of questions answering : victory:


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## HadesDragons (Jun 30, 2007)

My "long version" answer:

Sometimes, e.g. with recessive traits, such as albinism, the only way to carry on the line is by inbreeding. Ideally this should then be followed by a flurry of outcrossing then re-crossing, to ensure genetic diversity in the line.

With "line-bred" (generally meaning less intensive inbreeding) for a colour, direct sib-sib / offspring-parent inbreeding is often used as a shortcut to a fat wedge of cash, often at the expense of the long-term health of the line. That's why many high-colour animals / extreme morphs are more prone to "problems" / defects. Outcrossing can help, but obviously reduces the trait that you were breeding for in the first place, so you then have to keep selectively breeding for longer.

Inbreeding with animals such as leos that are sometimes available WC is less of a problem if you regularly outcross them to these WC animals. A WC animal is heavily pressured by natural selection, so usually has very solid genes. For animals such as bearded dragons, where no WC animals are (legally) available, inbreeding is more of a problem - it has been going on for a long time, so many animals in captivity aren't as gentically strong as their wild counterparts. That means that outcrossing can be less effective in bringing the line back up to strength.

Inbreeding "for the sake of it" - e.g. because someone bought a brother and sister and wants some babies, is irresponsible to the long term health of the line. Generally the same people who do that don't know what outcrossing is, so you will end up with animals that have the potential to become genetically weaker over time.

Inbreeding for a particular trait is debateable - some people are anti-morphs; some people like morphs. However, there is usually a "long-way-round" to the morph - e.g. breeding slightly related animals (cousins or less) helps to maintain genetic strength, whilst still enabling you to (_slowly_) build up the desired trait. For recessive alleles (such as albinism), after the initial, "required" inbreeding, animals can be crossed out continuously to distantly related animals for several generations to ensure fresh blood in the newly-created line. Again, it will take longer to get these animals on to the market.

In my personal opinion, there is no need to breed sib-sib or parent-offspring more than once in a line - people who do it frequently are taking shortcuts, whilst gambling with the long-term health of the line. This is especially important in species where there is no flow of fresh blood into the line from the wild. I would also not breed an animal to it's uncle / aunt (relatedness 25%). Cousins (relatedness of 12.5%) is around where I would draw the line, but only for lines that are genetically strong to begin with, and certainly not every generation.

People who inbreed intensely are jeopardising the long-term viability of many captive species, especially Australian ones (any any from other countries where export of fauna isn't permitted). Several morphs are already developing inherited "characteristics", such as stereotypical poor growth rates in certain beardie lines / morphs etc. This is after only 10-50 years of captive breeding in most cases; and not all of those captive breedings have been _in_breedings. If people don't stop inbreeding so intensely now, then some species are going to have real problems in another 50 or so years time.


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## Snake_Pliskin (Apr 7, 2008)

depends how fit ya sister is hahhaaha :whistling2:


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## DeanThorpe (Apr 9, 2006)

just to note with the "no probs breeding siblins" siblins that are already f3 inbred...? surely that would be a big no?
or where would it end?you could inbreed indefinetly with only ever having to breed siblins together couldnt you?


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## Ssthisto (Aug 31, 2006)

You could inbreed rather more than you expect if:

1. You have very strong, very healthy animals that exhibit the traits you want to start with.
2. You choose only the best of the best hatchlings to breed with - the strongest feeders, the fastest growers, the best temperament, no physical or behavioural anomalies.
3. You cull (and yes, unfortunately, I mean "remove COMPLETELY from the gene pool, no chance of ever being bred") any animal that is less than 100% healthy.
4. You keep records of pairings and what they produce - a pairing that produces unhealthy offspring more than once, no matter how distantly related the adults are or how closely, should not be bred again - and probably shouldn't be bred to other animals either.


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## HadesDragons (Jun 30, 2007)

Ssthisto said:


> You could inbreed rather more than you expect if:
> 
> 1. You have very strong, very healthy animals that exhibit the traits you want to start with.
> 2. You choose only the best of the best hatchlings to breed with - the strongest feeders, the fastest growers, the best temperament, no physical or behavioural anomalies.
> ...


That goes for most things though - the best way to breed is to follow those guidelines. Rather than "killing" when culling, I am now in a position that any animals less than 100% healthy will stay with me - that way they will never enter the gene pool.

Assuming those guidelines are followed regardless of how related the animals are, then inbreeding, except for the first generation of a novel gene, is still a short-cut to money, which increases the chance of deleterious alleles spreading through the population; if you have two siblings, both het for a deleterious gene, any offspring will have a 75% chance of carrying at least one copy of the gene (assuming the ~25% **** are "culled" - in whatever form that takes - the chance of an animal being an invisible carrier is 66%). 

If, instead of using a sibling, you used an unrelated animal that is *not* het for that deleterious gene, the odds of offspring carrying it undetected is only 50%, so the transmission rate (if that's the correct term to use for a gene being spread??) is theoretically lower. By using unrelated animals, the chances of deleterious hets pairing up in offspring should be less than if using related animals, simply because the chances of two siblings receiving the same allele from one parent at any given locus is 50%, whereas the chance of any given _unrelated_ individual in the population carrying the specific _deleterious_ (which should be at a low frequency population-wide, if responsible breeding has been prectised / the animal is not far-removed from the wild in terms of generations) allele at that specific locus should be lower than 50%.


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## Ssthisto (Aug 31, 2006)

HadesDragons said:


> That goes for most things though - the best way to breed is to follow those guidelines. Rather than "killing" when culling, I am now in a position that any animals less than 100% healthy will stay with me - that way they will never enter the gene pool.


I personally wish it was more possible to spay/neuter reptiles. That'd allow breeders to offer "less than perfect" specimens to people who want pets without worrying that a negative gene is going to wind up in the gene pool.



> If, instead of using a sibling, you used an unrelated animal that is *not* het for that deleterious gene, the odds of offspring carrying it undetected is only 50%, so the transmission rate (if that's the correct term to use for a gene being spread??) is theoretically lower. By using unrelated animals, the chances of deleterious hets pairing up in offspring should be less than if using related animals, simply because the chances of two siblings receiving the same allele from one parent at any given locus is 50%, whereas the chance of any given _unrelated_ individual in the population carrying the specific _deleterious_ (which should be at a low frequency population-wide, if responsible breeding has been prectised / the animal is not far-removed from the wild in terms of generations) allele at that specific locus should be lower than 50%.


To be honest, if you removed producers of negative traits from your breeding groups entirely instead of outcrossing, you could eventually get rid of the negative traits too. That's what they're trying to do with the "Stargazer" gene in corn snakes now - find "tested clear" lines of animals out of the known contaminated genegroup and hopefully produce only from the clear lines.

Besides, my family is a case in point of how easy it is to get a deleterious gene match in an unrelated pairing.

My father and my brother are both red-green colourblind. This is a genetic trait that is sex-linked, and is only carried on the X chromosome. As such, if a man gets an X chromosome with the colourblindness gene he will be colourblind; it takes getting the colourblindness gene on both X chromosomes for a woman to be colourblind. 

The key thing there is that my father AND my brother are colour blind. My dad didn't donate his defective X chromosome to my brother (otherwise he'd have been my sister as he could only have gotten an X from my mum as well) - my dad donated my brother's Y chromosome. Because I have a colourblind brother, I know that my mum is "het for" colourblindness... and thus, there was a 50% chance I could have been born colour blind too, since I DID inherit my dad's faulty X chromosome!


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## HadesDragons (Jun 30, 2007)

Ssthisto said:


> I personally wish it was more possible to spay/neuter reptiles. That'd allow breeders to offer "less than perfect" specimens to people who want pets without worrying that a negative gene is going to wind up in the gene pool.
> 
> To be honest, if you removed producers of negative traits from your breeding groups entirely instead of outcrossing, you could eventually get rid of the negative traits too. That's what they're trying to do with the "Stargazer" gene in corn snakes now - find "tested clear" lines of animals out of the known contaminated genegroup and hopefully produce only from the clear lines.
> 
> ...


I've often thought about how good it would be to be able to neuter reptiles as well...maybe it's something that will become more available in the future.

I think your family's case could be used as a nice example about why inbreeding is bad. Assuming your dad carries the mutated X chr., that would make you "het" (as you said, you must have received X from him). Therefore if you were to be bred to (keeping it in reptile terms - apologies for that) your dad / brother, the chances of a male child being CB is 50% (from your X). Chance of a female child being CB is also 50% (they inherit the mutated X from your dad / brother, then 50% chance of getting the X with the CB mutation from you), and the chance of a female being a carrier is 50% (they get your dad / brother's X with the CB mutation, but the non-mutated X that you also carry). Thus the chances of getting a child completely free of any CB genes is 25% (50% chance of a male, then 50% chance of being non-CB; all female offspring will be carriers or affected).

However, if you were to be bred to an unrelated male, the chances of him being CB is less than 50% (less than half the male population carries an X with a CB mutation). At this point the analogy falls down somewhat, as the CB mutation is detectable in males, as it is not possible to be het for CB and male at the same time!) However, hopefully you can see the point that you having children with an unrelated male (if it was possible for a male to be het for CB) would reduce the chances of having a child that is free from any X mutations for CB. It wouldn't affect the chances of a male child being affected, as that is determined by your Xs, but statistically it would reduce the chances of offspring receiving an X with a CB mutation from the father.

Removing star-gazing from the cornsnake line sounds perfectly possible if everyone behaves ethically (and let's face it, not everyone does). However, if unrelated pairings are used, the chances of a mutation such as stargazing actually entering a line in the first place should be reduced, as illustrated above, so the chances of having to "clean" the line in the future should also be reduced.


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## Ssthisto (Aug 31, 2006)

Of course, the way to get rid of colourblindness entirely would be to "cull" all the colourblind males - and known female carriers. A female who produces a colourblind male offspring obviously is a carrier; they should no longer be in the gene pool. To me, eliminating the deleterious genes - and knowing which individuals are carriers and which are clear - is as important as reducing the risk of producing visual negative traits.

Shame that not all deleterious genes are sex-linked and easy to sort out!


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