Linebreeding

[Kaifyre]

Okay, so since I'm new to the world of corn snakes, forgive me if I'm missing something or for any offence I may give to those who have been in the business of breeding these fabulous reptiles for years - I'm not trying to say anything, just making an observation.
I have dabbled in horses and dogs and cats and parrots and fish and any number of other critters for the vast majority of my life, and nowhere have I seen such rampant linebreeding (i.e. breeding brother to sister, or mother to son, etc.) as in this industry. In the case of every other animal breeding I've ever come across, linebreeding and inbreeding are considered a very bad thing. For example, most pugs nowadays have hip problems due to the excessive linebreeding necessary a long time ago to produce what were basically tiny little mastiffs with curly tails. In many species, linebreeding causes any number of health problems and mental and physical retardation, as well as lowering the resistances to many (if not most) diseases and illnesses that that species can catch.
However, I have found that this is not the case with corn snakes. In this industry, it is basically a standard occurance to linebreed, particularly brother to sister, to acheive a desired morph. Why is that? What, in the history of keeping corn snakes as pets, made someone way back when "break the rules," so to speak, and begin linebreeding? I mentioned the process of creating a snow to someone in the industry a while back, and when I proposed having three or more separate pairings going on so that the f2's could be crossed without linebreeding, the guy looked at me like I was crazy and said, "Just breed the siblings from one group - there's no need to have so many just to outcross."
This seems to be the general concensus when dealing with corn snakes. Having never been actively involved with any other snake species, I don't know if this is the industry standard for, say, ball pythons as well. For those of you in the know, is it?
I think it's interesting that this hobby, unlike any other, regularly practices linebreeding, in fact encourages it, to achieve one's goals. What are all your thoughts on this? Does anyone have the answers, or is it "it's always been done this way" territory? Of particular interest to me are those of you who have been breeding corn snakes for years (or, even better, decades!). Has anyone thought about this before, or am I whistling Dixie out of my bum?

Looking forward to this discussion,

-- Kaifyre

 

[BloodyBaroness]

Different genetic rules for different species.

Mammal genetics and reptile genetics handling linebreeding differently it's just how they are designed physiologically. Really cut and dry simple.

All reptiles are like this and it's pretty much the industry standard and completely accepted. Most breeders do outcross to strengthen lines as a project progresses, but without early crossing, the genes would not be available.

It's a completely normal practice, that if done with a little bit of common sense, has next to no ill effect on reptiles. You don't want to simply breeding brother/mother/sister forever, but doing a few generations, then adding in new blood once in a while is perfectly normal.

 

[Shiari]

Horses and dogs still have rampant line breeding and as a whole their populations are far more inbred than our corn snakes what with champions being bred to the most females, limiting the gene pool further with each generation. I've seen some pedigrees of horses and dogs. The looping back to grandfathers and aunts and cousins is astounding.

Most cases here are a simple brother-sister or parent-offspring. Just one generation of the inbreeding because the trait we're seeking to fix is a simple recessive trait.

I have 2 true line breeding projects in the work. The first project, my sweetcorns, will be much easier to outcross into as I am looking purely at temperament. The second, however, is to create black/near black corns with my near-black pewter female as the foundation. I hope to outcross every few generations, but finding a charcoal or pewter that wouldn't set me back entirely is going to be difficult. Non or difficult feeders, and kinked animals, will not be used for breeding. This will help ensure the continued health of the line.

 

[kc261]

Inbreeding in and of itself is not the problem. Careless inbreeding, where one does not pay attention to and make efforts to remove negative traits from your bloodlines can be bad. Inbreeding is bad in SOME cases, such has been done with many breeds of dogs where the traits being selected for are in and of themselves negative traits. Then again, selecting for those traits even if it was done without inbreeding is bad too. So I'm not sure how much inbreeding has to do with it. In the OPs example, producing tiny little mastiffs with curly tails may have been a bad idea, and it may not have mattered whether it was done with lots of inbreeding or none at all.

A lot of people think inbreeding makes negative traits show up spontaneously. It does not. What it does do is it increases the likelihood that a hidden gene (eg het recessive) for a negative trait will show itself (homo recessive). Or, perhaps, a not-so-bad trait (het co-dom or incomplete dom) will get worse (homo form). As long as the breeder is on the lookout for any problems and eliminates them from their bloodlines, the issues with inbreeding are minimal. You might end up with something that is not very noticeable, such as a heart defect that allows the snake to live a mostly normal life but causes them to die sooner on average, and it would take quite some time before even the most observant breeder began to suspect something was up with that line of snakes.

A good example how inbreeding isn't a problem as long as the breeder is careful and responsible is the stargazer gene. Inbreeding can cause a lot of stargazer babies to hatch out. However, as long as that breeder takes notice of the situation and eliminates snakes that carry the stargazer gene from their bloodlines, there is no ongoing problem. In fact, inbreeding allowed a negative trait that might otherwise have gone unnoticed, or at least not understood, to be identified and eliminated by responsible breeders. So in this case, inbreeding has helped to eliminate a negative trait.

A lot of people say reptiles can be inbred more than mammals because problems don't tend to show up as often. I'm not sure if this is true. Maybe it is just because so much of the reptile breeding has to due with getting as many morphs into one animal as possible, and this requires a lot of outbreeding. Or maybe it is because the mammals we are most familiar with (dogs, horses, etc) have been inbred so much for hundreds of years, and there just hasn't been that kind of time with reptile breeding for the real train wrecks to show up with any frequency. I also think that most reptile breeders (and most modern mammal breeders) may be more careful than previous mammal breeders were. For example, I don't know of anyone breeding FOR kinks or duckbills (a BP head deformity), but similar deformities, such as the smashed faces of certain dog breeds, have been bred for in the past with mammals.

If you think it is impossible to heavily inbreed without disastrous results, you should do some research on laboratory strains of mice & rats. Some of them have been inbred for 100 or more generations, each and every generation, never outcrossed. And, yes, some of them have issues, but usually (or perhaps always?) because the issue in question is what was being selected for. It is kind of sad, but there are advantages to having strains of mice that are prone to certain cancers or have similar issues. Other heavily inbred strains are very healthy, such as the swiss webster line, where large healthy litters was the trait being selected for.

In many species, linebreeding causes any number of health problems and mental and physical retardation, as well as lowering the resistances to many (if not most) diseases and illnesses that that species can catch.

Do you have a reliable reference for this? This is a popular belief, but I have yet to see it in a reliable source.

And, yes, BP breeders do a lot of inbreeding too. It is not quite as common as it is in corns. Most corn morphs are recessive, thus inbreeding is the easiest way to get a trait to show itself and/or to combine 2 different morphs in one animal. It seems like most BP morphs are co-dom, so you can get a morph to show itself without inbreeding, or get a combo without inbreeding, but inbreeding is still the easiest way to get the "super" or homo form.

 

[Guruofchem]

It's a fine line to walk - you want to fix the traits as quickly as possible, and since most are recessive, the only effective way to accomplish it is some degree of inbreeding. There are some unhealthy recessives that end up fixed too; sunkissed lines sometimes carry another recessive for a neurological disorder know as Stargazer, and there are signs of the really aggressive inbreeding some ball python morphers utilize degrading the quality and health of the animals. Reptiles, however, seem to tolerate genetic tinkering better than mammals do, with fewer side effects; this is likely due to their longer evolutionary history and generally less complex physiology.

 

[Chromatic Corns]

I'm glad you asked this question as I also had wondered.

 

[hikisquid]

I believe it's mostly because they are a new pet type. It's like how goldfish were linebred from pretty carp. When it first started, it was just everywhere, now it's a little better off (for koi at least) in outcrossing the genetics.

It's also popular because new morphs seem to only pop up in one or two individual snakes at a time, so the breeder crosses them in and out to prove the morph as quickly as possible.

I'm sure in time it will calm down, like it seems to have done for non-working animals of other types. But for now, breeders are in the "ooh this is new, let's get this great thing proven as quickly as possible" stage. It's a natural step in domesticating an animal.

 

[kc261]

I just checked this thread for new replies, and skimmed my post to be sure I remembered what I'd said, and realized I never got around to the flip side. My post, as it stands, could be interpreted along the lines of "go ahead and inbreed, just be careful about it and nothing will go wrong". However, my feelings on the issue are closer to "go ahead and inbreed to a limited extent, but be very careful about it and limit it". Sorry I apparently got distracted and never got around the the second half.

With something like Shiari's black corn project, it might be tempting to just keep inbreeding, due to the limited availability of suitable outcrosses. However, despite the fact that outcrosses will tend to set her progress towards an all black corn back a few steps, I'd still recommend doing it occasionally. The fact that laboratory mice have been extensively inbred successfully does not mean that should become standard practice.

there are signs of the really aggressive inbreeding some ball python morphers utilize degrading the quality and health of the animals.

I'm not aware of this, altho I'm certainly not up on all the BP breeding that has ever been done. Do you have any specific examples?

 

[Guruofchem]

Head Wobbling occurs in Spider morphs (somewhat analogous to Stargazer in corns, and all Spiders seem to have it to some degree or another). There are a lot of combos which include spider, so lots of balls have potential for wobble. Spider is a dominant trait, by the way.

Spinal kinks in Caramel Albinos are fairly common

Super Black Pastel and Super Cinnamon morphs can have snout deformities (upturns often called duckbills)

In general, there seems to have been a faster rush to create designer morphs with balls than has occurred with corns, and to make that happen requires pretty tight inbreeding. We may be catching up, though, as some breeders continue to chase bigger multigene combos in hopes of creating unique and profitable new looks. Personally, I think the best look going is SMR's Palmettos, and that was a wild-caught mutation, not a designer cocktail...

 

[BloodyBaroness]

Easy on the BP breeder accusations. There is just as many things wrong in corns that were spread. (Star gazing, short tail, etc...)

Vague assumptions can lead down a slippery slope.

Wobble, Duck Bill and kinks were not seen in many of the initial specimens.

Every breeder I know (and that's a lot) culls duck bills and kinked caramels. Many even x-ray caramels before selling, or they only work with choice and clean examples.

It's just as bad as the corn people who breed star gazing animals and lines without disclosure or testing.

The spider wobble is not a predictable problem, and nothing like stargazing at all. I have a male spider with ZERO wobble and every baby he produces has ZERO wobble. I also have a second male with no wobble, but every baby he produces wobbles. The worst wobblers are generally culled by breeders.

I'd like to see your evidence of really aggressive inbreeding in BPs. BP inbreeding is actually far less of a problem than it is in corns. Many of the genes are co-dom so you do not need to line breed. All the breeders I work with are constantly swapping offspring to freshen lines and keep a diverse pool.

 

[Guruofchem]

I'm not beating up on all BP breeders - just answering kc261's question about defects related to inbreeding/linebreeding. Nobody questions that you do things the right way, Autumn, and I'd be shocked if you spent much time working with people who didn't, but I think there is also little doubt that the high prices novel BP morphs command encourage some people to inbreed more aggressively or breed questionable/unhealthy animals to cash in before the price of the morph drops. It's a supply and demand issue, and the payoffs are bigger with balls. Smaller clutches of eggs and higher potential profits if you do hit something new logically encourage more aggressive risk taking among less scrupulous breeders and those who paid big money for their snakes and want to make their investment back. Does that mean everyone does it? Of course not, but the incentive is greater with balls.

Also consider the timeline - the first color morphs in balls didn't prove out until 1992, so in barely 20 years the huge panoply of morphs we see now has been developed. Corn snake morphs first cropped up in the 50s. The greater number of dom/codom genes available in balls explains some of the speed, since you get a higher percentage of offspring with the desired trait, but some of that explosion in paint jobs also comes from breeding as fast as possible, and fast leads to mistakes and encourages shortcuts - that's human nature.

I also agreed with you about similar problems in corn snake breeding, and you are correct that more of the traits in BPs are dominant or codom. The flip side of that coin is that any negative trait linked to the dom/codom trait spreads faster and crops up more often, not less, compared to heterozygous recessive traits.

The bottom line really lies in the breeder's motivations; those who treat profit as secondary to the health and well-being of their animals tend to do the right things (outbreeding, record-keeping, culling defectives, etc.), while those breeding primarily for profit are more likely to cut corners and allow poor genes to be propagated and spread through the gene pool, ultimately creating the potential for harm to everyone's lines. Honest breeders like yourself try to educate others and curtail the disreputable ones, but we aren't police and can't catch everybody doing shady things...

 

[kc261]

Head Wobbling occurs in Spider morphs (somewhat analogous to Stargazer in corns, and all Spiders seem to have it to some degree or another). There are a lot of combos which include spider, so lots of balls have potential for wobble. Spider is a dominant trait, by the way.

Spinal kinks in Caramel Albinos are fairly common

Super Black Pastel and Super Cinnamon morphs can have snout deformities (upturns often called duckbills)

In general, there seems to have been a faster rush to create designer morphs with balls than has occurred with corns, and to make that happen requires pretty tight inbreeding. We may be catching up, though, as some breeders continue to chase bigger multigene combos in hopes of creating unique and profitable new looks. Personally, I think the best look going is SMR's Palmettos, and that was a wild-caught mutation, not a designer cocktail...

I am not aware of any evidence that the problems you mention above have anything to do with inbreeding. In fact, I am aware of efforts that have been made to outcross in order to eliminate those negative traits, but they have not been successful. It seems, from what I've seen at least, that these problems are actually part of the genes that cause the morph, and so they'll be present regardless of how much or how little inbreeding has been done.

Some people argue that spiders shouldn't be bred because of the wobble. That's a valid argument, although many people feel that wobbles, especially the milder ones, are not an issue because it doesn't seem to have a negative effect on the snake. However, saying the wobble comes from inbreeding makes no sense based on my knowledge both of the spider morph in particular and how inbreeding problems work in general.

The stargazer gene in corns is totally different. Although it seems to have originally been found in sunkissed lines, it is possible to totally eliminate it by outcrossing and test breeding and eliminating carriers of the defective gene. At least as far as I am aware; I haven't done it personally. I guarantee you, if the wobble could be eliminated from spiders or the other defects you mention could be eliminated from the other lines as easily as stargazer is eliminated in corns, there would be LOTS of BP breeders working hard on doing just that.

So again, I'd like to see specific examples or other evidence of BP breeders utilizing "really aggressive inbreeding" that has been "degrading the quality and health of the animals", if you have any. I'm not saying it isn't out there. I'm just not aware of it, and if there is evidence of this, I'd sure like to know about it.

I think the reason there has been a faster rush to create bigger multigene combos in BPs as opposed to corns is partly because they are more popular right now. But a lot of it has to do with the fact that you can create multigene combos with a larger number of genes in each and every generation, due to the large number of dom and co-dom morphs. In corns, it is slowed down a lot by the need to alternate generations: one generation of hets, and then one generation of visuals. And, the need to breed hets together to get visuals is where inbreeding usually occurs, so I still think inbreeding is probably more common in corns than in BPs.

Based on your most recent post, Guruofchem, it seems like you are talking about unscrupulous breeding in general, rather than careless inbreeding in particular. On that point, I think we are in 100% agreement. That kind of breeder is scum. And yes, there definitely are some of those in the BP world.

 

[NiklasTyreso]

Selection creates good breeding results, not linebreeding.

If a linebreeder get good results it is because first he/she did good selection.

 

[Kaifyre]

Oooh, got some good responses here!! : )
I'm glad some of you mentioned Stargazer and BP head wobble; I knew Gazer originally came from Sunkissed but wasn't completely sure about it being an inbred deformity. I think it's interesting that problems resulting from (or partially resulting from, or indirectly related to) linebreeding can be bred out with corns but not as much with ball pythons. Perhaps, as some of you have mentioned, this is because we have been tinkering with corns for longer than we have with balls.
Shiari, you're absolutely right that with many mammals there have been varied linebred pairings in the bloodline to acheive a specific goal. I guess my point was that a large percentage of the corn breeders out there breed siblings regularly, but it is much less common for that to happen with mammals. However, I must now revise my earlier assumption that it doesn't happen as often - I failed to remember all of the linebreeding centuries ago that produced hairless cats, squash-nosed dogs, etc. I'd have to say now that it doesn't happen as often TODAY. Since keeping corns has really only come into its own as a hobby in recent years, I think it is safe to say that, perhaps, in fifty or one hundred years corn snakes will not be linebred as often as they are today.
Or maybe they will - as kc261 pointed out, a lot of the time an animal is bred FOR a specific trait. In fifty years everyone may think that kinked corns is the new thing, and we may all be swamped by zigzaggy little critters. : ) And I didn't mean to imply that linebreeding is necessarily a bad thing (though, looking back at my first statement, it does rather seem that way - sorry!), more like it's just, well, THERE. Look at all of our Thanksgiving turkeys - they are specifically linebred to grow very swiftly and put on a lot of weight, and then die. A friend of mine "rescued" one once and that thing lived to be almost three years old before it had a heart attack - it just couldn't handle the amount of weight it carried. Wild turkeys, on the other hand, can live for ten or more years if they aren't eaten first, and aren't nearly as heavy as their white counterparts.

-- Kaifyre

 

[SMDminnesota]

Kinks, headwobbles, and gazer are all things that should be bred away from. Breeding toward a kink is like breeding toward bad scoliosis. Obviously any hobby that breeds for specific phenotypes is going to have a certain amount of linebreeding, especially with recessive traits. Inbreeding for any organism should be minimalized.

Earlier it was mentioned that snakes have different anatomy than mammals that allows for inbreeding compensation? How would that even be possible? Inbreeding is a genetic issue. Combining genetics of the same family puts the organism at significantly increased risk of combining genes that will result in all sorts of mental/physical problems. I don't think they have a smaller risk but I do think we can't tell the difference between a normal snake or a snake with any number of issues. The only time we see a problem is when the snake has a kink, a head wobble, or something akin to gazer.

 

[airenlow]

The only time we see a problem is when the snake has a kink, a head wobble, or something akin to gazer.

Or a funky pupil...

 

[SMDminnesota]

Or a funky pupil...

Possibly. IF it degenerates visual function. If not then it is what it is.

 

[HerpsOfNM]

Just to throw out some other critters with wobble that appears linked to the desired mutation...

Jaguar carpets
Enigma leopard geckos
Waltzing or spinning mice

Unfortunately I'm on my iPhone so typing out a novel reply is a bit daunting at the moment.

 

[HerpsOfNM]

Possibly. IF it degenerates visual function. If not then it is what it is.

Who's to say it doesn't though. Snakes can fall back on their Jacobson's organ if vision isn't quite there. Furthermore, most boids have thermal pits among their labial scalation. These pits are typically tied into a nerve which then ties into the optic nerve allowing for a secondary sense of vision (simplistic description).

Who's to say that other internal anomalies, though non-detrimental aren't occurring at an internal anatomical or physiological level. Short of a vet or qualified animal anatomist (???), examining the internals all we have to go on is outward phenotypic discrepancies.

 

[dave partington]

In this industry,
I mentioned the process of creating a snow to someone in the industry
I don't know if this is the industry standard

-- Kaifyre

Is what we do as breeders of pets an industry? Perhaps to PETA or HSUS. It's not a word I apply to myself. I don't have a factory with employees and pensions and 401-k and benefits...
Looks like it's going to be a well-visited thread. Thanks for kicking it off.

It's just as bad as the corn people who breed star gazing animals and lines without disclosure or testing.

Been watching the thread awhile now. Figured stargazer SK would get tossed under the bus again.
Re: Testing. How many years should one test for stargazing? Cripes, I have corns I bred myself which are homo for 3 or 4 genes, het for up to 6 genes and traits, I know caramel is in there, but it has yet to appear. I'll try again this year. We seem to have omitted SG carriers which have been out-crossed to non-sunkissed. SG should have appeared in other color and/or pattern morphs. Maybe they have not been bred to cause SG (stargazer) appear in other lines? Or were the first SK's (sunkisseds) heavily inbred to produce a lot of SKs when SK was the hot new morph in its day?
On another lost thread somewhere here I asked if SG x SG = 100% SG?......... Never got an answer to that one...... :shrugs:

Many of the genes are co-dom

If they appear co-dom in F1, regardless of what is widely accepted simply because it has been published in an offline book,
Are they really genes if they appear in the first generation?
I ask because this is the behavior of trait, not gene.

The stargazer gene

Does SG x SG = 100% SG? Still looking for the answer.

Selection creates good breeding results, not linebreeding.

If a linebreeder get good results it is because first he/she did good selection.

^^^ Sometimes. Unless 25 different breeders all acquired their foundation stock from the same original cornsnake breeder who gave up cornsnakes and is now a ball python breeder. So if I get breeding stock from 5 different breeders, there is no guarantee it is unrelated stock. Ask questions crucial to the future before acquiring future breeding stock.

Kinks, ...are ... things that should be bred away from. Breeding toward a kink is like breeding toward bad scoliosis.

Is Kink simple recessive? Is kink an issue with incubation methods? Is kink always caused by a gene? Is kink caused by a variety of genes? If I hatch out a clutch with 60% kinks, should I start a BOI thread about the persons I acquired my foundation stock from? Or is it my fault for not having asked more questions before acquiring my foundation stock? Or Murphy's fault? Or am I incubating wrong? How do I KNOW the difference?

Combining genetics of the same family puts the organism at significantly increased risk of combining genes that will result in all sorts of mental/physical problems.

I'd noticed this in some personal friends of mine but have no comment.

--------------------------
Here's a copy/paste from another post I made a few months back on a lost thread.

Doing the math before starting any project:
So you have a Vanishing Pattern male. Vanishing Pattern is the removal of gene responsible for producing pattern.
3. Three female lavenders. I am using Lavender in this example because it has been around a relatively long enough time. So it will be easy to find un-related stock. These three female lavenders are from three different sources, and you have chosen them because visually they are the specific color variant of lavender you are shooting for. They are unrelated because you took the time to make certain they are un-related stock.

VP X Lvn1 = Group 1 (G1)
VP X Lvn2 = Group 1 (G2)
VP X Lvn3 = Group 1 (G3)

Keep the 3 groups separate. This is imperative.

Raise up G1 and breed F2 X F2; hold back targets.
Raise targets up, breed F2 X 3, F3 X F3.
Do this with G2 and G3.

Hitting F4 & F5.
G1, G2, and G3 are only 50% related, because they came from different mothers.
G1-F3 X G2-F3. = F4. Holdback, group. Repeat. F4 X F4 = F5.

F5 from G1 X G2. Breed these into G3. Has your cerebral cortex imploded yet?

By doing so, you are interlacing the trait of VP through several linebred generations, so when you outcross in F7 or F8 X stripe, the VP trait is so thickly interlaced, you should get back around 35-45% VP in the F1. So the VP in this instance appears to behave like a gene, when in fact, there is no gene. Only trait.

This is only an example of line breeding. Perhaps you have come across a cornsnake with no saddle borders, or one where yellow on the sides develops in specific regions, or has a single mid-dorsal stripe, or something else about the individual makes it stand out from other cornsnakes.

In the event the oddball is a female then it becomes necessary to breed her to a well-chosen male, save back the male babies which you suspect will pass the trait back to her, when you breed the male babies back to the dam in the hope of producing more like her.

I do not breed beyond F3 X F3 as this results in a few offspring which display some abnormalities, so why put them all at risk...