Inbreeding????

[iamwilso]

Hey Guy's,
Sorry in advance this may be a stupid question but Google searches aren't helping. Is there such a thing as inbreeding with reptiles? I mean obviously there is but are there any problems or implications in doing so? If so what are they? I don't breed and don't intend to but I do like to gather as much info as I can.

Thanks wilso

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[Jacknife]

Reptile genetics are miles apart from mammal genetics.
Things like inbreeding tend not to have detrimental effects for reptiles, and infact most breeders line breed or directly inbreed in order to produce and enhance desired genetic morphs and traits.

 

[andynic07]

Reptile genetics are miles apart from mammal genetics.
Things like inbreeding tend not to have detrimental effects for reptiles, and infact most breeders line breed or directly inbreed in order to produce and enhance desired genetic morphs and traits.

I may be wrong but I thought that breeders line bred to get the desired trait and then outbred to strengthen the line again. Maybe a long term breeder can shed some better light on this. I also thought that some of the morphs were caused buy inbreeding and the more desirable morphs are line bred? Like I said though I am no expert and this is just a cross of some things that I have heard and a little of my own thinking so it could be wrong.

 

[Jacknife]

really not much difference in line breeding and inbreeding. Line breeding just sounds nicer.

 

[Pythonlovers]

I'm not all to familiar with terms yet but by inbreeding do you mean mother and son or father and daughter? Might sound silly haha

 

[iamwilso]

Yes that's what I meant by inbreeding

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[Wing_Nut]

Line breeding is the cornerstone of selective breeding. There is nothing wrong with line breeding so long as it is applied correctly. Line breeding is in effect a term used to define the milder forms of inbreeding (uncle - niece, first cousins, half brother and sister etc) and inbreeding is generally used to describe closer matings (father - daughter, brother sister). Inbreeding is used to increases the probability that the two copies of any given gene will be identical and derived from the same ancestor. Sewell Wright developed what is called the 'inbreeding coefficient' and this related to the probability that both copies of any given gene are derived from the same ancestor. A father daughter mating would results in a 25% inbreeding coefficient, brother sister from unrelated parents 50% whereas a cousin to cousin would be low (less than 7%). Unfortunately, its far more complicated than breeding animals for a single gene so while you may be able to produce animals that are increasingly heterozygous for a particular gene, inbreeding is also likely to bring undesirable or unexpected combinations to the surface. This inevitably leads the formation of new and wonderful morphs, but also potential deleterious genes. If applied correctly, inbreeding is a very good method for breeding animals, and reptiles have shown a strong tolerance for this practice.

Regards

Wing_Nut

 

[Rogue5861]

Good post Wing Nut. Very informative.


Rick

 

[Bluetongue1]

In-breeding is the mainstay of line breeding, with out-breeding a ‘necessary evil’ under certain circumstances. Every animal carries a number of recessive mutations. These mutations have originated in ancestral individuals and been passed on along a given line of inheritance. Bear in mind that other mutations that have developed in this line of inheritance have been completely lost along the way as a result of random chance along the way.

By their very nature, the mutations carried by any given individual are essentially uncommon. By breeding siblings together or offspring to parents, one is able to often obtain a homozygous pair of recessive mutations which would rarely, if ever, occur through breeding of genetically unrelated individuals. Unusual patterns or colour morphs can often be obtained this way. The problems that arise from this are that undesirable or even harmful recessive mutations can also be produced, rendering an unusually patterned individual of limited viability. This is where out-breeding can assist in separating the two (or more) genes to produce a vigorous line of animals with the desired mutation.

Just so you get it right, reptile and mammalian genetics work on exactly the same principles, as do all living things, with very minor differences. This is why, for example, they have been able to splice a human gene into bacteria to produce human insulin for use by human diabetics.

Blue

 

[Xanthine]

As a note for this whole thing, line breeding can be a very effective way to get rid of a dominant trait. It will, however, never succeed in getting rid of a recessive trait, as hetrozygous individuals will have the dominant phenotype, and so can't be removed. I am always sceptical of people when they say it's a good thing, as really we have no idea what genes we're actually playing with. Yes, a recessive trait might give a pretty looking snake, but from a health stand point we really have little idea what we're looking at.

Having said all of that, from casual observation it certainly appears that inbreeding and line breeding reptiles is far less harmful than in mammals.

 

[andynic07]

I was also under the impression that a lot of line breeding happens in mammals as well for the same purpose, to fix traits.

 

[junglepython2]

As a note for this whole thing, line breeding can be a very effective way to get rid of a dominant trait. It will, however, never succeed in getting rid of a recessive trait, as hetrozygous individuals will have the dominant phenotype, and so can't be removed.

If done correctly line breeding certainly can eliminate recessive traits/alleles, it just takes more time. In fact line breeding is the only real way of eliminating recessive alleles.

 

[Wing_Nut]

Cows that produce high yields of milk and the chickens that we eat or lay our eggs. All have become commercially profitable as a result of inbreeding. Controlled inbreeding, with specific attention to breeding coefficient, has enough anecdotal evidence to suggest it's can be managed without detrimental effect to the particular line. Homosapians would be a example on a massive scale of inbreeding as we decend from very few individuals and a very limited gene pool. If Darwin's theory of evolution is correct, the world around us is constructed by inbreeding. The only question I believe need be answered is do we have the right to control Mother Nature, to play God.

Regards

Wing_Nut

 

[Xanthine]

If done correctly line breeding certainly can eliminate recessive traits/alleles, it just takes more time. In fact line breeding is the only real way of eliminating recessive alleles.

Tell me, how can you remove a recessive trait by line breeding?

 

[junglepython2]

Tell me, how can you remove a recessive trait by line breeding?

I'll use Bell's phase lacies as an example. With the Bell's morph being dominant and wild type recessive.
If you cross a two heterozygous Bell's you will get 75% of the clutch (on average) being Bell's. A third of these will be homozygous Bell's. (At this stage you cannot tell the difference between the homozygous and heterozygous Bells) If you then cross these Bell's over wild type lacies you will get either a 50:50 ratio of Bells to wild type indicating that the Bell's parent was heterozygous, or you will get litters of 100% Bell's indicating the Bells parent was homozygous for Bells. If you then take these Bells parents that produced clutches of 100% Bell's and breed them together and start up a new line you have eliminated the wild type recessive allele.
The same thing can be done for removing deleterious recessive alleles by selecting to only breed from parents that do not throw the recessive condition when bred with related individuals.

 

[Xanthine]

You're assuming the phenotype is easily recognisable. With the number of genes out there, the number of recognisable genes is vastly outnumbered by the number of genes which have internal morphology changes, cellular changes, or are silent for a period of time. Yes, you can remove some recessive genes like this, but most you can not.

 

[junglepython2]

You're assuming the phenotype is easily recognisable. With the number of genes out there, the number of recognisable genes is vastly outnumbered by the number of genes which have internal morphology changes, cellular changes, or are silent for a period of time. Yes, you can remove some recessive genes like this, but most you can not.

If you keep pedigrees and continually select for vigour, and cull/not breed from animals that throw undesirable traits or direct relations of these animals then you can remove the recessive alleles. Of course if the phenotype isn't easily recognisable it is going to be difficult but if that is the case then the need to remove the recessive allele probably isn't overly important in the first place.

 

[Xanthine]

If the gene in question is a tumour suppressor, then the phenotype, which is devastating, wouldn't manifest until late in life. In that case, you would be selling on animals which will likely die a slow, painful death from some cancer.

Not to mention, if a pedigree is culled for lack of vigour, then you're culling, assumingly, homozygous recessive traits. What about the heterozygous siblings? They will still be normal, continue on, and the recessive trait is not eliminated.

 

[junglepython2]

If the condition doesn't express itself until after sexual maturity then the only way of eliminating it is through pedigree records (or genetic testing). This of course takes a long time and immaculate records, admittedly these traits aren't renowned in the reptile hobby. In regards to your second point you need to not only cull the animals with lack of vigour but also there siblings and parents to try and eliminate the heterozygous individuals. The only way of discovering which animals are heterozygous is through line breeding which was my initial point.

 

[Bluetongue1]

Cows that produce high yields of milk and the chickens that we eat or lay our eggs. All have become commercially profitable as a result of inbreeding. Controlled inbreeding, with specific attention to breeding coefficient, has enough anecdotal evidence to suggest it's can be managed without detrimental effect to the particular line. Homosapians would be a example on a massive scale of inbreeding as we decend from very few individuals and a very limited gene pool. If Darwin's theory of evolution is correct, the world around us is constructed by inbreeding. The only question I believe need be answered is do we have the right to control Mother Nature, to play God.

Regards

Wing_Nut

Some simple dictionary definitions to remove the confusion...

In-breeding is the interbreeding of closely related individuals.
Line-breeding is the interbreeding of individuals derived from a particular line of inheritance.
Out-breeding is the interbreeding of two individuals that are not closely related (unrelated) to each other.

What makes you think humans developed from a small gene pool? (Adam and Eve did come to mind.) The Genus Homo arose in east Africa and spread north to Europe and Asia. I think there might have been a few of them...

Darwin’s theory of evolution states: More individuals are produced than can possible survive. Therefore there is a struggle for existence. Those best adapted to their environment (the “fittest”) are more likely to survive and therefore to be able to reproduce. This enables them to pass on their genes, from which their characteristics were derived. In this way, desirable characteristics that suit an organism to its environment become more common in a given population – a process Darwin termed natural selection.

Selection of traits such milk, meat or egg production involves much more then one gene and is called artificial selection as the selection is done by man rather than nature. At what stage do you call manipulating a part of your environment “playing God”? First tool use? Clubs for killing game? Sharp stones to cut through a carcass? Use of fire? Planting tubers? Cutting down trees? Slash and burn agriculture? Using natural hybrids to produce grain? Etc. Not an easy call I reckon.
Mammals are by far the most line bred of animals as they were the first animals to be domesticated. All the different varieties of cattle, sheep, horses, dogs, cats, rats, guinea pigs, rabbits etc. Some do have issues, particularly dogs as they have been so highly developed and unscrupulous individuals (who call themselves breeders) have not culled affected animals and carriers of undesirable traits, as was explained by junglepython2.

Blue