# ball python genetics (for a non b.p. guy)



## ern79 (Jul 26, 2007)

Im not into balls but i have a reasonable understanding, i read something this morning that confused me no end, its regarding the morph bumble bee, this is a spider x pastel yes? spider being dominant and pastel being co-dom.
someone posted that bumble bee to normal would give a 25% chance of bumblebees, initially this made no sense to me as i was thinking both were co-dom, in which case surely you will only get pastels, spiders and normals? even with spider being dom, i would have thought it would have to be a 2 copy dom (homozygous) to have the potential to throw bees bred to a normal i.e. offspring from a bee x spider clutch. It seemed to be accepted that a bee x normal would give 25% chance of bees, even searching for this outcome gave the same results, it makes no sense to me, please enlighten me:bash:


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## yardy (Sep 9, 2009)

Idiots guide that makes sense to me (because I am that idiot) The genes for spider and pastel occur at different points on the snake's chromosomes (loci) and at each relevant locus you also have a normal copy of the same gene. When combined with a normal that has 2 copies of the normal gene at each of the two loci then you have a 50% chance of producing a spider (spider + normal) and also a 50% chance of producing a pastel (pastel + normal). This gives you 1/2x1/2 =1/4 (or 25%) chance of producing another bumblebee


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## ern79 (Jul 26, 2007)

yardy said:


> Idiots guide that makes sense to me (because I am that idiot) The genes for spider and pastel occur at different points on the snake's chromosomes (loci) and at each relevant locus you also have a normal copy of the same gene. When combined with a normal that has 2 copies of the normal gene at each of the two loci then you have a 50% chance of producing a spider (spider + normal) and also a 50% chance of producing a pastel (pastel + normal). This gives you 1/2x1/2 =1/4 (or 25%) chance of producing another bumblebee


sorry, that made less sense to me, the way i read it it convinced me that there should be less of a reason to produce a bee. 
I spoke to my friend who keep royals and he said that this breeding is for some reason an anomally, im wondering does it happen with other combos. I am a retic keeper and if i bred a double co-dom animal ( lets say a suntiger) to a normal i would only expect to get sunfires tigers and normals, now i now the spider is dom not co-dom but it still doesnt make sense to me unless it was a 2 copy (homozygous) dominant, the thing that confuses me is peoples willingness to accept that every bee x normal breeding has a 25% chance of bees, surely its only in a specific case?


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## Ssthisto (Aug 31, 2006)

ern79 said:


> someone posted that bumble bee to normal would give a 25% chance of bumblebees, initially this made no sense to me as i was thinking both were co-dom, in which case surely you will only get pastels, spiders and normals? even with spider being dom, i would have thought it would have to be a 2 copy dom (homozygous) to have the potential to throw bees bred to a normal i.e. offspring from a bee x spider clutch. It seemed to be accepted that a bee x normal would give 25% chance of bees, even searching for this outcome gave the same results, it makes no sense to me, please enlighten me:bash:


Ok, I think the confusion might be that:

1. "homozygous" and "dominant" are not the same thing.
2. "heterozygous" and "codominant" are not the same thing.
3. Spider is not dominant *to Pastel* - it's dominant to "Not Spider".
4. Pastel is not codominant with Spider - it's codominant to "Not Pastel".

A Bee has a copy of Spider and a copy of Not-Spider; it also has a copy of Pastel and a copy of Not-Pastel. (I would express this as *S*/S P*/P*, where S* is Spider, S is not-Spider, P* is Pastel and P is not-Pastel).

Because all you need in order to get a Bee is *one *copy of Spider and *one *copy of Pastel, a Bee has all of the ingredients to do it by itself


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## ern79 (Jul 26, 2007)

sorry, still not getting it. 
Can we step away from bumble bee and look at another combo morph, are you saying that it will work in the same way? would say a fire fly to normal produce more fire flys? as i say, i work with retics not balls and i have not known people to breed double co-doms to normals and repreduce the combo. Also i am using the terms hetero and **** with inverted commas (in my mind) i.e. pastel = heterozygous state, super pastel being homozygous, i know this isnt the same as recessive genetics.


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## Ssthisto (Aug 31, 2006)

Yes, that's right. Firefly to normal = Normal, Fire, Pastel, Firefly (equal chance of each).

Imagine you had a Tiger retic (_heterozygous _for the codominant Tiger gene - a homozygous animal is a "Super Tiger").
Imagine you crossed that to a Platinum retic (_heterozygous _for the codominant Platinum gene - a homozygous animal is an "Ivory").

You have a one-in-four chance of producing a Platinum Tiger, right?

If you cross that Platinum Tiger to a normal, you have a one-in-four chance of producing Platinum Tigers too.


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## ern79 (Jul 26, 2007)

Ssthisto said:


> Yes, that's right. Firefly to normal = Normal, Fire, Pastel, Firefly (equal chance of each).
> 
> Imagine you had a Tiger retic (_heterozygous _for the codominant Tiger gene - a homozygous animal is a "Super Tiger").
> Imagine you crossed that to a Platinum retic (_heterozygous _for the codominant Platinum gene - a homozygous animal is an "Ivory").
> ...


well i'll be damned, this goes totally against my understanding, my zoologist mate interprets it the same as me too, its like creating something out of nothing!!!! I thought the morphs would need to overlay each other (i'll point out now that i have no scientific schooling on genes and have only picked up what i need to know as a hobbiest, i dont know what alleles are or how they work so i'll say it like i think it ;-)) i.e. the parents would need to be oposing morphs to create the combo so platty x tiger = platty tiger the layers building as each opposing animal brings extra genes to the table so platty tiger x tiger = platty super tiger. Now surely platty super tiger x normal could only recreate plattys, tigers and (now i'm lead to understand) platty tigers and not be able to produce the platty super tiger as both parents would need a tiger gene?
Maybe ive missed the point as i would never normally entertain the idea of breeding anything back to a normal only further increasing the number of genes in the combo. You really do learn something new every day. Im about to ask some retic mates if they also understand this to be true, maybe the whole retic community is missing something............ nah, its probably just me!:lol2:
thanks for showing me the way!


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## Ssthisto (Aug 31, 2006)

ern79 said:


> I thought the morphs would need to overlay each other (i'll point out now that i have no scientific schooling on genes and have only picked up what i need to know as a hobbiest, i dont know what alleles are or how they work so i'll say it like i think it ;-)) i.e. the parents would need to be oposing morphs to create the combo so platty x tiger = platty tiger the layers building as each opposing animal brings extra genes to the table so platty tiger x tiger = platty super tiger.


Right, you've got it about half right there. Each parent contributes HALF of the future offspring's genes, so if one animal ONLY has one copy of "tiger" and one copy of "not-tiger" to contribute (and two copies of "not-platinum") , and the other has a copy of "platinum", a copy of "not-platinum" and two copies of "not-tiger" ... you can get an idea of what would be passed between the two.



> Now surely platty super tiger x normal could only recreate plattys, tigers and (now i'm lead to understand) platty tigers and not be able to produce the platty super tiger as both parents would need a tiger gene?


Not _quite _correct.

A Platty Super Tiger has one copy of "not platinum" and one copy of "platinum" (so it's 50/50 which it hands to each offspring) but it doesn't have a copy of "not tiger" to hand to ANY offspring (it has two copies of "tiger" instead).

Therefore, all of its offspring would be AT LEAST Tigers, and some of them would be Platinum Tigers.

But you're right in that breeding a Platinum Super Tiger to a normal *cannot* produce Super Tigers OR Platinum Super Tigers, because the babies can't inherit one copy of "tiger" from each of their parents.


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## ern79 (Jul 26, 2007)

sorry, i tend to work on best case scenarios only, when i say y crossed with z equals x im oversimplifying it, i see it as best case scenario plus everything leading up to it (which in my head is obvious so i dont mention it to myself) i know you will get both individual morphs and a percentage of normals aswell.


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## Ssthisto (Aug 31, 2006)

But not all pairings have the potential to produce normals 

Super Tiger X anything = at least Tiger, no matter what else it is.

Just as Albino X anything = all offspring het Albino.

Genes work the same whether you're talking pythons, poodles or peas - a homozygous individual has two copies of the same gene, and will always pass that gene on to its offspring, no matter what that gene is; a heterozygous individual has two different genes on that gene pair and has a 50/50 chance of which one it passes on to any given offspring.


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## ern79 (Jul 26, 2007)

Ssthisto said:


> But not all pairings have the potential to produce normals
> 
> Super Tiger X anything = at least Tiger, no matter what else it is.
> 
> ...


yes im proficient with that part of it, its just the specific instance referred to in the o.p that has had me baffled, i was never aware that a double co-dom (or dom co-dom) was able to replicate itself when bred to a normal, it sounds like cheating! :lol2:


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## Ssthisto (Aug 31, 2006)

It might help to think of each gene pair as completely separate to the others. When you roll the dice for one pair, it usually doesn't directly affect the outcomes of the other pairs. Not so much "double co-dom" as that implies "homozygous for single trait" but "Multiple-codominant"

Of course, then you get into the complicated stuff, like Mojave/Lesser Blue-eyed Leucistics; there you've got two flavours of the same gene that are part of the same gene pair... and they CAN'T produce a Blue-Eyed Leucistic when bred to a normal


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## paulh (Sep 19, 2007)

ern79 said:


> well i'll be damned, this goes totally against my understanding, my zoologist mate interprets it the same as me too, its like creating something out of nothing!!!! I thought the morphs would need to overlay each other (i'll point out now that i have no scientific schooling on genes and have only picked up what i need to know as a hobbiest, i dont know what alleles are or how they work so i'll say it like i think it ;-)) i.e. the parents would need to be oposing morphs to create the combo so platty x tiger = platty tiger the layers building as each opposing animal brings extra genes to the table so platty tiger x tiger = platty super tiger. Now surely platty super tiger x normal could only recreate plattys, tigers and (now i'm lead to understand) platty tigers and not be able to produce the platty super tiger as both parents would need a tiger gene?


ern79:
I'm trying to get my head around this concept of levels.

The following questions refer to reticulated pythons.

How many levels are in a normal?
How many in a tiger?
How many in a super tiger?
How many in a platty?
How many in a platty tiger?
How many in a platty super tiger?
How many genes are in each level for each of the above snakes?

Starting with a platinum super tiger x normal mating, how many levels are there in the two parents, the platty babies, the tiger babies, and the platty tigers?


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## firebelliedfreak (Nov 3, 2008)

oh i think i get it

sorry to intrude:blush:

but say bee to normal would be -Pp Ss x pp- instead of -PSx pp-n or what i used to think -(SP)p x pp-


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## Ssthisto (Aug 31, 2006)

I'd express Bee to normal as:

Spider is *S** (see, it's got a little spider next to the S!)
Normal Not-Spider is *S*

Pastel is *P** (Ok, it's also got a little squashed spider, but ignore that, it's just to distinguish it from "not pastel")
Normal Not-Pastel is *P*

So a Bee (which is het spider/het notspider, and het pastel/het notpastel) X Normal (homozygous notspider and homozygous notpastel) I would show as:

*S*/S P*/P* X *S/S P/P*

So the possible results are:

S* from Bee, S from Normal, P* from Bee, P from normal = *S*/S P*/P* (Bumblebee)
S* from Bee, S from Normal, P from Bee, P from normal = *S*/S P/P* (Spider)
S from Bee, S from Normal, P* from Bee, P from normal = *S/S P*/P* (Pastel)
S from Bee, S from Normal, P from Bee, P from normal =* S/S P/P* (Normal)


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## ern79 (Jul 26, 2007)

paulh said:


> ern79:
> I'm trying to get my head around this concept of levels.
> 
> The following questions refer to reticulated pythons.
> ...


hmmm "levels" i must re-itterate, that this is a totally simplistic way of looking at it to my own ends, please do not read into it too much, id like to say again, im perfectly happy with my basic understanding of recessive and co-dom morphs, i just wasnt aware that a double co-dom morph could replicater itself with a normal. I hesitate to explain myself as i feel i am being drawn into some fun poking. 
The levels thing i mentioned only really related to the double co-dom x normal thing and really goes no further, i see bumble bee as pastel over spider or vice versa, it doesnt really matter which, i have always been of the understanding that a double co-dom x normal would give you each co-dom morph singly and some normals. Its like being able to drive a car and not being a mechanic, now that i know that this happens, i dont necesarilly need to know why.


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## paulh (Sep 19, 2007)

ern79 said:


> I hesitate to explain myself as i feel i am being drawn into some fun poking.
> The levels thing i mentioned only really related to the double co-dom x normal thing and really goes no further,


No fun poking intended on my part. I just feel that there is some point of basic biology that is being overlooked. But if you wish to stop here, that is your privilege.

IMO, the procedure is the same for solving all genetics problems. It doesn't matter whether the problem only involves recessive mutant genes, codominant genes, dominant genes, or any mixture of the three types.
1. Determine both genes in each relevant gene pair in the father and the mother. Normal and mutant genes are equally important in this and the following steps.
2. Make all possible combinations of genes in the sperm and eggs. 
3. Use a Punnett square or alternate method of your choice to make all the possible combinations of sperm and eggs.
4. Figure out the appearance produced from each possible combination of sperm and eggs.


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## ern79 (Jul 26, 2007)

paulh said:


> No fun poking intended on my part. I just feel that there is some point of basic biology that is being overlooked. But if you wish to stop here, that is your privilege.
> 
> IMO, the procedure is the same for solving all genetics problems. It doesn't matter whether the problem only involves recessive mutant genes, codominant genes, dominant genes, or any mixture of the three types.
> 1. Determine both genes in each relevant gene pair in the father and the mother. Normal and mutant genes are equally important in this and the following steps.
> ...


i know and i cant reitterate enough how embarassing it is that until this, aside from scientific explainations i felt i havd been fully aware and competent in predicting genetic patterns and their transfer, which i have succesfully appied to varying species, its just this one hiccup that i have no idea how i have managed to overlook . Again its probably because the thought of breeding a double co-dom to a normal is completelyabsurd to me and a total waste.


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