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I am new to the breeding of ball pythons and somewhat understand the breeding of a Homo to a normal you will get hets. Usually 50% het at that point. You take two hets and breed them to get...? I read where you breed a Homo to a het and will end up with 66% het. Can some one please break this down for me to understand? At what point will you have 100% het?

>>I am new to the breeding of ball pythons and somewhat understand the breeding of a Homo to a normal you will get hets. Usually 50% het at that point. You take two hets and breed them to get...? I read where you breed a Homo to a het and will end up with 66% het. Can some one please break this down for me to understand? At what point will you have 100% het?

if you breed.....

(recessive)
visual x normal = 100% hets
100% het x 100% het = 66% hets
100% het x normal = 50% hets

hope that helps...

Pitoon
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You have a few things confused, which is understandable when first getting into the hobby.

A homozygous bred to a normal will produce a litter of all 100% hets.

A homozygous bred to a het will produce a litter statistically that will be half homozygous and half hets.

Het to het will produce statistically 1/4 homozygous 1/2 het and 1/4 normal. This breeding is where 66% possible hets come from, as the 1/2 of the litter that are hets plus 1/4 that are normals all appear normal so you are unable to distinguish them from one another, so must sell them as 66% possible hets (since only 2/3 of them are statistically going to be hets.)

Het to normal will produce statistically 1/2 hets 1/2 normal, so this is where 50% hets come in as only half are actually het.

Thanks for clearing it up for me. So if I have a het pair and breed them I should get a 50/50 split with those hets being 50% het? Assuming my hets are 100% or does it matter what percentage my hets are as long as they are hets?
The reason for all the questions is, I just purchased a pair of het albino's for a good price and the guy said they were 100% het. Statically speaking if my snakes are hets I should end up with visual/50% hets out of the clutch?

>>Thanks for clearing it up for me. So if I have a het pair and breed them I should get a 50/50 split with those hets being 50% het? Assuming my hets are 100% or does it matter what percentage my hets are as long as they are hets?
>>The reason for all the questions is, I just purchased a pair of het albino's for a good price and the guy said they were 100% het. Statically speaking if my snakes are hets I should end up with visual/50% hets out of the clutch?

100% het albino x 100% het albino....

you have a 25% chance of creating an albino (this % is per egg) all remaining normals will be 66% het for albino.

Pitoon
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Thanks, it is just gonna take me some time to figure out all these percentages....lol Thanks for everyone that has helped me in understanding all of this.

100% het means the animal carries the recessive gene.

For 50% and 66% het animals, it means that animal has only that chance to carry the recessive gene. Only way to know for sure is to breed them (ie a 66% possible het albino to an albino. If any of your offspring end up being albino, then you know for certain the 66% possible het for albino snake is definitely carrying the albino gene. At this point you would call it a 100% proven het albino (or just 100% het albino).

Thus really only two ways to have a 100% het animal...by breeding a visual recessive morph (ie it looks like an albino (or other recessive trait) to a normal animal, all babies will carry the recessive trait. Or, proving out by breeding (and producing visual morphs of the recessive gene in question) either a 50% or 66% (or any other percentage below 100%).

Best way to prove if an animal carries a recessive trait is to breed it to a visual morph of the same recessive type.

Breeding a possible het to another possible het...makes it very difficult to determine if either really do carry teh recesssive gene or are both normals...as you will always have normal looking offspring, unless both are indeed carriers. (in which case, the odds are the same as breeding too 100% het animals in getting a visual morph.)
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PHLdyPayne

Hey Bass! Pitoon's first post should tell you everything.

Something to keep in mind...

Regardless of the breeding....all snakes in question will fall into one of the categories listed below (100% of the time):

Normal
Het.
Homo.

The snakes are NOT carrying percentages of the desired trait's genetics.
They are either carrying the genetics... or they are not.

Normal is fairly self explanatory.
Het. (heterozygous) can have a visual or non-visual phenotype.
Examples:
Het Albino is non-visual, meaning it appears normal but it is carrying the gene for homo ((Homozygous) phenotype of albino.
Het Russo, on the other hand, is a visual het phenotype.

The percentages apply to non-visual hets only.
Typically recessive morphs.

When people are talking about percentages...such as a 66% het....they are looking at the normal phenotype babies that came from a breeding involving a het parent..or het parent(s).

100% hets either have one parent that was a visual homozygous snake…or they have been raised up and proven out by breeding and producing some homozygous offspring….aka: a “Proven Het”.

The percentages pertain to the odds of it actually being a het.
For example when you purchase a 50% het...the snake you bought has a 50% chance of actually being a normal...and a 50% chance of carrying the genetics....as a het.

I often hear from new keepers who mistakenly believe that if they breed a 66% het with a 50% het....that they will have 116% chance of making an albino. This is NOT how it works! You cannot add up the percentages.

The snakes are not carrying "percentages of albino".
They either carry the genetics, as a het…. or they do not….and are normal.
The percentages imply the likelihood of the snake to be a gene carrier (het.) or not.
Hope that helps.

You are welcome to contact me by phone if you wish to discuss the genetics and how the percentages work.
I would be happy to help.

Harlin Wall - WALL TO WALL REPTILES!
970-245-7611
970-255-9255

>The percentages apply to non-visual hets only.
>Typically recessive morphs.

Actually, the percentages also apply to dominant mutant genes. In such cases, you can't tell the difference between animals with two copies of the mutant gene and animals with one copy of the mutant gene paired with a normal gene. But dominant mutant genes are rare. As stated in the quote, the typical situation involves recessive mutant genes, like albino.

>When people are talking about percentages...such as a 66% >het....they are looking at the normal phenotype babies that came >from a breeding involving a het parent..or het parent(s).

Yes. "66% het albino" is short for 66% PROBABILITY het albino. A snake is not 2/3 het albino and 1/3 normal. It is either het albino or genetically normal; you just can't tell which. With 66% probability het albinos, each snake has 2 chances out of 3 of being a het albino and 1 chance out of 3 of being genetically normal.

That is exactly right.

As you stated, I used the "typical" example of recessives...I did not include any information about dominant traits, because I was trying to keep it simple and less confusing for keepers who might be rather new to these other patterns of inheritance.
While the original post did not really pertain to dominant inheritance, it certainly is an interesting subject.

As breeding continues, I am sure we will begin to see different patterns of inheritance....such as sex linked genes etc.
Variability in the patterns, colors and types of inheritance is what helps to keep things interesting.
Take care Paul.

Harlin

Ok I just have to do this, I understand the 66% het only means that each snake has 2/3 chance at having the recessive gene and 1/3 chance at being normal. 50% each snake has a 1/2 chance at having the recessive gene or normal gene. Now if they are 100% hets, wouldn't that mean that there is a 100% chance of my snakes being a recessive carrier? Which in turn should produce a visual morph? Ok added question, are there any visual markers for the albino other than lack of pigment?

OK, let's try this:

100% Het X 100% Het = 25% Albino, 66% Het for Albino

Albino X 100% Het = 100% Hets, Albinos

100% Het X Normal = All offspring 50% Poss Het for Albino

Albino X Albino = Of course, all Albinos

Ok buzzard that sounds better.... 100% het to 100% het you will have the possible "chance" of 25% visual and the remainder being 66% het. I think I will just call Harlin cause I am missing something.

Hello Danny,

I really enjoyed our conversation. Thanks for the call.
Hope I was able to help a little.
Sounds like you are understanding it much better now.
Best of luck with your Ball Pythons. Hope you get some eggs this year. Send me some photos of the snakes you have questions about.
I look forward to seeing what you are working with.

Enjoy your weekend.
Your friend,
Harlin Wall - WALL TO WALL REPTILES!
970-245-7611
970-255-9255

>>Ok I just have to do this, I understand the 66% het only means that each snake has 2/3 chance at having the recessive gene and 1/3 chance at being normal. 50% each snake has a 1/2 chance at having the recessive gene or normal gene. Now if they are 100% hets, wouldn't that mean that there is a 100% chance of my snakes being a recessive carrier? Which in turn should produce a visual morph? Ok added question, are there any visual markers for the albino other than lack of pigment?

Keep in mind any gene we are breeding to reproduce has two alleles.In an albino it is expressed as AA,while a normal is expressed as nn..Offspring get a donation of one allele from each parent for it's own genetic makeup.Therefore,offspring from an albino bred to a normal MUST be "An" (or 100% heterozygous).

Albino x het:
AA X An = AA,or An..This has a 50% chance on producing albinos (per egg),since the het could donate an n instead of its A.
(However all offspring are at a minimum 100% het,since the albino doesn't have a normal allele to donate to the offspring.)

Albino X normal
AA X nn = An (Again,all offspring are 100% het since the albino does not have a normal allele to donate to the offspring.)

Het x het:
An X An = nn,or An,or AA...25% chance per egg for albino,and all normal offspring are only possible het since there is no way of telling. (ie,66%ers..Since both parents add a 50% chance each to the offspring.)

Het x normal:
An X nn = An,or nn...ie 50% hets..The reason it is 50% is due to the fact that only one parent had a coin toss to make.(Since the normal only had one option to donate.)

Albino x albino = All albinos..Since neither parent had a normal allele in their pairs to donate to the offspring.

btw..The same goes for non-recessive traits..Whether hets are visual or not doesn't change the mathmatical possiblities.

In other words:
Pastel x pastel has the same 1 in 4 odds of producing a super pastel that het albino x het albino does at producing an albino.
(Or lesser x lesser for BEL,or yb x yb for ivory,etc etc)

The only difference in breeding a het for albino to a normal,and breeding a pastel to a normal is that the offspring that catch the mutant allele from one of its parents is not visual in the recessive genes..(Co-dom is just a way of saying visual het.)..So you can see that the odds are interchangable between genetic types.

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Charles Glaspie
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