Reptile & Amphibian Forums

According to ralph davis's website, when dealing with DH snows the odds of getting a snow is theoretically around 1 in 16 (or 40 to 1 if dealing with a typical 4 egg clutch for a 1st time female laying). I'm not that great at this type of math and I am sure the fact we are not dealing in straight up double hets it will probalby complicate it further. Any ideas of what the odds on getting snows be with the following pairing?

Male Axanthic 50% PH snow
Female Het Axanthic PH Snow (daughter to the male and first tyime laying)

odds for a 4 egg clutch?_____
odds for a 6 egg clutch?_____
odds for a 8 egg clutch?_____

You can't even put an odds number on it when you are starting with a PH and breeding it in turn to his daughter. That is why you don't see people listing animals less than 50% ph. And if they do IMO it is a waste to put a number to it.

Odds are just that. I hit my snow, from dh x dh, in the second breeding and 12 eggs. Some have taken way longer. Others have done it first breeding.

IMO it would be in your best interest to prove or disprove the male first.

I have a pair of DH Snow from Ralphie. Last year's clutch produced two axanthics. I really did not know what to call the normal-appearing animals in the clutch.....50% what?

This year the pair bred again and she has yet to lay. I am hopeful that maybe the elusive snow will appear. I know we could see albinos, axanthics, snow and hets. This is the fun of the season!

I'd list them as 50% possible het for axanthic and albino.
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"What is man without the beasts?
If all the beasts were gone,
men would die from great loneliness of spirit.
For what happens to the beasts,
soon happens to men.
All things are connected."

-Chief Seattle (Duwamish Tribe)

My breeders came from RDR and proved first year with an albino and a vpi axanthic in the clutch. The normals in the clutch are 66%ers just like any het x het. So technically beings there are two genes at work chances are the normals are het for one or the other.

>>You can't even put an odds number on it when you are starting with a PH and breeding it in turn to his daughter.

I just am trying to figure out what the odds would be for a 4, 6 and 8 egg clutch for getting a snow going on the assumption that both snakes are in fact het snow. What info I could find only gives theoretical odds for snakes that are double hets - not visual y het z. I don't know if the odds change because our male is a visual axanthic.

The procedure is: Create a punnet square to find the percent chances of each gamete combination. There are hundreds of websites available through Google that can walk you through this step-by-step for any combination you want. Then multiply those percentages by the percent "Het". For instance, if you have a Het to Het breeding, you get a 25%, 50%, 25% ratio, then you multiply these percentages by the 50% or 66% percent Het of the adults. It is one of the rare combinations of family and population genetic statistics necessary to know when breeding Ball Pythons.

And I will say it again: The percentages you get from a punnet square are the odds of the GAMETES sorting to create that combination. They are NOT the percentage of a certain individual you get in a clutch of eggs. Those ratios only prove out phenotypically over hundreds and hundreds of eggs, not just one clutch. In one clutch, you are just about as likely to get all normals as all morphs. Frustrating, I know.
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Lincoln, NE
0.1 Pastel, 1.0 Pastel het Pied, 0.1 Pied, 0.1 Cinn, 1.0 Black Pewter, 1.0 Woma (hidden gene?), 0.1 Yellowbelly
2.0 Normals, 1.0 Thayeri, 0.1 Thayeri X Alterna, 0.1 crazy cat, 1.0 husband

yes LOTS of math in a fashion I am not used to dealing with LOL. ok. At least one variable can be changed for the better. Cut small slits in the eggs.

So now we have...

Male: Axanthic het Snow
Female: dh Snow

Punnet square gives (if I did this right):

12.5% = Snow
25% = Axan het Snow
12.5% = Axan
12.5% = Albino het Snow
25% = DH Snow
12.5% = het axan

What is the next math step? (assuming what I have below is not correct)

If I was dealing with 100 eggs theoretically we should see

12 or 13 = Snow
25 = Axan het Snow
12 or 13 = Axan
12 or 13 = Albino het Snow
25 = DH Snow
12 or 13 = het axan

And if I was dealing with 50 eggs theoretically we should see

6 = Snow
12 or 13 = Axan het Snow
6 = Axan
6 = Albino het Snow
12 or 13 = DH Snow
6 = het axan

And if I was dealing with 25 eggs theoretically we should see

3 = Snow
6 or 7 = Axan het Snow
3 = Axan
3 = Albino het Snow
6 or 7 = DH Snow
3 = het axan

And if I was dealing with 8 eggs theoretically we should see

1 = Snow
2 = Axan het Snow
1 = Axan
1 = Albino het Snow
2 = DH Snow
1 = het axan

And if I was dealing with 6 eggs theoretically we should see

0 or 1 = Snow
1 or 2 = Axan het Snow
0 or 1 = Axan
0 or 1 = Albino het Snow
1 or 2 = DH Snow
0 or 1 = het axan

And if I was dealing with 4 eggs theoretically we should see

0 or 1 = Snow
1 = Axan het Snow
0 or 1 = Axan
0 or 1 = Albino het Snow
1 = DH Snow
0 or 1 = het axan

Good job. Those percentages you calculated are referred to roughly as "family" genetics. Just your basic heritage possibilities. Now, since you don't know whether the parents are carrying those traits or not, you have to dabble in "population" genetics. This is where you figure in the percent chance that the parents are that specific genotype. And it can get a little confusing.

So, you have your female het snow. Since both traits involved are simple recessive, let's treat the possibility of her having both traits as 50% (IE, Female 50% het for Snow). This could be 66% too, depending on what *her* heritage was. You may or may not know this yourself. Then you multiply that percentage by the punnet square percentages you calculated. For example:
Snow 12.5% X 50% het for Snow = 6.25%

Now, I will reiterate that these percentages refer to the sorting of the gametes, NOT the eggs. By definition, you are calculating the possibility of *each egg* receiving a given combination of traits. You are close to correct by saying that, out of 100 eggs, you may get close to some number of Snows based on these percentages. However, those ratios are normally proven out over hundreds of eggs (often thousands). For the small numbers you are talking about, a single clutch of Ball Python eggs, anything goes. You could get all Hets, or you may even get all Snows. I only warn you of this because it is the common gambler's fallacy. A lot of what you get out of one clutch is punnet squares, praying, and luck. This is also why a Het can be proven in a single clutch, but may take a dozen to disprove.
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Lincoln, NE
0.1 Pastel, 1.0 Pastel het Pied, 0.1 Pied, 0.1 Cinn, 1.0 Black Pewter, 1.0 Woma (hidden gene?), 0.1 Yellowbelly
2.0 Normals, 1.0 Thayeri, 0.1 Thayeri X Alterna, 0.1 crazy cat, 1.0 husband

>>So, you have your female het snow. Since both traits involved are simple recessive, let's treat the possibility of her having both traits as 50% (IE, Female 50% het for Snow). This could be 66% too, depending on what *her* heritage was. You may or may not know this yourself. Then you multiply that percentage by the punnet square percentages you calculated. For example:
Snow 12.5% X 50% het for Snow = 6.25%

The female's father is the one we bred her to. And her mother is a solid 10 lbs of normal (likely a wild caught from more than 16 years ago)... so until proven otherwise it would 50% correct?

>> For the small numbers you are talking about, a single clutch of Ball Python eggs, anything goes. You could get all Hets, or you may even get all Snows. I only warn you of this because it is the common gambler's fallacy. A lot of what you get out of one clutch is punnet squares, praying, and luck. This is also why a Het can be proven in a single clutch, but may take a dozen to disprove.
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yes I am totally aware of the roulette wheel nature of the game LOL. I think we won this particular gambling round.

Male: '05 Jolliff Axanthic Het Snow
Female: '07 DH Jolliff Snow

8 egg clutch. First time breeding for the female.

First baby out of the egg... SNOW

Also out of the egg: 1 Axanthic and 1 normal (either het axan or dh snow).

Still in the egg looks like 2 Axanthics and 3 albinos (or 2 albinos 1 snow)

It is close. Using the het snow x DH change you will still have ph's on the albino gene. Which in turn changes your percentages because you also have to add normal in there. To much work for odds when it really comes down to the luck of the draw when you are breeding. Sometimes you win sometimes you lose.