Help with PH / DH snow percentages ???

[88Snakes]

OK, I currently have a 1.0 100% VPI DH snow and a 0.1 100% VPI DH Snow that I understand the odds on BUT here is where I am completing loosing my mind I also have .4 PH snows that were from the above 1.0 100% VPI Snow and what likely was a normal female(supposebly het girl but did not prove) So this would make the .4 50% HET Axanthic and 50% HET Albino correct? So now what would the odds/percentages if I breed back all 4 of these girls to the 100% Het Snow father? And last of all, there is a PH for sale that is 66% Het VPI Axanthic / 50% Het Albino....what would the odds be on this combo.

Thanks again

[OhhWatALoser]

OK, I currently have a 1.0 100% VPI DH snow and a 0.1 100% VPI DH Snow that I understand the odds on BUT here is where I am completing loosing my mind

I also have .4 PH snows that were from the above 1.0 100% VPI Snow and what likely was a normal female(supposebly het girl but did not prove) So this would make the .4 50% HET Axanthic and 50% HET Albino correct? So now what would the odds/percentages if I breed back all 4 of these girls to the 100% Het Snow father? And last of all, there is a PH for sale that is 66% Het VPI Axanthic / 50% Het Albino....what would the odds be on this combo.

Thanks again

Well depends what outlook you want to take... Technically the odds don't change, the snakes are either het or not, you always have the 1/16 chance if their truly dbl hets. chances of your PH being dbl het are 25%. so you could look at it as having a 1/64 chance.

the 66/50 to your male, well you have a 33% chance of it being truly dbl het, so your chances would be around 1/48

I could come up with other numbers looking at it with different logic, but I think that's what you were looking for. once some snakes prove or don't prove, your odds will get better or go directly to zero.

[dr del]

Hi,

I'm not sure those questions are answerable in the way you want.

The 50% het's are, in reality, either 100% het for each trait or normals.

So you can't really work out odds as such - they are either 25% per trait ( or 6.25% for snow ) per egg or 0% of any visuals and all the combinations inbetween.

All you can do is breed the poss hets and be meticulous recording what you get.

If one animal throws an albino then it is at least 100% het albino, if it throws an axanthic it is also 100% het axanthic and thus 100% het snow.

Assuming you got zero visuals then even if your unproven girl was 100% het snow then each animal still only had a 25% chance of getting both genes.

If she was a normal that chance remains exactly the same ( annoying isn't it? ).

Does that make it any clearer why there is no real answer to your question?


dr del

[RandyRemington]

First let’s consider the odds that you have a double het among your four possible double het girls. Each of the 4 girls has a 50% chance of being het albino and a separate 50% chance of being het axanthic for a combined 25% (1/2 X 1/2 = 1/4) chance of being a double het. Another way of saying that is it has a 3/4 chance of not being a double het. The combined chance of all four not being double hets is (3/4)^4 = 81/256. The chance of AT LEAST ONE (or more) being a double het is 100% minus the chance that all four aren't double hets so 175/256 or about 68%. So the odds that you have at least one double het in the four possible double hets are better than 2 to 1.

So "all" you need to do is get all 4 to breed and produce enough eggs to hit the 1 in 16 odds to get a snow from any females that are double hets. We can do a similar calculation for the odds of producing at least one snow from a pair of double hets. Once you hit the odds above and are actually breeding a pair of double hets each baby has a 25% chance of being a visual albino and a 25% chance of being a visual axanthic for a combined 1/4 X 1/4 = 1/16 chance of being a snow. Your odds of hitting snow go up with the number of eggs you hatch (just like your odds of having a double het went up with the number of possible double hets you raised up). Each egg has a 15/16 chance of not being a snow. The formula for your chance of getting one or more snow from a random group of eggs from a pair of double hets is 1 - (15/16)^n where n is the number of eggs. It works out that with 6 eggs your chance of getting one or more snows is almost 1 in 3. But if you could get 12 eggs (perhaps in two years) your odds go up to about 54% so more likely to get at least one than not. Once you get up to 24 eggs your odds are nearly 79%.

So, a lot of work and a lot of baby ball pythons but heck, we all like those anyway.