Reptile & Amphibian Forums

Hi,

Several of us are test-breeding animals that COULD be hybinos (hondurans). They're albinos 50% chance het hypo 25% chance homozygous hypo. We've tested them by breeding x hypos.

If ALL the babies are hypos, we've established the animals as hybinos--IF the sample size is large enough (I know it can never be absolutely proven this way, but it CAN be proven "without a reasonable doubt".)

So, in the case of the first snake, five eggs, five babies, all hypos. I'm thinking that if the male were merely het for hypo, the odds of each baby being hypo is 50%, or 1/2, so the way to determine the odds of a HET producing five hypos would be to multiply 1/2 x 1/2 five times....or .5 to the fifth power.

I calculate the odds as 1 in 32 that a het could produce five hypo babies. Do I have that right?

There's a second clutch (this is a snake a customer bought from me) so there will be further confirmation but we want to get the odds right.

The one I'm testing was bred x hypo females that produced eight and ten good eggs due to hatch within the next 10 days, so i'll have a real good look at whether or not he's hybino, just from those first clutches.

Any statisticians out there?

thanks
terry

Your calculations are correct. Yes you will never know 100% but you can certainly be darn close to that without being 100%.

If the snake was mine, I would feel that 5 out of 5 was a "good indicator" but if I had more than 10 or 15 animals that were ALL the desired trait with no "hets" produced I would consider it a near certainty.

Of course I had a female I bred last year that was supposed to be het for a specific trait. not one of her 15 eggs, when bred to a homozygous animal resulted in the desired trait. This year, however, when I bred her again, I got 6 visibles out of 9 hatchlings, so she WAS het all along, I just had bad odds last year.
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~Sasheena

thanks...you oughta calculate the odds on those 15 & no homozygous babies from last year--nearly astronomical. ANY chance another male was ever with the female, even for a second, even with no activity observed?

(I calculate that the odds of what you got were 1 in 40,960. See why i'm wondering just a little about other possible explanations?)

and hey, use that stat major for us all: how do you calculate getting 5 out of 9 this year--is that the same 1 in 32 chance i calculated? or is it 1 over 2 to the ninth, since there were that many possibilities? or 5 over 2 to the ninth? i'm hurrying and in a hurry none of these seems like the obvious answer, so explain methodology as well as the answer, ok?

thanks
terry

the more i think about it, i don't think any of my proposed solutions to the 5 out of 9 cluctch was right, since 4.5 out of nine would be the statistically expected results, 5 out of 9 would be relatively high odds of happening. but what's the method (formula?) for calculating it?
thanks
terry

Stop that Terry
Jason

I got back into snakes so I wouldn't have to do much math. Thanks. Thanks a lot.
Seriously, I am waiting along with you for an answer--so I can save and print it..You know...just in case I ever have to use stuff like that.
See ya Sat.
:Mark

>>the more i think about it, i don't think any of my proposed solutions to the 5 out of 9 cluctch was right, since 4.5 out of nine would be the statistically expected results, 5 out of 9 would be relatively high odds of happening. but what's the method (formula?) for calculating it?

I don't remember how to do this offhand (senescence is a terrible thing!), but just because getting 5 out of 9 will have among the highest odds, they don't necessarily have to be high. I suspect the odds of getting exactly 5 out of 9 are no higher than 50%.
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Chris Harrison
San Antonio, TX

>>thanks...you oughta calculate the odds on those 15 & no homozygous babies from last year--nearly astronomical. ANY chance another male was ever with the female, even for a second, even with no activity observed?

The odds are astronomical, so I was feeling a little bit "cheated" ... especially as I'd bought that girl from Kathy Love, which to me is synonymous with not getting "ripped"... I was glad that she proved out.

As far as her being with another male, at the time i had 4 adult cornsnakes living in a communal cage, and I had 1.2 (which later proved to be 2.1) corns that were yearlings and never even coexisted in the same ROOM much less the same cage. AND all three "females" laid eggs, so no chance that she got inseminated by the wrong snake unless I had one with multiple genders. So she never had a chance to be with any male but my striped male. Striped male and het motley female... I should have gotten 50% striped/motley babies, but I got all checkered bellies.

>>and hey, use that stat major for us all: how do you calculate getting 5 out of 9 this year--is that the same 1 in 32 chance i calculated? or is it 1 over 2 to the ninth, since there were that many possibilities? or 5 over 2 to the ninth? i'm hurrying and in a hurry none of these seems like the obvious answer, so explain methodology as well as the answer, ok?

I'll have to think about this as our AC is out, and it's 95* in the house and I'm just burning up. more later... if I don't die!
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~Sasheena

Well here's my 2 cents for what it's worth. JMO....To a certain extent I think your over thinking the whole thing. The albino animals are either homozygotic hypo, heterozygotic hypo or neither. Let the offspring tell the story. If the clutch yields all hypos then the only conclusion, AT THAT TIME, would be that the albino father is a hybino. Further breeding would need to be done to confirm this. If a portion of the clutch is hypo then the father can only be a het/hypo. If no hypos are produced then the only conclusion,AT THAT TIME, would be that he is neither homo or het but further breeding would need to be done to prove that as well. So all I'am saying is why hurt your head figuring possibilities as they are really useless in the determination of the animals genetics. Yeah, the father could be het/hypo and produce all hypos but subsequent breedings would still need to be done to show that as well.

Matt Woodhall
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www.theselectserpent.com

Hi Matt,

I agree completely with your 2nd and 3rd points.

I agree with your point on the first circumstance--is it a hybino?--generally, but I was wanting to know more specifically, at what point could an animal that produced xx babies, ALL of them hypos, be concluded to BE hybino, and be sold as a hybino?

It's true that in theory it could produce 1,000 babies, all of them hypos, and the 1001st one could turn out not to be a hypo, proving the animal is not a hybino. But the odds against that are "astronomical". On the other hand, 3 babies, all of them hypos, proves nothing at all. So IN PRACTICE, when is it right to conclude the animal's a hybino? After 10 babies, all hypos? 20? 30?

Knowing the odds makes it easier, i think, to know when it's fair to draw a conclusion, since in THEORY, again, test breeding can NEVER prove an animal absolutely to be a hybino, it can only prove it NOT to be. (in theory, you can't prove it not to be het, either--1,000 babies, none of them hypo, from the animal being tested bred x a hypo, doesn't prove it's NOT het/hypo, at least it doesn't prove it absolutely. But i think it would prove it satisfactorily, if i can make that distinction.

that's why the fuss over odds.

and even if it can never be concluded to BE a hybino, it's reasonable to sell something as a hybino based on breeding results which, for example, would show that based on breeding results there's only one chance in 40,000 that it's not.

peace
terry

>>Well here's my 2 cents for what it's worth. JMO....To a certain extent I think your over thinking the whole thing. The albino animals are either homozygotic hypo, heterozygotic hypo or neither. Let the offspring tell the story. If the clutch yields all hypos then the only conclusion, AT THAT TIME, would be that the albino father is a hybino. Further breeding would need to be done to confirm this. If a portion of the clutch is hypo then the father can only be a het/hypo. If no hypos are produced then the only conclusion,AT THAT TIME, would be that he is neither homo or het but further breeding would need to be done to prove that as well. So all I'am saying is why hurt your head figuring possibilities as they are really useless in the determination of the animals genetics. Yeah, the father could be het/hypo and produce all hypos but subsequent breedings would still need to be done to show that as well.
>>
>>Matt Woodhall
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>>www.theselectserpent.com

Hey Terry,

Again, let the breeding results be the guideline. The person can purchase an animal based on past performance and make their purchasing decisions based on that, but I would say after 3 or 4 clutches of nothing but hypos I would be pretty confident that the animal was in fact homozygotic for both traits. Calculating the odds still does'nt change the genetics of the animal, if you know what I mean. I think future breedings of hypos that are het/Albino will be the only way to be sure that a hybino is a hybino (I'am sure you've already done this pairing). Maybe after enough are produced in this way we can begin to see the phenotypic differances between hybinos and albinos. Thanks for the thread and take care

Matt
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www.theselectserpent.com