Possible Het Input to Morph Calculator [#1189]

By educating people like Travis has done through this entire thread and not give some false hope to people with illogical terms such as 33% and 25% hets.

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This is part of why I’m against adding it to the morph calculator. Give a man a morph calculator and he’ll predict his cross, teach a man basic mendelian genetics and how to use a punnett square and he’ll be able to figure out his own pos. hets.

For real though, this isn’t something specific to ball pythons, it’s just very basic mendelian genetics

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Understanding the probability that a snake is heterozygous for a certain recessive gene is not illogical, nor is it based on “false hope.” It is based on the very same logical and mathematical foundation as the terms “50% het” and “66% het.”

I understand that it’s not common practice in this hobby to track probabilities of hidden genes except for 50% het and 66% het. But a breeder that does has an advantage over a breeder that doesn’t.

Here’s an interesting hypothetical:

I have a 66% het male that I breed to a 50% het female. My goal was for some other genetics in that pairing, but I decided “hey, could get a nice bonus.” Unfortunately, none of the 5 eggs that hatch out are visuals.

Next season I’m looking to try for visuals. I have the “66% het” male from last year that didn’t prove, and I have a virgin 50% het male from a 100% het pairing. Which one should I pair to my visual female to maximize my chances of getting visual offspring?

(As an aside, I very much respect Travis and his knowledge of genetics. I’m actually choosing to engage with him on this because of that respect. I know he is approaching in good faith and I believe that our not quite seeing eye to eye is more a product of miscommunication than anything else.)

I wholeheartedly agree that learning basic Mandelian genetics and Punnett square is way more powerful than the MM calculator, and usually quicker to get your answer too once you’re used to doing it yourself.

Though I do use it to get a list of links to MM searches for the possible combinations to get a feel for what’s already on the market with the potential offspring.

John,

The easiest way to answer your question, without having you read everything posted here, would be this:

The numeric figure of a poss het comes from the potential outcome you get from looking at the results of a Punnett square. Specifically, it is the statistical number of animals that could be gene carriers divided by the total number of animals that are phenotypically WT.

So if I give you an animal and tell you that it is poss het (I am intentionally not giving you a value) how would you set up the Punnett square for breeding that animal to a WT?

Because gene pairs are binary, you set up the breeding as a 2x2. So your Punnett will look like this:

And again, because genes are binary, ultimately there are only two possible outcomes here, either 50% WT and 50% het or 100% WT and 0% het.

The reason you cannot have a 25% poss het is because, due to the binary nature of the genes, there is no way you can take a 2x2 Punnett and get an outcome where only one of the four grids is het while the other three are WT. Likewise, you cannot have a 33% poss het because you absolutely cannot get 1 1/3 of the four grids to be het.
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Or, if that is still confusing, perhaps I can try it this was. The snake itself is not 66% het or 50% het or any damn% het. The snake either is het or it is not het. The percentage is based on the statistical chance you have of picking an animal that is het. So, when you finally get around to breeding that snake, you have to set up a Punnett square to determine statistical odds. But again, at the end of the day, the snake either is het or it is not het so you must ignore those values when setting up the square for this breeding because the animal either has the gene and passes it on or it does not have the gene and does not pass it on.

Trying to put the values into play is like doing some Schrödinger’s cat game where the animal exists in both genetic states at the same time where the animal has the gene but actually does not but only 2/3 of the time (or only 1/2 of the time.)

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Maybe we should first clarify whether 50% poss het represents “50% of the clutch the snake came from will have x gene,” or “there is 50% chance this snake will have x gene.” These may seem subtly different in wording, but worlds apart in what they are saying. Which expression is actually most practically meaningful to us?

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Both are the same, just worded differently. If a parent is a 100% het, there is a 50% chance that any offspring will get the gene, resulting in ~50% of the offspring having that gene (as is indicated by the Punnett square above). Choose whatever phrase is most meaningful to you

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In some cases, like the one you point out, they come to the same value, yes. But not in all cases.

One case that they are not the same is any pairing where a poss het is involved.

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One case that they are not the same is any pairing where a poss het is involved.

Seems that no matter what you are going around in circle here making it more complicated than it is just for the sake of arguing :roll_eyes:

Your animal is either het or it is not which means run the following scenarios to know your possible outcomes.

Both animals are het
Both animals are normal
One is het one is normal

SIMPLE as that.

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Even in the case of a possible het, the possibilities are still 50/50.

If you pair a possible het to a normal, every single one of them babies is one of two things. Het or not het.

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I completely agree with you here - that shows all your possible outcomes. In the case of a 50% het to normal, 2 out of the 8 equally possible outcomes are hets. There is a 25% chance that any one animal from your clutch is het.

BUT it is not (on average over infinite results of this exact pairing of the same animals) 25% of the offspring you get that are het. Either 50% of the offspring is het, or 0% of the offspring is het.

So it’s apparent that, "(on average) 25% of the clutch the snake came from will have x gene,” is not the same as saying “there is 25% chance this snake will have x gene.”

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This is not actually correct.

While there is a 50% probability of any of the WT appearing offspring having the gene, this does not guarantee that 50% of the clutch will indeed have the gene. It is entirely possible that none of the offspring will inherit the gene.

As a visual example, if I breed a Pastel to a WT there is a 50% probability for each offspring to inherit the Pastel gene, but the odds gods could be fickle brats and kick me in the head with an entire clutch of normals.

Statistically 50% of the offspring SHOULD have the gene, if my experience with transgenic mice is anything to go by, luck is not always in your favor

And if you average that…it’s 25%

As others have said, you are making this way more complicated than it ever needs to be. However if this is something that really interests you and you want to dig deeper, I highly recommend this book and spending some time sitting down drawing out your crosses. There’s no better way to gain a thorough understand than doing the leg work yourself

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I am in complete agreement with you. The snakes from that pairing are 25% chance to be het.

I’m only going into such detail because I was immediately told by multiple people that it would be dishonest, illogical, and false to claim that there is a 25% chance that a snake from that pairing is het.

I’m genuinely trying to understand where the disconnect is between myself and those disagreeing with me. We are talking about something that should be objective, but reaching different results. So there has to be misinterpretation somewhere, and I’m open to that being within myself. So I offered up that I can understand that I am not approaching it correctly if we are actually debating over composition of clutches, instead of strictly odds of inheritance of genes.

Is it too simple to put it into the MM calculator? I know that you or I can calculate the odds of outcomes for a 66% het x 50% het pairing, but is it reasonable that most hobbyists should have to learn how to do the weighted probabilistic average of the possible outcomes of the pairing combinations for that poss het pairing?

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I’m only going into such detail because I was immediately told by multiple people that it would be dishonest, illogical

I’m genuinely trying to understand where the disconnect is between myself and those disagreeing with me

I will answer on the disconnect, because it is illogical people who are old school will see this when marketed that way as dishonest and preying on possible buyers a desperate attempt at a sale trying to take advantage of people’s hope and dreams.

Something many will look down on and not what one wants to do if they want to be taken seriously as a breeder, than again some people with 4 years “experience” can become an internet celebrity so who knows some people might be ok with it nowadays.

But that’s where it comes from and for good reasons.

I agree that the bottom line is no matter what, dealing with any hets you have to trust the breeder.

Assuming I already trusted someone’s honesty, and trusted them when they sold 50% hets. I guess I don’t see why I should no longer trust them if they shared honest, logically derived information that an animal has a 25% chance of being heterozygous.

In fact, I’d actually quite like it if a trusted breeder knew and shared that an animal I purchased was quantifiably 25% het. That information has value to me, but the current practice is to obscure it.

Anyways, It seems like this is trending towards the topic of whether sharing/advertising probabilistic information about inheritance beyond 50/66% het would be accepted in the hobby at large, and what are the benefits/drawbacks of evolving that standard practice. I don’t dispute your opinion that many people might be skeptical of it. I don’t want to stray too much further off the topic of a MM poss het calculator, the merits of it, and how the hypothetical calculator would work if it was developed.

I do sincerely appreciate hearing your opinions as someone who has been in the hobby much longer than I have.

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Get an entire season where you produce 87% males on 13 clutches and talk to me about luck :rofl: :crazy_face: :rofl:

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So if you pair a 50% het x 50% het, what are your chances of hitting a visual? 6.25%?

I think it’s better to save up some money and get a visual.

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Possible hets are a gamble they either are or they are not.

It depends if both or only one or none are actual hets.

So since an animal is het or it is not so to know your possible outcomes run the following.

Normal x Normal
Het X Het
Het X Normal