Reptile & Amphibian Forums

I'm wondering about hets. I know that Albino Hog x Albino Hog= Albino Hog babies. What I'm unsure of is when I see 100% Het, 66% Het, 50% hets. I understand that Albino is a simple recessive gene. What I'm unsure of are the ratios. Would 100% Het x 100% het give half albino, half normal looking that are also 100% hets? And how do you come up with the 66% and 50%? What sort of ratio would you expect with a 66% x 66% pairing, etc? Is there a simple rule of thumb to follow without needing a degree in genetic biology?
Thanks!!!
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Sam
Gecko Den
Email Me

I've included a helpful link at the bottom. It will basically tell you the outcome of any pairing. A het albino to het albino breeding results in 25% albinos, 50% het albinos, and 25% complete normals. Since you can't tell which ones are normals and which ones are hets from LOOKING at them, all you can do is say that any given normal appearing offspring has a 66% chance of carrying that gene. You should see the extrememly scary possibilities that result from double het to double het breedings, which I'm unfortunate enough to be messing with.
If you like (it's long, so I'll only do it if you ask), I've come up with a handy metaphor for how genetics works that is sort of silly but works quite well for me.
Genetics Wizard

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Peter: It's OK, I'll handle it. I read a book about something like this.
Brian: Are you sure it was a book? Are you sure it wasn't NOTHING?

what about the scary possibilities with the double het to double het.

I'm new to this thread... Hi, I'm MissHisssss

My brain is currently too fried for the metaphor.. but for the double het thing...
Let's say, hypothetically, that I had a pair of Chinese king ratsnakes (Elaphe carinata)named Ryu and Ho-oh that were both heterozygous for amelanism and hypomelanism. King rats that are double homozygous for hypo and amel don't really have a name yet, it seems to be called sunglow in other snakes. Anyway, if I bred these hypothetical snakes together without them hypothetically eating each other, here is the ratio of genetics I would get in the offspring. Keep in mind that I will have no way of telling who is het for what by looking at them-

6.25% Wild Type
12.5% Het. Hypomelanism,
6.25% Homozygous Hypomelanism,
12.5% Het. Amelanism,
25% Het. Amelanism, Het. Hypomelanism,
12.5% Het. Amelanism, Homozygous Hypomelanism,
6.25% Homozygous Amelanism,
12.5% Homozygous Amelanism, Het. Hypomelanism,
6.25% Homozygous Amelanism, Homozygous Hypomelanism,

So one has to figure out, say, what the odds of an amel appearing animal being het for hypo. OUCH! This is why I generally pass up breeding combinations that produce poss hets, hypothetically.
Handy genetics site

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Peter: It's OK, I'll handle it. I read a book about something like this.
Brian: Are you sure it was a book? Are you sure it wasn't NOTHING?

You must be left handed. Not very many right handed people would have the intelligence to be able to figure all that out. LOL Anyway, now I see what you mean. Thanks so much for telling me all that, and for the genetic link. Everything will be of great help.

I LOVE these forums,
MissHisssss

Well... I hate to admit I'm right handed. Must be the two X chromosomes that do the trick for me.
(my husbands says he helped, but he was mostly asking for pies. het for pecan. I kept trying to tell him that pecans are co-dom but he wouldn't listen.)
I'll type up that metaphor pretty soon. I gotta save it to a text file so I don't have to keep remembering it.
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"The serpent crams itself with animal life that is often warm and vibrant, to prolong an existence in which we detect no joy and no emotion. It reveals the depth to which evolution can sink when it takes the downward path and strips animals to the irreducible minimum able to perpetuate a predatory life in its naked horror."
Alexander Skutch

I'm still laughin. Het for pecan. LOL. I'll bet you're a kick to be around.

I LOVE these forums....
MissHisssss

>What sort of ratio would you expect with a 66% x 66% pairing, etc? Is there a simple rule of thumb to follow without needing a degree in genetic biology?

Simple rule of thumb: mate a 66% or 50% probability heterozygous albino to either an albino or a heterozygous albino (AKA 100% het), first. That way, you will find out if the 66% or 50% is a heterozygous albino or a normal.

Here's the reasoning:

You get a male and a female, and both are 66% probability heterozygous albino. So you could have purchased either a heterozygous albino male (probability 2/3 = 66%) or a normal male (probability 1/3 = 33%). And you could have purchased either a heterozygous albino female (probability 2/3 = 66%) or a normal female (probability 1/3 = 33%).

Here are the possible pairing and progeny:
1) male = heterozygous albino x
1a) female = heterozygous albino --> 3/4 normal looking, 1/4 albino
1b) female = normal --> all normal looking

2) male = normal x
2a) female = heterozygous albino --> all normal looking
2b) female = normal --> all normal looking

As the probability of getting a heterozygous albino male is 2/3, and the probability of getting a heterozygous albino female is 2/3, the probability of getting a pair of heterozygous snakes is 2/3 times 2/3 = 4/9 = 44%. In other words, just over half the matings will produce all normal looking babies. And you can't tell whether the male is heterozygous albino and the female is normal, whether the female is heterozygous albino and the male is normal, or whether both male and female are normal.

If you start with one snake that is either albino or heterozygous albino, then you can fairly easily find out whether it's normal looking mate is normal or heterozygous albino.

Hope this helps.

Paul Hollander

The most important thing to keep in mind is that the snakes are either Het or NOT Het. The 50% and 66% ratios are ONLY probabilties within the normal looking babies of being Het. If at least one of the parents is Homozygous for a trait, in this case Albino, than ALL of the babies will be 100% hets beacause the Albino parent ONLY has a albino gene to give. A known het to a normal gives you half a clutch that is also het from the het parent and the other half is simply normal. They are all phenotypically (look the same)normal so you say they are 50% possible het for albino. Het to Het gives 25% albinos 50% hets and 25% normals. Now to attain your probability you are only concerned with the normal looking babies, that is 75% of the clutch since the hets also LOOK normal. 2 out of three should be het so you call them 66% possible hets. Future breeding with KNOWN hets or albinos can prove these possibles out for you.