het...?

i am looking for ball pythons on kingsnake.com and alot of them say 50% het... 100%het or pos het. i was wondering what that means. i would like to breed snakes but my parents probably wont let me. if i get a job then i might have a chance. But i know if i can i have much to learn.... is it difficult to breed snakes?

Het means that a snake carries one gene for a particular trait. It stands for heterozygous. Homozygous means that it has two genes for that particular trait. Recessive traits (example: albino) require two genes for the trait to show up, while dominant traits (such as normal type) require only one. Other traits may be co-dominant or incompletely dominant (such as pastel), which essentially means that a snake with one of the genes looks different from a normal type and a snake with two genes for that trait looks different from both normal and the heterozygous form.

You can be certain that offspring are heterozygous if one parent is known to carry two of that gene and the other has none, for example breeding an albino to a normal. All of those offspring will be 100% certain to be heterozygous for albinism. If two of those offspring are bred together, then you have a 25% chance of producing an albino, a 25% chance of producing a normal, and a 50% chance of producing hets. Because the albinos are visibly different but the normals and hets can't be told apart, all the ones that look normal are referred to as 66% possible hets for albino (because 2/3 of normal looking are statistically het, 2/3=66%). If you bred a 100% het to a normal, the resulting offspring have a 50% chance of being het and so are referred to that way. A "possible het" can be upgraded to a 100% het if it breeds with another animal (either a het or a homozygous recessive) and produces a homozygous recessive offspring, because then it's been proven.

Hope that helps!

I'm going to go ahead and move this to the Ball python: Breeding forum. :)

Now, you can look at this thread for a bit of information on it: http://ball-pythons.net/index.php?na...iewtopic&t=509

There are also websites you can go to such as: http://www.newenglandreptile.com/care.html On that page, scroll down to the bottom of the page, and you will see 4 different links to genetic-type pages.

I would explain it further to you myself, but then it would sound exactly like Marla's post. ;)

Jennifer

Good point, Jennifer -- not the right place for this post. :)

ok...

so if i were to get 2 100% het clowns would all of the snakes be clowns or would they be hets?


and what would 2 50% het clowns get me?

From het X het each baby would have a 25% chance of being homozygous (clown in this case). That isn't the same as saying that for every 4 babies you will get one clown since it is a separate roll of the dice for each but long term you should see about 1/4 clown. The remaining would all look normal but each have a 2/3 chance of being hets. Since you probably couldn't tell by looking at them which ones where hets you could refer to the group of normals as “66% chance hets”.

Like Randy said, 2 100% het clowns would give you a 25% chance of getting a clown, though you could end up with all clowns or no clowns in any given clutch. 2 50% het clowns would most likely give you a bunch of nice normal ball pythons.

If you bred a 50% possible het with a 50% possible het, you have a 50% chance that both of those are actually 100% het. If they are BOTH hets (which you won't ever know unless you bred them) you will get the statistically said 1/4 clowns. If one is 100% het and the other is normal (out of that 50% x 50%) than you will get ALL normal looking babies that are 50% possible het. Again, you won't actually know these are hets because you don't know if the parents are actually hets. It gets confusing, lol. What I did to understand it was go on some science websites and looked up Punnett Squares. It helped alot.

Jennifer

But just as likely as their both being actual hets is that they're both normals, in which case all you will get are normals. Even if both do turn out to be hets, it could be 3 to 5 years' worth of clutches before you can prove them out, though statistically odds are with you in the first clutch.

Not to nit pick BUT...

The chance that a pair of 50% hets are BOTH hets is actually only 25%. However, the chance that they are both not het is only that also so if the original pair doesn't produce clowns you could breed offspring back to both parents and have a good chance of eventually producing a clown.

Of course you also have to deal with the odds of hitting on the 25% chance in one of the eggs in a small clutch. Here is a chart I made with the odds for certain clutch sizes:

http://snakemorphs.home.comcast.net/odds.htm#table

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Originally Posted by RandyRemington

Not to nit pick BUT...

The chance that a pair of 50% hets are BOTH hets is actually only 25%. However, the chance that they are both not het is only that also

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That's exactly what I said above ...

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Originally Posted by Marla

But just as likely as their both being actual hets is that they're both normals, in which case all you will get are normals.

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Originally Posted by RandyRemington

so if the original pair doesn't produce clowns you could breed offspring back to both parents and have a good chance of eventually producing a clown.

Of course you also have to deal with the odds of hitting on the 25% chance in one of the eggs in a small clutch. Here is a chart I made with the odds for certain clutch sizes:

http://snakemorphs.home.comcast.net/odds.htm#table

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Thanks, Randy. I hadn't seen a formula for calculating odds across clutches yet. That will come in handy.

this stuff is so confusing..... i think i understand though.... thank you all for helping me out


THIS IS THE BEST BALL PYTHON SITE EVER!!!!


sry i had to let that out. everyone is so helpful here

Someone said that the odds where 50% that they where both hets, however, you find the odds of both things happening (them both being hets) by multiplying together the odds of each unrelated event (the 50% chance that each one has) in order to come up with the 25% chance that both are hets. Since they each are also both 50% chance not hets it does come out the same as was also stated by someone.

Oops, you're right. Jennifer said

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Originally Posted by emroul

If you bred a 50% possible het with a 50% possible het, you have a 50% chance that both of those are actually 100% het.

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and I think what she meant was

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If you bred a 50% possible het with a 50% possible het, you have a 50% chance that each of those is actually 100% het.

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but you're quite right that you multiply your odds to come up with the odds of both events occurring (ie., 50%*50%=25%). I was working out a lot of this stuff recently, so it's pretty fresh in my head, but I can certainly see how it would confuse someone who hasn't had a biology class with a portion devoted to genetics recently, and having to be careful on wording to avoid misinterpretation makes it even more of a challenge.