Genetics

[tai_pan1]

I know about dominant and recessive genes, but when it comes to corns, are there any "recessive" genes that are dominant over other "recessive" genes?

I have 1.0 common (het) for unknown
1.0 hypo
0.1 anery A
0.1 reverse okeetee

I want to try breeding them, but am unsure of what I will come up with or which male to breed with each female. If I breed the hypo with the anery a, will they all come out as hypos, all as anery's, or some combination of the two?

Any help, words of wisdom, or examples of past experiences would be appreciated.

Mike

[Jeff_Favelle]

All three of those are recessive genes, and thus you need TWO snakes that carry each gene to get any offspring that'll look like it. Also, the amel + anery gives you the snow corn, and the hypo + anery gives you the ghost corn (so there's no "overriding" of genes).

Breeding any one of those genes to a different gene will simply give you normal animals that are "double het" for both genes.

[tai_pan1]

you lost me. If I breed the hypo and the anery, will I get ghost corns, or common corns with that are het for both hypo and anery?

[Jeff_Favelle]

Each gene that codes for each morph you mentioned operates seperately from each other. Therefore, they have no effect on each other. So if you breed them together, you will get all normal babies that are het for each gene.

[tai_pan1]

I'm not sure that I agree with that, and need you to explain to my why I'm wrong. My hypo should have two genes for hypomelanism, and my anery should have two genes for anery. How would any of them come out as normal corns? Wouldn't the babies have one hypo gene and one anery gene? If so, is any one "stronger" than the other? Would half come out anery and half hypo? I don't see how they'd come out as normal corns without the gene for being normal.

Sorry, I'm a little slow, and it's been a looong time since my last high school biology class.

Thanks for your help.

Mike

[Jeff_Favelle]

Yeah but being RECESSIVE genes, you need TWO of them to express anything. Hence, your snakes will look normal but be heterozygous for the aformentioned morphs. (ie. if anery is "aa", your babies will be "Aa").

[tai_pan1]

If the annery is "aa" and the hypo is "hh", shouldn't all the babies be "ah" or "ha"? How can they get the common gene when it is not present in the first place?

[reverendsterlin]

you need to remember that genes are pairs, here you get into alleles, the best way I can explain it is that the mutated 'recessive' gene 'acts' as a normal gene unless paired with it's matching partner where it becomes expressed. Two dissimilar genes the anery 'AA' and the amel 'hh' are on different alleles. The anery at it's 'amel' allele is normal 'aa', likewise the amel at it's 'anery' allele is 'aa'. When bred together 'AA' X 'hh' because we are treating these as not compatible each offspring gets it's parent's 'A' and 'h' gene at the appropriate allele and the normal gene to the other allele from the other parent, so what you get are 'Aa'+'ha' otherwise called double hets that look normal. These bred together can produce AAaa, hhaa, AAhh, Aaha, Aahh, aaha, Aaaa, aaaa. The AAaa would be/look anery, the hhaa would be/look amel, the AAhh would be Snow (Amel+Anery), the rest would be normals het for amel or anery or both and regular normals, this is where 'possible hets' (66% and 50%) come from.

Co-dominante genes which 'hypo' can be (why I changed it to amel above) can be expressed even when combined with a 'nornal' gene but may be expressed differently or better combined with itself such as 'Tiger Retic' and 'Super Tiger Retic' or 'Salmon Boa' and 'Super Salmon Boa'

This is pretty simplified and the notation is wrong but I think it gets the point across.

[jay76]

this is a fascinating subject. are there any online resources for herp genetics?

[Big Mike]

OK...I read this thread and it's not sinking in (not yet anyway)...but I think I forgot a bunch of stuff I used to know. lol

I now go place where live I... :P

[Jeff_Favelle]

Exactly what the Rev. said!! Yes there are TWO genes at each loci that control each morph (in your own words!). Therefore, for hypo, there are two genes, and for Anery there are two genes. If we are looking exclusively at those two genes alone, a normal would be AAHH. Each morph has TWO genes that control it. They don't combine, they don't talk, they don't affect each other. So to get each morph to express itself, you need to have both parents carrying the recessive allele (small "a" or "h") and only then can you get the morphs.

[Tim_Cranwill]

Interesting.... so, not to sound too redundant, when I breed my Hypo and my Amel, I will only get normals who are %100 double het?

[vanderkm]

There are a couple pretty good cornsnake genetics sites for more info on line. The corn progeny predictor site at Mick's site http://home.epix.net/~nspencer/cornprog.html has a downloadable program to predict the genotype and phenotype of almost any color cross you would work with in corns. You put in the types of the parents and what they are het for and it will give proportions of progeny colors/patterns.
The Superwidgets site is also a great one for corn genetics info and pictures of many of the morphs at http://serpwidgets.com/cornsnakes/morphs/morphs.html.
A hypo bred to an amel will give all normals het for both hypo and amel because they are recessive mutations at two different sites on the chromosome. This assumes that both animals are homozygous for normal coloration at the other site - if either is het for the recessive at either of these sites, I believe you could get hypos and amels in the litter - so if you know the color of the parents of your snakes it will help you predict further. Someone might correct me if I am wrong on this - its been a while since I dabbled in genetics.

Mary v.

[Quervo]

Jeez .. and I thought computer programming was confusing. :confused:

[Pixie]

Seriously, this isn't very easy to grasp!!! Eventually, I'd like to breed some of my corns but this is pretty complicated!!! I don't want to breed if all I'm going to get is normals... I have an albino, normal/okeetee, anery and hopefully one day a butter. Which would be the best breeding pair to get interesting offspring???

I'll look into corn genetics in more depth when the time nears for me to be contemplating breeding more seriously (they're all juvies now) but I am curious :)

[tai_pan1]

OK, I think I got it now and have made some sense of it. Thanks Jeff. I am in agreement with Pixie though, I would like to breed my snakes so I get more than just common corns. Oh well, I'll breed them in the spring of 2004 and wait for their offspring to get big enough to breed.

Thanks everyone for your input, it is very helpful.

Mike

[Jeff_Favelle]

OR, because they can be inexpensive, you could buy KNOWN hets from a reputable breeder right now! And then you can produce a ton of morphs even sooner!!

Good luck man! It sounds like you've got a project to work towards!! Its gonna be fun!


:D

[Tim_Cranwill]

Ok, each post about these crazy corn genes teaches me something new. That's a good thing. But it also confuses me a bit more as well.....

I have:

-1 pair of normals which are 50% possible het amel (basically a crap shoot)
-1 Hypo female
-1 Amel het hypo male

So, breeding the normals would give me all "normals" with a % of possible hets.

Breeding my Hypo x Amel het Hypo should give me something like 25% Hypos het amel and 75% normals double het.

Does that sound about right?

Also, since I'm unaware of any other recessive mutations in my snakes, I would need to breed parent x offspring or offspring x offspring to prove these traits. Correct?

I really should reread my books and the recommended sites, but these forums are just easier to digest....

Thanks all!:)

[Jeff_Favelle]

Cranwill:


Morph x het morph gives you 50% hets, 50% morphs.

In your case, 50% hypo, 50% het-hypo.

[Tim_Cranwill]

Cool.

Thanks Jeff!

[tai_pan1]

Jeff,

So with my mix of 1.0 common, 1.0 hypo, 0.1 anery a, and 0.1 reverse okeetee, any of the pairings that I make will only produce commons? Wow, now I have to wait 4 or 5 years instead of 2. I'm bumming.

Anyone have a 0.1 female het hypo I can borrow?

Mike

[Tim_Cranwill]

You could still breed them and get a bunch of hets. That's what I'll likely do. I'll try to pair them up next year to breed in 2005.

Can you imagie if snakes were like mice and could be sexually mature at 3 months?!?!?

[crimsonking]

Don't forget there's a good chance that some/all of your snakes are carrying genes that you don't know about! -Just to make it more interesting/confusing/mind-numbing!

[Tim_Cranwill]

No doubt. It will be interesting to see what come out in/of the end. :)

[crimsonking]

I have this 3x het (amelxhypoxstriped motely) I'm gonna breed to my snow striped motley female. O.K. wizards... step up ! What will I get from this pairing???
Mark

[tai_pan1]

Baby snakes!

[vanderkm]

The real fun of genetics is in the hets because of how they increase the scope of offspring that can result. My best guess is that you should get equal number of normals and amels, half of each will be striped/motley and those that don't show it will be het for it. Half the amels will be het ghost (both anery and hypo), half het anery. Half the normals should be het snow (both amel and anery), half het snow and hypo. If your snow was het hypo, which might be hidden by the amel, you might get hypos. The problem comes with knowing who is het for what in selecting who to breed in the next generation.
I find the striped/motley pretty confusing still, but they are so beautiful. Can you post a photo of your striped motley snow female? They are one of my favorite corns.

Mary v.

[Jeff_Favelle]

Piece of cake Crimson!! (ha ha, not!).

Here's my answer; keeping in mind I know nothing about corns and I'm assuming that striped is recessive and so is motley. I left motley out of the equation because as both are motley, there is no need to include it (all babies will be "mm", or, motley). Also, its not known if the female is het for hypo so that would change stuff. I assumed she wasn't.

Here goes:


http://members.shaw.ca/jefffavelle/genetics.jpg

Summary:

12.5% het for everything but hypo
12.5% het for everything
12.5% striped, het for snow
12.5% striped, het for everything
12.5% albino, het anery, het striped
12.5% albino, het everything
12.5% albino-striped, het anery
12.5% albio-striped, het anery, het hypo

[crimsonking]

$hi++! Maybe I don't wanna know! My head hurts! I'm going to breed them anyway and let mother nature surprise and amaze me. Like she always does!

[Jeff_Favelle]

Well, what made it somewhat easy, was the fact that the female could only give one set of alleles. So it was just figuring out what the male was going to give.

[Tim_Cranwill]

There goes Dr. Favelle again, solving yet another genetics mystery.

Did you's go to one of them fancy universities or something? How come you's so educated 'n all?

[Jeff_Favelle]

Ummm......now I forgot what I was going to say. Damn, and it was smart-a$$ too!!

:D

[tai_pan1]

Jeff,

If I breed my hypo and my anery, then breed the babies together when they are old enough, I should get 1/2 normal, 1/4 hypo and 1/4 anery right? If this isn't right, what will I get?

How about my normal (which I think is het for ?) and my reverse okeetee. If I breed their babies together, I should get 3/4 normal, 1/4 reverse okeetee?

Man this will take a lot of years!

Mike

[Jeff_Favelle]

Hypo X Anery will give you double het for ghost. If you breed those babies together, here's what you'll get:

http://members.shaw.ca/jefffavelle/genetics2.jpg

Each square represents a 1/16 shot (or 6.25%) of hitting that combination of alleles. "aa" = anerythristic and "hh" = hypomelanistic. "Aa" is het anery and etc etc etc

[vanderkm]

Babies from hypo X anery will be double het for ghost so you will get about 56% normal (some het for each of hypo and anery or both ), 18% each anery and hypo (some het for the gene they don't show) and 6% chance of a ghost.

You are right on the second generation from your normal X reverse okeetee, if the normal doesn't carry amel, and the normal appearing babies from the second generation are 66% het amel. If the normal carries amel, you will get amel in the first generation, which will clarify that. They may not be reverse okeetee because the selection for the broad white bands and intense coloration is not a simple recessive and can be lost with outcrosses, so they may look like normal amels.

Mary v.

[tai_pan1]

I just read all these posts over again and I think I've got it. I did go to http://serpwidgets.com/cornsnakes/default.html and there was some very good stuff there. More or less, it went over what Jeff told me, but it had pictures so it was easier to understand. Told you I was slow! Thanks again everyone.

Mike

[Cas]

For the snow stripe/motley one.... aren't stripe and motley at the same locus? I thought I heard somewhere that motley and stripe are co-dominant recessives... (for example, a normal striped corn was AAss, a normal motley was AAmm, and a stripe motley was AAms)... hence why you can breed a stripe and a motley together and get some interesting things.

So, breeding 2 stripe motley together could give you some stripes, some motleys, and some stripe motleys... but not all stripe motleys (unless you really beat the odds).

But, they also interact in odd ways... that is, the single motley in a 'striped motley' may override or mostly override the striped, and the striped may override or mostly override the motley. So you can get all sorts of patterns!

Dawn

[Jeff_Favelle]

Yeah, that's why I said I didn't know. I heard in another life that motley's were dominant or something like that, but my game is not corns.

But yeah, it definitely changes the outcomes. For sure.

[Cas]

Jeff, I'm not sure about it either... I just know motley stripe is a fun combo if you're trying to prtedict anything!

Just a thought, but have you ever used forked-line diagrams instead of the Punnett's squares? They're a lot easier to manage when you start getting into 3 or 4 and more gene combinations. :)

Dawn

[Tim_Cranwill]

Hey Dawn, how does the forked-line thing work?

[Jeff_Favelle]

Yeah, but I'm a die-hard Punnet guy!! Ha ha, I don't know why! Limited brain? LOL!!

:D

[Cas]

cranwill, the forked-line diagrams require a really good basic understanding of genetics... and they're for large numbers of genes, where a punett's will just get too large (like 64 boxes and up). Let's say, for example, you're crossing a snake (or plant, or whatever) with the genotype AaBBccDd with one with the genotype aaBBCcDd. The likelyhood of an offspring getting an Aa is 1/4, and the likelyhood of getting an aa is 3/4. Likelyhood of getting BB is 1(4/4). Cc 1/4, cc 3/4. DD 1/4, Dd 2/4, dd 1/4.
So, the diagram looks like this:

<img width="400" height="300" src="http://image.photoloft.com/opx-bin/OpxFIDISA.dll?s=cano&src=/PhotoLoft/Asset20/2002/10/27/10144/10144274_0_8873.fpx,0,0,1,1,400,300,FFFFFF">
(hopefully this will show up, I'm on my b/f's comp and he has no graphics software: had to do it as a bitmap)

Simply put, it tells you that, say, out of 64 offspring, 6 will havve the genotype aaBBCcDd, 1 will be AaBBCcDD, and so on.

As a more concrete example, lets pretend these are cornsnakes. If 'a' were amel, 'c' were anery, and 'd' were stripe (B is normal... we could say 'b' was hypo... but since neither snake has it, it doesn't matter). The parents of this cross then are an anery het for amel and stripe, and an amel het for anery and stripe. Going by the results on the diagram, of their snow offspring, 9 will be snow stripes, 18 will be snows het for stripe, and 9 will be snow NOT het for stripe (27 will look like regular snows)

I know it looks complicated... but a Punnet's square for this would have 64 compartments... and if BB weren't homozygous in both parents, it would make a punnet's square with 256 compartments! (in a forked line however, it will still fit on one page)

You can also do a faster diagram just for phenotype (or add up the phenotypes from the genotype chart... I added them and included them on this one)... I can do a phenotype chart and post it if you like.

Dawn

[Jeff_Favelle]

Its all coming back to me now (like a bad nightmare!!!).

Good stuff! Better you than me!!

[Tim_Cranwill]

Hey, thanks Dawn. I see what you mean. Your example is actually very similar to what I was trying to figure out earlier today. I appreciate the time you took to help me.

:)

[Cas]

cranwill, you're welcome... I rather enjoy genetics (odd, considering I never liked math word problems, which is basically what genetics boils down to!) so it was no trouble. :) In fact, it gave me an excuse not to study for my animal physiology midterm for a little while, so it's all good! *L*

Dawn

[tai_pan1]

My brain is spinning!