Reptile & Amphibian Forums

Is this flame gene a heterozygous dominant trait? I had someone e-mail me and tell me that this was so because flame x normal =all flame babies
That has to be incorrect, and I would like to clear it up on here for him to see.

I don't believe that because then everyone would be buying those big wc garters from the importers in FL to make tons of flame babies. The true flame garter, at least in my mind, are from that Canada locale and from Blais. I know there are reds in FL and the eryth. types.

Any comments? I have been told by flame breeders that flamexflame can even result in litters with some normal babies! Also, the degree of red varies within litters, correct? There has got to be something else at work here.

This can't be a het dominant trait.

Someone please help...
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Anthony Chodan

www.gradeareptiles.com

If you have a really high red flame and breed it to a normal.It is possible to get some high end flames.I had a breeding like this a couple of years ago.3 high ends 3 others with a little color and all the rest were normal.Lat year when I bred my two high ends I got 6 flames(3 were stillborn)and 6 that were pretty much normal.This years bred the same snakes and got 13 high ends 1 normal.definitely not a het trait.Some kind of dominant trait.

Hey AC,

Saw your post on the Pine Barrens, very cool! On the flame issue, I bred a flame to both erythristics and a leucistic. The leucistic originated in PA, flames from Canada. On this cross, all of the babies ended up as flames, most high ends and a few moderate. On the erythristic/flame cross, there seemed to be a combination of the 2 in the F1's. For the last 2 years I bred the same male and female together and last year got flames, this year got erythristics. Go figure?! From this would assume both traits are dominant? Paul H., if you read this any thoughts?

Scott

Hi Scott,

If leucistic here is like leucistics in other species, the mutant gene is recessive to its normal allele. The result from your flame x leucistic mating is consistent with that idea, but more matings would be needed to prove it.

Erythristic -- don't know yet. Not enough data.

Flame seems to be acting like a dominant mutant gene that has some variability in expression. A heterozygous flame has a flame mutant gene paired with a normal gene in the cells and shows the flame appearance.

Mate a heterozygous flame to a normal, and statistically, half the babies would be normal, while the others would be flames (heterozygous flame).

Mate two heterozygous flames, and statistically, 25% of the babies would be normal, while the others would be flames. Broken down further, 25% normal, 50% heterozygous flame, 25% homozygous flames.

Have any flames from a flame x flame mating produced more than 20 babies in a mating with a normal? If none of the babies was normal, then the flame parent could be homozygous flame (with a pair of identical flame mutant genes in the cells). A homozygous flame would be great for maximizing production of flames.

Paul Hollander

Paul,

Thanks for the response to the post. Interesting genetics with the flames. When you say dominant as in "Flame seems to be acting like a dominant mutant gene that has some variability in expression" do you mean dominant as in a truly "dominant" trait or dominant as in domineering? If the trait is truly dominant in nature then wouldn't that make it impossible to produce hets?
Like some of the ball python and boas, some of the mutations are dominant and co-dominant, meaning they only produce the particular morph that the adults are.

Scott

Hi Scott,

If leucistic here is like leucistics in other species, the mutant gene is recessive to its normal allele. The result from your flame x leucistic mating is consistent with that idea, but more matings would be needed to prove it.

Erythristic -- don't know yet. Not enough data.

Flame seems to be acting like a dominant mutant gene that has some variability in expression. A heterozygous flame has a flame mutant gene paired with a normal gene in the cells and shows the flame appearance.

Mate a heterozygous flame to a normal, and statistically, half the babies would be normal, while the others would be flames (heterozygous flame).

Mate two heterozygous flames, and statistically, 25% of the babies would be normal, while the others would be flames. Broken down further, 25% normal, 50% heterozygous flame, 25% homozygous flames.

Have any flames from a flame x flame mating produced more than 20 babies in a mating with a normal? If none of the babies was normal, then the flame parent could be homozygous flame (with a pair of identical flame mutant genes in the cells). A homozygous flame would be great for maximizing production of flames.

Paul Hollander

I use standard definitions for various genetics terms like dominant, recessive, and heterozygous. The boa and ball python guys use their own pseudogenetics slang. I strongly encourage everyone to dump the pseudogenetics and talk the pro geneticists' talk.

Standard genetic definitions:
heterozygous = the two members of a pair of genes are different.
homozygous = the two members of a pair of genes are the same.

In other words, a garter with a pair of flame genes is homozygous flame. A garter with a flame gene paired with a normal gene is heterozygous flame. A garter with an albino gene paired with a normal gene is heterozygous albino. Please note that the snake's appearance does not affect whether the snake is heterozygous or homozygous. The appearance of the heterozygous snake does affect whether a mutant gene is classed as a dominant, codominant, or recessive mutant gene.

More standard genetics definitions:
Recessive mutant gene = A mutant gene which produces a detectable effect on an animal only when the gene is homozygous. The heterozygous animal looks normal.
Dominant mutant gene = A mutant gene which produces a detectable effect on an animal when the gene is homozygous or heterozygous. The heterozygous animal looks like the homozygous animal, and neither looks normal.
Codominant mutant gene = A mutant gene which produces a detectable effect on an animal when the gene is homozygous or heterozygous, but the heterozygous animal does not look like the homozygous animal.
Trait = a difference from the normal appearance which is caused by a mutant gene. See phenotype in a genetics text. Traits are not dominant or recessive; genes are dominant or recessive to another gene.

As a heterozygous flame garter does not look normal, the flame mutant gene is either dominant or codominant to the normal gene. Maybe someone can tell me whether the homozygous flame looks significantly different from the heterozygous flame. Right now I'm just classing flame as either dominant or codominant.

Paul Hollander

Paul,

Thanks for the explanation. I almost bred a Florida to a flame this year but didn't. Hopefully will try that cross next year, will be interesting to see how the babies turn out w/ that combo.

Scott

thank you Paul & Alice. I havent done this since middle school. We studied Mendel then, so I'll go over that site and see how well it helps me understand, it might take a couple tries though.

Scott,
How is that lucy project going anyway?When can we expect lucy offspring?

I was glad to see that we were all on the same page. Tom, when I said that it was heterozygous dominant, all that meant was that only one parent had the gene, not that it was het for it (like in simple genes like albinism). When it comes to dominant genes, traits can be expressed when the offspring are heterozygotes. Its been 2 years, since college genetics, so I have to brush up myself.

This flame gene certainly sounds to be exhibiting co-dominance or incomplete dominance.
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Anthony Chodan

www.gradeareptiles.com

I have not (yet) considered breeding, but I still have a genuine interest in learning as much as humanly possible about anything I might look to in the future when I can get me some snakes. (I want more something terrible, I still can't believe I don't have my Gopher anymore)

Okay, this genetic stuff is kind of confusing to me, (science was never my strong point, and I have a Chemistry class next semester ……….oy!) and if anyone can help me figure this out I would greatly appreciate it. So, if you had a certain coloration or pattern, you would have to breed the snake to a normal, to rule out dominant, then another w/ that trait to determine if it’s a recessive gene? Can you determine co dominance from 1st gen?

So desired trait x normal = het…… regardless of dominance?
So DT x normal = DT babies, then it’s dominant
And, if DT x normal = all normal, then its codom??
But DT x DT = definite recessive

The only part I have ever really comprehended was the XY male/female thing, if someone could please help explain it using that as a starting point example, which might help.

This is a little tricky for me, sorry.
-lisa

Some traits are polygenetic, they are controled by multiple genes. Skin color in people would be an example. In the case of snakes, it could be that the green color on Gopher was controlled by multiple genes, it this was the case, you'd want to pair her up with a snake as close to her color as possible, keep the best colored babies and breed them. With a few generations of this selective breeding you can produce snakes that display better more consistant color.

The color could also be recessive like in albino. In this case, when bred to a normal, all the babies would be normal, but would be carrying the recessive gene. In order for a recessive gene to be displayed the snake must have two copies; one from mom and one from dad. Sine the babies would all have one albino gene they would be termed heterozygous for albino (hets). If you were to breed one of the hets back to the albino parent, half the babies would be hets and half would be albinos. The albino parent can only give albino genes, but the offspring would have 50% cnance of getting an albino gene from the het parent and a 50% chance of getting the dominant normal gene. If you were to breed two hets together the babies would have a 25% chance of getting the albino gene from both parents, and a 50% chance of getting an albino gene from one parent and a normal gene from the other, and a 25% chance of getting normal genes from both parents. The problem with doing this cross is that you wouldn't be able to tell the normals apart from the hets. Probability wise, 2/3rds of the normal looking babies should be hets and 1/3 should be normal. 2/3rds = 66% and this is why you see some herps marketed as 66% possible hets meaning that they have a 66% chance of being a het.

In the case of co-dominat traits, there can be an intermediate form. An animal with two copies of the co-dominant gene would be termed a super. The hets would express the trait but in an intermediate form.

In the case of dominant traits the animal would express the trait with a single copy of the gene. In most cases, the normal coloration is a dominant trait.

-Alice

>So, if you had a certain coloration or pattern, you would have to breed the snake to a normal, to rule out dominant, then another w/ that trait to determine if it’s a recessive gene? Can you determine co dominance from 1st gen?

You have to breed the shake to a normal to begin the process of determining whether a trait is caused by one or more mutant genes. If the trait is caused by only one mutant gene, then two or more generations are required. If there is only one mutant gene, and that gene is a recessive, then two generations are the minimum. If the mutant gene is a dominant or codominant, then multiple matings and more than two generations are required.

>So desired trait x normal = het…… regardless of dominance?
>So DT x normal = DT babies, then it’s dominant
>And, if DT x normal = all normal, then its codom??
>But DT x DT = definite recessive

No, for all of these four cases.

>The only part I have ever really comprehended was the XY male/female thing, if someone could please help explain it using that as a starting point example, which might help.

I can't even do that. Because the garter snake sex chromosomes are Z (big) and W (small). Males are ZZ, and females are ZW.

The reason I answered "no" above is because each parent in the cross has two genes. It is the combination of the two genes that determines what the parent individual looks like. And as each parent contributes one of its two gene to each offspring, the babies do not have to all look alike.

Maybe this will help. Take some quarters and pennies. The rules of the dominant/recessive game:
1) you can have two quarters or two pennies or a quarter and a penny in a two coin stack.
2) the quarter is always on top.
3) you can't tell what the bottom coin is.

Results:
If the top coin is a penny, then the bottom coin must also be a penny.
If the top coin is a quarter, then the bottom coin is either a quarter or a penny.

If you have a stack of two quarters, then the stack is homozygous quarter.
If you have a stack of two pennies, then the stack is homozygous penny.
If you have a stack of a quarter and a penny, then the stack is heterozygous quarter/penny.

The quarter is dominant to the penny because it masks the presence of the penny in the heterozygous stack.
The penny is recessive to the quarter because the penny's presence in the heterozygous stack is masked by the quarter.

Take some quarters and pennies. The rules of the codominant game:
1) you can have two quarters or two pennies or a quarter and a penny.
2) you can see both coins rather than just one.

In the dominant/recessive game, the gene for the DT could be the equivalent of the quarter, and the normal gene could be equivalent to the penny. If so, then the gene for the DT is a dominant mutant gene.

Or in the dominant/recessive game, the gene for the DT could be the equivalent of the penny, and the normal gene could be equivalent to the quarter. If so, then the gene for the DT is a recessive mutant gene.

In the codominant game, it doesn't matter which coin is equivalent to the DT and normal genes. Because you can see the effect of both in the stack.

Breeding tests are required to determine whether the genes are playing the dominant/recessive or codominant game.

I'm adding a link to the "Blue Genes" genetics web site. It may be helpful, though it is not perfect.

Paul Hollander
"Blue Genes" genetics web site

30 years since I had any genetics. I do like those red snakes. Has anyone tried to puzzle this out on the advanced genetics wizard? I have looked at the site and couldn't do it.

http://www.geneticswizard.com

Mike B

I prefer pencil and paper to the Genetics Wizard. Just remember, there are only six possible crosses when there are two alleles (A and a):

1. AA x AA --> all AA
2. AA x Aa --> 1/2 AA, 1/2 Aa
3. AA x aa --> all Aa
4. Aa x Aa --> 1/4 AA, 2/4 Aa, 1/4 aa
5. Aa x aa --> 1/2 Aa, 1/2 aa
6. aa x aa --> all aa

There are three inheritance modes:
1. The allele A could be a dominant mutant gene, and a is the (recessive) normal gene.
2. The allele a could be a recessive mutant gene, and A is the (dominant) normal gene.
3. The allele A could be the mutant gene and codominant to a, the normal gene.

I will leave it as an excercize for the reader to work out the differences in the appearances of the parents and babies in the six matings in the three inheritance modes. In a breeding test, the first generation hopefully matches cross 3 but could be cross 5. In cross 3, all babies are alike. In cross 5, there are two groups of babies. In the second generation, similar babies from the first generation are mated together. At least some of those crosses should be cross 4, and the numbers and appearances of those babies, along with the parents' appearance, will exclude all but one inheritance mode.

Paul Hollander

Mike B

According to Blais it's a polygenetic trait like human skin color.

Anytime you want to get back into flames just let me know during the breeding season.I will have some babies for you.

Scott and Paul,
Basically all of this is telling me that Certain colors/patterns are dominant traits? Erythristic first cross with normal has given me mostly erythristics? I had 3 normal colored babies out of 15 why does this not sound correct?

Three normals out of 15 babies does seem pretty far off the number I'd expect, but it's not impossible. You may have just been lucky. As to whether erythristic is actually a dominant mutant gene, I don't have enough information to be able to say. But if anyone wants to post about 10 matings of erythristic x erythristic and erythristic x normal with the number of normal and erythristic babies in each litter, I might be able to get a handle on it.

Paul Hollander

Paul,
I cannot give that kind of data yet but maybe Scott can? I was actually led too this thread by someone offline and I was told that erythristic babies go through a color change as they age?
Paul Pipes

Hey Tom,

How ya, doing. That's ok. I don't need any snakes. That is a very nice snake you have there. Good luck.