Reptile & Amphibian Forums

what percentage of what type of ball python will i get my crossing the following?

normal to spider
spider to spider (assuming super spiders do not exist)

thank you
-z

Well if you bred spider X normal with them being dominant you would get 100% spiders and with breeding Spider X Spider you would just get 100% spiders also because there is no super Spider...

Correct me if im wrong..........Mike
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Mike and Eric
Captive Bred Reptiles

I believe they are incomplete dominance because there is no "super spider" as of yet.

But Spider X Normal is statistacally 50% spider/50% normal.

Spider X Spider is 100% Spider... possible Super Spiders.

>>Well if you bred spider X normal with them being dominant you would get 100% spiders and with breeding Spider X Spider you would just get 100% spiders also because there is no super Spider...
>>
>>Correct me if im wrong..........Mike
>>-----
>>Mike and Eric
>>Captive Bred Reptiles
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- Joel Smith

"If you're not part of the solution, you're still part of the problem"

boa boy, what happen to your pastel post?

::
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Mike and Eric
Captive Bred Reptiles

do you have any pics of your racks or anything? right now ive got a heavy @$$ rack made of MDF and pegboard. what other morphs do you have? are they in the gallery?

We have het albinos gravid by hets. A ghost male that is breeding now, a couple pastels, our tiger balls and our super tiger ball. We dont use racks, we have cages 10g-20g and some of my snakes are pictured on the gallery.

Thanks
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Mike and Eric
Captive Bred Reptiles

:::

mike
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Mike and Eric
Captive Bred Reptiles

It is a different type of dominance, like I said above. It's not co-dominant like the Pastel, which has the visually different Super Pastel.

It all depends on the dominance, and like you said that breeding a Spider to a normal will yield a 100% spider clutch, that is wrong.

Statistically a Spider X Normal Breeding will yield a 50/50 mix of normals and spiders.

I'm not going to argue anymore about this, I may have some terms wrong but I know that a spider doesn't throw a 100% spider clutch. Have a good night..

carry on.

Joel

>>:::
>>
>>
>>
>>mike
>>-----
>>Mike and Eric
>>Captive Bred Reptiles
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- Joel Smith

"If you're not part of the solution, you're still part of the problem"

arguing, I didn't mean it that way. Just in context of the debate.

>>It is a different type of dominance, like I said above. It's not co-dominant like the Pastel, which has the visually different Super Pastel.
>>
>>It all depends on the dominance, and like you said that breeding a Spider to a normal will yield a 100% spider clutch, that is wrong.
>>
>>Statistically a Spider X Normal Breeding will yield a 50/50 mix of normals and spiders.
>>
>>I'm not going to argue anymore about this, I may have some terms wrong but I know that a spider doesn't throw a 100% spider clutch. Have a good night..
>>
>>carry on.
>>
>>Joel
>>
>>>>:::
>>>>
>>>>
>>>>
>>>>mike
>>>>-----
>>>>Mike and Eric
>>>>Captive Bred Reptiles
>>-----
>>- Joel Smith
>>
>>"If you're not part of the solution, you're still part of the problem"
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- Joel Smith

"If you're not part of the solution, you're still part of the problem"

np

Mike
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Mike and Eric
Captive Bred Reptiles

The short answer is that even though spider may be a completely dominant mutation, heterozygous spider X heterozygous spider does not produce 100% spiders - each egg has a 25% chance of producing a normal.

The following is the long answer on why and how I find it easier to understand inheritance by ignoring mutation types and looking at genotypes and then use the mutation type later to figure out the phenotypes.

There seems to be a lot of confusion over the term "dominant".

For one thing, people use "dominant" to describe both any type of non-recessive mutation before we know yet if it's co-dominant (some prefer "incompletely dominant" and the proven "completely dominant" mutation types. To avoid this confusion I prefer to use "some type of dominant" for mutations such as spider where we know it's not recessive but we really aren't completely sure yet if it's co-dominant or what I like to call "completely dominant". I don't think "completely dominant" is really a text book term but then in the scientific community they probably would wait until they knew the inheritance for sure before they described it and we need a way to talk about it for the years that it's sold before being completely figured out.

The next point of confusion is between the mutation types (recessive, co-dominant, and completely dominant) and the inheritance. The mutation type tells you what the mutant genotypes (heterozygous mutant, homozygous mutant) look like relative to each other and normal. It doesn't change the basic rules of how the genes are inherited which apply to all non sex linked mutations and are pretty simple until you start throwing in mutant alleles (different mutations of the same gene).

With the recessive mutation type, the heterozygous mutant (one mutant copy of the gene and one normal copy of the gene) should look normal. Heterozygous refers to the genotype (describing it's genes) of the animal and it's appearance is it's phenotype.

With co-dominant (or perhaps better referred to as incompletely dominant) the heterozygous genotype does not look normal and the homozygous mutant genotype looks different yet. Usually the phenotype of the homozygous mutant genotype is more extreme than the heterozygous genotypes (i.e. super pastel vs. pastel).

With the completely dominant mutation type we would expect the homozygous mutant to look just like the heterozygous mutant but different than normal. If it turns out that spider is completely dominant then homozygous spiders will look just like heterozygous spiders. Even just one copy of the mutant gene is completely dominant over one normal copy of the gene so the heterozygous spider is just as spider as the homozygous one with two copies.

As far as inheritance of the genotypes, you can forget for a minute what type of mutation you are talking about. If we are talking about single non-sex linked mutant genes without multiple mutant alleles then the same simple rules apply regardless of the mutation type.

Each egg has the following odds:

1. Heterozygous X Normal = 50% chance heterozygous, 50% chance normal

2. Heterozygous X Heterozygous = 25% chance homozygous, 50% chance heterozygous, 25% chance normal

3. Heterozygous X Homozygous = 50% chance homozygous, 50% chance heterozygous

4. Homozygous X Homozygous = 100% chance homozygous

5. Homozygous X Normal = 100% chance heterozygous

If you can remember these 5 rules then all you have to do is figure out what you are breeding.

The vast majority if not all spiders so far have been heterozygous for the spider gene. From #1 above you can see that heterozygous spider X normal should produce babies that each have a 50% chance of being heterozygous spider and a 50% chance of being normal for the spider gene. From #2 you see that heterozygous spider X heterozygous spider produces babies that still have a 25% chance of being normal. However, here is where it gets a little interesting, will 1/3 of the spiders produced be homozygous super spiders and the other 2/3 heterozygous spiders like the parents? If the mutation is completely dominant the homozygous spiders will look just like the heterozygous spiders and you will not know for sure that they have been produced until you grow them up and produce a large number of only spiders breeding one of the homozygous ones to normals as in #5. This takes time and is why we can't be sure yet if spider is completely dominant.

Maybe spider will turn out to be co-dominant after all and NERD just hasn't been lucky enough to produce a homozygous spider from heterozygous spider X heterozygous spider breedings so far. Maybe two copies of the gene are lethal and there will never be a homozygous spider (this will take even longer to reasonably prove).

I love your genetics posts.

>>The short answer is that even though spider may be a completely dominant mutation, heterozygous spider X heterozygous spider does not produce 100% spiders - each egg has a 25% chance of producing a normal.
>>
>>The following is the long answer on why and how I find it easier to understand inheritance by ignoring mutation types and looking at genotypes and then use the mutation type later to figure out the phenotypes.
>>
>>There seems to be a lot of confusion over the term "dominant".
>>
>>For one thing, people use "dominant" to describe both any type of non-recessive mutation before we know yet if it's co-dominant (some prefer "incompletely dominant" and the proven "completely dominant" mutation types. To avoid this confusion I prefer to use "some type of dominant" for mutations such as spider where we know it's not recessive but we really aren't completely sure yet if it's co-dominant or what I like to call "completely dominant". I don't think "completely dominant" is really a text book term but then in the scientific community they probably would wait until they knew the inheritance for sure before they described it and we need a way to talk about it for the years that it's sold before being completely figured out.
>>
>>The next point of confusion is between the mutation types (recessive, co-dominant, and completely dominant) and the inheritance. The mutation type tells you what the mutant genotypes (heterozygous mutant, homozygous mutant) look like relative to each other and normal. It doesn't change the basic rules of how the genes are inherited which apply to all non sex linked mutations and are pretty simple until you start throwing in mutant alleles (different mutations of the same gene).
>>
>>With the recessive mutation type, the heterozygous mutant (one mutant copy of the gene and one normal copy of the gene) should look normal. Heterozygous refers to the genotype (describing it's genes) of the animal and it's appearance is it's phenotype.
>>
>>With co-dominant (or perhaps better referred to as incompletely dominant) the heterozygous genotype does not look normal and the homozygous mutant genotype looks different yet. Usually the phenotype of the homozygous mutant genotype is more extreme than the heterozygous genotypes (i.e. super pastel vs. pastel).
>>
>>With the completely dominant mutation type we would expect the homozygous mutant to look just like the heterozygous mutant but different than normal. If it turns out that spider is completely dominant then homozygous spiders will look just like heterozygous spiders. Even just one copy of the mutant gene is completely dominant over one normal copy of the gene so the heterozygous spider is just as spider as the homozygous one with two copies.
>>
>>As far as inheritance of the genotypes, you can forget for a minute what type of mutation you are talking about. If we are talking about single non-sex linked mutant genes without multiple mutant alleles then the same simple rules apply regardless of the mutation type.
>>
>>Each egg has the following odds:
>>
>>1. Heterozygous X Normal = 50% chance heterozygous, 50% chance normal
>>
>>2. Heterozygous X Heterozygous = 25% chance homozygous, 50% chance heterozygous, 25% chance normal
>>
>>3. Heterozygous X Homozygous = 50% chance homozygous, 50% chance heterozygous
>>
>>4. Homozygous X Homozygous = 100% chance homozygous
>>
>>5. Homozygous X Normal = 100% chance heterozygous
>>
>>If you can remember these 5 rules then all you have to do is figure out what you are breeding.
>>
>>The vast majority if not all spiders so far have been heterozygous for the spider gene. From #1 above you can see that heterozygous spider X normal should produce babies that each have a 50% chance of being heterozygous spider and a 50% chance of being normal for the spider gene. From #2 you see that heterozygous spider X heterozygous spider produces babies that still have a 25% chance of being normal. However, here is where it gets a little interesting, will 1/3 of the spiders produced be homozygous super spiders and the other 2/3 heterozygous spiders like the parents? If the mutation is completely dominant the homozygous spiders will look just like the heterozygous spiders and you will not know for sure that they have been produced until you grow them up and produce a large number of only spiders breeding one of the homozygous ones to normals as in #5. This takes time and is why we can't be sure yet if spider is completely dominant.
>>
>>Maybe spider will turn out to be co-dominant after all and NERD just hasn't been lucky enough to produce a homozygous spider from heterozygous spider X heterozygous spider breedings so far. Maybe two copies of the gene are lethal and there will never be a homozygous spider (this will take even longer to reasonably prove).
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- Joel Smith

"If you're not part of the solution, you're still part of the problem"

explaining all that. I took a genetics class in college but I couldn't begin to explain what you said! SJM

I only had biology in High School, took Physical Oceanography for my college science elective (can't remember why now). It's just something that interests me and I think about. Hope I'm not too far off textbook correct.

quite famously with a guy named Mendal!!! SJM

Of course, the field is developing and genetics is becoming much more complicated as more factors are discovered... very interesting stuff!

Spider X Normal = 50% Spider, 50% Normal

Spider X Spider = 75% Spider, 25% Normal

Randy, Your explaination was very informative. Thanks.
Markus Jayne Ball Pythons