Reptile & Amphibian Forums

How is this possible? Spider is a dominant trait so how can there be normal siblings to a spider? Please help me understand.
Thanks
Mitchell Dudley

TWO alleles for every trait. Simple genetics. One allele is non-spider (wild-type).

Of Course they can have siblings, they just aren't spiders. They are normal ball pythons that are captive bred and born and command higher prices then wild caught or farmed balls.

Mark

>>How is this possible? Spider is a dominant trait so how can there be normal siblings to a spider? Please help me understand.
>>Thanks
>>Mitchell Dudley

in the trade we call it co-dominant eventhough thats a completly different thing.

Spiders are NOT co-dominant (well, most likely not). Please inform is where you got the impression that they were. I'd very much like to see a super spider.

can you give me a quick clarification on the difference between incomplete and co dominance, please? I think that I may be misinformed or misunderstand the terminology.

thanks
Tom

Co-dominant is when both traits are equally expressed to the offspring while incomplete dominant is where the trait like a pastel will be expressed in the first generation but not inherited to all the offspring. I did not major in genetics so this is as far as I understand it but I did recently ask a phd in genetics about this and from what I was told the term co-dominant is incorrectly used in the snake trade. It honestly does not matter though. It is really only used for the market anyway and nobody is going to change what they are used to. And I have no idea about super spider..I was always under the impression it just was not done yet. I too would like to know what the genetics are then.

Incomplete dominance is what the reptile industry calls "co dominant".

Incomplete dominance is when two traits combine to create a "mixture" of the two. An example would be if you mixed a super pastel and a normal and came with a pastel. The normal and super pastel mix to make something inbetween.

Co dominance is when two traits combine to fully express each trait. An example would be if you mixed a leucistic ball python with a normal and made a piedbald. A piedbald has white (leucistic) and normal (normal) colors.
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0.1 "Tremper" looking Albino Leopard gecko (Lex)
0.0.1 tiger crested gecko (peachs)
0.1 Red blood python (Rhianon)
0.0.1 ball pythons (FELIX!!!!!)
2.1 Feral cats that we adopted (Fuzzy, Bear, and Tony)

"scientia est vox"

to my understanding both of what you stated would be co-dominant...incomplete dominant is expressed fully in offspring but is not expressed to the entire clutch. like your 50% pastels and 50% normals.

to my understanding both of what you stated would be co-dominant...incomplete dominant is expressed fully in offspring but is not expressed to the entire clutch. like your 50% pastels and 50% normals.

NO.

Here's an idea...if your going to tell someone they're wrong, then you should atleast follow up with WHY they are wrong. What good does it do otherwise? Make you look better than someone else? I doubt knowing the genetics of a ball python makes anyone superior to any other person. For some general info, and a place where they obviously know what they're talking about, visit NERDS website. Newenglandreptile.com and do some reading. Understandably, there is no reason Jeff should have to spell out things for people when the info is readily available to anyone willing to search it out, but I think if he's going to correct someone it should atleast be informative rather than just insulting. Just my opinion, take care

MAYBE, instead of spending 2 hours telling someone why YOU think they posted a short answer, you would just take the time to answer it yourself.

liliroach explained how it works. Then eunectes explained how he thought that was wrong. I agreed with liliroach. What is the point of regurguing what liliroach JUST posted? For YOUR benefit?

No thanks.

I don't need your input to understand the question posted. It just kills me how arrogant you are, but you can't take the time to explain to someone how they're wrong? Maybe you really don't know yourself? It's pretty easy to read someone else's post and say....yeah, I agree with him-WOW, now I'm impressed! Maybe, the problem is you can regurgitate something you read to SEEM like you KNOW the answer, yet you don't TRULY know enough to correct someone when they are off the track a little bit? I had a teacher in high school like that once. She was flunking the entire class because if your answer was not word for word out of the book, she wasn't able to decipher what you really meant. Funny thing about this was the fact that one of my classmates was also in college level science classes running a 4.0 average, yet supposedly he couldn't handle high school biology??? I'm starting to think this might be your story. Yes, YOU know the answer, but without a FULL UNDERSTANDING of it yourself, you can't properly correct someone so that they will understand the problem when your done. So, you hide behind the little tough guy, smart a@@ posts and assume we will all be either impressed with your cracker jack knowledge or too intimidated to question you. I'm neither, so insult away Jeff, I'm here to live it up and laugh my a@@ off at your attempts to make me feel beneath you. By the way....two hours???? I don't hunt and peck the keys, and I don't have to take breaks to rest my head, or look up words, so I'd say this response to you took, about 2 minutes. See ya! P.S...feel free to answer my posts with a one word response, and save me some time. If you are dying to insult me, click the little PBM at the top of this post and e-mail me to your hearts delight!

You could change your nick to PMS.

nm

LOL, I hadn't read lilroaches post. So, in your words and his, since you agree with him. I can breed, potentially, a lucy and a normal and get pieds, and that explains it all perfectly? Why on earth would this be a plausible explanation???

we all know pied is recessive but if both genes were co-dominant you would get 50% white pieds.

"we all know pied is recessive but if both genes were co-dominant you would get 50% white pieds."

Would you? Can you prove this? There really is no need to make things up, as there are multiple proven traits available to use as examples. Can you not see how this example may confuse someone? Look around, there are people on here asking what size cage their NEW ball python should be kept in....SO, EVERYONE knows pieds are recessive? I'm thinking probably not.

honestly I think the majority of people here (including myself and I go by what I read and hear but thats not always an accurate means) know very little about genetics and this is almost useless

I would assume anyone that can find this web-site would know what to feed their new ball python....Ya just never know! Either way, I'm done, take care!

Paul

I cannot think of a morph that is truely co-dominant.

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3.12 Ball Pythons
0.1 Mutant Thayeri

The Ebony appears to be the combination of two genes - yellow belly and granite. I would think that the mutation type would be defined in relation to the normal copy of that gene. So yellow belly appears to be either co-dominant or incompletely dominant (which ever word you think is right) in respect to normal because you can see the hets and the homozygous are different mutants than the hets. The gene may behave differently with regards to other non-normal copies of the same gene but I think the definition of the mutation type would be how it behaves with normal.

I don't know if a homozygous granite has been proven yet. It will also be very interesting to see what the ebony produces as that may help us figure out if granite and yellow belly are related (maybe they are different mutations of the same gene - alleles).

To expand on MarkS' post below, you need to remember the difference between the genotype (heterozygous, homozygous) and the mutation type/inheritance (recessive, co-dominant/incomplete dominant, completely dominant). There is a lot of confusion in this area.

The NERD site is a wealth of information they apparently worked hard to provide to the herp community but even it falls into this confusion on http://www.newenglandreptile.com/genetics_codom.html

In places they are using the word "dominant" where they should be using "homozygous". The mutation type doesn't chance depending on if you are looking at a homozygous animal (example super pastel) or a heterozygous animal (example regular pastel). The pastel gene is still the same type of gene (I'm frankly not sure if co-dominant or incomplete dominant is the more correct term). The breeding outcome changes when you change the genotype (heterozygous or homozygous) of the parents but that doesn't change the mutation type from co-dominant to dominant.

Actually I find it helpful to use the genotype terms whenever possible (like heterozygous spider) because the same rules of inheritance apply regardless of mutation type. For example, het X normal = 50% chance of being a het either with a recessive mutation like albino or with a dominant one like spider. The big difference is that you can identify which ones hit their chance with a dominant type mutation. So the mutation type (dominant, recessive, etc.) tells you what the different genotypes (heterozygous, homozygous) look like (phenotype) in relation to each other. When you start getting into more complicated combination of different mutation types it's nice to know that they all follow the same genotype rules (at least for now, some day we might find a sex linked mutation to complicate things).

So then it would'nt be...?

pastel (het) = "Incomplete dominant" ?
Super pastel = "Complete dominant" ?
spider = "dominate" ?

"""The Ebony appears to be the combination of two genes - yellow belly and granite"""

So then its a co-incomplete dominant. lol

...and here i thought i had a good understanding of these things.sigh
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3.12 Ball Pythons
0.1 Mutant Thayeri

"So then it would'nt be...?

pastel (het) = "Incomplete dominant" ?
Super pastel = "Complete dominant" ?
spider = "dominate" ? "

The same gene (pastel) can't be both incomplete dominant and complete dominant, at least in relation to the normal version of that gene. The mutation type stays the same and is actually defined by the difference between the heterozygous, homozygous, and normal.

The genotype is what is changing, from heterozygous (regular pastel) to homozygous (super pastel).

>pastel (het) = "Incomplete dominant" ?

Should be pastel (het) = heterozygous codominant (or heterozygous incomplete dominant)

>Super pastel = "Complete dominant" ?

Should be super pastel = homozygous codominant (or homozygous incomplete dominant)

Paul Hollander

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Chad Bachman

I really do not care about the bickering back and forth and i did not read 80% of it. What I was saying is a lucy and a normal making a pied (eventhough we know it isnt the case) is the same explaination as a super pastel and and normal making pastels...both genes express equally (co-dominant). These were examples that would be easy to visualize. If a gene like a spider is expessed to % of the offspring and the % would be normal than this is incomplete dominant. Where was I wrong? I have been to NERDs website a number of times and looked at tons of punet squares. All I am saying is from what I have looked into as far as genetic terms go is the entire industry (including NERD) is incorrectly terming co-dominance.

...incomplete dominant is expressed fully in offspring but is not expressed to the entire clutch. like your 50% pastels and 50% normals.

Nope, that just proves that the pastel parent is heterozygous. All genes are paired. When the two genes are identical to each other they are called homozygous, if they are different from each other, then they are heterozygous. Only one half of each gene pair goes into the making of either a sperm or an egg. If the pastel half of the pair goes into it, the offspring will be a pastel (thats why it is a form of dominant). If the normal half of the pair goes into it, the offspring will be normal. It works the same way as producing 50% possible hets with recessive traits, the difference being that you can visibly tell which ones are the hets and which ones are not. Just think of pastels as being het for super pastel.

you are more correct than I originally thought...I believe you just got it mixed up. Incomplete would be more like a normal x lucy =pied and super x normal = pastel. Either way the industry has it a little off and to my understanding the spiders and pastels being % spider or % pastel is a form of incomplete dominant. This was all that could be determined after explaining this goofy snake trade to someone with a phd in genetics.

way too confusing and not exactly correct either.

For the record, your explaination was correct so dont confise me saying "not quite" with you being incorrect. After reading it a few times I saw what you ment by it..the first time I read it it looked like the same thing (I saw what you mean by the "mixture" later...but I am still not so sure that can't be used to explain co-dominant and incomplete dominant as you did with the superxnorm=pastel and the lucy x norm= pied but I think I follow you). The only thing I am still hung up on is the % offspring as normal and the % as pastel or spider or whatever being a form of incomplete dominance. I never claimed to have a degree in genetics but that was the consesus reached when talking to someone with one. However, someone who studies fruit flies may not have been exactly with me on my talk of snake genetics.

Dominant just means that even one mutant copy of the gene completely dominates a normal copy of the same gene so that a het is just as much mutant looking as a homozygous mutant would be.

So far, most if not all spiders have been heterozygous for the spider mutation. That is, they have one copy of the spider mutation and also have one normal copy of that mutation. On average, 50% of their offspring to a normal get the normal copy of the gene from the spider parent (and of course also from the normal parent) making them normals for the spider gene.

Even with spider (het) X spider (het) you should still get 25% that get the normal gene from both parents and are completely normal for spider. The big question is what happens with the 25% that should get the spider gene from both parents and be homozygous spider. If the gene is completely dominant they should look just like the heterozygous spiders but they will produced 100% spiders when bred to a normal because they don't have a normal copy of the spider gene to give.

I'm not aware of any homozygous spiders proving out yet which makes me wonder if it just hasn't been long enough for enough spiders produced from spider X spider pairings to have bred yet to find the 1/3 that should be homozygous or if somehow a homozygous spider isn't possible.

Hey Randy, I thought Kevin had produced from spider x spider and found the "super" to be no different visually. Kevin labels spiders as Dominant. But, I'm not sure, so I guess we all need to get Kevin to put his thoughts in on this somehow. Take care

Paul

My understanding is that even though there have been many spider to spider breedings, there have been none produced that look visually different. The only way to tell if a spider is homozygous is to breed it and see if all of it's offspring are spiders.

Mark

>>Hey Randy, I thought Kevin had produced from spider x spider and found the "super" to be no different visually. Kevin labels spiders as Dominant. But, I'm not sure, so I guess we all need to get Kevin to put his thoughts in on this somehow. Take care
>>
>>Paul

If we could know how many spiders from spider X spider have been bred and if indeed none have yet produced all spiders it would help on figuring if there is no homozygous spider or if it just hasn't been long enough to prove one yet.

This subject comes up every so often.

Mendel found that if there were two alleles, they could be arranged in three pairs -- two copies of the first allele, two copies of the second allele, and a copy of the first allele paired with a copy of the second allele. His work showd that these three pairs produced two different physical appearances. IOW, the organism with a copy of the first allele paired with a copy of the second allele looked like one of the other two. He used dominant and recessive to refer to the two different alleles.

Later, a number of people independently discovered that sometimes there were three physical appearances rather than two. The organism with a copy of the first allele paired with a copy of the second allele did not look like one with either of the other two allele pairs.

Various people gave this condition a variety of names -- incomplete dominant, codominant, semidominant, less than dominant, transdominant, partial dominant, etc. While each has a slightly different shade of meaning, part of every definition includes having three phenotypes, one for each of the three gene pairings.

The Encyclopedia of Genetics defines "codominant" as both alleles producing a functional gene product. And "incomplete dominant" is defined as one allele making a functional gene product and the other allele making a nonfunctional gene product.

Unfortunately, we do not know whether pastel and other such mutant genes produce a functional or nonfunctional product. Even if we did know, it would make sense to simplify and have only one term for all mutant genes that are not dominants or recessives. So which term should be used? IMHO, at this stage, use the one you want. I prefer "codominant" because it uses the fewest letters.

Paul Hollander