Reptile & Amphibian Forums

I've heard if you breed spider to spider that the clutches all come out sluggs. Is this true? If so does that mean you can't breed a bee or any other spider combo to a spider too?

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Brad Chambers

The Avalanche has already started-it is too late for the pebbles to vote....

I'm not sure how many times it's been done or if it's been done by anyone other than NERD but I don't believe spider X spider would/has produced all slugs. That idea is probably a misunderstanding of one of my theories as to why we don't yet have a public proven homozygous spider.

Each egg from spider X spider should have a 25% chance of being normal, a 50% chance of being a spider (the heterozygous kind we've seen so far) and a 25% chance of being homozygous spider. The 25% normals and 50% spiders should be no different than any other normals or spiders. So no doubts about 75% of the odds. It's only the 25% homozygous that are in question. Have enough possible homozygous spiders been produced and failed to prove yet for us to reasonably assume that a homozygous spider isn't possible or will we eventually see one? If spider is homozygous lethal it would only effect those 25% from spider X spider clutches and not normal spiders from spider X normal clutches or even the 50% expected heterozygous spiders from spider X spider. I believe someone from NERD once posted that they hadn't noticed any extra slugs in spider X spider clutches – not even just the 25% expected from that one possible explanation for why no proven homozygous spider 8 years into captive breed spiders.

i thought (excuse the spelling) homosygenus meant they displayed the genetic trait aka spider ,pastel, pied..etc and heterozygenous meant they carry a certain gene but ar normal in appaerance. spider being a codom(codom meaning that heterozygenus doesnt exist if they carry the gene they display the gene) trait like mojave or pastel just like those breeding a spider to a spider should either get really nice looking spiders , regular spiders, and possibly normals.and theoretically even with recessive genes like albino and pied if one parent is homozygenus then 1/2 offspring should show the gene trait. if you breed two animals both homozygenus for a trait then technically all the offspring should show the gene.
thats just as far as i understand genetics but nerds website explains everything pretty well.

I think mostly you just need a few corrections on your terminology:
Simple Recessive - if a trait is simple recessive, then an animal that is heterozygous for the trait will be a carrier, and an animal that is homozygous for the trait will be a visual of the trait
Co-Dominant - A co-dominant trait (I believe) means that the heterozygous form is visually identifiable from either the "normal" homozygous form and the homozygous form of the visual. Example: Pastel. A heterozygous pastel is just a Pastel, a homozygous pastel is a Super Pastel, and the two are visually distinct.

As far as I can tell from reading, the spider trait is dominant. Meaning, the heterozygous and homozygous form of the spider is visually the same. However, a heterozygous spider bred to a normal will produce 50% Heterozygous Visual Spiders and 50% Normals, and a homozygous spider would produce all heterozygous Spiders (assuming that the Spider gene is not homozygous lethal).

Some traits that you mentioned (Albino, Pied) are simple recessive, and therefore work differently genetically than the co-dominant (Pastel, Mojave) or the dominant (Spider) genes.

I hope that helps a little bit...
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-Jaime Palma
Mad-City Constrictors

im confused by"Co-Dominant - A co-dominant trait (I believe) means that the heterozygous form is visually identifiable from either the "normal" homozygous form and the homozygous form of the visual. Example: Pastel. A heterozygous pastel is just a Pastel, a homozygous pastel is a Super Pastel, and the two are visually distinct"

if there is no super form wouldnt the spider trait be the homozygenus form..

"The "Super" is a dominant form of a co-dominant gene, and can be bred to a normal animal to produce entire clutches of the visible het, or co-dominant form. There is a marked difference between the visible het/co-dominant form and the homozygous super form. When we do not see a visible difference between the het and homozygous forms, the mutation is referred to as dominant as opposed to co-dominant" thats directly from new england reptile distributors website

so thats saying that spider since there is no super form is the dominant trait right?

Genes come in pairs, one from each parent. Some genes have two or more different versions due to mutations that are then passed on to later generations. With most appearance genes it seems that one version gets selected as the best for survival in the wild and becomes the most common and what we call the normal type.

Heterozygous is a genotype term and describes a pair of genes that aren't matched, the animal has inherited two different versions of the gene in question from its two parents. When the genotype is heterozygous for a gene where a receive mutation has been paired with the normal type of that same gene the animal looks (phenotype) normal. This is part of what defines the mutation as recessive. However, if the mutation is dominant or co-dominant then the heterozygous animal does not look normal with respect to that mutation. Spiders and pastels are just as much heterozygous for their respective mutations as het albinos or clowns. It's probably because most snake people first learned about genetics with recessive mutations that the incorrect belief that heterozygous means normal looking gene carrier is so widespread.

Homozygous means having a matched pair of whatever genes you are talking about. The same version is inherited from both parents. Homozygous normal if it was the wild type of the gene or homozygous mutant if the same mutant type was inherited. An albino and a super pastel are both homozygous for their respective mutations. The difference is that albino is recessive because the hets look normal and pastel is co-dominant because the hets don't look normal but the homozygous mutant looks even different.

If we do eventually prove a completely dominant ball python mutation it will be because the hets and the homozygous mutants have the same not normal look.

It is a common incorrect use in ball python sites (and maybe books) to see "dominant form" used where homozygous should be used. What they are really talking about is an animal with the homozygous genotype. Dominant refers to the mutation type and doesn't change depending on if you are looking at the heterozygous or homozygous version of the same mutation. For example, pastel is still co-dominant regardless if you are talking about the heterozygous form (pastel) or the homozygous form (super pastel). It's the difference between the two and the normal type that defines the co-dominant mutation type.

If we eventually prove a homozygous pinstripe that is just like the heterozygous pinstripes we see today except for breeding results (100% pinstripe bred to a normal) it will be a dominant mutation type because of that relationship and it's the genotype that will change between the heterozygous and homozygous pinstripes, not the mutation type.

No one has yet come forward to claim a homozygous spider. There are any number of possible explanations for this:

1. Maybe 8 years just hasn't been long enough to produce and prove a homozygous spider. There has been a lot of interest in spider combos with other mutations and not much interest in proving a homozygous spider after a visually stunning one wasn't produced in the early years.

2. Maybe spider is homozygous lethal and when a sperm carrying the mutation fertilizes and egg carrying the mutation the resulting homozygous spider is not capable of reproduction. I don't know enough about the egg production process to know if it would be possible that the homozygous spider eggs might not even get produced but it is possible they are and they just don't hatch. I think technically it would still be considered lethal even if they do hatch but don't live to reproduce, like the pearl. Any version of this scenario would be hard to prove since you are trying to prove something by its absence.

3. Maybe homozygous spiders have been produced and even proven through breeding but they are not being claimed for some reason. Maybe they are not presentable in some way or there is some idea of a competitive edge by not making them known publicly.

That's all I can think of but maybe the real reason is something I haven't thought of.

so basically to prove spider homozygenus you would have to breed an offspring of spiderxspider to a norm and have the babies all come out what we call spider. what i was trying to say was that if there is no super form of spider, and spider to spider just made spiders or slugs wouldnt spider be considered homozygenus since the pattern and lighter color are proven to be a gene trait and then it would just not be a dominant gene.mojave xmojave you should get blue eyed lucys along with the like 7 other morphs u can combine to get them right so that means that mojaves carry two mutant genes, mojave would be het for a blue eyed lucys.so i understand how co dom genes are het for a super but if that super doeasnt exist then all its het for is the trait it shows and normal right....which would make it homzygenus for the spider trait.... all im doing is trying to understand as what your saying isnt making any sense to me ..lol

thats it im buyin a pair of spiders and a pair of norms..lol

Ok I want to attempt to make this understandable. I am going to start with Hetero and Homo visual expression. Then once you understand that I will post on the breeding and inheritance.

1. Let's say that for every trait (Morph i.e. Spider, Pastel, Albino, ect.) an animal has a pair of ALLELES. A pair of alleles makes a gene. Every animal gets one allele from each parent for to complete their pair of alleles for that gene.

2. HOMOzygous means that the allele from each parent are the same ( They have a matching pair ) for that gene (Morph).

3. HETEROzygous means that the allele from each parent are different ( They have a un-matched pair ) for that gene (Morph)

--- HETERO and HOMO by definition does not describe the ---
--- appearence of the snake only the genetic pairing of ---
--- alleles for that specific gene (Morph) ---

RECESSIVE ( Albino, Pied, ect.)
Recessive = Weaker alleles it gets in a fight with the normal allele and always loses. It only wins when there is no normal present.
For a recessive gene to be VISUAL in an animal the pair of alleles for that gene (Morph) must be HOMOzygous. Lets use Albino for this example. An albino animal is carrying a pair of albino alleles for it's gene since both are the same it is HOMO They must be the same from each parent. If the alleles don't match they are HETERO and thus you have an animal that looks normal but carries one allele for Albino, and one allele for normal so it is known as a HET.

CO-Dominant ( Pastel, Mojave, ect.)
For a co-dom it gets tricky to understand but once you do it makes complete since.

CO-DOMINANT = Allele that is equally matched to normal allele.
When they fight It is a draw

---- THIS IS WHERE IT GETS TRICKY ----
An animal that is HOMOzygous for a co-dom trait fully expresses that trait ( i.e. Super Pastel known as the OPAL, Super Mojave known as the Leusistic, ect.)

An animal that is HETEROzygous for a co-dom trait has a normal allele and a morph allele they fight and it is a draw. So they agree that they will visually express themselves together. So you end up with an animal that is Visually different from both the normal form and the HOMO form.

DOMINANT ( possibly Spider, possibly Pinstripe, ect.)
This is a tricky one also. Once you get it though it is easy.

DOMINANT = Allele that is Stronger than the normal allele. When they fight the Dominant always wins.

An animal that is HOMOzygous for a dominant trait visually expresses that morph.

An animal that is HETEROzygous for a dominant trait has one normal allele and one Dominant allele. Since it is Stronger it always wins and so It to Visually expresses it's self. So the HOMO and HETERO for a Dom. morph appear the same but not normal.

OK after you confirm that you understand this I will get into Inheritance of the genes.
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Joshua A. Mills
2.1 Pastels
1.0 Yellow Belly
0.7 Normals not including the babies
And many more to come

ok i understand all that i have understood all that.

my confusion stems from the fact that if spider has no super(dominant, homo gene) form then the only trait is what we call the het trait.

and if there is no super form why is it still a codom trait.

thanks everybody for puttin up with me ..lol
this spider thing will just bug the hell outta me til i figure it out

>my confusion stems from the fact that if spider has no super(dominant, homo gene) form then the only trait is what we call the het trait.

>and if there is no super form why is it still a codom trait.

There are two possibilities:
1. A snake with two spider mutant genes looks like a snake with a spider gene paired with a normal gene. In this case, the spider mutant gene is dominant to the normal gene. Or fully dominant to the normal gene if you prefer.

2. A snake with two spider mutant genes dies while a snake with a spider gene paired with a normal gene lives and does not look normal. In this case, the spider mutant gene is codominant to the normal gene.

Accurate definitions of dominant, codominant, and recessive:
A mutant gene is dominant to the normal gene when a snake with a mutant gene paired with a normal gene looks like a snake with two copies of the mutant gene.

A mutant gene is codominant to the normal gene when a snake with a mutant gene paired with a normal gene does not look with a snake with two copies of the normal gene and does not look like a snake with two copies of the mutant gene. If spider is a codominant (lethal) mutant gene, then a ball python with two normal genes looks normal. A ball python with two spider mutant genes is dead in the egg. And a ball python with a spider mutant gene paired with a normal gene does not look normal and does not die in the egg.

A mutant gene is recessive to the normal gene when a snake with a mutant gene paired with a normal gene looks like a snake with two copies of the normal gene.

Most herpers have a good grasp of a recessive mutant gene. Incorrect definitions of dominant and codominant commonly used among herpers:
Dominant = having two copies of a non-recessive mutant gene. (AKA super)
Co-dominant = having one copy of a non-recessive mutant gene paired with a normal gene.

Sometimes figuring out whether a herper is using these genetics terms accurately or inaccurately is difficult. Unfortunately, many herper web sites use them inaccurately.

Paul Hollander

lol exactly ok im done talking about this now..lol good discussion though

Maybe it's because most breeders are using the term "super" for codominant genes only. They refer to the cases where the homozygous animal looks different from the het. If the spider gene were dominant, the homozygous snake would look the same, hence no VISUAL "super spider."

"You take the blue pill and the story ends. You wake in your bed and believe whatever you want to believe. You take the red pill and you stay in Wonderland and I show you how deep the rabbit-hole goes."
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Joshua A. Mills
2.1 Pastels
1.0 Yellow Belly
0.7 Normals not including the babies
And many more to come

that has got to be one of the most funniest things i read in a long time!!!!!!!!!

yea i know, good thing im not goin to school for biology or somethin right...

>so basically to prove spider homozygenus you would have to breed an offspring of spiderxspider to a norm and have the babies all come out what we call spider.

That is correct. I would stop testing after ten babies. If at least one is normal, then the spider parent is proven to have a spider mutant gene paired with a normal gene. If all ten babies are spiders, then the chance is one in a thousand that the spider parent is not homozygous.

By the way, the spelling is "homozygous".

>what i was trying to say was that if there is no super form of spider, and spider to spider just made spiders or slugs wouldnt spider be considered homozygenus since the pattern and lighter color are proven to be a gene trait and then it would just not be a dominant gene.

Spider ball pythons would not be considered homozygous in this scenario.

To be homozygous, there would have to be two spider mutant genes in the gene pair.

If all the snakes with two spider mutant genes die in the egg, then all the living spider ball pythons have a spider mutant gene paired with a normal gene. A heterozygous gene pair has two different genes. A spider mutant gene is not the same as a normal gene, which makes the two genes different. So these snakes are heterozygous even though they do not look normal.

>mojave x mojave you should get blue eyed lucys along with the like 7 other morphs u can combine to get them right so that means that mojaves carry two mutant genes, mojave would be het for a blue eyed lucys.

A mojave does not have a mojave mutant gene paired with a blue-eyed lucy mutant gene. A mojave has one mojave mutant gene paired with a normal gene. A blue-eyed lucy has two mojave mutant genes. All other genes in the snakes' genome are (or can be assumed to be) normal. This is the simplest way to get a blue-eyed lucy, though there are other ways.

Hope this helps.

Paul Hollander

There seems to be a lot of confusion and misuse in the herp (and probably other hobbyist) worlds about the above terms. I see codominance applied over and over again to mutations like pastels, yellowbellies, spiders, womas, etc., but be careful not to throw around incorrect terminology too often or knowledge gets distorted.

Both are blends of the parent phenotypes. However, they are both expressed very differently.

Ex: Cross a red flowering plant with a white flowering plant.

Codominance - the resulting offspring plant will have flowers with red and white patches.

Incomplete Dominance - the resulting offspring plant will have pink flowers.

So which are all these bp morphs? I'm betting pastels, at the very least, are incomplete dominant. Spiders and yellowbellies? Not a clue personally. Probably incomplete dominant as well as there's nothing on a spider that's completely the same as what would be on a normal. Unfortunately, as has been shown, we've yet to produce a possible homozygous spider so we don't have a critter to which we can compare.
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Chance Duncan
www.rivervalleyexotics.com

>Codominance - the resulting offspring plant will have flowers with red and white patches.

Codominance does not work this way. The term was originally applied to A and B blood types in humans, which have both A and B antigens on the same cell. You cannot separate human AB blood cells into a group of A blood cells and a group of B blood cells.

With dominant and recessive genes, there are three possible genotypes, AA, Aa, and aa. But there are only two phenotypes, one for aa and a second for both AA and Aa.

With codominant genes, there are also three possible genotypes, AA, Aa, and aa. And there are three phenotypes, one for aa, a second for AA, and a third for Aa. Using this definition, "incomplete dominant" is a synonym of "codominant". So are "partial dominant", "semidominant", "transdominant", and about a dozen other terms.

We are using "codominance" very loosely, for simplicity. If you want to use "incomplete dominance" instead, go ahead. But there are a lot of herpers and their web sites that do not understand the difference between a dominant mutant gene and a codominant (loose definition) mutant gene. So I'm against multiplying the terms. There is already enough confusion and misapplication without throwing in more jargon to make it worse.

Paul Hollander

Regarding seeing evidence in terms of some sort of non viability theory. This would not be seen in the form of a slug. "Slugs" are roughly one half sized ovulated ova that no matter how many sperm are present can not be viable. So at this point you are not really testing the theory of viability of the "spider spider" combination. If there were full sized eggs in a clutch that had either no development or started to develop and failed to develop, among eggs that developed and hatched normally containing spiders and normals that might be interesting to note. Even having perfectly developed eggs (meaning snow white perfectly shelled with no veins or just started development that fail to produce a baby), though rare, happens. Because of this you can't 100% be sure that non viability was the cause. If you had multiple clutches where this happened, while simultaneously breeding the male to normal females producing perfect clutches-well that might be some evidence. Tracy

Proving the fatal theory would take alot of trials and many factors to prove. Thank you for pointing out the difference in Slugs and non-fertile or dead eggs.
Oh, and I love the Book and DVDs. I have had both for about a year and I still watch the DVD and pick up the book and read on a regular basis even though I have read it many times already. Have a wonderful New year and a great breeding season.
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Joshua A. Mills
2.1 Pastels
1.0 Yellow Belly
0.7 Normals not including the babies
And many more to come

I have heard of several people who own spiders that produce ALL spider babies. These breeders were from spiderXspider breedings or spiderXbee breedings. So basically there is no visual super spider, but a snake can have the spider gene from both parents. The only way to know is to grow it up and breed it out.

Can you get any of these people to come forward and post about their possible homozygous spiders with details like how many only spider offspring did they produce with normals, what do does the homozygous spider look and act like?