Reptile & Amphibian Forums

Ok Spiders have been out for a few years now. Now that they aren't worth much, has anyone proven out wether or not the Homozygous Spider exists or is it still a great mystery??? why not release this info.??? You would figure by now somone would have proved this out or not??? Any info would be great.

I think spiders don't have a 'super' form. Either the SS looks just like a SN, or is lethal and embryo with this gene never form. I suspect it is more spiders are not what is considered 'co-dom' but is more just dominant in the same way the typical wild type is dominant (normal/normal looks just like a het recessive normal looks like, except with spiders, the 'normal' is spider)
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PHLdyPayne

I believe it was rumored to be a lethal gene combo, BUT...someone else might have tried it.

The problem is, if it doesn't have a super form and can be homozygous without said super form...proving it is a pain.
You'd have to breed it, get all spiders, wait another season, breed it AGAIN, get all spiders, and possibly breed it one more time to make sure you just didn't have lucky odds the first two times.

Why waste a female spider on something like that when you can toss a super pastel to her and get all pastels and bees?
It's just not really worth it. The spider gene is fine the way it is. (My opinion)
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"What is man without the beasts?
If all the beasts were gone,
men would die from great loneliness of spirit.
For what happens to the beasts,
soon happens to men.
All things are connected."

-Chief Seattle (Duwamish Tribe)

I believe the Homozygous form of the Spider morph to be lethal. Spiders have been around for almost ten years now. I think in that time, if there was a super form that could produce all Spider offspring, someone would have figured it out by now.

personally i think that people are to busy trying to make combo's rather than worrying about a homo spider.

everyone keeps talking about a killer gene. but how do you?

i plan on proving this once and for all next season.

i will post my results at that time.

Pitoon

I understand how the Visuals will look. Why not ahve a Homozygous dominate animal, could be very valubale. First of all if you had a homozygous Spider you can produce all spiders when breed to a normal. That animal would be very valuable for certain breeding programs if it were still a morph that held some value. Second is if nobody has proven this out to exist isn't the Homozygous Spider just speculation. Sure it's possible for it to exist but until it's done and proving out aren't we just kinda guessing that it could happen. I wish someone would clear this up. The main reason I am asking this is there is a new Leopard Gecko Morph out now (Enigma's). As of now it's known only to be a dominate trait, but some feel the Homozygous form could exists. So until someone starts to prove all the dominate Homozygous traits out( In the Ball world and Boa) everyone is going to be speculating that there could be Homozygous form in the future. Some breeder are even list the morph as a Homozygous Animals saying that you can get 100%hets from crossing with a normal, when in fact this has not even been proven out??? They(other leo breeders) are comparing this particular morph to spiders saying that it is possible to get a dominate Homozygous animals. I have heard that some breeders are trying to keep this a Genetic possibility a close secret??? I understand that these animals would be a tremendous asset to any breeding program but why not tell the public who supports the trade the truth about the genetics involved??? Will somebody Finally prove this out. 10 years and not 1 person has tried. I find that very hard to believe. Release the info now!!! LOL

>I have heard that some breeders are trying to keep this a Genetic possibility a close secret???

ROTFLMAO.

>I understand that these animals would be a tremendous asset to any breeding program but why not tell the public who supports the trade the truth about the genetics involved??? Will somebody Finally prove this out. 10 years and not 1 person has tried. I find that very hard to believe. Release the info now!!! LOL

I can believe it. The people who could do it don't understand the genetics involved or are too busy to keep records. The rest don't have the spare money/space/time. Enigma would be a good project for half a dozen people to cooperate on. Though sometimes I think that herding cats would be easier than getting herpers to cooperate. LOL.

Paul Hollander

"I can believe it. The people who could do it don't understand the genetics involved or are too busy to keep records. The rest don't have the spare money/space/time. Enigma would be a good project for half a dozen people to cooperate on. Though sometimes I think that herding cats would be easier than getting herpers to cooperate. LOL."

I heard that a group of corn snake breeders got together to share test cases and breeding info and finally proved the allele relationship between stripe and motley and that the motley appearance dominates in the animal with both. That was less than 20 years after “The Color Guide to Corn Snakes” proposed the allele relationship and got me interested in breeding snakes. Maybe as ball python mutant prices stabilize more breeders will be willing to work together here too.

I don't think that enough matings have been done to prove anything, yet.

Here is a parallel situation:

A retired pro geneticist that I know raises zebra finches. He is trying to determine whether the crested mutant gene, which is some sort of dominant mutant in zebra finches, is lethal when homozygous. For what it's worth, there is a crested mutant gene in ducks and another in canaries. Both of those mutants are lethal when homozygous. Here is how my friend is doing it.

1. Mate crested x crested. The crested offspring have a 33% probability of being homozygous. He keeps these for breeding tests.

2. Test the possible homozygous crested finches by mating them to normals (non-crested). Seven crested babies and zero noncrested babies produces a 99% probability that the crested parent is homozygous. If a mating produces one or more non-crested babies, then the crested parent must be heterozygous (with a crested mutant gene paired with a normal gene). Failed matings are replaced with new test matings.

3. Continue the test matings until either there are some >99% probability homozygous crested finches or there is a less than 1% probability that he missed getting a homozygous crested finch simply by the luck of the draw. So far, there have been nine test matings. In each, the possible homozygous crested parent was not homozygous. My friend has been at this for several years and is shooting for 20 failed test matings before deciding the crested mutant gene is lethal when homozygous.

I would use the same protocol for testing whether or not the spider mutant gene is lethal when homozygous. This is a very time consuming procedure, so it's fairly obvious why nobody has done it yet.

Paul Hollander

Paul thanks man. Thats some very interesting stuff there. Have there been any conculsive findings yet? I can see why that would be a long and lenghty process for Ball pythons and other animals. But the genetic advantage to Produce Homozygous Dominate animals I would think would be worth the time and effort. Especially if you are breeder who is trying to make money. If get all 100% Visual het offspring that's a boost to any breeding program. Your 50% odds go up to 100%. Thats just my opinion though. Leos would be the perfect trial for this. They reproduce very easily and early. You Ball breeders wish you start breeding Females at 7-12 months. Then have 2 egg clutch every 15-30 days and average 4-8 clutches. After about a 15-30 justation period. Yes it would be much eaiser to prove it out in Leos.

I am out in the boonies, so most of what I know about the gecko and python breeding scenes comes from these forums. I can't add anything new to what has already been written here.

I think that the time and effort needed to produce homozygous spider balls or homozygous enigma leos would be worth it, too, eventually. But that's a decision each breeder must make for himself, and I don't have much influence with the breeders. I've not bred either species, so what do I know?

Paul Hollander

Paul's retired pro geneticist acquaintance is taking the noble scientific task of trying to prove to an acceptable degree of certainty (can never be truly be 100% sure) that a mutation is homozygous lethal. I would be surprised if given the results so far and the similar accepted homozygous lethal mutations in other species if this geneticist was continuing the experiment with great hopes of producing a viable homozygous animal.

In the case of the spider ball pythons we may well have passed the point where many would still breed spider X spider hoping to produce a homozygous spider (regardless of what it might look like). I agree that a homozygous spider would be a valuable thing to have for breeding purposes but I think most have given up on a homozygous spider. Perhaps now it's just to be seen if anyone has the energy and tenacity to spend the perhaps decades it might be necessary to mathematically approach proving spider homozygous lethal.

Sure we still could just have missed proving a homozygous spider this long. Hard to even say how many possible homozygous spiders have been produced with very little breeding results available to the public. But if there is a viable homozygous spider it will only take one to eventually prove the possibility. But if it turns out spider is homozygous lethal it could take a very long time to prove that from the absence of a homozygous spider. Our best bet might be if a group of consciences ball python breeders can work together to both produce a fair number of possible homozygous spiders and then breed them all out and pool the carefully recorded results. It's probably too big a job for even a large breeder to do by themselves.

Randy or Paul... Exactly how does the Leathal Homozygous Gene effect the offspring? Are all the "Homozygous" offspring still born. The offspring never gets a chance to develop. Or would the leathal Gene just cancel out the Donimate gene. I would really like to have a Basic understanding of it. Thanks in advance.

A gene pair is homozygous when both genes are the same. A homozygous spider ball python would have a gene pair containing two spider mutant genes. The spider ball pythons that we see are not homozygous -- they have a spider mutant gene paired with a normal gene.

If the spider mutant gene is lethal when homozygous, here is the way things would work. When a spider gene is paired with a normal gene, the spider mutant gene does something that is enough to change the snake's appearance while the normal gene does the normal thing enough to keep the snake reasonably healthy. Two copies of the spider gene could make such a big change from normal working that the effect kills the snake.

Different lethal mutant genes affect different organs. Different lethal mutant genes also kill the owner at different times. Death might occur any time between fertilization of the egg and sexual maturity. The final effect doesn't even have to be death; sterility would be adequate.

Nobody knows exactly what effects the spider mutant gene has beyond the effect on the pattern.

Disclaimer: The rest of this post is brainstorming, with no claim of accuracy.

I have read that some spiders show some head tremors. Perhaps the spider mutant gene also has an effect in the brain or nervous system. Two copies of the spider gene might affect the nervous system enough to make the snake's heart stop beating. Death would be the result.

Paul Hollander

Although every year a public proven homozygous spider is more conspicuous by it's absence we shouldn't forget that it still might happen. Maybe it's just been missed so far in all the interest over spider combos etc.

However, give how difficult it will be to prove IF spider is homozygous lethal we are left to speculate with the small amount of evidence available. Maybe with any new mutation you should start out assuming it's lethal and build a case for evidence proving it's not. Either way there isn't a lot of evidence here.

1. I believe one of the big spider producers once posted that they had NOT noticed any higher rate of non hatching eggs in spider X spider clutches.

2. I heard from another breeder who tried spider X spider last year and did report a few undersized eggs that didn't hatch.

3. There was a report several years back that a homozygous spider had even been proven but was being kept secret.

It’s hard to know what to make of these isolated points. Could a lethal genotype cause the embryo to die before even getting shelled or cause the egg not to reach full size? Could the homozygous spider be viable (i.e. not lethal at all) but in some way not presentable or being kept under wraps for some other reason (maybe it's awesome and there are marketing angles)?

>Although every year a public proven homozygous spider is more conspicuous by it's absence we shouldn't forget that it still might happen. Maybe it's just been missed so far in all the interest over spider combos etc.

Agree 100%.

It's fun to speculate, but what we really need now is data and people willing to share it. And of course they have to be both internet connected and have some connection to this forum. I don't have a clue how many different herp-related forums there are on line, not to mention mailing lists. I can't even keep up with the ones that I do know of.

Paul Hollander

Paul... Here is a reply from Kelli Hammock from another forum about the Enigma Morph.

"The first season I bred Enigmas I bred them to only each other. Those offspring are what I bred last season. You would think that out of one of the 2nd generation breedings there would have been a "Super" Enigma in there somewhere, but anything's possible."

So from Enigma x Enigma= 50%Enigma 50%Normal
I believe she got the same ratio's from the offspring as well.

Homozygous enigma (genotype) does not necessarily produce super enigma (appearance). I could give you a number of examples of mutant genes where there is no obvious difference between an animal with two copies of the mutant gene and an animal with one copy of the mutant gene paired with a normal gene. Enigma may be another such mutant. With that sort of mutant, only pedigree or breeding test can tell you what the genes are in any given animal.

Can you point me to Kelli Hammock's post? I'd like to ask her some questions about the breedings and numbers of babies. My expectation would be closer to 3/4 enigma to 1/4 normal rather than 50:50. But the luck of the draw does not have to match expected results. That's why someone can walk into a casino with $2 and exit with a pocket full of cash.

Paul Hollander

Paul... I don't know exatly what you work with. But do you know of ANY animal or reptile that is a Homozygous Dominate?

Sorry should have been DOMINANT not dominate. LOL

Sure.

In pigeons, there is ash red, spread, checker, and T-pattern.

Mice: viable dominant yellow, sombre

Horses: gray and several others.

Salmon (aka hypo) in the boa constrictor. Striped in the California king snake. Though these have variable expressivity where you can sometimes tell the difference between an animal with one copy of the mutant gene and an animal with two copies of the mutant gene. But it's not reliable.

These are just the ones on the tip of my tongue. The description of mouse mutant genes fills a book two inches thick. The description of fruit fly mutant genes may fill a book that is even thicker. There are plenty of dominant mutants that I never heard of or haven't thought of at this moment.

Paul Hollander