Whoa! I've got to get me a Yellow-Belly!

Quote:

---

Originally Posted by cueball

Sure doll...if you lived in TX :P

---

I was born and raised a Texas girl...I just happen to be living in Virginia...Virginia sucks. O_O

Mendel, are you thinking chimera?

It would be nice if we could know if all paradox where produced by breedings involving at least one het. Maybe these paradox ivories could be the melding of a homozygous ivory embryo with a non homozygous ivory embryo which wouldn't be possible in an ivory X ivory or ivory X normal breeding.

Breeding results of the paradox animals themselves would also be helpful. Do they always prove homozygous for the morph or in some cases could the reproductive portions of the snake be from the het or possible het sibling?

Quote:

---

Originally Posted by RandyRemington

Mendel, are you thinking chimera?

It would be nice if we could know if all paradox where produced by breedings involving at least one het. Maybe these paradox ivories could be the melding of a homozygous ivory embryo with a non homozygous ivory embryo which wouldn't be possible in an ivory X ivory or ivory X normal breeding.

Breeding results of the paradox animals themselves would also be helpful. Do they always prove homozygous for the morph or in some cases could the reproductive portions of the snake be from the het or possible het sibling?

---

I think that the possibility of chimerism is an "easy" explanation for what we're seeing with the paradoxing going on in ball pythons, but I don’t personally feel that it’s likely. To the best of my knowledge, all paradoxes have proven to be true homozygous animals.

My main problem with the chimera theory is that it is happening way too frequently within ball pythons to be probable.

There have only been about 30 cases of true chimerism in humans after hunderds of years and billions of people .... the notion that it would just suddenly start appearing with such great freuqency in ball pythons just doesn't seem likely. Also, most of the documented cases of chimerism that I've read about involve whole organs having either one set of chromosomes or the other ... skin being an "organ" would mean that we wouldn't see the blend that we see with ball pythons ... There is "microchimerism" that could result in some "cells" having one set of chromosomes and others having another, but that is even more extremely rare.

It would be nice if we could find a ready made explanation, wrap it up, but a bow on it, and call it a chimera ... unfortunately, nature it's always that simple.

-adam

Wicked smart response, Adam! :colbert2:

Chimerism may not be the most likely explanation for paradox balls but I think the rarity of documentation has to do with it NOT being a simple explanation. We haven't been doing paternity testing very long and the example I saw of recent documentation of chimerisim in a woman who’s children didn’t match her took years of fighting against more simple explanations (like that she abducted her previous children – chimerisim was only documented after a court representative witnessed the birth and immediate testing of a new child). Most paternity testing is done for possible fathers where a non match is easily dismissed with the simpler explanation. They did mention mixed race human chimeras with patches of different skin color but in many cases human chimeras may never be noticed or explained away with simpler explanations.

Maybe chimerism is fairly common in ball pythons and we are just now seeing the evidence as we start to produce mixed type clutches.

I do agree we certainly aren't ready do declare that chimerism is responsible for any of the paradox balls but even if it isn't the most likely explanation it is a possibility until we gather information to disprove it. This early in the ball game there isn't a huge track record of every possible breeding but if a chimera was ever produced by a breeding that didn't involve a het on at least one side that would disprove it. If a chimera it’s self reproduced as a het or a normal that would also tend to support it. It’s hard to "prove" chimerisim by the lack of either but maybe after enough time the missing disproof factors into the likelihood of chimerism relative to other candidates for an explanation of some paradox types.

Quote:

---

Originally Posted by RandyRemington

Maybe chimerism is fairly common in ball pythons and we are just now seeing the evidence as we start to produce mixed type clutches.

---

10's of thousands of ball pythons are exported from Africa every year and have been for the last 10 years ... due to the ball python "craze", every one of these has been scrutinized for abnormalities by tons of people ... if it was "fairly common", we would know it ... the reality is that it's limited to a small number of captive breedings a year.

I'm just not a big fan of the "least likely theory" approach ... I would much rather focus the limited resources we have on pursuing the "most likely theory" until every possibility of that theory is exhausted and then move on to the next "most likely theory" ... seems a lot smarter to me than spinning wheels over things that in many cases can't even be proven if they are true ... I was always taught that good science is using the process of attempting to eliminate likely possibilities in pursuit of the truth ... but hey, that's just me.

-adam

Quote:

---

Originally Posted by Adam_Wysocki

There have only been about 30 cases of true chimerism in humans after hunderds of years and billions of people ...

-adam

---

The tools to prove chimerism have been around for most of human history though...maybe the last 10-15 years......the incidence could be much higher. These tools are hardly widespread throughout the entire world.

Quote:

---

Originally Posted by Adam_Wysocki

My main problem with the chimera theory is that it is happening way too frequently within ball pythons to be probable.

-adam

---

Quote:

---

Originally Posted by Adam_Wysocki

10's of thousands of ball pythons are exported from Africa every year and have been for the last 10 years ... due to the ball python "craze", every one of these has been scrutinized for abnormalities by tons of people ... if it was "fairly common", we would know it ... the reality is that it's limited to a small number of captive breedings a year.

-adam

---

Which is it?

I think science is only getting a handle on the true incidence of chimerism now.

With a morph like ivory or albinism you have the possibility of seeing chimerism visually. No one would look or think twice about the genetics/cellular origins of a "chimeric WT ball python"......

Quote:

---

Originally Posted by Mendel's Balls

Which is it?

---

You completely misunderstood.

From the first quote ...

In my opinion, paradoxism is happening way too often in ball pythons for a "chimera theory" to be likely given the highly rare nature of chimeras known in science.

From the second quote ...

Randy stated that maybe chimeras are very common in ball pythons and I respond with the second statement above ... if chimeras were that prevalent, we would have seen many more paradoxes in all of the animals that have come in over the last few years.

Hope that makes it clearer for you.

Quote:

---

Originally Posted by Mendel's Balls

No one would look or think twice about the genetics/cellular origins of a "chimeric WT ball python"......

---

If you believe that, you have NO IDEA what is going on in the world of ball pythons ... every trapper, exporter, importer, distributor, wholesaler, jobber, flipper, flopper, etc on the planet is looking for the "NEXT BIG THING" in normal ole WC/CH ball pythons ... if there was a "spec" of something "not right" it would be found so that someone could profit from it. You'll learn. ;)

-adam

Quote:

---

Originally Posted by Adam_Wysocki

If you believe that, you have NO IDEA what is going on in the world of ball pythons ... every trapper, exporter, importer, distributor, wholesaler, jobber, flipper, flopper, etc on the planet is looking for the "NEXT BIG THING" in normal ole WC/CH ball pythons ... if there was a "spec" of something "not right" it would be found so that someone could profit from it. You'll learn.
-adam

---

That was a little harsh don’t you think?

I am very new to the ball python world…….but I think I know a few things. And I’ve always been a firm believer of using your prior knowledge and experience to help you learn new things.


And you certainly don’t know everything about these animals (no one does) to make such a strong statement.


I think you didn’t understand what I meant when I said a “chimeric WT ball python”…..but that’s not your fault because I didn’t explain what I meant very well.

Basic Chimerism occurs when two genetically distinct zygotes fuse early in development. What happens is Dizygotic (fraternal/sibling) twins fuse. This creates an embryo with two distinct cell populations. One of the cell populations comes from one twin, the other comes from another twin. Each cell population randomly gives rise to parts of the developing person. One example....What was twin 1 may give rise to the skeletal muscle and internal organs, while what was twin 2 may give rise to the nervous system and pancreas. Each of these cell populations and resulting organs/tissues would have their own unique genome.


Fraternal twins (i.e. siblings) u will agree are much more common in balls then in humans. Most breeders from what my limited knowledge has taught me go for a clutch size larger than 1.


A het ivory or a normal BP zygote could fuse with a ivory zygote. This could give rise to an ivory with patches of normal BP coloration/pattern.

Now imagine you mate two WT ball pythons, two of the zygotes fuse during development. Since both of them carry genes for WT BP coloration/pattern you would not see a chimera simply by looking at it. This doesn’t mean that it doesn’t exist. The two different genomes of the one organism simply don’t manifest themselves in the phenotype (appearance).

If you did DNA testing to this hypothetical ball python, you’d find that certain tissues or organs don’t match one another. As far as I know “breeders, exporters, and distributors” in the ball python world aren’t doing DNA testing to their animals to find those "interesting" WT chimeras.....I had a genetics professor in college say "IF you dont look in the right palce, you cant find....."

Quote:

---

Originally Posted by Adam_Wysocki

Paradoxism is happening way too often in ball pythons for a "chimera theory" to be likely given the highly rare nature of chimeras known in science. (my emphasis)

-adam

---

As far as I know science does not have a good grasp on the incidence of chimerism for any organism. And the reason for this uncertainty is because of what I explained above-- we can’t read genomes with our eyes. I will list my sources……



“The natural incidence of chimerism is unknown.”

• Train, Lisa; Dean, John C.S.; Hamilton, Mark P. R.; Bonthron, David T “Brief Report: A True Hermaphrodite Chimera Resulting from Embryo Amalgamation after in Vitro Fertilization.” New England Journal of Medicine. 338(3):166-169, January 15, 1998.

From Discover Magazine Vol. 27 No. 04 | April 2006:

["For all we know, there could be chimeras out there who aren't recognized because the condition hasn't caused them any problems," says Lynne Uhl, a pathologist at Beth Israel Deaconess Medical Center at Harvard University.

Twins researcher Charles Boklage, a biologist at East Carolina University, says chimerism is underdiagnosed: "The great majority of people who are spontaneous chimeras will never be detected by any means whatever. It's a spooky thing. It's very difficult to find when it's there." He estimates that about 15 percent of people were conceived alongside a twin who was then lost.]

From Autoimmunity. 2003 Feb;36(1):5-9.

“some studies lend support to the concept that microchimerism is involved in the pathogenesis of selected autoimmune diseases, studies also indicate microchimerism is not uncommon in other human conditions and in healthy individuals”

From Wikipedia:

“Recent studies of tortoiseshell male cats and unusually coloured tortoiseshell-like cats suggest that natural chimerism is far more common than previously realised and that it frequently goes undetected”

As you can see the jury still out on how rare this genetic condition really is……

It is true very few cases of chimerism have been proven in humans……but most people of the population do not get genetic tests done to them. And when they do its usually for health, paternity, maternity, or the criminial justice system. And if they do most don’t have the resources to disput the findings with the depth of the investigation seen in the paternity case of CELEBRITY HAIRSTYLIST Andre Chreky (see Discover article.)

Because I believe I have made a good case for the jury being out on the prevalence of chimerism I think it is premature to reject the hypothesis that chimerism is the basis for paradoxism.

I certainly don’t see how you can reject this hypothesis based on the notion that chimerism is too improbable. You might have another reason to reject that idea…..but your reason thus far is wrong cause your premise is not really a fact-science tells us it is unknown!

I realize it is a speculative hypothesis that is very hard to test in ball pythons…and it practically impossible to nail down without the tools of molecular genetics…..but answers to some of the questions Randy and I proposed might shed some light on the situation.

As you can see from the links…..natural chimerism is important phenomenon to gain a grasp on…..it could be involved in autoimmune diseases….and it’s a problem that can screws with paternity and criminology cases….it also important to transplant biology in a good way (chimeras are less likely to get suffer from organ rejection).

Other links of interest for those interested in this phenomenon.

http://www.thetech.org/genetics/ask.php?id=172

http://www.damninteresting.com/?p=412


I dont belive Your reason that skin is one organ also doesn’t exclude the possibility of chimerism…….skin is an organ derived from two different embryonic germ layers…..

dermis is derived from embryonic mesoderm while epidermis is derived from the ectoderm.

Also microchimerism could produce it and it also might not be as rare as one thinks (see quote above from the Journal Autoimmunity)

Finally, although the title of the following journal article is somewhat irrelevant to the argument at hand……I do find it ironic….. “The paradox of chimerism: induction of tolerance or cause of autoimmunity?”

It’s a small world after all! Hehe

PS>If you have other sources detailing the incidence of chimerism…..please share them. These represent some of the sources I was able to find. Mike

Quote:

---

Originally Posted by Mendel's Balls

That was a little harsh don’t you think?

---

No, actually I don't ... If you took it as "harsh", you are mistaken.

-adam

I've found the key to online communication and reading posts, etc, is to assume every comment and post is meant in a friendly, helpful, informative manner. Even if someone says something somewhat negative, you can take it as a friendly critique...

It is hard to do, but without voice inflection a lot of posts end up being open to translation.

Ive learned the hard way when over-reacting to a post and telling the poster what they were saying, when in fact they meant it in a different way but didnt manage to convey it in the proper wording to make it obvious.

This is just general commentary, not directed at any previous posts, just at the apparent miscommunication people sometimes have :)

Quote:

---

I'm just not a big fan of the "least likely theory" approach ... I would much rather focus the limited resources we have on pursuing the "most likely theory" until every possibility of that theory is exhausted and then move on to the next "most likely theory" ... seems a lot smarter to me than spinning wheels over things that in many cases can't even be proven if they are true ... I was always taught that good science is using the process of attempting to eliminate likely possibilities in pursuit of the truth ... but hey, that's just me.

---

As with the possibility that albino and caramel might be alleles we disagree on the relative improbability. Mendel’s point is good that there should be much more opportunity for chimerism in a species where one offspring at a time isn’t the norm. And I would agree that it is likely under documented in humans and pretty much hopeless to see in the vast majority of non morph ch ball pythons. If it is happening in ball pythons the place it would be seen would be in morphs from mixed clutches and as those become more common even a low rate of chimerism could be responsible for the handful of paradox animals seen so far.

Given that probabilities are difficult to agree on or even calculate I like the approach of considering all the possibilities I can come up with in parallel and then using the available information to eliminate as many as possible. That’s why I’m asking for instances of paradox being produced by homozygous mutant parents as that would tend to rule out chimerism.

Yes I realize that the possibility of half an apparent caramel’s offspring only being het albino or of a chimera morph’s offspring being completely normal have economic and marketing impacts. However I think it’s best to get to the answers as quick as possible even if it has more impact on sellers now it will have less impact on buyers later.

Quote:

---

Originally Posted by RandyRemington

Mendel’s point is good that there should be much more opportunity for chimerism in a species where one offspring at a time isn’t the norm.

---

But there are many many more species beyond just ball pythons that have more than one offspring at a time, have multiple different mutations including leucism, and have been breed for many more years and in FAR greater numbers than ball pythons ... without any documented instances of chimerism. I don't feel that the "has more than one offspring" argument gives ball pythons any greater weight than any other species when is comes to the possibility of chimerism. If that argument held water, we would have surely seen it happen in corn snakes.

Quote:

---

Originally Posted by RandyRemington

However I think it’s best to get to the answers as quick as possible even if it has more impact on sellers now it will have less impact on buyers later.

---

I agree, and that's what people that are actually working with these animals are doing. I think it’s one thing to sit around and speculate, it’s another to actually invest in the animals and do the breedings that it takes to find the answers. It's a shame that there are not enough of these animals out there to pursue every single theory at the same time, but we'll get there. ;)

-adam