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In looking over some of the anerys out there, some, where there would be red on a normal have shades of washed-out grayish pink. At what degree of pink would you differentiate an anery from a normal?
Where does an axanthic fall in regards to color on gbk's?

Could the ones with pinkish-gray banding be a visible het?

Take a look at these 2 that hatched last season. I'm not calling them anery, 1 has pinkish-red scales bordering the white.

thanks

>>Where does an axanthic fall in regards to color on gbk's?

I hope I don't botch this up, but I believe Bechtel describes anery and axanthic as synonymous terms, or at least, he uses the word axanthic in place of anery, for herps.

Red and yellow pigments are classified as the same type of pigment cell called xanthophores. Different degrees of intensity controlled by different genes make them yellow, orange, or red. But us herpers coined the term anerythristic to differentiate between a lack of red xanthophores and yellow xanthophores, in other words, to differentiate phenotype. Genotypically, or at least "cytotypically", they should all be called axanthic. (Confusing, because doesn't the prefix xanth- mean yellow?)

But anyway, there's no such thing as erythrophores, according to what I remember from Bechtel's book on color mutations in herps. Since we think in terms of red color in GBKs, we usually say anery, but I think Bern Bechtel wanted to get rid of that term.

DR

Suboc.com

Dusty,

Xanthin (yellow pigment) and erythrin (red pigment) are both produced in a specialized pigment cell called xanthophores. Production of the two pigments is often, but not always, linked. Some species produce only xanthin or erythrin, while other species produce a combination of the two. Erythrophores are cells that produce predominately red pigment. Looking at corn snake genetics is probably the easiest (or not... LOL) way to illustrate this:

There are mulitple forms of "anerythrism" which look visually different. One form totally wipes both red and yellow out of the animal. Another form removes the red, but leaves traces of the yellow. Another form removes the red, but leaves (or enhances) the yellow. This is sort of skimming of the topic, and a much deeper explanation is possible.

I'm sure you're already aware of the above, but I just felt like rambling. Maybe Vinny will chime in here - genetics is his specialty.

-Cole

Have you looked closely at Hypo Stillwater Bullsnakes? I would be curious to hear your take on that mutation if you have.

Forks
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

I've never investigated them much, to be honest. Awesome looking snakes, though! From photos it appears that there is a reduction in the depostition of melanin (melanophores are the second major pigment cell) in the cells, but that could be the result of many things. The formation of melanin follows a cascade of enzymatic events (one commonly referenced is the synthesis of tyrosinase), and a malfunction at any one of steps can cause varying forms of hypomelanism on through to amelanism. Once the pigment is made, another cascade of genetically controlled events determines its deposition within the skin - both location and quantity - which can also lead to varying forms of hypo- or amelanism. Lots of things can go "wrong" during pigment synthesis or deposition, and without testing for the presence of certain enzymes within the cells, it's anyone's guess as to what's really going on.

Interesting topic, and thanks for bringing it up.

How are things in TX? Any word on how filming is going with Dan's documentary?

-Cole

Dan is posting updates over on that other Field Herping site. He just posted a south Texas report.

Things are moving along slowly. I am cautiously optimistic.

I agree, very interesting topic. Thanks for that info.

Best
Joe
-----
Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

I saw 2 of his updates (OK and one from TX) and await more!

-Cole

Thanks Cole,

Boy, it's been awhile since I've glanced at Dr. Bechtel's book or anything substantial on the synthesis of herp chromatophores, so like I feared, I was liable to make a hash out of my statement earlier. LOL

But I'm in the library now and have Bern's book in my hands.

One point that I tried to make was that, on a cellular level, Bechtel does not make any distinction between erythrophores and xanthophores (pigment-containing cells). He states that erythrophores are xanthophores with predominantly red pteridines, and that we call them erythrophores based on appearance or phenotype only. In other words, they're still xanthophores. (You've already said some of this stuff...I'm just thinking "out loud" here.)

The reds and yellows (and intermediates) are a combination of pteridines (pigments synthesized by the xanthophores) and carotenoids (not synthesized by the xanthophores, but are dietary in origin).

My point is that, on a cellular level, Bechtel does not recognize anerythrism. He even calls what we usually refer to as anerythristic Hondos and anerythristic Corns as axanthics.

Using the Corns as an example, an Anery type A is one that is born black and grey with no yellow or red, but as they mature and ontogenetically change with the xanthophores incapable of producing pteridine reds and yellows, they still accumulate dietary carotenoids of yellow color in the neck, chin, and other close-by areas.

Anery type B (charcoal) is a bit confusing using this example, because, when they are born, they are also a variant of black and grey, but they appear to accumulate much less dietary yellow than type A aneries. Or, could they be a manifestation of a higher degree of axanthicism (similar to the way a T-negative albino demonstrates a greater degree of amelanism than T-positive albinos -- this is an oversimplification here) than type A aneries?

Maybe Caramel Corns should be classified as a "hypoxanthic", reducing or eliminating red pteridine-containing xanthophores while leaving the yellow pteridine-containing xanthophores, which enhance in yellow even more as they mature and accumulate carotenoids.

Of course, "hyperxanthic" would appeal to most hobbyists here, since we tend to mostly think in terms of phenotype. And maybe an overproduction of yellow pteridines is what is happening anyway. Then, where does that leave Bloodreds?

Whew!! I agree that we should have an expert post in here (like Dr. Bechtel), instead of someone who is trying to interpret his work.

DR

p.s. More later! This is very interesting stuff.

I think we're on the same page here. While the same name is applied to cells which produce red and yellow pigments, not all cells produce both. Different genes control the production of xanthin and erythrin, and although they often get shut on and off in sync with one another, they aren't always. Broadly speaking, axanthic would mean that no pigment is produced by the xanthophores. Anerythrism would be a subset of axanthism, in which only the red pigment gets turned off. Caramel Corns would be an example. It would't be surprising to learn that the pigment precursers to erythrin were cycled through the xanthin pathway, thus increasing the production of xanthin and making a yellow-tastic snake.

More rambling.

-Cole