Some rehash on corn genetics

[Steven@HumboldtHerps]

Hello Everyone!

Zephyr and I have recently been corresponding about issues concerning corn genetics, and I just got the obsessive-compulsive desire to relay a few pointers on understanding some of the combos...

Corn genetics is amazing, but you have to watch out for what's going on with certain traits, understand how they work. Most of us may be familiar with the "simple" recessive traits, those that you can track with punnett squares - which you can use to make statistical predictions. In corns these are:

Amelanism ("Red Albino", no melanin/black)

Anerythrism Type A ("Black Albino" [silly name], no red)

Anerythrism Type B ("Charcoal", no red, sometimes no yellow)

Hypomelanism Type A (reduced melanin, perhaps not necessarily the reduction, but the narrowing of the field where melanin would show up -THUS often enhancing other colors! Also, sometimes reduces belly-checkering)

Hypo Type B ("Sunkissed" - linked to an "Okeetee" line... Kathy Love has these)

Hypo Type C ("Lava" - not common)

Hypo Type D ("Ultra-hypo": this is a recessive gene that is co-dominant with Amelanism; one of each of these recessive genes produces "Ultramels")

Lavender (anomalous variable beauties with hypo/anery appearance topped with lavender-gray hues).

Caramel (exactly what it sounds like - reds and yellows take on dark and light caramel colorization).

Motley ("not so simple!" - highly variable pattern reversal that may include reverse-blotching, striping, and anything in between; complete ventral pattern loss; sometimes has a hypo effect on color. This gene is interestingly co-dominant with as well dominant over the Striped gene.

Striped (laterally striped head to tail [dorsal stripe is wide compared to dominant potential striping of Motleys]; complete ventral patttern loss; somewhat hypo effect.

Those are the basics, MORE TO COME (I haven't forgotten the Bloodreds!).

Wow! 11 traits to start with... Let's look at a few popular combos:

Snow (Amel + Anery Type A)
Blizzard (Amel + Anery Type B)
Ghost (Anery Type A + Hypo Type A)
Phantom (Anery Type B + Hypo Type A)
Sunglow (Soderberg line[rare]= Amel + Hypo Type A) "Sunglows" are usually selectively-bred low or no-white Amels (not a combo)
Butter (Amel + Caramel)
Amber (Caramel + Hypo Type A)
Opal (Amel + Lavender)

Mind you, these are among the fancier titles. Some are more basic like: Hypo-Lavender, Lavender-Anery A, etc.; visual differentiations in the appearances become more subtle with some of the hypo/lavender/anery combos - many will have pastel/gray hues that are difficult to distinguish.

Okay, how about a headache: Bloodred (the original most-awesomest blood-red line is gone - sterility and feeding issues!) Many attempts have been made to bringing it back. The bloodred trait, however is available, if still misunderstood. This snake is Hypererythristic (overproduction of red pigment expression dorsally and ventrally), but it also lacks both a dorsal and a ventral pattern. Young have a charctersitic gray head. Some believe up to 3 different mutations may be involved with this trait. Bloodred characteristics may show up in the 1st generation of a crossing with the Normal Type; this implies co-dominance as well. Bloodred may of course be crossed with other simple morphs to produce the likes of :

Pewter (Bloodred + Anery Type B)
Anery Type A Bloodred (sexually dimorphic color expression)
Amel Bloods, Hypo A Bloods, etc.

Yes there are triple recessives:

Coral Snow (Amel + Anery A + Hypo A)
Hypo (A)-Lavender Bloods

Keep mixing and matching; the fun never ends!Then there are the polygenic phases that are blended with the recessives:

Okeetee (not a regional morph, but a common variant with bold, rich reds, oranges, and bold black borders (Includes the highly defined Abbott's Okeetee)

Miami (not a regional morph; characterized with thinner black borders and very light ground colors ranging from lt. orange, tan to lt. gray to white)

Additionally regional morphs such as the Kisatchie corn or the Rosy rat may also have blending effect on a mix (usually ill-defined however)

Common recessive/phase combos include:

Reverse Okeetee (Amel + Okeetee; may include "Flourescent Orange" morph which is selectively bred for "no white where melanin would appear around the blotches")

Crimson (Hypo A + Miami)

Silver Queen Ghost (Zuchowski line: Hypo A + Anery A + Miami)

Candycane (Amel + Miami)

I could go on and on with the combos... Don't forget you can add Motley or Striped to any of the combos already or not yet listed. As for pattern mutations, there is also "Cubed" or "Aztec" or "Zig-zag", all related and equally unpredictable, implying co-dominance; I mean 2 zig-zags might produce all normals; I had a normal and a partially zig-zagged Okeetee produce only a couple more fully z-z'd young in the 3rd annual clutch!)

And what about Creamsicles?! These are a blend of Amel + the creamyness derived from blending corns with Emory's Rat Snake (many still agree it's a sub-species of corn). A normal variant of this sub-specific intergrade is the dull "Chocolate" corn. Add to that an additional Emory's variation of Amelanism, and you've got even more new possibilities on the horizon. Creamsicle may also be produced by hybridizing corn Amelanism with Black Rat Snakes and their sub-species.

Perhaps I have only scratched the surface of all the possibilities, but maybe this will give some of you a better understanding of how all is not as it sometimes seems in the wonderful world of corn genetics!

Steven (not a morph!)

[aSnakeLovinBabe]

Great little tutorial!!! this is stuff that I have been researching for yearssss! I love studying it... but I must admit... my favorite morph of cornsnake is the ultra rare... the mythical normal corn!!!

[infernalis]

do they eat swedish fish and poo glittery rainbows?

[aSnakeLovinBabe]

HAHAHA!!!

Yes, absolutely!

[tyflier]

Nice little tutorial.

You missed Cinder(anerythrism type C), and a couple trade names, though.

Also...bloodred is now recognized as a line-bred trait from the diffused gene, but really...it's just semantics.

I put the following incomplete morph list together last year. I've tried to keep up with the newest combinations and discoveries, but...it's difficult to do. It's an accurate listing as far as the publication of the 2008 Cornsnake Morph Guide, and next year will be upgraded to include new things that are being figured out right now...like "terazzo"...or a couple other new genes that are popping up...

Selectively Bred Looks:
Okeetee Phase-displays bright, clean orange ground color, clean, deep red saddles, and thick black borders.
Miami Phase-displays clean tan, grey or silver ground color with clean, bright red saddles.
Upper Keys-Once a seperate subspecies. Displays an overall "lighter" appearance with a ground color that leans more towards tan, and contains less contrast between the ground color and saddles
Milksnake Phase-A.K.A. Banded. These snakes have been bred to display wide saddles that typically join to the side splotches, giving the snake a banded appearance.
Aztec-saddles are asymmetrical in appearance, joining with each other at apparrently random locations, giving the snake the appearance of ancient Aztec markings
ZigZag-saddles join in a zipper-like pattern forming an obvious zigzag pattern down the back.
Frosted-saddles will display visible "whiteout" spots where each scale appears to have the pigmentation focused towards the center of the scale.
None of the above looks are the result of simple recessive genetics, and as such, no snake can be considered to be "het" or heterozygous for these traits. These looks are the result of linebreeding the best examples of each phase to each other in an effort to "perfect" the look. Most often, there is a wide range of variety in what is accepted as a particular phase, and each example is subject to one's own opinion.
Pattern Mutations
Motley-this pattern mutation causes the saddles to connect at the sides, leaving a circular pattern down the back of the snake. There is a WIDE variety of "perfection" to this gene, and no two motley snakes will look the same. One discerning feature is the lack of ventral "checks" on the belly of the snake. Considered co-dominant with the Stripe gene. Linebred variations include Hurricane and Cubed.
Stripe-in homozygous form, this mutation will cause stripes to form down the back of the snake. It appears as though the saddles join completely on the sides, leaving two perfect stripes that run the length of the snake. There is a variety to the appearance of these stripes with some being disconnected towards the tail and others "vanishing" as the snake matures. Ventral checks are not typically present. Considered co-dominant with the Motley gene.
Diffusion-A.K.A. Bloodred. This gene causes the side blotches of a snake to fade or "diffuse", leaving the snake virtually patternless on the sides in the best examples. Ground color usually "seeps" into the ventral region, causing orange or red bellies with no ventral checks.
The above pattern mutations are of a simple recessive genetic nature, and are predictable in offspring of homozygous and heterozygous parents to a highly reliable degree.
Single Recessive Color Mutations
The following mutations are the result of homozygous recessive genes causing the absence or reduction of certain pigments in the snake's skin.
Amelanism(amel)-this mutation causes a complete lack of melanin, which removes all of the black from the snake's coloring. Ground color will appear orange, red, or white, and saddles will typically be bright red. Linebred variations include Candy Cane, Reverse Okeetee, Crimson and Sunglow. A.K.A. Red Albino or Albino. Considered co-dominant with Ultra
Anerythrism type A(anery)-This mutation prevents the developement of erythrin, which produces the pigment cells that create the oranges and reds found in normal corns. Ground color is pale grey or silverish in appearance. Saddles are black, dark brown or grey in appearance. Snake's will typically develope concentrations of yellow along the chin and sides as snake matures. A.K.A. Black Albino
Anerythrism type B(charcoal)-Very similar to anery, but snake's do not typically develope as much yellow as in anery type A snakes.
Caramel-These snakes are typically very yellow. Ground color is usually yellow or "caramel" in color with saddles being varying shades of brown.
Cinder-A.K.A. Z or Ashy. Not a lot is known about this gene. It appears to be a third form of anerythrism, with hathclings appearing as a brownish "anery" and developing a certain amount of reddish coloration as the snake matures.
Dilute-appears to be a "hypo" gene, wherein a reduction of malanin is present. Also appears to be linked to anerythrism type A.
Hypomelanism type A(hypo)-causes a reduction, but not an elimination, of melanin pigment, which gives the snake a lighter and "cleaner" appearance.
Lava-another hypo trait that reduces melanin and brightens the appearance of the snake.
Lavander-typically a very "strange" grey coloration...almost purple. Very difficult to describe. You need to see one to understand.
Pied-sided-displays areas on the side of the snake that have no coloration resulting in patches of pure white. Believed to be linked to the diffusion pattern trait.
Sunkissed-a hypo-like trait that reduces melanin content and also appears to effect saddle size and shape. Unrelated to other known forms of hypomelanism.
Ultra-Highly reduced melanin. Almost non-evident. Considered co-dominant with amelanism.
All of the above mutations are the result of a single recessive gene appearing in a homozygous state to produce the resultant look. These genes are extremely predictable in breeding as simple recessive. Snakes that are heterozygous for these traits will look "normal" but still carry one copy of the gene hidden.
Recessive Combination Morphs
All of the following morphs are the result of combining two or more recessive genes in homozygous status. The motley or stripe pattern mutations described above can be combined with any of the following morphs for a different look.
Amber-Caramel + Hypo
Avalanche-Amel + Anery + Diffusion
Blizzard-Amel + Charcoal
Butter-Amel + Caramel
Coral Snow-Amel + Anery + Hypo A
Fire-Amel + Diffusion
Ghost-Anery + Hypo
Golddust-Caramel + Ultra or Ultramel
Granite-Anery + Diffusion
Hybino-Amel + Hypo
Ice-Anery + Lava
Lavamel-Lava + Amel
Opal-Lavander + Amel
Pewter-Charcoal + Diffusion
Phantom-Charcoal + Hypo
Plasma-Lavander + Diffusion
Snow-Anery + Amel
Topaz-Lava + Caramel
Whiteout-Charcoal + Amel + Diffusion
Ghost Blood - hypo + anery + diffusion
Sulfur - caramel + amel + diffusion
Caramel Bloodred - caramel + diffusion
Amber Bloodred - caramel + hypo + diffusion
Anery Lavender - anery + lavender
Ice Blood - Lava + anery + diffusion
Snopal - amel + anery + lavender

[infernalis]

Garter snakes are cool.

[Steven@HumboldtHerps]

Tyflier!

Very impressive list! Yeah, anery C.... I guess I stopped keeping track over a year ago... I too have come to appreciate the NORMALS. I've had too many defects pop out among my triple recessives and quadruple hets. I love corn genetics, and as much as I'd love to dive back into its wondrous diversity, I have as of late had way too much info on the brain (moving, final papers, being a docent at the museum, I have no clue regarding the holidays this year!).

For now it's specializing in NW CA herps all the way! Have a presentation coming up in January. Gotta count those costal grooves !

Steve

[tyflier]

Thanks, Steven. I try to keep my list updated every year, using the Cornsnake Morph Guide, and cornsnakes.com. It will never be "complete"...but it's pretty close. There are a couple new genes being tested right now that I'm waiting to hear results on, but that could still be a year or more out...

I just love the genetics of corns. So many possibilities, and the list I wrote doesn't even begin to get into quadruple recessives or beyond...

So many genes, so few snakes...

Of course...the Cali native speices need attention, too...