The Miami "phase" corn snake...what is it?

[abell82]

Before you pick this apart because I am not "in" or part of the "click".
PLEASE read what this says, and actually THINK about what it means.
Please forgive me if I go "ALL-OVER" the place. If you need clarification I will be happy to try. PLEASE KEEP IT CIVIL!! :bang:


In another thread, it has been suggested that Miami Phase is NOT an inheritable trait, in a Mendelian fashion.
I suggested that it was and could be discussed in it's own thread, so as not to hijack from the OP.
So here it is. And here are my "Crack pot" ideals and theory on the subject.
( See the Original thread here: )http://www.cornsnakes.com/forums/showthread.php?t=65137

1.) What is a Miami "phase" Corn snake.

TO ME, A Miami "Phase" corn snake is, (in general) a corn snake having a silver / grey ground
color with light orange to dark red saddles. (Not unlike Texas Kistachies.)
These occur NATURALLY, however some of the cleaner animals have been bred in captivity for these traits.
The Miami Phase coloration is NOT a form of albinism, but a "wild type" or Natural coloration.

2.) How does a Miami "phase" Corn snake differ from a "Normal" Corn?

Quite simply they have a silver/grey ground color instead
of an orange or red ground color found in most "Normal" IE:red rat corns.
(For clarification:Wild type Miami Phase corns also prefer anoles to mice etc...)

Now for the fun part.

3.) Is Miami "phase" an inheritable trait?

MY Theory!!

Yes it is inheritable. HOWEVER, It is NOT an on/off, recessive / dominant trait like that of albinism.
It is NOT a form of albinism. It is a natural coloration.
My "theory" is that Miami "phase" is or acts more like an
Incomplete Dominance trait.
Meaning that the miami "phase" coloration, will "mix" with a "normal" snakes coloration and you will get a
blending of the two.

Let's use an analogy here to help. Let's say Miami Corns are akin to Blonde haired Humans, and Red Rats IE: Normal Corns are akin to Brunette haired Humans. Brown hair is dominant to blonde hair. So you get Brown Hair. In subsequent breedings, you will get blonde off spring. BUT, since it is an incomplete dominance, you will get dirty blondes, or strawberry blondes instead of platinum blondes or pure blondes.


So what breeders are doing, by breeding Miami "phase" Corns to "Normal" Corns is in effect breeding blondes to brunettes to try to get Platinum blondes. Will it work? What do you think?

it was suggested By Carol Huddleston, that...

... Miamis are a pain in the a$$. Two perfect Miamis can make very substandard offsring, and even hatchlings that look amazing can turn on you. A lot of my holdbacks end up being sold at 18 months because they start to change. Then after all those years and work, no one wants to pay that much for a "normal". So it really is a labor of love, but to me, they are the most attractive corn out there. It's really a shame it's not a recessive trait.

Analogy:Sounds alot like some human babies that are born Blonde haired and blue eyed, only to change later, correct?

IS the Miami "phase" corn snake coloration REALLY a pain in the @$$ or is it the just the way we are looking at it, and what we are trying to do and breeding with it?

IF Miami phase were truly not recessive, How could you breed a Miami to a
Miami and get more Miami's? You wouldn't.
It would be like breeding a polydactyl cat to a polydactyl cat.
All normal toed (or in this case red rat) offspring.


I asked in the other thread, if anyone had ever bred Kisatchie corns to "Normal" Red rats. I did this (and was accused of being all over the place)as I suspect that the Kisatchie corns are also akin to "blondes" so to speak and so when outcrossed the coloration will react, in the exact same or nearly the exact same way that the Miami coloration does.
And that is that the red ground color's of "normal" red rats will dominate the Kistachie's silver grey.

Crack pot idea, or not that far off after all?

 

[KJUN]

TO ME, A Miami "Phase" corn snake is, (in general) a corn snake having a silver / grey ground
color with light orange to dark red saddles. (Not unlike Texas Kistachies.)

Have you even SEEN a Kisatchie from Texas? Show me the orange/red saddles. Below is an image of a WC from Texas.

KJ

 

[Susan]

Miami phase, and the other selectively bred morphs, can be considered heritable only in the manner of the group of genes that create the look are inherited. But in order to perpetuate the look, ALL of those genes must be inherited by the offspring. We don't know how many genes are involved in the look and how each one works in conjunction with the others. Some may be simple recessive, some dominant, some co-dominant, etc. By breeding Miami phase to Miami phase, you do increase the chance of getting all the genes correct because both parents will pass those genes on. But because some genes may not work like simple recessives, those parents may have genes that are not being expressed that, when passed to the offspring, cause a non-Miami phase appearance. Given enough time, we will eventually eliminate all of those non-Miami phase genes to produce snakes that breed basically true, like we have done with the dog breeds. Right now, we are about at the Malamute or German Shepherd stage away from wolves. Eventually, we'll make it to the Chihuahua stage.

 

[Ssthisto]

3.) Is Miami "phase" an inheritable trait?

MY Theory!!

Yes it is inheritable. HOWEVER, It is NOT an on/off, recessive / dominant trait like that of albinism.
It is NOT a form of albinism. It is a natural coloration.
My "theory" is that Miami "phase" is or acts more like an
Incomplete Dominance trait.
Meaning that the miami "phase" coloration, will "mix" with a "normal" snakes coloration and you will get a
blending of the two.

The problem with that is that single-gene codominants and incomplete dominants ALSO follow very clear rules, and the rules are the same for both (it's just the visual appearance that differs).

I'll jump to royal pythons for a moment, which have some very well-documented co/incomplete dominant traits. Mojave's one of my favourites, so I'll use that as an example.

An animal with no copies of the Mojave gene looks completely normal.
An animal with one copy of the Mojave gene is a visual 'mojave' and shows pattern and colour mutations.
An animal with two copies of the Mojave gene is a 'super mojave' - a very pale to white snake with faint head markings and dark eyes.

There are three distinct phenotypes, and offspring can be predicted.

If Miami worked the same way as Mojave, you would expect that:

Breeding a visual Miami (equivalent to a 'super mojave') to a normal would produce 100% 'half Miamis' which have a lessened effect of the colour mutation. Now, this in practice DOES tend to work. You cross a stunning Miami to a normal, and you'll probably get animals that are varying shades of tan in the background and have reddish saddles. This means it's not a true dominant - otherwise you'd expect true Miamis in the initial crossing.

Breeding a visual Miami to a "half miami" (equivalent to a Mojave) should produce half "half miami" with tan ground colour and reddish saddles and half true Miami with grey ground colour and red saddles. This DOESN'T happen in real life. What you get is animals with slightly greyer tan ground colour.

Breeding two visual Miamis should NEVER throw out a "Half miami" or a normal if Miami is a co/incomplete dominant gene - you would only ever get other 'supers' that are true grey and red Miamis. Again, it's already been said by Carol Huddleston, someone who breeds the morph extensively, that two stunning Miamis may not produce 100% grey and red Miami offspring. This means it can't possibly be a recessive, by the way - if it were, two perfect Miamis wouldn't be able to produce a non-Miami offspring.

Those two facts - that the offspring cannot be predicted in genotype or phenotype based on their parents - means that there is not a simple, single mutation that makes a Miami corn - not a dominant one, not a recessive one and not a codominant one either.

The way it probably works is that a Miami has traits like:

"reduce yellow in ground colour" gene locus AA or BB
"reduce red in ground colour" gene locus CC or DD
"reduce yellow in saddle colour" gene locus EE or FF
"increase red in saddle colour" gene locus GG or HH

Now, if you have one Miami who is AA bb CC dd EE ff GG hh (where it's using the second possible way of doing those things in each possible pair) and another Miami who is aa BB cc DD ee FF gg HH (where it's using the first possible way of doing those things in each possible pair) ... breeding those two perfect Miamis together could get you 100% normals... who are Aa Bb Cc Dd Ee Ff Gg Hh. This is what's usually called a "polygenic" trait - there are multiple ways to get a phenotype, but in order to get the phenotype in successive generations, you've got to match up the genotypes.

That's where selective breeding comes in. If I bred my 'normal' who is carrying all those het traits back to one parent, I might get more of the genes matching up to produce a more Miami-like animal. If I bred the 'normals' together, I might get a more Miami-like animal that combines DIFFERENT traits than its parents. And if I linebred to a degree, I could eventually select for animals who carry most, if not all, of the genes to produce only Miami offspring... but it would take many generations of selecting the most Miami-like animals and only breeding animals that consistently PRODUCED more Miami-like offspring.

IF Miami phase were truly not recessive, How could you breed a Miami to a
Miami and get more Miami's? You wouldn't.
It would be like breeding a polydactyl cat to a polydactyl cat.
All normal toed (or in this case red rat) offspring.

Whoops... there are known lines of genetic polydactylic cats, including Maine Coon cats... you CAN breed a polydactyl to another polydactyl and get more polydactyls... and other radial hypo/aplasic variants.

You can breed a Pastel royal to another Pastel royal and get Pastel royals... but pastel is NOT a recessive trait You'll also get normals (who don't carry pastel at all) and "super pastels" which have a double dose.

It would be lovely if Miami were simple to inherit - I'd love to work the traits that make Miamis into, say, a line of Anerythristics to get as dark a saddle colour as possible and a pale, silvery-grey background colour - but it isn't a simple, sensible single trait at all. It's the sum of lots of little traits.

 

[Suncoast Herps]

I actually started a post but I doubt on my best day that I could explain it better than Susan and Ssthisto did.

I'll take the easy way and simply say "What they said"