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Attention SerpWidgets:

Gregg

Gregg

Ancient Elder
I need your genetics talent.

First: I understand what heterozygous means, but I'm confused as to the meaning of Homozygous, if it means something other than what the animal is is what you see. I was always under the impression that it was the same as Phenotype, though I've read people using it otherwise.

Second: I've been using Mick's Corn Snake Progeny Predictor, as many others do, and occasionally I get something like, "hypomelanistic (masked)", or some other trait "(masked)". What's that all about? I mean, what does this mean? Thank you. :confused:
 
Terminology

The Zygote is the name of the fertilized egg. It is the first individual cell from which all other cells of that animal will be made. So as the cells divide and divide, they will all have the same exact genetic makeup as the zygote--theoretically anyway... this isn't 100% true in reality but still close enough for practical purposes.

Thus if the zygote has a particular gene pairing for one trait, so does every cell in the whole animal. That's where the suffix "zygous" comes from.

As you know, when you breed say a normal to an amel, you get offspring that are normal, heterozygous for amel. You know this is the case because--at the amel locus--they each inherit one copy from each parent, and these copies are different. "Hetero-" means "having different kinds."

And of course "homo-" means "the same kind."

So Heterozygous has a pair for a given trait that consists of two different genes, and Homozygous has a pair for a given trait that consists of two identical copies of the same gene.

---

The "Masked" note means that the trait may not affect the phenotype. For example, if you breed two snows het for charcoal together, the ones that are homozygous charcoal (and amel and anery) will look like blizzards. In that case, the Anerythrism is masked.

I still have not seen definitive proof that hypomelanism is masked by amelanism. When someone can show me a reverse Okeetee that is homozygous for hypo, I will then believe that it's true. Until that day comes (which I bet will be never) I will continue to fight against the assertion that amel masks hypo. ;)
 
Thank You.

I knew you'd be the one who could clear that up for me.

I thought homozygous meant exactly as you described, but I had read it being used as if it was comparable to heterozygous, e.g., a normal being het for blah-blah-blah, and homo for blah-blah-blah. It left me very confused as to what the person was asking/saying. Anyway, thanks for clearing that up.

Also, thanks for giving me a very good description as to what "Masked" means. That had me completely lost. I'll have to re-read what you said over and over a few times before I can beat it into my burnt-celled brain so it will stick, but it was written so that a very clear picture popped into my mind. (I work better when I see mental images.)

Gracias Mi Amigo

:cool:
 
Until that day comes (which I bet will be never) I will continue to fight against the assertion that amel masks hypo.
Click to expand...

And what effect do you think that Hypomelanism has when homozygous in tandem with Amelanism? If Amelanism does not mask Hypomelanism, then there must be some identifiable visual cues that we should look for. I would be curious to hear your arguments for your opinion. I don't have an axe to grind either way with this but the evidence I have seen and the logic I apply to the situation causes me to disagree with you.

Personally, I have produced Snows from Ghosts, and apart from the pink coloration, which I believe is from the roots of what originally made the Ghosts the variant called 'Pastel Ghosts' and has nothing at all to do with Hypomelanism, I cannot see any indication of Hypo peeking through the Amelanism. After all, many of the Ghosts themselves can have that pinkish coloration to their blotches. I also have Butters that I believe are likely homozygous for Hypomelanism as well, and I strongly suspect the no one could pick them out from regular Butters.

My opinion has been that no one has adequately controlled the subject matter, and results are more likely influenced a whole lot more by the ground color of the base stock used, rather than anything Hypomelanism would contribute to the appearance of the animal. Someone would have to start with identical looking animals, breed Hypomelanism to one animal, Amelanism to the other. Then grow these resulting offspring up, and breed them into their respective projects to produce Hypomelanistics on one hand, and Amelanistics on the other. Then breed the homozygous Hypos and Amels together producing double heterozgous animals. Then grow THEM up, and take any resulting Amelanistics, grow them up and breed them to Hypomelanistics to uncover which ones are also homozygous for Hypomelanism as well as Amelanism. Once the animals that are homozygous for both Hypomelanism and Amelanism are identified, then compare them visually with the Amelanistics that have proven to NOT be homozygous for Hypomelanism. Proably a double blind test would have to be done at this point to see if it were possible to visually detect those double homozygous animals. My guess is that, taking into consideration the random variation in any given clutch, it will not be likely to be able to tell the difference.

Just by breeding a Hypomelanistic of indeterminant heritage into an Amelanistic of a non identical heritage, and somewhere down the line getting a 'different' looking resultant Amelanistic would not be even close to conclusive evidence of Hypomelanism having any influence.

IMHO.
 
Rich, I understand your reasoning and you make some good points. What drives me insane is the assertion--not by you but by other people--that "you cannot reduce what isn't there," because that statement assumes that hypomelanism's mechanism is determined by the name we've given to it. To me it's like saying that the sun never shines on the dark side of the moon because it can't be dark if the sun shines on it. ;)

(If anyone reading this thinks the dark side of the moon is dark, just ask yourself what part of the moon the sun is shining on during a new moon. I've actually had that argument with people before...)

I don't think anyone can say for sure until the mechanisms for both traits are truly understood. I tend to lean in the other direction for a few reasons. One is because Don Soderberg produces sunglows by using Hypo X Amel. He has told me that the double homozygous F2s from certain lines make good sunglows. (I don't know if that means the ones from other lines have lots of white, or they just don't have bright enough reds and oranges to make the grade.)

I don't think this necessarily proves that Hypo is being "expressed" in these animals, but I do think it's possible that the thinning of the (normally black) borders is either a part of hypo or a closely linked trait. That's why I say, "produce a hypomelanistic reverse okeetee and I will shut up" because I think that would be a pretty solid rebuttal.

Another thing is that Hypo is used to try to brighten the reds and oranges, and so you'd think if people were selectively breeding for "Hypomelanistic Okeetee-looking cornsnakes" that they (or at least someone) would be selecting for the thickest possible borders. I'll freely admit that I haven't seen a bazillion hypo okeetee-phase corns. But every one of them I have seen has black borders that are not nearly as thick as the best non-hypo Okeetees. Again not proof, but it makes you say "hmmm." ;)

I think there's something more going on with Hypo. Maybe it's only in certain lines, and maybe we don't see it because it's very subtle and we're not looking for it. I don't think anyone can "prove" anything either way at this point.... but it drives me up the wall when people act like it's a given that amel masks hypo just because of its name. :)
 
Serp,

I have nothing but respect for you and your ability with the genetics questions. I really appreciate your responses and I try to read them all. However, your statement about the dark side of the moon is off base.

The dark side of the moon is ALWAYS dark because the moon is in a solsyncronous (sp) orbit. The moon turns on its axis at a precise rate so as to have the same exact side always facing the sun as it also rotates around the earth. It is this fact that actually allows us to have the various "phases" of the moon as we see it. When the moon is full, the earth is actually between the moon and the sun (this is why the lunar eclipses take place when the moon is full or nearly so). When the new moon is showing (or not as the case actually is), the moon is actually between the earth and the sun (solar eclipses take place during or near the new moon phases). The waxing and waning moon phases are simply the moon at side view for us as it continues to rotate around the earth with the same side always facing the sun.

No big deal. I know this isn't a corn topic, and Rich may feel free to delete it if he deems necessary! However, in the intrest of accuracy, I thought I'd through in my astronomy information (limited though it is)!:D
 
Serp, Rich,

Would the hypomelanism gene have the effect of supressing the full expression of the gene that governs melanin? I know that in dogs, cats and canaries there is a gene called "pastel" or "dilute" whose only job is to tone down the manifestation of melanin. Therefore a genotypically black cat appears gray. These pastel genes occupy a separate locus than the one for the amel or normal melanin alleles.

If that were the case with corns' hypo gene, then in an amel snake that has no melanin manifesting the hypo gene would have nothing to tone down. Thus a hypo amel and a plain amel should look the same, and the only way to know the first one is hypo is by its parentage (hypo het amel x hypo het amel).

As to the width of the black borders of the saddles: a) either the hypo gene also affects the width in addition to tone down the amount of melanin; or b) part of the borders in a normal snake is red with black on top and we can't see the difference, meaning that when the melanin is reduced, more of the red portion of the saddle is visible, making the border appear narrower.

Since melanin is black or brown, when toned down the other pigments (red and yellow) will show up more intensely.

Would any of this seem plausible to you?
 
*****pets her pretty corn**** ****rocks back and forth*****
****brain hurts**** "nice pretty pretty corn" ****Drool***
 
Darin,

Either my understanding of astronomy is severely flawed or you are mistaken. I believe that the moon makes one complete revolution about it's axis as it transits around the earth. In this manner, the same face of the moon always points towards the EARTH, and not the sun. If such is true, then when the moon comes between the earth and the sun (as in a solar eclipse if there is a direct lineup), then with the same face pointing towards the earth, the opposite side of the moon MUST be facing towards the sun. Therefore there is NO permanently dark side of the moon.

OK, now you real astronomy experts: How long is a 'day' on the moon?
 
I've been out of school for a while, but isn't a day on the moon around a month on Earth. Mercury's rotation lasts its whole revolution too, I think.
 
My guess...

If one feeds their corns one jumbo mouse each week, on exactly the same day of the week, then I would guess a day on the moon--depending on where one is standing--should last about two feeding periods of a captive, adult corn snake, or approximately fourteen EARTH days. But then, if you were standing on the Moon, you would have to watch the Earth's rotation in order to determine when a week has passed.

Wonder what a cornsnake would look like in a pressurized environment suit. Using crudely constructed atlatls, we could see who could throw their corns the fathest.

I had to work in the "CornSnake Forum" thingy you know.
 
Well,

I wrote what I did above with an admitted lack of memory from my college astronomy class. I was not necessarily surprised by what I saw Serp and Rich write in response, but I was sure of my "facts" so I too went web surfing to see what I could find. The result? We now have a bona fide mystery on our hands here!

The web sites I found that explained the illumination of the moon as I had been taught in college are as follows:

http://aa.usno.navy.mil/faq/docs/moon_phases.html#top

(This one is set out by the U.S. Naval Observatory, and briefly touches on the subject, adding some pictures along the way)

http://www.astronomynotes.com/nakedeye/s13.htm

(This one is EXTENSIVE in its explanation, using charts and diagrams to show how the moon rotates around the earth AND keeps one side always facing the sun)

Guys, I have no "bone to pick" with this issue at all. Frankly, I'm too busy to worry about why it is that the moon appears as it does, and I know we all are (Babies are hatching, after all!)). I just find this type of stuff fascinating. We just need to find THE DEFINITIVE Source on this matter so the right answer can be had by all. If I'm wrong in my assertions previous and current, I'll be the first one to admit it, but it appears that even the "experts" don't have their stories straight yet, Huh? LOL


P.S. Delete this anytime you like, Rich. Not too corn snake intensive, I know. How 'bout this question, then? What gravitational forces are needed to get a corn hatchling to always pip its egg near the top side?
 
green cheese...

this info taken straight from the new york public library science desk reference....
"rotation and revolution: 27.32 days (because of its equal rotation and revolution, the same side of the moon is always facing the earth)"
if you click on the first link provided by darin and scroll down to the movie clips of the phases of the moon you can see this quite clearly illustrated that we are always facing the same side of the moon.... enjoy... :) ---jim
 
NEED COFFEE

If I were to pull my pants down over a corn snake, will I get a Moon Over Miami ?
 
OK, ok, ok . . .

I give up; you guys are most likely correct. Guess it's a good thing I sell insurance and breed corns instead of being responsible for sending someone to the moon, Huh? Oh well, I got my "A" in astronomy and then immediately began to let the data ooze out of my ears after the final. Guess I let too much fall out!


Delete away!
 
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