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This is just a question followed by an observation on my part, and I would love some feedback on this please.
Question:
Is T Albinism actually and Albinism and not a different form of hypomelanism?
To me at first glance they have never resembled an albino, but rather a very nice looking hypo.
Any thoughts?
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www.imageevent.com/gmherps
gmherps@sbcglobal.net
Should be T Albinism
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www.imageevent.com/gmherps
gmherps@sbcglobal.net
,,,,
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www.imageevent.com/gmherps
gmherps@sbcglobal.net
This is Marcus from Louisville, KY.
I feel the same way about T positives. I do not see why they are considered albinos either. Maybe it is just that they have similar genetics at work with one affecting the melanin production to a lesser degree than the other or in a totally different way than the other. I am no genetics buff and I have never saw a T pos in person but just by looking at them I would not think albino. Not even the red eyes would have me think albino because I have calico mice with red eyes.
Listening to myself talk I can see why they could be considered a form of albinism. It is confusing to me but whatever the case may be they are still some beautiful snakes.
Shot
I just don't understand the whole browns and tans on the t-pos boas. This should be an interesting thread as it gets rolling.
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www.imageevent.com/gmherps
gmherps@sbcglobal.net
Okay, this is my understanding, though I have not tried to explain it in a while, and a person more well-informed than myself will probably correct me in several ways very soon. Ever notice the plus sign doesn't show up at these forums? It gets parsed as code, and so we don't see it, I guess.
T , T-plus, or T-positive means Tyrosinase positive. Tyrosinase, if I remmeber correctly, is an enzyme which allows melanin to bind to the melanophore, so that you and I can see the lovely black overwash on our prize "het". Normally, "Albinos" (amelanistic) do not produce Tyrosinase, which is what facilitates the failure of the melanin to bind to the cell. (Again, please, this is my best understanding of it. Go ahead and correct, but don't flame, k?)
In what we call "T-Pos Albino," animals, apparently the Tysosinase remains, and yet the Melanin still fails to bind correctly, actual possible reasons for which are as mysterious as they are multitudinous.
It is really not known exactly how Tyrosinase does its job, nor have we confirmed, in many cases, that what we are calling "T-positive" animals, actually are producing Tyrosinase. This sort of testing is very expensive, and if it makes a purple and orange snake, that's good enough for me. (have you seen the Clumper Strain T-positive Pituophis catenifer annectans? WOW)
As far as whether the term is appropriate for common usage; Well, I would say there are more misleading names out there, and this one will do for now. Though technically it may be considered more closely akin to what we currently call "hypomelanism," than true amelanism, it is misleading to use the term "T-plus Hypo," as well.
Hypomelanism is surely arrived at by different mechanisms both within species and across species. I believe there are now 5 different kinds of identified, genetically heritable hypomelanism mutations in Corn Snakes. One of these is an allele to common amelanism within that species. (if you want to stretch your brain, go learn about how alleles work, they are different mutations on the same gene pair.) I believe that it would take an especially naive individual to think that what we call "Hypo" in Boa constrictor is the same as that which we call "hypo" in any other species, and vice- in- ex- intra- infra- ultra- and contra- versa. Similarly for "T positive" critters, it is an unknown function for now.
Most of the actual molecular genetic complexities, specifics, and causal relationships of color and pattern mutation and variation are unknown, and will remain unknown for quite some time, I'd guess. The world isn't really interested in the "pretty" genes of our snakes, so we'll have to wait until Apple releases "iGenome."
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Jeremy J. Anderson
Gem State Reptiles
The T pos gene is supposedly incompatible with the other forms of albinism but it passes in the recessive form just like the other forms of albinism. So just like the snow boa is formed with two types of recessive genes combining statistically in 1 of 16 offspring, why would or would not two boas both het for both t pos and sharp strain albino produce or not produce a T pos sharp strain albino?
Shot
I misread what you were saying in another of my replies, sorry.
Well, 2 generations of breeding could produce a double homozygous Sharp strain and T-pos albino, but would we be able to SEE the difference?
I vote that the sharp Strain, presumably lacking in Tyrosinase entirely would override the visual appearance of the T positive strain, but I could be totally wrong.
Genetically it could certainly be exhibiting both genes, but I think it unlikely for it to look much different than a "regular old" Sharp strain.
That is, unlesss one happens to be an allele of the other, and then it would depend which as dominant over the other, or there could be an intergrade appearance that had some properties of both.
In the case of the discovery an allelic mutation in boas, and the intermediate appearance when both gene variations are present in a single animal, such an "albino" would be homozygous for neither strain, and heterozygous for both.
How's that for a brain teaser?
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Jeremy J. Anderson
Gem State Reptiles
Jeremy you get deep man, thanks for the very informative reply. I guess we would have to actually cross some of this stuff up to get the real results and thats what makes this so fun with its endless possibilities.
Shot
That helps me to know the relationship between the T enzyme and melenin. Question----
>>>>>> "It is really not known exactly how Tyrosinase does its job, nor have we confirmed, in many cases, that what we are calling "T-positive" animals, actually are producing Tyrosinase. This sort of testing is very expensive"
Has this test ever been done at all? This may be expensive testing, but so are these Boas. And don't get me wrong, I think they are among the best looking proven morphs out their. But I haven't heard of any solid evidence that they are indeed a solid form of Almenism. They sure don't look like they are to me. I'm talking primarily about the Columbian type, and not the CA's or Argies. I personally would've liked to have seen them given a character name such the Halequins and Arabeque's were given, and not linked to Albinism based on a good guess. If their were tests given, then I digress.
Again, I think these are wonderful Boas that deserve the recognition that they've gotten. I'm just too thick-headed to link it to Albino status. This is just based on the pics that I've seen, for I can not afford to own one.
Have a good weekend everyone. Congrats on the new litters this week. They are exciting to see. David
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--aka DMOG68
I believe the testing has been done on a few species, Argentine Boas among them I think, but I may be mistaken.
As far as the reply about the possibility of Kahl Sharp Amels producing a T positive, it is definitely proven negative.
It could happen, I suppose.
"Ultra Hypo" in corn snakes is on the same gene pair as Amelanism, and there is an intergrade, called "Ultramel" which looks like a T/ to me.
The part about the testing being expensive is purely hearsay, I haven't investigated the cost of such testing myself.
I did read that there was some of this sort of testing that had been done on snakes, but I can't recall where I read it, or by whom was the testing performed, it was years ago.
I reserve the right to be completely wrong.
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Jeremy J. Anderson
Gem State Reptiles
H.B. (Bern) Bechtel has done some tyrosinase testing on a few colubrid snakes. See his Amphibian and Reptile Variants book. My impression is that it isn't costly enough to break most of us. But it does take some equipment, lab skills, and access to bits of skin from various albinos.
A few years ago I asked Dave Barker if anyone had done tyrosinase tests on boas. He said that nobody had done such testing on any species of boa or python. That may have changed by now, but if so, I have not heard of it.
Back around 1985, Bechtel had a paper about black rat snakes in the Journal of Heredity. Using the tyrosinase test, he found one strain of albino black rat was tyrosinase negative, and the other was tyrosinase positive. Crossing the two strains produced a normal-looking, double heterozygous black rat snake. Aside from the tyrosinase test, the Kahl and Sharp strains of albino boas parallel the results from the rat snakes. In my opinion, one could be tyrosinase positive and the other tyrosinase negative, but I don't know which. Or both could be tyrosinase positive. I think it very unlikely that both are T-negatives. It doesn't work that way in mammals, at least.
I also think that hypo in boa constrictors is not the same as hypo in colubrids. That is one of the reasons I favor calling Rich Ihle's line "salmon boas" and not hypos.
There are lots of ways to make animals lighter colored than normal. Malfunctioning tyrosinase is only one. There are lots of things that break in a car and keep it from running. A dead battery is only one. If T-negative albino equals a dead battery, then T-positive is equivalent to making a grouping of cars with a good battery but something else wrong (broken ignition switch, plugged gas line, disconnected battery wire, burned out alternator, etc.). This sort of grouping is the result of ignorance masquerading as knowledge. Better would be an honest admission of ignorance.
The pro geneticists give a unique name to each mutant gene to minimize confusion among them. I think that boa fanciers are missing a bet by lumping at least three mutants together as T-positives. Unique names, especially sexy unique names, would minimize confusion and avoid giving the impression that anybody has a clue to the biochemistry involved. There are also sound marketing reasons for giving them sexy unique names. 
By the way, melanin does not bind to the melanophore. Melanin is made inside the melanophore. Tyrosinase catalyses the first two chemical reactions in the series that changes tyrosine into melanin. Ultimately the melanin is deposited in a protein matrix and becomes a pigment granule. The process is complex and still not fully understood, as far as I know.
Paul Hollander
I did post that pic 2/3 days ago and no reactions. Here is a columbian T+ toungue. I haven't seen for the moment this pink/purple color in any other boa morph.
Concerning how they are called, I have often been changing my mind, I know one thing they are stunning and must be seen in person !
Oh yes ! They definitely are stunning, and I could see that their tongue is purple/pink, but I also see the moustache, and dark stripes in back of the eyes, which seem to bold in the melanin area to be calling these a form of Albino. I think that I'd have to see reports of lab studies done with this strain to believe that they really are a form of Albino. Great now I'm going to have to do some researching, so I'm not completely talking out of my butt. . . lol. If anyone has more info or opinions, please input. -------I'm in no way trying to dis-credit anyone, or put down excellent strains of Boas at all. Just so you know.
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--aka DMOG68
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