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what does this mean?
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by codeman on June 2, 2008
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what does it mean when you read het. for albino? ive seen that a few times. what does the het. mean?
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RE: what does this mean?
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by GaryOrner on June 2, 2008
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The animals will be normal looking but will carry the albino gene.
Say you breed a 100% het albino to a 100% het albino
In a perfect world you should get 25% of the clutch to be albino.
That is the simplest way I could put it.
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RE: what does this mean?
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by Crotalusssp on June 4, 2008
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Het is short for Heterozygous. The other possibilities are Homozygous either dominant or recessive. A GENE is a portion of DNA which codes for a trait. Different forms of genes are called ALLELES. You receive an gene from the mother and a gene from the father. Together they provide the information for the specific trait. If both genes are the same allele the organisms is said to be HOMOZYGOUS or same genes. If the genes are two different alleles then the organism is said to be HETEROZYGOUS meaning different genes. A HOMOZYGOUS Dominant individual would be nearly indistinguishable from a Heterozygous individual. A homozygous recessive individual would show the recessive trait such as albinism and of course would very easily identified. The terms DOMINANT and RECESSIVE refer to the alleles ability to mask in the case of a dominant or to be masked in the case of a recessive. This is why a heterozygous individual appears like a homozygous dominant, because although it has a recessive allele such as albinism, the dominant alleles masks it. This is Classic Mendalian genetics. Keep in mind that some traits are controlled by multiple alleles.
Charles
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RE: what does this mean?
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by Cro on June 4, 2008
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Charles, you stated "A HOMOZYGOUS Dominant individual would be nearly indistinguishable from a Heterozygous individual."
That is generally true and expected in classic Mendalian genetics, and works great for many animals.
However, I am starting to question this when it comes to snakes. I have 5 Heterozygous for Albino Cottonmouths, 1 male, 4 female. All of these snakes had an Albino father, and a normal colored wild mother.
When I bred the Hets to the Hets last year, I got 4 distinct colorations of offspring. We would expect 25% Albino, 50% Het for Albino, and 25% Wild Type. And we would expect that the 75% of the offspring that made up the Wild Type and the Het for Albino would all look like the Wild Type.
However, I got 4 very distinct colorations in the offspring, and that was true for all 4 females. I wound up with Albinos, Wild Looking, and two "in-between" shades, that were both lighter than Wild Type, but less than Albino.
Now, this raises the question if the Wild Type looking offspring are the 25% that are are carrying the Wild Genes, and if the two intermediate colorations represent the 50% of the offspring that should be Heterozygous, and if the Albino Coloration represents the 25% of the offspring that are supposed to be Albino.
I have no way to know the actual genetics of the offspring that are not Albino. However, the ratios are holding up. I am getting about 25% Normal looking young, 25% Albino young, and 50% of the intermediate looking young.
So, is it possible that we are seeing expression of coloration in the 50% of the young that are Heterozygous that would tell us that they are the Hets, simply because they are lighter colored than normal ? Perhaps. That is the theory that I am working on.
In other words, if you capture a extra light colored Cottonmouth in the wild, does that mean that it is Heterozygous, and does it mean that one of its parents was an Albino, or Leucistic, etc.....
Am I seeing incomplete expression, or perhaps increased expression due to Heterozygousness ?
Anyway, just an idea to throw around. After all, Cottonmouths are not Fruit Flies, and just might express their genetics in a different way. If that is the case, we might have to modify the Classic definition of Mendalian Genetics just a bit.
Sure wish I had access to an mDNA lab so that I could determine if the two light phases are indeed the Hets.
Best Regards John Z
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RE: what does this mean?
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by Crotalusssp on June 4, 2008
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That indeed sounds like a form of incomplete dominance. Have you considered there being more then 2 genes controlling color? If multiple genes are at work the lack of a second dominant allele may allow expression of another gene. I am not a geneticist, so this may be completely off base. The question is however a very interesting one. I was told by a breeder of Burmese Pythons that he could distinguish Hets from normal by looking at the pattern also. This was many years ago and I did not even think at the time to question it.
Charles
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RE: what does this mean?
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by Cro on June 4, 2008
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Charles, I have considered incomplete dominance as a possibility. But, how the heck do we test it, LOL ???
That is why I wanted to throw this question out there, as the folks who have bred Ball Pythons and Corn Snakes and King Snakes have a lot more experience in genetics than the folks working with venomous snakes.
If we can indeed tell the Het offspring from the Wild offspring, based on pattern or coloration, that would be a very significant finding.
It would also let us distinguish a $35.00 Wild Type Cottonmouth from a $500.00 Het Cottonmouth, visually, without growing them to adulthood, and putting them into a breeding program.
Hopefully, others will ad to this thread.
Best Regards John Z
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RE: what does this mean?
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by Crotalusssp on June 5, 2008
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John, I am going to ask around to couple of non-venomous breeders I know and see what I can find out. I was told it was a possibility with Burmese, but I will do a little digging. I will let you know what I find out.
Charles
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