Reptile & Amphibian Forums

Anyone know if these albino genes are allelic? Anyone try to breed hets? Just asking here, will also on the hybrid forum.Thanks,J

I bred the two together a couple years ago to see what they look like and I ended up with all normals. Both the parents were albinos a male nelson and a female ruthven. All the babies were cooked in a stir fry so they did not get released to the public LOL.

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i'm not over weight i'm under tall

I know alot of you guys dont appreciate hybrids, but the scientist in me is always interested in these things,lol. I know there are genes that are aligned even between sp. and sharing info like that saves a ton of time. Personally I like the albino mexicana complex, I think a albino orange thayeri X is just about the prettiest snake I have seen. OK, enough,thanks again

Hey Jeff,

What do you think those results mean? Even if they weren't allelic I would still expect the offspring to be albinos since they inherit defective copies of the gene from both parents. So both copies are defective and it doesn't matter what the specific allele is, right?

So does that mean different genes are the cause of albino in nelsens and ruthvens?

Best,
Vinny
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

Natural Selection Reptiles

Vinny, it means that all albinism in colubrids isnt housed in the same locus on the chromosone. The first albino ratsnakes were bred together and they produced normal offspring. These snakes were then studied and found to be T and T-(the original tyrosinase test). Now we know about different looking albinos, but we are still understanding that there can be multiple loci responsible for color change even within species. There are more than 1 "type" of anerythrism in corns, more than 1 type of hypomelanism, and should be more than 1 type of amelanism. Considering each milk a ssp, breeding albino ssp A to albino ssp B is important for knowledge of genetics even if the offspring arent notable or in demand.

>>...since they inherit defective copies of the gene from both parents. So both copies are defective and it doesn't matter what the specific allele is, right?

Hi Vinny,

"Defective" is not the right term. All the evolutionary changes that have occurred in plants and animals are the result of this sort of genetic variation. Three examples:

1) People are inches taller today than their grandparents. Defect?
2) In Australia, the colorful Gouldian finch exists in three head-color morphs: red, black, and yellow. Which are the results of "defective" genes? The two that are less common in the wild? The two that occurred most recently? (Hint: the two "twos" are not the same)
3) Louis Porras theorizes hondurans at high altitudes have evolved to be darker--to have that typical melanin-gain over time, that turns tricolors into black-and-red "bicolors" because being darker, they're better able to thermoregulate in higher (colder) environments. Is that shift toward melanism a defect?

Love your Darwin quote, which i think supports the idea that "defect" isn't an appropriate term. (btw--another aside!--there's a multi-million dollar "Creation Museum" in the Greater Cincinnati area that has displays and argues several controversial ideas, among them that the earth is only several thousand years old and that dinosaurs and humans co-existed. The founder just released a book blaming Darwin for racism, or for promoting racist views, because--i'm simplifying here--Darwin's theory said different races could evolve differently. The creationist-author argued that Darwin was responsible for the rise of governments like Hitler's. In an article here about the book, a reporter interviewed some other scientists, one of whom observed that ironically, Hitler used God to support his theory of Aryan supremacy. A low-budget "evolution farm", which, like the museum, allows visits from schoolkids, sprung up to counter the Creation Museum.)

peace
terry
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>>“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859
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>> Natural Selection Reptiles

Hey Terry,

I have heard about that crazy creation museum, I think one day I am going to go and protest and give alternate interpretions of the displays like they do at the American Museum. Although, like Luis Black says, you cant reason with people who think that the Flinstones is a documentary

I still think in the case of the albino gene that defective is an OK term to use, but I see you point about the social conotations of that term. I use it because the examples you gave a all quantitative traits, so theres no defect. But in terms of things like albanism there is a functioning copy of the gene and a nonfunctioning copy. So, guess I will use the term nonfunctional copy instead.

By the way, I am an evolutionary biologists and have personally gotten hate mail. Its pretty scary stuff sometimes.

Best,
Vinny
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

Natural Selection Reptiles

It means that the two genes responsible for albinism reside at different locations and do not line up to create a homozygous recessive. Look at it this way:

The albino Ruthvens is:

aa BB

and the albino nelsons is:

AA bb

The offspring would inherit a dominant and a recessive from each parent making them:

Aa Bb - technically making the neonates double het.

"It means that the two genes responsible for albinism reside at different locations and do not line up to create a homozygous recessive. Look at it this way:

The albino Ruthvens is:

aa BB

and the albino nelsons is:

AA bb

The offspring would inherit a dominant and a recessive from each parent making them:

Aa Bb - technically making the neonates double het."

I guess this is where I am having a mental block. Why should the genes particular location on some chromosome matter? Lets say the particular gene responsible for albino is both species is tyrosinase. Albino nelsons are homo tt and albino ruthvens are also homo tt, regardless of where the genes are located. So, if you cross them the nelsons parent contributes a tyrosinase null allele (t) and the ruthvens contributes a tyrosinase null allele (t), so the offspring inherit two null alleles (tt). Where is the functioning copy of the gene coming from? In my mind I can only resolve this if two different genes are responsible for albino in each species (but I am totally open to being convinced I dont know what the hell I am talking about).

I think in your example A and B would be different genes not just different locations on some chromosome for the same gene in different species.

Best,
Vinny
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

Natural Selection Reptiles

I can't help you with the mental block. If you're like me sometimes you just have to push the "I believe" button! We know from the example that the two types produce normal animals so the genes are not allelic or on the same loci of a chromosome. What may be tripping you up is that the resulting phenotype appears to our eye as being the same.

Perhaps your T T- example would help. Here the offspring would be:

T t AND T- t-

In each case neonates would have single good copy of a gene for making tyrosinase and another good copy of the gene for proper synthesis of melanin further along the metabolic pathway. At both steps the necessary genetic instructions exist for the synthesis of melanin despite the fact that both parents were albino.

>I think in your example A and B would be different genes not just different locations on some chromosome for the same gene in different species.

Correct, A and B are different genes. One codes for one thing (perhaps tyrosinase), and the other codes for something else. If both function properly, the snake looks normal. If the A gene pair is not functioning, the snake does not have black pigment. If the B gene pair is not functioning, then there is no black pigment. If neither the A pair nor the B pair is functioning, there is no black pigment.

Tyrosinase does not make melanin all by itself. Tyrosinase catalyses two of the chemical reactions in the synthesis of melanin. There are a number of other chemical reactions before melanin is formed. Then the melanin is laid down in a protein matrix to form the pigment granule. Maybe A codes for tyrosinase production and B codes for one of the steps in the production of the protein matrix. I don't know. But I do know that the making of normal coloration requires a lot more than one gene pair.

Paul Hollander

you had to being up the albino thayeri cross. When I hear pastel kings I end up cleaning my guns. I'm not sure why but it just happens.
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i'm not over weight i'm under tall