Genetics questions you were afraid to ask... - Page 2

Ssthisto · #11 (**permalink**) 16-12-2007, 11:27 AM

Quote:

Originally Posted by paulh

I come at it from the other side -- there is a normal or wild type gene for every locus.

Good point - though to me it's quite obvious you and I both have a thorough ... 'grokking' of how genetics works, overall.

It's not so straightforward for everyone, which is why it's useful to remember that for every morph-producing gene there is a "not-morph" gene too. It should be self-evident, but even I need reminding sometimes!

Quote:

In other words, each creature has dozens or hundreds or thousands of pairs of genes -- think of these as being like paired machines on an assembly line. Each pair of machines can do only one or a few things before passing the product on to the next station in the line. If each pair of machines works normally, as it is expected to work, what rolls of the end of the assembly line is the normal product of the line.

What makes my animal look different to a normal?
Going back to the assembly line analogy, if at least one pair of machines malfunctions, the product that comes off the end of the line is not what was expected. The product has an abnormal or mutant phenotype even though most of the machines in the assembly line are working normally.

That is a marvellous analogy. And it also explains things like the different strains of albino in leopard geckos - if the Tremper Machines are not working quite right, you'll get a Tremper Albino, but if the Bell machines aren't working right, you'll get a Bell Albino. Which leads neatly into:

I bred my (this named) Albino/Anery to my (that named) Albino/Anery. Why did I get all normals?

Because, despite the similarities in the names of the morphs, they're different genes completely and work in different ways. An Anerythristic A is no more like an Anerythristic B (Charcoal, at least in corns) than an Anery A is like an Amelanistic; a Tremper Albino is not the same thing as a Bell Albino.

In the second generation, you could get homozygous animals - and indeed animals who are homozygous for BOTH genes.... but it would be pretty difficult to prove out that this is what you have.

They'd probably be fairly difficult to distinguish from a specific morph - they're likely to look like one or the other - this is because of the way Albinism and the other colour/pattern morphs work. Albinism is a failure to produce melanin.

Now, call "Driving to the Store" equivalent to "Able to produce Melanin Correctly". "Can't find my keys" is one reason I might not be able to drive to the store; "No petrol in the car" is another; "My car's been stolen" is another again. Different stages of the "going to the store" process that can go wrong. Now, there are also several stages at which melanin production can go wrong, and it's a pretty good bet that each strain of albinism is due to a different stage going wrong.

But if you can't get to the store because "Car's been stolen" ... it doesn't matter whether you have your keys or not OR whether there was petrol in the tank - because the failure to get to the store is rooted in "Car's stolen."

So, depending on which step of the melanin production is broken 'first' - that's what the albino is likely to look like. Carry this on to the other colour morphs, where erythrin or xanthin are not produced correctly, and you're likely to get similar results. There is currently some evidence that Anerythristic in corns 'breaks' the xanthin/erythrin production sooner than Caramel does - a homozygous caramel, homozygous anerythristic looks like an Anerythristic.

eeji · #12 (**permalink**) 16-12-2007, 12:12 PM

Quote:

Originally Posted by Ssthisto

There is currently some evidence that Anerythristic in corns 'breaks' the xanthin/erythrin production sooner than Caramel does - a homozygous caramel, homozygous anerythristic looks like an Anerythristic.

does this mean the two genes are somehow linked, or going back to the production line, the two genes both work on a different section of 'erythrin', with the snake going through the 'Anery machine' before the 'Caramel machine'

Ssthisto · #13 (**permalink**) 16-12-2007, 01:26 PM

It's more likely that the erythrin production relies on the Anerythristic machine to work first, THEN the Caramel machine - and if the Anery machine is broken, it doesn't matter whether the Caramel one is or not as far as the physical look of the snake goes.

Especially since a homozygous caramel, homozygous Anery can produce Anery if, say, bred to a snow (and those Anery would be het Caramel and amel) and caramel if bred to, say, a Butter (and those caramels would be het anery and amel).

intravenous · #14 (**permalink**) 16-12-2007, 06:00 PM

Another way to look at (same theory, different analogy) it is that most genes code for enzymes and enzymes convert one product to another so say that:

product A goes to product B goes to product C goes to erythrin

you would call this an erythrin pathway and an enzyme will control each step in this pathway. So lets say there are three enzymes involved:

enzyme 1 - converts product A to B

enzyme 2 - converts product B to C

enzyme 3 - converts product C to erythrin

Each of these enzymes is coded for by a different gene (the wild type of each gene) and these genes could be anywhere in the genome, they don't need to be next to each other or on the same chromosome (i.e. not linked).

Now lets say that the wild type form of the anery gene codes for enzyme 1 and the wild type form of the caramel gene codes for enzyme 3. If enzyme 1 is broken (i.e. both copies of the gene are mutant anery) then the whole pathway is blocked. It doesn't matter if you have wild type caramel because it never gets that far. And vice versa if you have wild type anery and mutant caramel the pathway is still blocked.

paulh · #15 (**permalink**) 16-12-2007, 11:37 PM

Quote:

Originally Posted by Ssthisto

Good point - though to me it's quite obvious you and I both have a thorough ... 'grokking' of how genetics works, overall.

Yes, that was pretty obvious by the time I read three of your posts.

Feel free to use the assembly line analogy whenever you wish. the same goes for everyone.

Voodoo Royal Morphs · #16 (**permalink**) 02-01-2008, 03:01 PM

Het albino x het albino gives you a chance of 50% normal 50% albino i think but what will normal x het albino give you just normals het albino or is there a tint tiny chance you would get an albino ?

Ssthisto · #17 (**permalink**) 02-01-2008, 03:13 PM

There is a tiny, tiny chance - but it is SO tiny it is... well, you're as likely to win the jackpot in the lottery. Basically, if you DID get an albino, what it means is that your normal is in fact a normal het albino - but wasn't sold as such. Possible, but very unlikely.

Normal X Het Albino will produce some genetic normals who are not het albino at all and some visual normals who are het albino; you can't necessarily tell which are which.

Normal het Albino X Normal het Albino will not give you 50/50 odds; it will give you 25% visual albinos, 50% Normal het Albinos and 25% Normal non-hets - the visual normals are what are called "66% het albinos".

Voodoo Royal Morphs · #18 (**permalink**) 02-01-2008, 03:16 PM

Quote:

Originally Posted by Ssthisto

There is a tiny, tiny chance - but it is SO tiny it is... well, you're as likely to win the jackpot in the lottery. Basically, if you DID get an albino, what it means is that your normal is in fact a normal het albino - but wasn't sold as such. Possible, but very unlikely.

Normal X Het Albino will produce some genetic normals who are not het albino at all and some visual normals who are het albino; you can't necessarily tell which are which.

Normal het Albino X Normal het Albino will not give you 50/50 odds; it will give you 25% visual albinos, 50% Normal het Albinos and 25% Normal non-hets - the visual normals are what are called "66% het albinos".

cheers Ssthisto was planning on breeding my normal male and wondered if i breed him with a het female what the chance of any visual morph would be.

Ssthisto · #19 (**permalink**) 02-01-2008, 03:20 PM

The only way to get a visual morph is if you breed him to a codominant or dominant morph - spiders, pastels and mojaves leap to mind. And then, it's because the FEMALE is donating the morph gene, not the male

Also: I am desperately envious of your pinstripe - if he'd been a she, you could have gotten pinstripes from your normal male, too

Voodoo Royal Morphs · #20 (**permalink**) 02-01-2008, 03:24 PM

Quote:

Originally Posted by Ssthisto

The only way to get a visual morph is if you breed him to a codominant or dominant morph - spiders, pastels and mojaves leap to mind. And then, it's because the FEMALE is donating the morph gene, not the male

Also: I am desperately envious of your pinstripe - if he'd been a she, you could have gotten pinstripes from your normal male, too

i already have breeding plans for him. but i want to get some breeding exsperince before i start to breed with my exspensive morphs.

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