# Genetics Quiz 1



## Ssthisto (Aug 31, 2006)

Answers to be posted on the thread please - you don't win any prizes, but maybe we can all learn something!

First, basic definitions:

A *capital letter* in the genotype denotes a *dominant*, *codominant* or *incomplete dominant* gene. In most cases this means "wild type not mutant" ... but there are exceptions. In all cases, if the animal CARRIES the gene, they SHOW the gene in some way.
- If a gene is *dominant*, it looks the *same* whether the animal has *one copy of the gene* (het) or *two copies of the gene* (homozygous). If *Red* is dominant to *White*, then an animal with either one _or_ two copies of the gene is *Red*.
- If a gene is *codominant*, when you only have *one copy of it,* it *combines its appearance* with the other gene of the pair - if *Red* is codominant to *white*, an animal with *two copies of white is white*. An animal with *two copies of red is red*. And an animal with *one of each is pink* (combined appearance).
- If a gene is *incomplete dominant*, when you have only *one copy of it*, it *splits its appearance* with the other gene of the pair. If *Red *is incompletely dominant to *white*, then an animal with *two copies of red is red*. An animal with *two copies of white is white*. And an animal with *one of each is red with white spots*.

A *lower case letter* in the genotype indicates a* recessive* gene. In most cases this is the "mutant"... but there are exceptions. An animal can carry a recessive gene invisibly - and *only a double dose* of the gene will produce a visual morph.

An * in the genotype indicates an *unknown* gene.

Now for the questions 

1. If you see a snake who is visually anerythristic and its genotype has been written as ee, what can you say about the anerythristic trait, and what would you expect to get if you bred this to a wild-type "normal" ?

2. I want to produce Hypo Pewter corn snakes (hhDDchch - this is Hypo plus Bloodred plus Charcoal).
I have the following corns to work with:
Male Granite (DDee - this is Bloodred plus Anery)
Female Ghost (hhee - this is Hypo plus Anery)
Female Blizzard (aachch - this is Amel plus Charcoal). 
Charcoal is very similar in outward appearance to Anery - both present as "grey snake with black blotches". 

What would you expect to get from my first year's pairings?
What generation would you FIRST expect I would get a definite hypo pewter? 
What would be a shortcut to getting hypo pewters that are not hypo granites?


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## captaincaveman (Nov 6, 2006)

1) its charcoal and you would get 100% normals het charcoal

2) male granite with female ghost would give

first year =normals het anery a, bloodred, charcoal and hypomel

that would give hypo pewters in f2

I thought hypo granites and hypo pewters were same thing, *anaanaDDDD*


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## tripper23 (Feb 20, 2007)

the antheristic gene think thats how its spelled is not dominant so u need a pair of them to produce that snake if bred wit a normal u will get a normal as for the other question i think i wil think bout that a bit more hope i'm close


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## Ssthisto (Aug 31, 2006)

captaincaveman said:


> 1) its charcoal and you would get 100% normals het charcoal


Actually, I tend to use *e* for An*e*rythristic  *Ch*arcoal is *ch*. But you're correct on half of the question (they'd be normals 100% het for the trait).



> 2) male granite with female ghost would give
> 
> first year =normals het anery a, bloodred, charcoal and hypomel
> 
> ...


No, hypo granite is hypomelanistic + anerythristic + Bloodred (hheeDD)
Hypo pewter is hypomelanistic + charcoal + bloodred. (hhDDchch)

Your Granite + Ghost would produce 100% *eeHhDd - what would this look like?*


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## tripper23 (Feb 20, 2007)

well least i had a crack at it still find genetics hard but i'm slowly learnin stuff


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## Aquilus (Feb 22, 2007)

1) It's recessive, and I'd expect 100% het anerythristic eE offspring who would look normal.

2) Breeding your male to each female in turn would give in each clutch:

a) 100% h*D*ee - anery het bloodred hypo (who look just like the father)
b) 100% a*D*e*ch* - het anery bloodred amel charcoal (who look like normal bloodreds)

And then my brain melted! :crazy:


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## captaincaveman (Nov 6, 2006)

Ssthisto said:


> Actually, I tend to use *e* for An*e*rythristic  *Ch*arcoal is *ch*. But you're correct on half of the question (they'd be normals 100% het for the trait).
> 
> 
> 
> ...


 
Im used to the other system
aa=amel
bb=anery
cc=bloodred
dd=caramel
ee=charcoal
ff=hypomel
gg=lava
hh=lav
kk=sunkissed
uu=ultra
au=ultramel

is that not a standard system?

Ignore me on the other:lol2: i got pewters and peppers mixed up:lol2: thats why its not making sense:lol2:


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## cjreptiles (Nov 13, 2006)

First off, let me say I think the genetics quiz is a very good idea, although I'll let other peopleanswer the questions. However, it seems to me you have your defintions of codominance and incomplete dominance the wrong way round. Also, it is not generally considered good practice to use a two letter symbol to represent an allele (although obviously there may be cases when it is necessary, e.g. if over 26 genes are being considered) - maybe better to just use 'c' in this case to avoid confusion.


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## eeji (Feb 22, 2006)

1. the trait is recessive (two lower case letters)
if bred to a normal, the babies would be 100% normal het anery (-e -e)

2. first years crossings:
DD ee x hh ee = 100% anery het bloodred & hypo (i've never done a punnett for double traits, so i cheated on this and used a predicter and tried to work back to the punnett square and couldn't work it out )
DD ee x aa chch = 100% normal het diffuse, anery, charcoal & amel (educated guess)

the last bits waaaaay over my head!


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## captaincaveman (Nov 6, 2006)

i'm lost on the lettering used, is there not a standard for this, i used the lettering system in the generic gen wiz program


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## eeji (Feb 22, 2006)

lol! on my site i use another, completely different system (as used by some of the american breeders). wouldn't it be great if it could be standardised so everyone knows what everyone else is on about!


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## BELIAL (Nov 10, 2006)

captaincaveman said:


> i'm lost on the lettering used, is there not a standard for this, i used the lettering system in the generic gen wiz program


and I got lost ummmm yep right about halfway through the first post! i just don't get genetics...


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## captaincaveman (Nov 6, 2006)

BELIAL said:


> and I got lost ummmm yep right about halfway through the first post! i just don't get genetics...


im slowly getting bits, but slowlys the word:lol2:


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## Ssthisto (Aug 31, 2006)

captaincaveman said:


> i'm lost on the lettering used, is there not a standard for this, i used the lettering system in the generic gen wiz program


No, there isn't a standard set of lettering, because corn snakes have not yet been studied and sequenced and given specific gene names like mice or humans or horses or dogs. Once it's actually been done, there will be a standard.

That's why I defined a Granite as (eeDD - anery + diffuse) - to make it clear that I'm using *e* to represent Anery.

And CJReptiles: You're exactly right. I used *ch* and I really should have used *c* - though if I were going to use a SINGLE letter symbol I'd be inclined to use *b*... because Charcoal was originally called "Anery B". That said... there's a precedent for double letter gene names - the Cornsnake Morph Guide written by Charles Pritzel does call Charcoal *ch*.


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## eeji (Feb 22, 2006)

i think i got my punnett sorted for the first cross. it condenses down from a 16 square punnett to...










(because all the gametes are the same)

making 100% anery (2 e's) het bloodred (1 D) and hypo (1 h)


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## Ssthisto (Aug 31, 2006)

eeji said:


> i think i got my punnett sorted for the first cross. it condenses down from a 16 square punnett to...
> 
> 
> 
> ...


That's right. That'd be your first generation from the Granite X Ghost - anery het blood and hypo.

And your first generation of Granite X Blizzard would be normals het anery, charcoal, amel and bloodred, as you said.

But that's still not produced a hypo pewter  

*CJ:* Are you sure I've got Codom and Incomplete Dom switched? I probably have - today's been a real crap of a day, so my brain's half off. That said, the Codom/Incomplete isn't too important for these two questions, since we're not dealing with the fact that a "het" blood is visual... yet.

*Aquilius:* You're almost right on the bloodreds - a "het bloodred" is visual but isn't QUITE a dominant gene - it's either co/incomplete dominant, and produces some effects, but not the entire effect, in a heterozygous state. 

An Anery het Bloodred will probably have the "zipper" belly markings, maybe the head markings - but wouldn't have the full uncheckered belly of a true blood, and it wouldn't show the diffusion of the pattern on the back either.


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## eeji (Feb 22, 2006)

i'll have a go at that tomorrow! i need beeeeer!!!


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## eeji (Feb 22, 2006)

you could get hypo pewters in f2, and could you cheat by using Phantom het bloodred?


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## brittone05 (Sep 29, 2006)

Ok I know my alphabet but you lost me as soon as you said genetics hahahahaha

It amazes me how you can all remember all the lettering codes adn the possible colours and hets and stuff - brainy bunch you are


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## Ssthisto (Aug 31, 2006)

eeji said:


> you could get hypo pewters in f2, and could you cheat by using Phantom het bloodred?


I'm not sure you could get hypo pewter in F2 - remember you've got:

F1 Anery het hypo, bloodred
F1 Normal het charcoal, bloodred, amel, anery

Crossing within those.... you don't have a way to get a charcoal + hypo + bloodred.

I personally would cross a pair of the latter animals and keep a pair of F2 pewters; you know they're 66% possible het anery and amel, but that's not so bad.

I'd also cross a pair of the anery het hypo blood to get F2 Ghost Bloodreds. 

Once you've got a Ghost Bloodred (eeDDhh - anery, blood, hypo) and a Pewter (chchDDE*A*) you can cross those together to get:

F3 Bloodreds het Charcoal, Anery, Hypo poss het Amel

Cross a pair of those to get your F4 Hypo Pewters (a 1 in 16 chance) ... but have fun telling them apart from Hypo Granites!

Of course, the shortcut would be buying something like a Phantom, to avoid having to use the Ghost at all... or a hypo bloodred


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## ballpiefun (Mar 8, 2007)

Ssthisto said:


> 1. If you see a snake who is visually anerythristic and its genotype has been written as ee, what can you say about the anerythristic trait, and what would you expect to get if you bred this to a wild-type "normal" ?


The wild type would not carry the trait for anerythrism and would therefore be written as EE. I would therefore expect all of the offspring to be normal looking as they would all inherit the dominant "Not Anerythristic" gene from the wild-type parent but they would all be 100% heterozygous for anerythrism as they all would have inherited the recessive anerythristic gene from the other parent. All offspring would be recorded as Ee.

I will have a go at the harder one if this one is correct. I therefore await your feedback. Cheers.


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## eeji (Feb 22, 2006)

oops! my answer should have read F3....
if you cross the F1's (ee Dd Hh x Dd Ee CHch Aa) i worked out there would be enough hets in the F2 offspring to pair up for hh DD chch in the F3's. Its a mega long shot (1/32 of producing the correct F2 hets, then if you DO get lucky, you've got to find them!). I don't even want to think of the odds of hitting it right in the F3!

This is why clever people do the breeding for us! (especially past F1's - its hard work!!)


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## ballpiefun (Mar 8, 2007)

ballpiefun said:


> I will have a go at the harder one if this one is correct. I therefore await your feedback. Cheers.


Also, before attempting the harder one..........can you tell me if any of my following statements are incorrect where "a" equals the recessive gene for amelanism and "b" equals the recessive gene for anerythrism.

Aa Normal looking snake but heterozygous for amelanism
Bb Normal looking snake but heterozygous for anerythrism
AA Normal looking snake with no recessive gene for amelanism
BB Normal looking snake with no recessive gene for anerythrism
AABB Normal looking snake with no recessive genes for amel or anery
aa homozygous for amelanism and therefore is no longer normal looking 
bb homozygous for anerythrism and therefore is no longer normal looking
aaBB **** for amel with no recessive anery genes
AAbb **** for anery with no recessive amel genes

Thanks.

The reason I'm asking is because I want to know if you need to include the nots as well as the haves when building your punnet square. For example if I was crossing a visual amel(aa) to a visual anery (bb) would I just use aa and bb or should I use aaBB and AAbb to get the correct results.


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## Kenorsanc (Dec 10, 2006)

I think that this is a very good idea but next time with the genetics challenge can you not but anery a and b in it together thanks. I got a bit confused with it and managed to make everything but hypopewters (I even made granite phantoms)


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## eeji (Feb 22, 2006)

ballpiefun said:


> Also, before attempting the harder one..........can you tell me if any of my following statements are incorrect where "a" equals the recessive gene for amelanism and "b" equals the recessive gene for anerythrism.
> 
> Aa Normal looking snake but heterozygous for amelanism
> Bb Normal looking snake but heterozygous for anerythrism
> ...


all correct  for the last four, aa is the same as aaBB, and bb is the same as AAbb.
for the punnett square, you'd use aB x Ab = AaBb = normal (one functioning A amel and one functioning B anery), het for snow (one a and one b)
punnett squares still make my head hurt, i'm only learning myself!!


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## ballpiefun (Mar 8, 2007)

ballpiefun said:


> AA Normal looking snake with no recessive gene for amelanism
> BB Normal looking snake with no recessive gene for anerythrism


Does this mean that a DD would be a normal looking snake with no recessive gene for Bloodred and that a dd would be a snake that would be homozygous for Bloodred? What exactly is the Bloodred trait?


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## Ssthisto (Aug 31, 2006)

ballpiefun said:


> Does this mean that a DD would be a normal looking snake with no recessive gene for Bloodred and that a dd would be a snake that would be homozygous for Bloodred? What exactly is the Bloodred trait?


Bloodred is not a recessive trait 

It's either codominant or incomplete dominant - it has visible "hets" which make an intermediate form. 

So a DD is a homozygous bloodred (visual). A dd is a non-carrier of the gene.


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## ballpiefun (Mar 8, 2007)

Ssthisto said:


> So a DD is a homozygous bloodred (visual). A dd is a non-carrier of the gene.


Every time I think I'm making sense of this genetics another spanner gets thrown in the works.

I thought that every set of upper case letters led back to a normal looking snake with no mutant genes. Does that mean that a normal could be described as a AABBdd (not amel not anery not bloodred) and that a Bloodred could be described as AABBDD (not amel not anery but having Bloodred gene). This appears to be a paradox?

What is the result of having the Bloodred gene?

Would Dd be visual or non visual for Bloodred?

Cheers.


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## Ssthisto (Aug 31, 2006)

ballpiefun said:


> Every time I think I'm making sense of this genetics another spanner gets thrown in the works.
> 
> I thought that every set of upper case letters led back to a normal looking snake with no mutant genes. Does that mean that a normal could be described as a AABBdd (not amel not anery not bloodred) and that a Bloodred could be described as AABBDD (not amel not anery but having Bloodred gene). This appears to be a paradox?
> 
> ...


Nope, upper case just means 'dominant' - and wild type is NOT always dominant to 'mutant colour morph' 

Yes, a normal is dd - so a not-amel, not-anery bloodred is AAEEdd.

A bloodred is DD, and it affects the pattern of the animal. A homozygous bloodred has a belly with no checkers and the blotch pattern on the back is diffused as though it's dissolved into the base colour of the animal.

A heterozygous bloodred (Dd) usually has some visual clues that it's carrying the bloodred gene - often there's a clear "zipper" down the middle of the belly checkers, and there's sometimes some changes to the head markings.


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## ballpiefun (Mar 8, 2007)

Ssthisto said:


> A bloodred is DD, and it affects the pattern of the animal. A homozygous bloodred has a belly with no checkers and the blotch pattern on the back is diffused as though it's dissolved into the base colour of the animal.
> 
> A heterozygous bloodred (Dd) usually has some visual clues that it's carrying the bloodred gene - often there's a clear "zipper" down the middle of the belly checkers, and there's sometimes some changes to the head markings.


Thanks again for the explanation.

Is there a web-site where I can get a complete list of all traits including details of the effects that the gene has to the visual appearance of the snake, including eyes and belly patterns?

How did I get on with my answer to question one?


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## HABU (Mar 21, 2007)

sorry, i just raise my "chickens". that's why i like the wild types. you lost me somewhere around homozygous he he!!:lol2:


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## eeji (Feb 22, 2006)

ballpiefun said:


> Thanks again for the explanation.
> 
> Is there a web-site where I can get a complete list of all traits including details of the effects that the gene has to the visual appearance of the snake, *including eyes and belly patterns*?
> 
> How did I get on with my answer to question one?


 thanks, you've just given me another idea for yet another update to my website!


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## cjreptiles (Nov 13, 2006)

Ssthisto said:


> *CJ:* Are you sure I've got Codom and Incomplete Dom switched? I probably have - today's been a real crap of a day, so my brain's half off. That said, the Codom/Incomplete isn't too important for these two questions, since we're not dealing with the fact that a "het" blood is visual... yet.


I believe so, though I can't really see it mattering much because, as far as I am aware, most (if not all) "codominant" morphs in reptiles (or at least leopard geckos!) are incompletely dominant.


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## ballpiefun (Mar 8, 2007)

Ssthisto said:


> 2. I want to produce Hypo Pewter corn snakes (hhDDchch - this is Hypo plus Bloodred plus Charcoal).
> I have the following corns to work with:
> Male Granite (DDee - this is Bloodred plus Anery)
> Female Ghost (hhee - this is Hypo plus Anery)
> ...


Would the punnet square calculations be;

DD De eD ee x hh he eh ee
and
DD De eD ee x aa ach cha chch

HELP!!!


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## Ssthisto (Aug 31, 2006)

ballpiefun said:


> Would the punnet square calculations be;
> 
> DD De eD ee x hh he eh ee
> and
> ...


No - just keep in mind that pairs of letters for each gene belong together. You wouldn't see your DD bloodred getting spread over other gene pairs for example - the Granite only has one pair of Bloodred genes, and they stay in the pair they're put. If you've got three animals showing the following visual morphs:

Anerythristic (ee - this is shown in the Granite and the Ghost)
Hypo (hh - this is shown in the ghost)
Bloodred (DD - this is shown in the granite)
Charcoal (chch - this is shown in the Blizzard)
Amelanistic (aa - this is shown in the blizzard)

Your actual crosses are:

Granite (D/D e/e H/H A/A CH/CH) X Ghost (d/d e/e h/h A/A CH/CH)
Granite (D/D e/e H/H A/A CH/CH) X Blizzard (d/d E/E H/H a/a ch/ch)


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## captaincaveman (Nov 6, 2006)

eeji said:


> thanks, you've just given me another idea for yet another update to my website!


 
dont forget head patterns too:lol2:


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## eeji (Feb 22, 2006)

captaincaveman said:


> dont forget head patterns too:lol2:


dont push it!!!


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