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Genetics Tutorial

bump.....Bump.........BUMP.
for me again and anyone else who is new or has never seen it before. thanks again Susan.
 
This is a killer guide ... most impressive work. This really should be stickied up in the genetics area - as it seems to anwer 90% of those questions I have read in that alcove of the forum.

Anyway, glad I stumbled into this post - thanks for the work put into this guide.
 
Jayque said:
This is a killer guide ... most impressive work. This really should be stickied up in the genetics area - as it seems to anwer 90% of those questions I have read in that alcove of the forum.

Anyway, glad I stumbled into this post - thanks for the work put into this guide.
Click to expand...


The FAQ didn't answer any of those questions you had?
 
Joejr14 said:
The FAQ didn't answer any of those questions you had?
Click to expand...

Oh, don't get me wrong - the FAQ is great too. I wasn't saying "my questions" ... I was just making an observation that between the FAQ and this step by step guide with building block teaching (starting simple and working towards complex) that many of the more common questions are addressed - from "how do I" to "what do I get" ...etc. I feel the FAQ is great to understanding what the terms are and what the basics mean - while this guide delves into the how it works aspect of undertsanding how genes match up ... Hope this clears things up in my intent - as opposed to muddying the waters further.
 
Jayque - Don't pay too much attention to Joe! He has done an absolutely terrific job with all his FAQ threads, but being the GBB, he has a special job to do, making sure others don't let any compliments go to their heads. Thank you very much for finding my efforts helpful.
 
Thanks so much Susan, for taking the time and effort to make this tutorial! :bowdown: I really appreciate you sending this my way. It took me about 2 hrs to get it, but at least I believe I understand it now. I really hope I do. -.-;;; The only thing I didn't understand was the last topic. When you started talking about the motley, stipe, ultra, and amel, I was completely lost. But, I'm sure I'll somehow get it over time. At least for now, I think I feel secure with working on the other genes.

Jayque said:
This is a killer guide ... most impressive work. This really should be stickied up in the genetics area - as it seems to anwer 90% of those questions I have read in that alcove of the forum.
Click to expand...

Jayque said:
Oh, don't get me wrong - the FAQ is great too. I wasn't saying "my questions" ... I was just making an observation that between the FAQ and this step by step guide with building block teaching (starting simple and working towards complex) that many of the more common questions are addressed - from "how do I" to "what do I get" ...etc. I feel the FAQ is great to understanding what the terms are and what the basics mean - while this guide delves into the how it works aspect of undertsanding how genes match up ... Hope this clears things up in my intent - as opposed to muddying the waters further.
Click to expand...

I totally agree with Jayque. I wish that this was stickied in the genetics area. The current FAQ helps with understanding terminology, however it doesn't explain anything about how to actually compose the calcuations/predictions. And, I don't believe that something like this was posted in the FAQ in the breeding section either. *goes to check* Yup, not in there either. Just Murphy's laws on breeding. I really feel that this tutorial would undoubtedly help newcomers to the forum and field (like me) who are looking to understand combining and creating morphs, but can't (for the life of them) properly use the search function.
 
shaberry said:
Thanks so much Susan, for taking the time and effort to make this tutorial! :bowdown: I really appreciate you sending this my way. It took me about 2 hrs to get it, but at least I believe I understand it now. I really hope I do. -.-;;; The only thing I didn't understand was the last topic. When you started talking about the motley, stipe, ultra, and amel, I was completely lost. But, I'm sure I'll somehow get it over time. At least for now, I think I feel secure with working on the other genes.
Click to expand...

The relationship between motley and stripe. as well as ultra and amel was left out in this tutorial because it can be confusing to someone just trying to grasp simple Mendelian genetics. I may eventually get around to going into those here, as well as going into tessera (once it's genetic "actions" have been full determined). You can, however, search for some threads on those genes in the Genetics forum that will probably answer your questions on them just as well, if not better than I could here.

shaberry said:
I totally agree with Jayque. I wish that this was stickied in the genetics area. The current FAQ helps with understanding terminology, however it doesn't explain anything about how to actually compose the calcuations/predictions. And, I don't believe that something like this was posted in the FAQ in the breeding section either. *goes to check* Yup, not in there either. Just Murphy's laws on breeding. I really feel that this tutorial would undoubtedly help newcomers to the forum and field (like me) who are looking to understand combining and creating morphs, but can't (for the life of them) properly use the search function.
Click to expand...

I suppose I could at least post a link to this thread in those other sections. I haven't copied this and stickied it there to avoid stepping on any toes for all the work that was done in those areas already.

Edited one post to include a little bit on motley/stripe and amel/ultra.
 
Last edited:
I understand where you're coming from, but at the same time I don't see why people would be upset. Yes, they have put in a lot of work and effort into the faqs that have been posted in the (mentioned) sections. (And it's VERY MUCH appreciated.) But, it's not like you're deleting their post and replacing it with yours. It's merely just an addition. I'd like to think of it as a "new edition" of a book. It's not like the information already provided wasn't substantial. It's just that another topic that wasn't covered has been noticeable enough to include with the previous material.

I mean, isn't providing hobbists of corn snakes with information what this forum is about? And as for FAQs, aren't they used to address Frequently Asked Questions? I may be going out on a limb here, but I'd like to think that the material that is covered in this thread is asked pretty often, to the point of frequent.

Meh, but I do understand what you're saying Susan. This is the internet, and some people get a little overzealous with their positions in forums.

Susan said:
I suppose I could at least post a link to this thread in those other sections. I haven't copied this and stickied it there to avoid stepping on any toes for all the work that was done in those areas already.
Click to expand...

Well, if you posted a link to this thread, it would be better than nothing. =) Sorry, for requesting so much and yammering about my own personal thoughts. I just thought I would speak up for those newbies to the hobby and the site, who aren't quite familiar with forum territory. (I didn't realize it, but forums are gigantic. There's always somewhere new to go. It's kinda intimidating.)

And, I just realized that this thread was in your Member's Forum. Wow, I NEVER would have thought to look here for a tutorial on genetics. I'm usually just browsing the general corn snake forum. Once again, THANKS SO MUCH Susan for directing me here. Your tutorial was exactly the "corn snake genetics predictions for dummies" that I was looking for. It was very educational! :bowdown: I can even kinda understand the punnet square results in MP's genetics program! =) ( Now I just need to learn how to use the darn thing. -.-;;; )
 
I have a question about interactions between the different genes . . .

In simple mendelian genetics you expect the dominant to overshadow the recessive traits, but when you start mixing multiple genes together that flies out the window.

an amel het anery snake (aaBb) shows the red but not the black, but looking at the genotype you would expect the gene that has a dominant allele in it to show through.

It is as if the recessive trait is "stronger" than the homozygous or heterozygous trait of another.

So, my question is (finally :)) when trying to determine what your snake will look like, if you have any recessives in the mix, is that what will show?

Ex. aa Hh DD Ww BB Rr since the aa is the only trait that has 2 recessive alleles, it will be the one that shows, not matter how many other dominant alleles there are for other genes?

Thanks (in advance) for the clarification . . .I understand mendelian genetics, co-dominance, incomplete dominance, multiple alleles, polygenic traits, etc. but this doesn't seem to follow any of those patterns . . . Is there a name for the way the genetics of cornsnakes behave?
 
sweet~nichole~marie said:
I have a question about interactions between the different genes . . .

In simple mendelian genetics you expect the dominant to overshadow the recessive traits, but when you start mixing multiple genes together that flies out the window.

an amel het anery snake (aaBb) shows the red but not the black, but looking at the genotype you would expect the gene that has a dominant allele in it to show through.

It is as if the recessive trait is "stronger" than the homozygous or heterozygous trait of another.

So, my question is (finally :)) when trying to determine what your snake will look like, if you have any recessives in the mix, is that what will show?

Ex. aa Hh DD Ww BB Rr since the aa is the only trait that has 2 recessive alleles, it will be the one that shows, not matter how many other dominant alleles there are for other genes?

Thanks (in advance) for the clarification . . .I understand mendelian genetics, co-dominance, incomplete dominance, multiple alleles, polygenic traits, etc. but this doesn't seem to follow any of those patterns . . . Is there a name for the way the genetics of cornsnakes behave?
Click to expand...

Corn snakes perfectly follow Mendelian genetics. The dominant genes are what we call the "wild-type" phenotype...the normal/classic corn snake. Each of the recessive genes affects the phenotype "away from" the dominant wild-type phenotype. So far, all but one currently recognized corn snake gene are recessive to wild-type. Only the tessera gene seems to be dominant to wild-type when in het form. We should know by this year's breeding results if there is a "super" form of tessera when it is in homozygous in an individual.

For example, the amel gene removes the black that is normally seen in the wild-type. The anery gene removes the red that is normally seen in the wild-type. A snake that is homozygous for amel has 2 recessive genes and no dominant wild-type gene to produce the black. If that snake is also het anery, then it has one recessive gene to remove the red, but one dominant wild-type gene to produce the red, so that amel het anery corn snake will still have the red but no black.

Now that same amel het anery corn snake still have both dominant wild-type genes at the lavender, caramel, motley, hypo, etc loci, so you do not see any of those recessive traits in the phenotype, just the amel as that is the only gene that has been changed from the wild-type normal-looking corn snake.

If your amel snake is now also homozygous for anery instead of just being het, the dominant wild-type genes to produce black and red have been replaced vy the recessive mutant genes so the snake will not have black or red and will be a snow corn snake. Add yet another pair of recessive genes to replace the dominant wild-type ones, for say, the pattern, and suddenly you have a snow motley corn snake!

Now some recessive genes can mask the effect of other recessive genes. For example, if a snake is homozygous for both caramel and anery, the phenotype will be anery as the effect of the caramel gene cannot be seen (for the most part; in some individuals with this particular genetic make-up, the yellow may be increased, but that really hasn't been proven 100%). The effects of hypo in an amel snake is also masked, but some of the other melanin-decreasing genes, like lava, some people say you can see a difference.

If you are still confused, I'll try again. :)
 
*smacks forehead* I am such a dork *LOL* I was misunderstanding what the phenotype was . . . I thought the recessive amel alleles said to ADD red, but they are actually REMOVE black.

a+/a amel = normal/remove black

a+a+ = normal, normal (wild-type)
a+a = normal, remove black but because a+ is dom, snake looks normal
aa = remove black, removes black so only red is left

same with anery (n+/n) only says to remove red

so,
n+naa = says normal (don't remove any red) but aa says to remove the black, so you end up with amel (aa) het anery (n+n)

Did I get it right? :crazy02:

Thank you :) I really appreciate you taking the time to clarify the genetics to me.
 
Susan said:
The same thing would happen when any or all the recessive corn genes are used. For example:
aa - says don't make black - produces an amel
bb - says don't make red - produces an anery
hh - says reduce the amount of black - produces a ghost
cc - says to change alot of red to yellow - produces a caramel
dd - says to create the diffuse pattern - produces diffuse/bloodred
mm - says to create the motley pattern - produces a motley
ss - says to create the stripe pattern - produces a stripe
ll - says to create the lavender appearance - produces a lavender
Etc.
QUOTE]

Are these used by all breeders (Universal)
Click to expand...
 
Smokey-Steve said:
Susan said:
The same thing would happen when any or all the recessive corn genes are used. For example:
aa - says don't make black - produces an amel
bb - says don't make red - produces an anery
hh - says reduce the amount of black - produces a ghost
cc - says to change alot of red to yellow - produces a caramel
dd - says to create the diffuse pattern - produces diffuse/bloodred
mm - says to create the motley pattern - produces a motley
ss - says to create the stripe pattern - produces a stripe
ll - says to create the lavender appearance - produces a lavender
Etc.
QUOTE]

Are these used by all breeders (Universal)
Click to expand...

Susan said:
And you can use whatever letter you want for these morphs as well as all the other recessive morphs.
Click to expand...

You must have skipped over the very next line of my post. :) No, these are not "universal" letters. The Cornsnake Morph Guide uses the letters they like, another breeder uses letters that he or she likes, I happen to like those letters. Use whatever makes it easy for you...letter, number, symbol...
Click to expand...
 
Ok thank you feel stupid for missing that part lol.

The Punnett Square looks like a good way to track what the possible outcome are.

I think i still need to have another couple of read throughs but im starting to understand this genetics business, would like to know it for when i start breeding
 
Smokey-Steve said:
The Punnett Square looks like a good way to track what the possible outcome are.
Click to expand...
Punnett squares are all right for problems using one or two gene pairs. Only masochists use a Punnett square for more than two gene pairs. A branching system is faster than a Punnett square, but the textbooks seldom discuss anything but Punnett squares.

I have a post about using a branching system about 3/4 of the way down the first page of this link:
http://iansvivarium.com/viewtopic.php?f=21&t=2120
 
Learning about my snake

I have been reading what I can find online in reference to my corn snake. When I bought him I was told he is a Crimson corn snake. I had no idea what that meant but hey I like red snakes!! So from the small amount I have found he would be a Miami or Miami phase hypo. So now the questions begin....

From what I have read a Miami corn snake is a normal corn snake from a certain part of Florida. Unless it can be directly related back to a WC Miami it would need to be referred to as a Miami phase or Miami like. So what makes a Miami or Miami phase a Miami in looks?

Would the Hypo (is it Hypomelanistic?) reduce the amount of black?

Why is he called a Crimson, where did that come from?

When he is an adult what would be different about him compared to any other Miami or Miami phase?

Thanks so much for any help you can give me on understanding my snake better!!! I would love to explain to my friends why he is a Crimson!
 
A Crimson (which is a trade name made up that "kind of" lol describes the look of a hypomelanstic Miami. You are correct in saying a Miami would be a corn from known Miami lines vs a Miami "phase", which looks like a Miami. Miami corns are generally silverish grey with deep red saddles. The hypo gene does reduce black.
 
Well, actually I coined that name way back when I first started producing Hypomelanistic Miami Phase Corns. Oh yeah, I coined "Miami Phase" as well.... :D The reason for that name was because that particular stock came from the Miami area that I personally obtained back in the late '70s. I caught a few in the wild, and also bought a few from local mom and pop pet stores (there weren't any mega pet store chains back then) that local kids had brought in to them. I also had obtained a few individuals that had slate gray backgrounds with bright orange blotches, that came from the same area, but I don't have any idea what ever happened to that line. Haven't seen any like them for a LONG time.
 
What caught me was the contrast between the red saddles and the grey body color I love that. I checked Ian's and really like the adult Miamis and Crimsons so I am very sure I made the right choice. So Miami and Miami phase are the same?
 
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