Question about Genetics

[Talley Reptiles]

Snark:
http://ball-pythons.net/gallery/file...img_0010_2.jpg

Lucy: (She is shedding real soon)
http://ball-pythons.net/gallery/file...img_0011_2.jpg

Both together:
http://ball-pythons.net/gallery/file...img_0007_2.jpg
http://ball-pythons.net/gallery/file...img_0005_2.jpg

I got Snark for christmas about 5 years ago, and bought Lucy on craigslist about 2 years ago.

[paulh]

And there are visual hets.

A normal-looking het (generally just written "het") occurs when a recessive mutant gene is paired with a normal gene. That's the most common type of het and has been well covered in this thread.

A snake is a "visual" het when a dominant or codominant mutant gene is paired with a normal gene. These snakes do not look normal.

There is no 50% or 66% probability het with codominant mutant genes. You can tell what the snake's genes are just by looking at the snake.

With dominant mutant genes, a snake with two copies of the mutant gene (a super) looks like a snake with a mutant gene paired with a normal gene. In such snakes' matings, the probabilities are generally expressed as the probability of getting a super. The probabilities only apply to the baby snakes that do not look normal. The normal-looking snakes have two copies of the normal gene and are genetically normal.
0% probability super = 100% probability het. Occurs when a visual het or super is mated to a normal.
33% probability super = 66% probability het. Occurs when two visual hets are mated.
50% probability super = 50% probability het. Occurs when a super is mated to a visual het.
100% probability super = 0% probability het. Occurs when two supers are mated.

[Eric Alan]

And there are visual hets.

A normal-looking het (generally just written "het") occurs when a recessive mutant gene is paired with a normal gene. That's the most common type of het and has been well covered in this thread.

A snake is a "visual" het when a dominant or codominant mutant gene is paired with a normal gene. These snakes do not look normal.

There is no 50% or 66% probability het with codominant mutant genes. You can tell what the snake's genes are just by looking at the snake.

You're going to have to forgive me for giving the OP exactly as much information as was needed to answer their question as it relates specifically to this hobby. Not everyone wants to sit through a genetics lesson in order to understand the terminology in full detail.

[Talley Reptiles]

That's okay, I'll just come up with more questions lol.

And there are visual hets.

A normal-looking het (generally just written "het") occurs when a recessive mutant gene is paired with a normal gene. That's the most common type of het and has been well covered in this thread.

A snake is a "visual" het when a dominant or codominant mutant gene is paired with a normal gene. These snakes do not look normal.

There is no 50% or 66% probability het with codominant mutant genes. You can tell what the snake's genes are just by looking at the snake.

With dominant mutant genes, a snake with two copies of the mutant gene (a super) looks like a snake with a mutant gene paired with a normal gene. In such snakes' matings, the probabilities are generally expressed as the probability of getting a super. The probabilities only apply to the baby snakes that do not look normal. The normal-looking snakes have two copies of the normal gene and are genetically normal.
0% probability super = 100% probability het. Occurs when a visual het or super is mated to a normal.
33% probability super = 66% probability het. Occurs when two visual hets are mated.
50% probability super = 50% probability het. Occurs when a super is mated to a visual het.
100% probability super = 0% probability het. Occurs when two supers are mated.

If this is the case, how come when I run a normal and a banana ball through the calculator it says half will be bananas and half normal. With what you said, shouldn't some be a visual mix of both?

[Eric Alan]

If this is the case, how come when I run a normal and a banana ball through the calculator it says half will be bananas and half normal. With what you said, shouldn't some be a visual mix of both?

Nope. Dominant and co-dominant (more correctly: incomplete dominant) genes are an on/off thing. Either they have been passed along and will be seen in the offspring or they won't - there's no middle ground. There's a 50% chance at passing along these genes, just like the recessive example we used with albino, only you'll be able to see a yes/no answer right away. You also don't need a copy of the gene from both parents to get full expression:

• Trait passed along from a single parent = Het Albino (recessive example) = Pastel (incomplete dominant example) - we don't use the term "het Pastel" because it's understood as such
• Trait passed along from both parents = Albino (recessive example) = Super Pastel (incomplete dominant example) - not all genes will have a super form - we call those genes "dominant"

Hope this helps!

[Daigga]

That's okay, I'll just come up with more questions lol.

If this is the case, how come when I run a normal and a banana ball through the calculator it says half will be bananas and half normal. With what you said, shouldn't some be a visual mix of both?

Normal and banana are both dominant traits and very different from each other. In the case of most ball python morphs, you don't actually see a visual mix of two genes. The babies will come out either all normal or all banana with no normal-banana whackjob thrown in there (usually, sometimes paradoxes happen, but those follow no known genetic rules).

For clarification! There are three types of morphs; Recessive, dominant, and incomplete dominant (also called co-dominant). In recessive genes, two copies of the gene are needed to produce visible offspring. If one parent is homozygous (has two copies of the gene and displays it visually) and is bred to a non-carrier of the gene, all offspring produced will be het for that trait (remember punnet squares? They come in handy here)

In dominant traits, such as pinstripe, a single copy of the gene is visually expressed. This is like brown hair in humans, BB (homozygous) or Bb (heterozygous) will both give you visually brown hair, but it won't look any different either way.

Incomplete dominant, or codominant, is interesting in that the same rules apply as in recessive, except that a heterozygous offspring still expresses a visual version of that trait, just not in such a way as the homozygous version.

[h00blah]

That's okay, I'll just come up with more questions lol.

If this is the case, how come when I run a normal and a banana ball through the calculator it says half will be bananas and half normal. With what you said, shouldn't some be a visual mix of both?

Look up punnet squares, as they may help you understand that part a bit more if you're a visual learner. In punnet squares, each animal you consider is broken into 2 parts, and when you pair A with B, the babies inherit each piece of the parent.

Co-doms are 1 normal and 1 co-dom.. (Pn)
Normals are 2 parts normal.. (Nn)
Supers are 2 parts of the co-dom... (Pp)
Recessives are just like Supers, but rather than saying they're 2 parts co-dom, we call them 2-parts recessive. (Cc).
(the letters in parentheses are just examples of what it would look like in a punnet square).

Recessives are the same as supers. The difference is that if a snake is 1 part co-dom and 1 part normal (totaling 2 parts), that snake will look like the co-dom mutation, not normal.

In your example, you're doing banana x normal... Start with the banana (Bn). B stands for banana, and n stands for normal (no mutation). Next is the normal (Nn). If you break down all the potential offspring, the only combinations you'll get are "Bn"s and "Nn"s (bananas and normals).

However, if you pair a banana to a banana, things get more interesting! You can get Bn, Bb, and Nn... (bananas, super bananas, and normals).

sorry if i confused you... here's a link I used when I was first getting into morphs and genetics and junk. Don't rely too heavily on WOBP for your genetic research. It's a good tool to see the different kinds of morphs and combos, but yeah.. As Eric mentioned, falls short in the genetics department.

http://www.newenglandreptile.com/gen...recessive.html

[paulh]

New England Reptile Distibutors are first rate breeders, but they are not first rate geneticists. Much of their page is good, parts are hard to understand, and parts are just wrong. The trick is figuring out which is which.

Here are links to pages that I consider better than the New England Reptile Distibutors page. The bottom link is to a book that can be downloaded free of charge.

http://www.ballpython.com/index.php?page=genetically

http://ballpython.ca/gallery/genetics-101/

http://www.corncalc.com/dcr.html

http://www.redtailboas.com/f115/no-f...s-guide-53782/

http://ghr.nlm.nih.gov/handbook

At the genetics level we breeders are on, codominant and incomplete dominant can be used interchangably. Codominant is preferable (IMO) because it has fewer letters to type.

By the way, every gene is either a normal gene or a mutant gene. A normal gene is the most common gene at a given location in the chomosomes in the wild population. A mutant gene is NOT the most common gene at a given location in the chomosomes in the wild population. Every mutant gene has a corresponding normal gene. The normal gene at one location is quite different from the normal gene at a different location.

The normal gene is used as the standard of comparison to determine whether a mutant gene is dominant, codominant or recessive. If the mutant gene is dominant to the normal gene, then the normal gene is recessive to the mutant gene. If the mutant gene is codominant to the normal gene, then the normal gene is codominant to the mutant gene. If the mutant gene is recessive to the normal gene, then the normal gene is dominant to the mutant gene. It's just easier to write that the mutant gene is dominant/codominant/recessive to the normal gene and skip the reverse version.

It takes all the normal genes to make a normal-looking snake (one that looks like most of the snakes crawling around in the wild). A morph somehow looks different from a normal snake. Changing one gene from a normal gene to a mutant gene is enough to produce a morph.

Questions are always welcome.

[paulh]

That's okay, I'll just come up with more questions lol.



If this is the case, how come when I run a normal and a banana ball through the calculator it says half will be bananas and half normal. With what you said, shouldn't some be a visual mix of both?

The calculator assumes that a banana ball python has a banana gene paired with a normal gene. When paired with a normal (2 normal genes) all the babies get a normal gene from the normal parent. Half the babies get a normal gene from the banana parent and are normal snakes. The other half of the babies get a banana gene from the banana parent and are banana ball pythons -- visual hets.

I do not know what a snake with two banana genes looks like. It may have been done, and I just never heard of it. But, as far as I know, the huge majority of existing banana ball pythons are visual hets.

[OhhWatALoser]

That's okay, I'll just come up with more questions lol.



If this is the case, how come when I run a normal and a banana ball through the calculator it says half will be bananas and half normal. With what you said, shouldn't some be a visual mix of both?

banana is the visual mix of both, full expression of banana looks like this (aka super banana): http://www.reptileradio.net/ball-pyt...er-banana.html