Genetics confusion

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Originally Posted by JLC

He's saying that lessers should be referred to as "het" because they only have one mutated gene of an alelle pair. That condition is known as "heterozygous" or "het" for short.

When the two genes at an alelle are the same, it's referred to as "homozygous".

When both genes at that alelle are lesser genes, you get a blue-eyed-leucistic. So, the BEL could be referred to as a "homozygous lesser."

In recessive animals, the alelle must have both mutated genes to express itself. All albinos are homozygous for albino. An animal that carries one albino gene will look normal and will be called "het albino."

I HOPE that makes sense! I need more coffee..... :oops:

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It does, thanks! I understand the basics of genetics, but that calculator really threw me for a loop.

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Originally Posted by JulieInNJ

Okay, I may be confused, but I may not. So you're saying that there are true lessers, but there are also het lessers that look like lessers. So how do you know which one you've gotten, other than years of breeding or genetic testing?

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Definitions (paraphrased from King & Stansfield, A dictionary of genetics.):
Homozygous = a gene pair in which the two genes are the same. A snake with a homozygous gene pair.

Heterozygous = a gene pair in which the two genes are NOT the same. A snake with a heterozygous gene pair.

There are homozygous lesser platinum ball pythons and heterozygous lesser platinum ball pythons. I'm not sure what is meant by a "true lesser", but it has to be one of these two.

Homozygous lessers have two lesser mutant genes. They are known in the trade as blue eyed leucistics or super lessers. These snakes do not look normal.

Het lessers have a lesser mutant gene paired with a normal gene. They are known in the trade as lessers. Every lesser is a het lesser. These snakes do not look normal.

You can look at homozygous lessers and heterozygous lessers and tell the difference between them. That makes the lesser platinum mutant gene codominant to the normal gene and not recessive to the normal gene.

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Originally Posted by OhhWatALoser

But to say there is no het lesser is wrong. ALL lessers are het. But since they are we just dont say it

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I have to disagree with this statement. I thought about getting into it with my previous post, but that post was already all over the map and I didn't want to confuse things any further.

It would NOT be accurate to call a lesser a "het lesser". It would be accurate to call it a "het BEL", though.

As applied to ball python morph names, the term "het" means that the animal is expressing ONE HALF of the morph's genetic pair. A "het albino" means the animals has one half of the pair of genes needed to make up an albino.

A "het ivory" has one half of the genetic pair that makes an ivory. It's also known as a "yellow belly". But if you refer to an animal as "het yellow belly" it implies that the animal is carrying one half of the genetics needed to make a yellow belly.

There IS a difference between "het BEL" and "het lesser"....at least in the very casual genetic language of ball python morphs. There's no such thing as a "het lesser".

"Technically".... BUT.... When explaining something like this to newcomers, like Paulh did, in a terribly confusing way with no mention of leucistics (the super form), that is where the problem lies..

Yes technically co doms are het for their super form, whereas recessives have normals that are het for their visual forms.

Make sense?

But we don't say het when referring to co doms. Is either lesser or super lesser (lesser x lesser -----> blue eyed leucistic) etc etc..

And this was all that needed to be said... Not a long drawn out, agitated, scientific reply that will confuse newcomers.

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Originally Posted by Foschi Exotic Serpents

Yes technically co doms are het for their super form, whereas recessives have normals that are het for their visual forms.

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This is the clearest explanation! I guess the OWAL calculator was a little too advanced for my purposes, lol. So sorry to OhhWatALoser! I never meant to cast any doubt. ;)

...again, I was a criminal justice major in college... :D

best advice I can give would be to research the differences between dominant, co-dominant, and recessive. dominant genes (alelles) will look the same whether an animal is homozygous or heterozygous, and there is no super form, e.g. spiders. co-dom traits like pastel, lesser, mojo, etc. will look different from the wild type and different from the super form. that's why it's not technically inaccurate to refer to a lesser as a 'het' because it is heterozygous, with the lesser mutated allele paired with a normal. however, it's more confusing to use the term hets with co-dominant mutations because, as Judy mentioned, there are several mutations that yield a leucistic in the super form, e.g. yellowbellies, russo, fire, lesser, mojo, etc.

having said that, it is helpful to think of co-dom snakes as 'heterozygous' for _____ because there is a difference between the heterozygous and homozygous forms. it will help you understand the differences between a pastel and super pastel, a lesser and a lucy, etc. because the super form is the result of a homozygous mutation on each allele.

my apologies if I've only further muddled things, but hope that helped a little. as mentioned previously, for your own purposes, if you pair a lesser with a normal, each egg has a 50/50 chance of being a lesser.

You all are absolutely amazing with all this knowledge. I should be so lucky to get to that point eventually!

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Originally Posted by JLC

I have to disagree with this statement. I thought about getting into it with my previous post, but that post was already all over the map and I didn't want to confuse things any further.

It would NOT be accurate to call a lesser a "het lesser". It would be accurate to call it a "het BEL", though.

As applied to ball python morph names, the term "het" means that the animal is expressing ONE HALF of the morph's genetic pair. A "het albino" means the animals has one half of the pair of genes needed to make up an albino.

A "het ivory" has one half of the genetic pair that makes an ivory. It's also known as a "yellow belly". But if you refer to an animal as "het yellow belly" it implies that the animal is carrying one half of the genetics needed to make a yellow belly.

There IS a difference between "het BEL" and "het lesser". ...at least in the very casual genetic language of ball python morphs. There's no such thing as a "het lesser".

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Het just means a pair of mismatched genes, not half a morph. Het bel and het lesser are the same thing. You basically have two names for the same gene in that sense. Your dealing with the heterozygous form of the gene. But if im looking at a at the alleles sitting there i call them lesser genes not het bel. While there technically nothing incorrect about besides we have many ways to make a bel, so i see it as less accurate.

Start here:

http://en.wikipedia.org/wiki/Zygosity

And feel free to move on to here:

http://en.wikipedia.org/wiki/Genetics

It works best when you recursively read all the links, but that takes time.

I don't really understand what's so confusing about a 9th grade bio topic.. but for the record, it would be great if people stopped confusing "incomplete dominant" and "co-dominant". Also it would be great if we could separate our phenotype and genotype descriptions of animals.

The phenotype of the animal in question is referred to as a "lesser".
The genotype is heterozygous for the allele that causes the above phenotype.

Wikipedia may not be the best source if you're trying to write a 10-page analysis of something read in a masters-level english course, but if you're trying to learn something in the maths and sciences, you can't really go wrong.

that's a good point too. the difference between phenotype and genotype is criminally overlooked. it's very helpful to someone just starting out in understanding the differences.