# Hetro and Homozygous...huh?



## Hardwicki (Jun 18, 2007)

Hi guys

I'm doing my best to swat up on royal breeding as i would just be over the moon if i could ever get hold of a spider female royal...much saving to do.

I'm on the Markus Jayne sight and its really useful but i am struggling to understand some wording.
What is the diff between het and ****...in my understanding you have normals, hets(they carry the gene) and what are homos? Visuals without carrying the gene?

Could anyone help me with this?
I'm struggling to get it!!:blush:


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## Razzler79 (May 1, 2008)

homos are visuals carrying only that gene- no hets!


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## Hardwicki (Jun 18, 2007)

Razzler79 said:


> homos are visuals carrying only that gene- no hets!


Right so a normal can be a het for spider (eg) and if i breed this with a normal i get 2 spiders and 2 normals. Normals are not het for spider.

But when it says breed 2 hets together, i'd get 2 spiders one **** and a normal.
Is the **** a super??

Sorry its melting my brain??:blush:


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## GlasgowGecko (Feb 23, 2008)

Ok, im not really familiar with the "spider" trait, but I can explain the basics for you.

Ok, for each gene, an individual has two alleles, one from each parent. These can be the same or different, and have associated dominance hierarchies. 
Example
So simply put (A) = Normal and (a) = Albino 

Male Normal, and female albino 
Female Female
a a
Male A Aa Aa
Male A Aa Aa

So the male in Homozygous with AA genotype and the female is Homozygous with aa genotype.

All the offspring in the F1 are Heterozygous with the Aa genotype. (A) is dominant to (a) so each hatchling is normal "het" albino.

Hope this helps.
Andy


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## Hardwicki (Jun 18, 2007)

GlasgowGecko said:


> Ok, im not really familiar with the "spider" trait, but I can explain the basics for you.
> 
> Ok, for each gene, an individual has two alleles, one from each parent. These can be the same or different, and have associated dominance hierarchies.
> Example
> ...


To be honest i'm more confused now. I remember allelles and genetics at school but the fact that royals have co-dom, dominant and recessive genes is confusing. The albino is a recessive gene so the odds are different arent they?

I'm seriously considering just breeding normals and save myself a headache. I'm one of these ppl unfortunately if i read it it doesnt sink in, if someone tells me to my face and shows me i click.

Thanks for your help, think i might just go draw some squares!:lol2:


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## paulh (Sep 19, 2007)

Genes come in pairs. See Handbook - Genetics Home Reference

When the two genes in a pair are the same, the gene pair (and the animal with the gene pair) is homozygous. There may be two copies of the normal gene or two copies of a mutant gene such as albino or pastel or spider.

When the two genes in a pair are not the same, the gene pair (and the animal with the gene pair) is heterozygous. There may be a normal gene paired with a mutant gene (examples = spider//normal or normal//albino) or two different mutant genes, such as lesser platinum//mojave.

When you breed any two animals together, you first figure out their genes. and use the FOIL technique. Or the Punnett square; the results are the same. Let's say that two royal pythons are not normal at one location in the totality of genes (the genome). Each one is heterozygous albino (= het albino). In other words, each parent has a gene pair made up of a normal gene and an albino gene (normal//albino). Each egg has either a normal gene or an albino mutant gene, and each sperm has either a normal gene or an albino mutant gene.

The FOIL technique tells what babies can turn up from a mating between a male with the gene pair m1//m2 and a female with the gene pair f1//f2. In this case, m1//m2 = normal//albino, and f1//f2 = normal//albino.

FOIL is the initial of First, Outer, Inner, Last, the combinations of one male gene and one female gene:
F = First = m1//f1 = normal//normal (looks normal)
O = Outer = m1//f2 = normal//albino (looks normal)
I = Inner = m2//f1 = albino//normal (= normal//albino) (looks normal)
L = Last = m2//f2 = albino//albino (albino)

The albino mutant gene is recessive to the normal gene because a heterozygous animal (with a normal gene paired with an albino mutant gene) looks normal.

Lets try het pastel (pastel//normal) X het pastel (pastel//normal).
F = First = m1//f1 = pastel//pastel (homozygous pastel, AKA super pastel)
O = Outer = m1//f2 = pastel//normal (heterozygous pastel, AKA pastel)
I = Inner = m2//f1 = normal //pastel(= pastel//normal) (heterozygous pastel, AKA pastel)
L = Last = m2//f2 = normal //normal (looks and is normal)

The pastel mutant gene is codominant to the normal gene because a heterozygous animal (with a normal gene paired with a pastel mutant gene) does not look like a normal snake and does not look like a homozygous pastel.

Lets try het spider (spider//normal) X het spider (spider//normal).
F = First = m1//f1 = spider//spider(homozygous spider)
O = Outer = m1//f2 = spider//normal (heterozygous spider, AKA spider)
I = Inner = m2//f1 = normal //spider(= spider//normal) (heterozygous spider, AKA spider)
L = Last = m2//f2 = normal //normal (looks and is normal)

The spider mutant gene is dominant to the normal gene because a heterozygous animal (with a normal gene paired with a spider mutant gene) looks like a homozygous spider. At least that is what we think at this time. Nobody has reported a homozygous spider by breeding test. But in other species, which have been studied longer than snakes, there are many dominant mutant genes.

The useage above is standard genetics lingo. Many of the first herpers who did genetics did not understand the standard definitions. Their incorrect ideas have continued, unfortunately. 

When a herper says super, he means a herp that is homozgyous for a codominant mutant gene or (sometimes) a dominant mutant gene.

When a herper says codominant, he usually means a herp that is heterozygous for a codominant mutant gene or (sometimes) a dominant mutant gene.

When a herper says dominant, he usually means a herp that is homozygous for a codominant mutant gene or (sometimes) a dominant mutant gene.

When a herper says there is no such thing as a heterozygous (het) pastel or heterozygous spider, he means that there is no such thing as a heterozygous (het) pastel or heterozygous spider that looks normal.

Clear as mud?


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## Kenorsanc (Dec 10, 2006)

Heterozygous means that for a given morph it carries one of that morph and one normal.

Homozygous means it carries two genes for a particular morph.

I think that there is no end to how many different genes a royal can hold.

For example a homozygous albino has two copies of the albino gene and therefore looks albino . A heterozygous albino only carries one gene and so doesn't look albino as the albino gene in royals is a simple recessive and needs to copies to be seen.

The spider gene is co-dominant or dominant.

So a heterozygous spider with one spider gene and one normal gene will look like a spider as it only needs one gene to express it. If you got a homozygous spider then it would carry two copies of the gene but would look no different to spider carrying one gene or a heterozygous spider because it is a dominant gene and so looks the same whether it has one or two copies of the gene.

Just think that all genes are passed on in the same way. Just that if a royal has one albino gene it wouldn't be an albino whereas if it had one copy of the spider gene then it would look like a spider.

If you breed a het albino to a normal you get 

50% normals
50% het albinos

If you breed a heterozygous spider to a normal you get

50% Normals
50% Spiders

So although people say a royal can't be het spider it can just that it will look like a spider and so people call het spiders, spiders.

Hope that makes sense. Feel free to ask any more questions.


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## Hardwicki (Jun 18, 2007)

paulh said:


> Clear as mud?


Definately, to be honest its early days, i was the same with corn genetics and i'm getting there now, its so different.
Its gonna be a long time before i can afford a high strain royal female anyway so plenty time to read up.

Its just trying to get my head around terminology etc!: victory:


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## Ssthisto (Aug 31, 2006)

Kenorsanc said:


> Heterozygous means that for a given morph it carries one of that morph and one normal.


Or one flavour of allele for that gene plus a different flavour for the same gene - for example, a blue-eyed-leucistic could be heterozygous Mojave, heterozygous Lesser. There's no "normal" gene in there


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## paulh (Sep 19, 2007)

Hardwicki said:


> I'm one of these ppl unfortunately if i read it it doesnt sink in, if someone tells me to my face and shows me i click.


Try taking two small boxes, with one marked male and the other female. In the male box, put a scrap of paper marked normal and a scrap of paper marked albino. This is the male's gene pair. In the female box, put a scrap of paper marked normal and a scrap of paper marked albino, her gene pair. Pull a scrap of paper out of each box. This is the gene pair for one baby. Write the gene pair down on another piece of paper. Put the papers back in their original boxes. Repeat 20 times and then add all the like gene pairs together.

Do the same with another mutant gene. In this case, the male has a pastel mutant gene paired with a normal gene. And the female has a pastel mutant gene paired with a normal gene. 

Do the same with a male having a spider mutant gene paired with a normal gene and a female having a spider mutant gene paired with a normal gene.

Repeat with a male having a pastel mutant gene paired with a normal gene and a female with two normal genes.

Repeat with a male having two pastel mutant genes and a female having two normal genes.

Repeat with a male having two pastel mutant genes and a female having two pastel mutant genes.

Pretty soon you will start seeing the patterns.


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## Hardwicki (Jun 18, 2007)

Kenorsanc said:


> Heterozygous means that for a given morph it carries one of that morph and one normal.
> 
> Homozygous means it carries two genes for a particular morph.
> 
> ...


Thanks i am doing a lot of reading up and its all well and good but terminology is confusing and i'm new to all this!
I do really want a spider!! and if i breed my normal male to a female spider i know what i will come out with, but from then on i'm baffled. 
If i buy a normal het spider, can i guarantee it is het?
Hmmm...lots of work to be done...
Thanks you guys, it is becoming clearer now...promise:2thumb:


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## paulh (Sep 19, 2007)

Hardwicki said:


> If i buy a normal het spider, can i guarantee it is het?


No such thing as a het spider that looks normal. If it looks normal, it has two normal genes at the location where a spider royal python would have the spider gene.


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## Ssthisto (Aug 31, 2006)

Hardwicki said:


> a normal het spider, can i guarantee it is het?


Because spider is dominant, any animal that CARRIES the gene at all shows the gene.

A normal-looking animal doesn't look like a spider, therefore it doesn't have the gene at all.


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## bothrops (Jan 7, 2007)

Hi Hardwicki

Stick with it, it will click eventually. I teach A level biology and have a number of powerpoints that may help you. PM me your email and I'll send you a few bits and pieces!

Cheers

Andy


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## Hardwicki (Jun 18, 2007)

bothrops said:


> Hi Hardwicki
> 
> Stick with it, it will click eventually. I teach A level biology and have a number of powerpoints that may help you. PM me your email and I'll send you a few bits and pieces!
> 
> ...


Thanks so much. I'll drop you a PM soon.
x


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## Daveyboy (Dec 27, 2007)

New England Reptile Distributors, designer Ball Pythons, Reticulated Pythons, and much more!

Try this sight for info. Its the NERD genetice page written by the legend Kevin Mccurly.
It helped me lots. it explains everything and pretty pictures to help along the way.

Hope it helps you


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## paulh (Sep 19, 2007)

Kevin McCurley is a legendary breeder, worthy of great respect. But he's a self-taught geneticist, and not a very good one. Trying to learn genetics from the NERD site could mess up your mind so badly that you might never get the subject straight. The same is true of many herp genetics web pages.


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