# Hypo x Albino



## portsmouthtortoises (May 26, 2016)

I have a hypo redfoot. The father of this hypo is albino (with red eyes) and the mother is hypo (with normal eyes.) It has some albino siblings (with red eyes) and some hypo siblings (with normal eyes.) If albinism and hypomelanism are both recessive genes and deemed to be different to each other, is my hypo classed as a hypo or albino or something different?

I also have an albino and some het albinos with both parents being het for albino. If any of these were to be bred with the hypo mentioned above, what are the likely outcomes and how would the genetics work?


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## SarahChelonoidis (May 26, 2016)

sulley13 said:


> I have a hypo redfoot. The father of this hypo is albino (with red eyes) and the mother is hypo (with normal eyes.) It has some albino siblings (with red eyes) and some hypo siblings (with normal eyes.) If albinism and hypomelanism are both recessive genes and deemed to be different to each other, is my hypo classed as a hypo or albino or something different?



My understanding is that albinos are completely amelanistic (no dark pigment) which is different from hypomelanism, which is just a reduction in melanin not a total absence. If there is some melanin, it is hypo not albino.


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## wellington (May 26, 2016)

@N2TORTS can help with this


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## portsmouthtortoises (May 26, 2016)

SarahChelonoidis said:


> My understanding is that albinos are completely amelanistic (no dark pigment) which is different from hypomelanism, which is just a reduction in melanin not a total absence. If there is some melanin, it is hypo not albino.




So where did the two recessive hypo genes come from if one of the parents is amelanistic?


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## SarahChelonoidis (May 26, 2016)

sulley13 said:


> So where did the two recessive hypo genes come from if one of the parents is amelanistic?



I don't think you need them. The regular melanin gene is dominant so if you have one copy, you get a regular coloured animal. To be hypomelanistic, you can't have a regular melanistic gene so that usually means you need to be homozygous for hypo. You don't have a homozygous hypo though. You have one hypo and one albino gene. To be albino, you need to be homo for albino so you're not albino. You end up being hypomelanistic, heterozygously.

Is that right, @N2TORTS?


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## portsmouthtortoises (May 26, 2016)

SarahChelonoidis said:


> I don't think you need them. The regular melanin gene is dominant so if you have one copy, you get a regular coloured animal. To be hypomelanistic, you can't have a regular melanistic gene so that usually means you need to be homozygous for hypo. You don't have a homozygous hypo though. You have one hypo and one albino gene. To be albino, you need to be homo for albino so you're not albino. You end up being hypomelanistic, heterozygously.
> 
> Is that right, @N2TORTS?



I thought that to be hypo, you need to be homozygous for hypo, the same as albino. Being hypomelanistc heterozygously would produce normal looking red foots with no reduction in melanin, wouldn't it?


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## SarahChelonoidis (May 26, 2016)

sulley13 said:


> I thought that to be hypo, you need to be homozygous for hypo, the same as albino. Being hypomelanistc heterozygously would produce normal looking red foots with no reduction in melanin, wouldn't it?



But it can't produce normal looking redfoots with no normal genes.


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## portsmouthtortoises (May 26, 2016)

SarahChelonoidis said:


> But it can't produce normal looking redfoots with no normal genes.



True. If hypomelanism and albinism are are only produced with two matching recessive genes though, how can a visual hypo be a het?


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## SarahChelonoidis (May 26, 2016)

sulley13 said:


> True. If hypomelanism and albinism are are only produced with two matching recessive genes though, how can a visual hypo be a het?



But what is the alternative? How can it be normal looking without a normal gene?


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## jaizei (May 26, 2016)

The following assumes that both traits are separate recessive genes. 



sulley13 said:


> So where did the two recessive hypo genes come from if one of the parents is amelanistic?



Until they're proven out, you don't know what they're het for. Even though the father is visual albino, he could also be het for hypo. Ditto for the mother, she could be het for albino. 

So, 
Normal or Albino = A or a
Normal or hypo = H or h

The father could be either aaHH or aaHh. He's visual Albino and maybe het for hypo or not
The mother could be Aahh or AAhh. She's visual Hypo and maybe het for albino or not

So your possible outcomes would be aaHH x Aahh, aaHH x AAhh, aaHh x Aahh, or aaHh x AAhh.

Have fun making punnet squares.  Or try this. http://scienceprimer.com/punnett-square-calculator


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## N2TORTS (May 27, 2016)

Just my two cents and still doped up from out of the hospital ........


Jazie is right, …..Something to keep in mind when dealing with Punnett squares and simple recessive genetics is that the numbers involved are theoretical. But I wouldn’t make fun of them, unless you have done/tried and proved it yourself. Then we can get detailed.

First let’s look at some other terms for some of those who may not know ……(in this version I don’t like using the term “normal” as Phenotype is more correct and this can very soo.. much within the Redfoot world – due to color local and variations within)

Anerythristic is a recessive trait which gives the animal a lack of erythrin (a protein-pigment complex) causing the animal not to produce any red pigment.

Axanthic - While albinism is the lack of all melanin or pigment color, Axanthics only lack red or yellow or both.

Albino lack melanin which is black pigment,

Hypomelenisti*c* retain some of their black pigmentation while losing most of it.

Tyrosinase is an enzyme that acts on tyrosine, an amino acid that is the basic building block of melanin and a suite of other dark pigments that are called melanin-related pigments.

A tyrosinase-negative albino is an albino that does not have functioning tyrosinase or has a defective tyrosinase that does not work correctly, and so no black melanin can be produced. Also no melanin-related pigments are produces. A tyrosinase-positive albino has functional tyrosinase and it is able to complete the first and second steps of the multi-step process of black melanin synthesis. Some other enzyme along the synthesis is missing. Tyrosinase-positive albinos do not make black melanin, but they do make other melanin-related pigments. Melanin-related pigments are mostly dark colors and they include a purple-gray.

This can apply to Hypo’s as well. As here at the Cove we have hatched out neo nates carrying this trait.

As others have mentioned……

The word Het is short for short for heterozygous which means the animal will receive a dominant allele from one parent and a recessive allele from the other parent, and have a visual “normal” looking appearance. We will use an Albino for an example in this scenario. Breed an albino to a normal and all of the babies will appear normal but will all carry the gene for albinism….aka”Het. This makes them 100% het for albino.

In order to produce 100% visual albino babies every time, both parents must gene for albinism. Breeding an albino to an albino will give all 100% albino offspring.
Breeding an albino to a 100% het for albino gives you half of the offspring being actual albinos and half being normal appearing offspring which are 100% het for albino.
This is where it gets confusing. Breeding a 100% het for albino to another 100% het for albino will make approximately 25% of the offspring being albino. 50% of the entire clutch will be normal appearing which het are for albino. The remaining 25% will be normal which do not carry the gene for albinism. But since 75% of the clutch are normal appearing, there is no way to differentiate the het offspring from the non-het offspring without breeding them when they mature. Therefore, the normal appearing are labeled as 66% possible hets, meaning there is a 2 out of 3 chance that they are actual carriers of the albino gene.
Breeding a 100% het to a normal will give you all normal appearing offspring. The het parent passes on its gene to half of the clutch. Again, there is no way to tell the gene carriers from the non gene carriers. So with this pairing, the babies will be called 50% possible het for albinism. There is a 50/50 chance that they carry the gene.

It would be very interesting to breed one of the Hypo’s to an Albino and see the results…..although any of the Albino’s I know of here in the States are not yet of size/maturity ready to breed successfully. If so and any one knows one for sale contact me……


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## Koen (Sep 6, 2018)

Hi,

I know it is of topic but just trying to understand genetics and thought it this would be the place 

So if you breed a 100% het to a 100% het the result should be 25% albino 50% het and 25% normal. Are these numbers theoretical and can they vary? So can you also have for example a 100% albino clutch, or 100% het clutch when breeding 100% hets? And are the odds calculated per egg or per clutch?

Sorry when some consider these as stupid questions but just trying to understand 

Thx


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## jaizei (Sep 7, 2018)

Koen said:


> Hi,
> 
> I know it is of topic but just trying to understand genetics and thought it this would be the place
> 
> ...




Yes the numbers are probability. It might help to think of it like flipping a coin; there may be 'streaks' but overall, long term, you end up at about 50/50. Individual clutches may skew one way or the other, but over time you should expect the results to resemble the probability.


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