# Het for Ivory breed with homo no ivory what do you get?



## motero (Dec 23, 2014)

Does a het for ivory tortoise need to be breed to another het for ivory tortoise to produce ivory offspring? Or will a het breed with a normal produce any ivory off spring? Does any one have a link to easy to understand explanation of this stuff.
Thanks


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## jaizei (Dec 23, 2014)

Het to het or het to ivory may produce ivories. Het to normal may produce either hets or normals, no ivories.

There are multiple videos in this series. I'll link the first one and you can go from there


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## motero (Dec 23, 2014)

Nice Videos, Thank you for the link.


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## TopNotchBoas (Dec 23, 2014)

"Ivory" is a form of albino.

Mutations are either recessive or they are dominant. (there are also sub-forms)

The albino mutation is always recessive. 

With a recessive mutation both parents must carry the gene in order to produce visual offspring, be it in heterozygous (non-visual) or in homozygous (visual) form. 

Another fun fact: The "Ivory" mutation is actually a tyrosinase positive form of albino, which can produce melanin (darker pigment). In contrast to tyrosinase negative albino, which is completely devoid of all dark pigment.


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## N2TORTS (Dec 23, 2014)

http://www.hobart.k12.in.us/jkousen/Biology/psquare.htm


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## N2TORTS (Dec 23, 2014)

TopNotchBoas said:


> "Ivory" is a form of albino.
> 
> Mutations are either recessive or they are dominant. (there are also sub-forms)
> 
> ...


Sort of like this ....RED Foot Hypo's with polymorphic gene


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## TopNotchBoas (Dec 24, 2014)

N2TORTS said:


> Sort of like this ....RED Foot Hypo's with polymorphic gene



I'm bogging down with semantics but, I wouldn't personally label a polygenic trait as a "mutation". For me, applicable to the "reptile trade", the term mutation applies solely to single gene mutations. Admittedly, my terminology and knowledge stems from my experience with breeding snakes. I know nothing of the red foot hypo "polymorphic" phenotype.


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## Telid (Dec 24, 2014)

N2TORTS said:


> http://www.hobart.k12.in.us/jkousen/Biology/psquare.htm


Ah, Punnett squares. An oversimplification, but still a very useful tool


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## motero (Dec 24, 2014)

So If I got this right Breeding a het with a normal would get you 50% of the offspring being het. But you can't tell witch ones with out test breeding. Thanks all.


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## N2TORTS (Dec 25, 2014)

TopNotchBoas said:


> I'm bogging down with semantics but, I wouldn't personally label a polygenic trait as a "mutation". For me, applicable to the "reptile trade", the term mutation applies solely to single gene mutations. Admittedly, my terminology and knowledge stems from my experience with breeding snakes. I know nothing of the red foot hypo "polymorphic" phenotype.


Well myself still learning and a not much researched in the area of tortoises. Another forum I chat in were some other enlightening insights/explanations On polymorpisims and mutations.
All mutation is a form of polymorphism in genetics, but the reverse is not true. Just like all enzymes are proteins, but not all proteins are enzymes. "Genetic polymorphism is the occurrence in the same population of two or more alleles at one locus, each with appreciable frequency", where the minimum frequency is typically taken as 1%, defined by Cavalli-Sforza & Bodmer (1971).
*Jagadish Hansa· Siksha O Anusandhan University*
Mutation and polymorphism are distinct concepts of distinct domains. The former refers to any change of DNA sequence while the latter stands for a mutant allele with a frequency in an intraspecies poputation reaching a given threshold (like 1% for a regular population size). Polymorphism is related to population diversity. Mutation can be germ line or somatic. Germline mutation is the cause of polymorphism in sexual reproductive population of a species. Polymorphisms of DNA repair genes might be linked to distinct mutation rate, which is a genomic trait. For RNA virus, RNA sequence changes also refers to mutation yet mostly due to the reverse transcription step of the virus life cycle. An expanding of mutation concept is that mutation can also be caused by the transcription and translation if mutant protein is invoked. Apparently, such mutations will not be heritable. Somatic mutations in somatic cells of sexual reproductive population will not be inherited to the next generation but can be somatically inherited in the somatic cell population. Mutation can be neutral, deleterious, or beneficial, in terms of the fitness of the corresponding phenotype, yet such a classification is only meaningful in an evolving population, i.e., invoking the concept of polymorphism, which itself does not have any functional implications.
*Youngzhong Zhao· Mount Sinai School of Medicine*
And then let’s not forget the T+ / T- albino and Hypermelanistic and or Anerythristic/ Ananthic gene coding ….which you do see much of in the snake world .

JD~


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## TopNotchBoas (Dec 25, 2014)

motero said:


> So If I got this right Breeding a het with a normal would get you 50% of the offspring being het. But you can't tell witch ones with out test breeding. Thanks all.



Correct. With any recessive mutation, such as sulcata "ivory" T+ albinos, hets are indistinguishable from normals.

het x normal = 100% normal looking (50% of which will be het)

het x het = 25% visual ivory, 75% normal (50% het / 25% normal, aka 66% chance of being het)

het x ivory = 50% visual ivory, 50% normal (100% of which will be het)

ivory x ivory = 100% visual ivories

In some reptiles, breeding albino to albino results in weakened offspring. I'm unsure if that applies to ivory sulcatas.


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## TopNotchBoas (Dec 25, 2014)

Hey JD,

I was re-reading your post and realized I misinterpreted your example of the "Red Foot Hypos". Sorry for the confusion. The variation within melanin production of those guys is interesting indeed!

Hypomelanism (a reduction in melanin) and T+ albino (a reduction in melanin) have very similar (identical?) definitions. I'm not completely sure what the defining line is that separates them. Often reptile breeders shape scientific genetic definitions based on how it best applies to ... breeding reptiles ... and it's not always cut and dry determining what the terminology actually means. I'd guess hypomelanism is considered a less intense form of T+ albino and T+ albino as a less intense form of T- albino (which produces absolutely no melanin). It all boils down to differing levels of melanin (dark pigment) reduction.


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