# Co dom x co dom



## LarkaDawg (Aug 2, 2011)

Just a really quick question. It might sound stupid, but if you breed two co-dominant (or dominant, doesn't matter) gene carrying animals together, each snake has different gene, will you get any wild types?

E.g.

hom Hypo x het Motley = 50% het Hypo, 50% het Hypo het Motley.

By het I mean that there's only 1 copy of the gene, but it's still visible because of the co-dom / dom nature.

Thanks.


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## SnakeBreeder (Mar 11, 2007)

There is a big difference between co-dominant or dominant genes.
I’ll use corn snake genes as an example.
Co-Dom shares its allele with another gene. Ultra and Amel share the same allele.
You can’t get a snake with two ultra genes and the Amel gene as each allele only has two “slots”. So you one of each, 2 of one and none of the other or just one gene and a normal, or 2 normal genes. ( I use the tern normal to express a none morph gene at that allele location)
In the ultra genes and the Amel gene situation this results in Ultra’s, UltraMels or Amels, if the genes are expressed. Normal corns if they are not expressed.
In Dominant genes you only need one gene in a location for it to be expressed.
So the “het” state would produce a visual morph.
Hypo and Motley are both recessive genes and you need two copies of a recessive gene for it to be expressed / make it visual.
Hope this helps.


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## bothrops (Jan 7, 2007)

co-dom does not necessarily need to be allelic with another non-wild type gene in order to be considered co-dom.


Lets take a single mutation of a single gene at a single locus.


If N = normal/wild type and M = the mutation

then there are only three possible combinations in any individual animal (namely NN, NM and MM)


It is what these combinations look like that defines a mutation as recessive, co-dom or dom.



If 

NN = looks normal
NM = looks normal
MM = looks different from normal

then the mutation is considered recessive




If

NN = looks normal
NM = looks different from normal
MM = looks different from normal but the same as NM

then the mutation is considered dominant



If

NN = looks normal
NM = looks different from normal
MM = Looks different from BOTH NN and NM

Then the mutation is considered co-dom









However, some loci have multiple alleles(mutations) that can sit at the same place and sometimes these mutations have different relationships with each other than they do with the wildtype.


For example, as SB points out, 'ultra' and 'amel' share a locus and, although that fact does not make them codominant, the fact that they both have an affect on the phenotype when they are both present does define them as codom to each other. (Although both are recessive to normal).









OP - I'm going to assume you where talking boas when talking hypo and motley?

If so then:

hypo = het hypo
super hypo = **** hypo

motley = het motley
super motley = **** motley




HOWEVER - in boas, it turns out that motley and hypo are allelic and share the same locus. This has an effect on how they are inherited.


Lets code hypo as 'H', motley as 'M' and normal/wildtype as 'N'

Therefore we have the following possible combos:

NN = normal
NH = hypo
HH = super hypo
NM = motley
MM = super motley
MH = hypo motley


Note you can not get a super hypo motley or a super motley hypo (no space for all the genes) and that a hypo motley has no normal allele at that locus.


Therefore:

hypo x motley = HN x MN

gives

25% NN - normal
25% NH - hypo
25% NM - motley
25% MH - hypo motley



super hypo x motley = HH x NM

50% NH - hypo
50% MH - hypo motley



super motley x hypo = MM x NH

50% NM - motley
50% MH - hypo motley



hypo motley x normal = HM x NN

50% NM - motley
50% NH - hypo




etc etc


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## bothrops (Jan 7, 2007)

However, for other, none allelic co-dom/dom gene combos it's slightly different:


lets take pastel (P) and lesser (L). Both these mutations are codominant to normal. As they sit on a different locus from each other they are inherited independently and therefore they are not defined as recessive, codominant or dominant to each other as it is not a relevant point.



So, in this case we have to look at two gene pairs.

NNNN = normal

NPNN = pastel

PPNN = super pastel

NNNL = lesser

NNLL = super lesser (AKA blue eyed lucy)

NPNL = pastel lesser

PPNL = super pastel lesser

NPLL = pastel super lesser (pastel BluE lucy)

PPLL = super pastel super lesser (super pastel BluE Lucy)




Now, you'll notice that because these two mutations are found at separate loci, there are more 'normals' about and this will affect how they are inherited.



To save doing all the possible combos from above, I'll stick to your original question and just mate the two simple 'hets':


lesser x pastel

NNNL x NPNN


=

25% normal - NNNN
25% lesser - NNNL
25% pastel - NPNN
25% pastel lesser - NPNL







So, in answer to your question, yes, you will get wild types when you breed two animals that are het for to different co-dom mutations.

:2thumb:


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## LarkaDawg (Aug 2, 2011)

Thanks guys!


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