This journal is out-of-date and no longer updated!
Please check the Breeding Guide on Tokotna for current information!
Trying to figure out how tokota genotypes work can be a bit confusing, we know! To help you guys out, we've put together a guide for coats and manes so that you can better understand how genetics in the tokota world work! Other useful resources to go with this one include the
Genetics and Mutations guide, and the
Design Guide Handbook.
Genes and Coats
There are four different possible coat colors that a tokota can have. From most common to most rare these are
tundra,
tawny,
brown, and
black. As you may have seen before, a tokota genotype always starts with some combination of letters that looks something like this:
ee/Aa/Tt
This is actually the tokota's "code" for its base coat color! Right now, that probably seems like just a random jumble of letters, but each one means something.
The Code
- In genetics, letters are used to describe the genes that an animal has.
- Each part of the genotype between slashes is called a locus, meaning "place". In the example tokota, Aa is a single locus.
- Each locus controls a gene. In the example tokota, the A locus controls a certain part of coat colour.
- Each locus has two letters in it which are variants of the gene - one from each parent. These variants are called alleles, meaning "other form". In the example tokota, "A" is one allele, while "a" is another.
Allele Effects
Base coat colours are slightly more complex than 90% of other tokota genetics, so we need a new example. Let's say that the letter "U" stands for the locus that controls whether or not the subject has an ultraviolet nose.
In this example, a capital "U" allele would give the subject an ultraviolet nose, and a lowercase "u" would not give the subject a particularly note-worthy nose. Noseworthy, heh. A lowercase "n" can be substituted for a non-effective allele letter, and is used throughout a tokota's genotype except for the base coat loci.
Zygosity - Allele Pairs
When you have the same allele twice -
UU, uu or nn - the gene is
homozygous for that trait. When they are different -
Uu or nU - the gene is
heterozygous for that trait. So our example tokota above there could be said to be homozygous for e (or not-E), and heterozygous for A and T.
Allele Dominance
Different alleles on the same locus will have a certain order of
dominance, meaning that some alleles may mask others. All allele relationships on the same locus in tokota genetics are "complete dominant"s with only two variants (effective and non-effective).
This means that if the effective allele is present then the result of heterozygous effective, Uu, is the same as homozygous effective, UU - an ultraviolet nose.
The only way for the effect to not show is to be homozygous non-effective - uu or nn. These non-effective/normal loci, with the exception of the three base coat loci, are never written in the genotype and will simply not appear.
Code to Coat
Now to find out what that example tokota actually
looks like.
Tundra
Tundra is controlled by the T locus.
TT = Homozygous tundra
Tt = Heterozygous tundra
Brown
Brown is controlled by the A locus.
AA = Homozygous brown
Aa = Heterozygous brown
Tawny
Tawny is created by the combination of T locus and the A locus.
AA/TT = Homozygous tawny
AA/Tt = Heterozygous tawny
Aa/TT = Heterozygous tawny
Aa/Tt = Heterozygous tawny
Black
Black is controlled by the E locus.
EE = Homozygous black
Ee = Heterozygous black
So our example tokota is a tawny! As you can see the base coat genes do interact between loci, but this is not the case for most tokota genes.
How Alleles Pass to Offspring
Reproduction works by taking each parent's genotype, ripping it in half along the loci (leaving only one out of every pair of alleles) and then mashing the half-genotype together with whatever half-genotype the other parent has produced. In real life there is a 50/50 chance of each allele on a locus being the one the parent passes on, as there are two alleles on each locus and only one will be passed.
However in Tokotas this has been simplified in some areas and altered in others to simulate real rarity and natural selection in the gene pool - to account for, for example, black tokotas not being nearly as camouflaged against snow as tundras. Super-rare genes such as lilac are even more difficult to pass.
- UU x UU = UU
- UU x nU = UU (chance of nU for super-rare)
- UU x nn = nU (chance of nn for super-rare)
- nU x nU = UU or nU (chance of nn for super-rare)
- nU x nn = nU or nn
- nn x nn = nn
T passes more easily than A, which in turn passes more easily than E. In the event of no base coat passing at all, the pup will inherit the most common base coat available from the parents. All this means is that the rarer the colour you're breeding for, the more care you should take in selecting the parents' genes!
Breeding for Certain Coats
Breeding for specific coat colors can get a bit confusing, but it basically boils down to looking at what you need, and making a parent shopping list.
What do you need?
First, take a look at the possible genotypes for the coat colour you want. For example, we'll try and breed a tundra. That means we want
ee/aa/TT or
ee/aa/Tt. If there were any A alleles, it would be a tawny, and any Es would mess it up too!
Making the shopping list
The next bit is a little complicated; you have to work out what each parent could pass and how that would work out.
So our old tawny example toko from the top - ee/Aa/Tt if you'd forgotten - could pass an A or an a, plus a T or a t, and it would be guaranteed to pass an e, because there's no other option on that locus.
Those single alleles would then be paired with the other parent's passed alleles, to produce the offspring's full genotype. Depending on the pairing, each allele may have a chance of being the one that is passed to the offspring, and that is an important consideration when breeding.
So back to that tundra we want. Looking at the genotypes we can have, we can deduce a few things.
- Neither parent should pass an E
- Neither parent should pass an A
- At least one parent should pass a T
And with that little "shopping list" of sorts, you can start looking at parents!
Finding parents
The most ideal combination you could find for this scenario would be two tundras, whether
ee/aa/TT or
ee/aa/Tt. Since neither would pass an E or an A and the only result from the T locus would be TT or Tt, you will always get another tundra!
But say you couldn't find that. Well, tokos have multiple puppies in their litters, so you have several chances and you can settle for less ideal combinations. Just take care what you pair up. For example:
- ee/aa/TT x ee/Aa/TT
This pairing could still work well because both parents will always pass T, and even though the presence of Aa means that there is a chance for tawnies in the litter it is a lower chance. - ee/Aa/TT x ee/Aa/Tt
On the other hand, this pairing would not work at all. Aa x Aa will always give either AA or Aa, which coupled with the always-passing T will give you a full litter of tawnies. - ee/AA/tt x ee/aa/Tt
This pairing would also not work; A will always pass and T will only pass some of the time, giving you a litter of browns and tawnies.
This same approach can be applied to breeding just about any coat or marking.
Black
Black is intended to be rare - after all, there's a reason polar bears are white! Because of this it behaves slightly differently to the other base coat colours and can disappear without trace if you're unlucky, even if one parent is EE.
A black pup will be
EE/aa/tt or
Ee/aa/tt. This time your shopping list will be:
- At least one parent should pass an E
- Neither parent should pass an A
- Neither parent should pass a T
Again, your best bet is to breed two black parents. But that's not always possible!
If you're breeding a black to a non-black and looking to get a black pup, you'll need to pay a great deal of attention to the parents' coat zygosities. As a rule, the zygosity of the As or Ts in the non-black parent should be equal to or less than the zygosity of the Es in the black parent in order to have a chance of black pups The closer the numbers the less the chance.
That was a lot of long words; let me give some examples with a black x brown pairing.
- EE/aa/tt x ee/Aa/tt
This breeding has a chance of black pups: the black parent has two Es and the non-black parent only has one A. - Ee/aa/tt x ee/Aa/tt
This breeding also has a chance of black pups, though less than the previous pair: the black parent has one E and the non-black parent also has one A. - EE/aa/tt x ee/AA/tt
This breeding also has a chance of black pups, though again less than the previous pair: the black parent has two Es but the non-black parent has two As. - Ee/aa/tt x ee/AA/tt
This breeding has no chance of black pups: the black parent only has one E and the non-black parent has two As.
The same applies with one black and one tundra parent, though the chance for blacks is less than the brown equivalent.
Tawnies cannot produce black pups.Cross Coats
Crosses are a mutation of black that occur when blacks are bred with tundras, browns, or existing crosses. Additionally crosses may be bred together. Any black pups in one of these breedings has a chance to roll for the Cross mutation.
- Bronze Cross is the result of breeding Bronze Crosses, or Brown with Black
- Silver Cross is the result of breeding Silver Crosses, or Tundra with Black
- Gold Cross is the result of breeding Gold Crosses, or Silver Crosses with Bronze Crosses
