Note: If you found this page through any means other than via the Pure Felinity site, you should be aware of the fact that this page was written about cyber cat breeding, not real cats, and that it is tailored to the breeding rules of this site. The genetics of this site are a simplified version of reality, so there may be some principles that do not hold true in real life.

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The 'physical' traits (Body Type, Body Size, Head Shape, Ear Size, Nose Length & Eye Shape) are on a numerical scale, and are unconnected to the genetic make-up of the cat (although it does depend on the traits of the parents). All other traits (including leg and tail length) are given to a kitten as a pair of genes, one from each parent.

The list of the genes and their abbreviations can be found on the Overview page, and their effects can be found on the Explanations page. In each case there will be two letters, to represent the two genes. For example, shorthair is represented by the letter 'L', so if a kitten gets a shorthair gene from each of it's parents, it's hair-length genetic code will be 'LL'.

Each gene has 'alleles', which are different 'versions' of that gene. For example, the hair-length gene has a shorthair allele and a longhair allele.

A cat 'shows' a gene if it is visible when you look at the cat. A cat 'carries' a gene if it is one of the two genes but cannot be seen when looking at the cat.

Dominant and Recessive: -
With a few exceptions, all genes have dominant and recessive alleles. Dominant alleles (represented by a capital letter) will show as long as the cat has one of that allele in its gene pair. Recessive alleles (represented by a lower case letter) will only show if the cat has a pair of that allele - if there is no dominant allele present in the gene pair. The shorthair (L) allele is dominant over the longhair (l) allele. A cat that is LL will obviously be shorthair, because it has no other allele present. However, a cat that is Ll will also be shorthair, because the shorthair allele over-rides the longhair allele. Only if a cat is ll (i.e. it gets a longhair allele from each parent), will it show longhair, because there is no shorthair allele present.

Homozygous and Heterozygous: -
If a cat has two of the same allele, then it is 'homozygous' for that allele, for example 'LL' or 'll'. Recessive alleles only show if the cat is homozygous for that allele. If a cat has two different alleles for a gene, then it is 'heterozygous' for that gene, for example 'Ll'. Only dominant alleles will show in this case.

Phenotype and Genotype: -
The outward appearance of a cat is known as its 'phenotype'. The genetic properties of a cat are its 'genotype'. So the phenotype of a shorthaired cat is 'shorthaired', but the genotype could either be 'LL' or 'Ll'.

For more information about the Hair Length gene, see the relevant section of the Overview or Explanation pages.

Go to:
Genetics Help Home
The basics (current page)
Overview of the different genes used
Explanations of the genes
How to work out the results of a breeding
Some examples of breeding calculations
Further help