GENES DON’T LIE : Phenotype vs Genotype - What You See vs What They Really Carry

Every cat has two stories, although most people only notice one of them. The first story is simple because it is written on the surface: the colour of the coat, the shade of the eyes, the length of the body or the shape of the head, the kind of things you notice immediately when you look at a photograph.

The second story is harder to read because it is hidden in the genetic code, and even when it does not show on the cat itself it can still be passed on to the kittens, often in ways that surprise even experienced breeders.

This is the difference between phenotype and genotype. Phenotype is everything you can see and describe straight away, the visible side of the animal, the traits that seem to define it. Genotype is the complete set of instructions that sits behind those traits, including the recessive or silent parts that never appear until the right pairing brings them out. It is perfectly possible for two cats to look almost identical on the outside, yet one of them may carry the gene for blue while the other does not, and you only discover the truth when the litter is born and the contrast becomes impossible to ignore.

A useful way to picture this is to think about a suitcase. The outside of the suitcase, whether it looks polished and expensive or old and battered, is like the phenotype: it tells you something, but not enough. The inside of the suitcase is the genotype, and until it is opened you have no idea what is packed away, what combinations have been folded in, what has been hidden at the bottom. Breeding is like opening two suitcases at the same time, because once the contents spill out, everything inside becomes part of the new story whether you expected it or not.

This is the reason looks alone can never be the foundation of responsible breeding. Some of the most important qualities of a line, both the ones we hope for and the ones we try to avoid, do not exist on the surface at all. They live in the hidden layer, in the code that shapes the future of the kittens long before they are even born.

Next week we will look at what happens when the two sets of instructions do not agree with each other and only one side is able to speak.

Genes Don't Lie

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