Natural cat breeds or landraces (locally adapted domesticated variety that has developed with minimal human intervention or selective breeding) arose through mutation. This is the same as the way natural selection produces new species, the natural breeds and landraces may be considered a step along the road to speciation.

The mutation was advantageous and natural selection caused it to dominate.

• long, water-resistant fur in a cold climate gave rise to Maine Coons, Norwegian Forest Cats and similar types; moderately cobby bodies further conserved heat.
• short, close-lying fur gave rise to the oriental varieties in hotter climes and the slender body type was better suited to hotter regions.
• the mutation had both a visible and invisible (e.g. physiological) effect and natural selection favoured the physiological effect, the visible effect being incidental.
• Long hair in domestic cats appears to be an adaptation to cold as the paws do not have long fur underneath; in desert species of wildcat long hair is found on the paws and protects against hot surfaces.

The mutation was neutral.

• The temperature-sensitive colourpoint mutations in Asia do not appear to have advantages or disadvantages (as far as we know). Such mutations remain in the population and the attractive cat might get preferential treatment from humans (e.g. feeding), but are not selectively bred.
• Because cats are territorial, a mutation might become fixed within a colony that repels incomers e.g. a farm or village colony.
• The bobtailed mutation in Japanese and some Russian cats doesn’t seem to have adverse effects and has become common over the centuries, perhaps being attractive to humans (but not selectively bred).

The mutation occurred in a geographically isolated location and was perpetuated even though it was not advantageous.

• the tailless mutation in Manx is detrimental due to the incidence of lower spine abnormalities (lethal in utero if a cat has 2 copies of the gene), but geographical isolation allowed it to continue in the population.
• The tailless mutation also occurred in Cornwall, but because the cats were not geographically isolated the mutation was eliminated because natural selection worked against it (cats without the mutation did not have spinal issues and had viable offspring).
• Where cats are not geographically isolated, a disadvantageous mutation is not perpetuated e.g. hairless cats are perpetuated by human intervention; they would be at a disadvantage in the wild.

Founder effect

• Cats moving into a previously uncolonized area carried mutations that became widespread in their descendants e.g. bobtailed cats from China being taken to Japan.

A recessive mutation will stay in populations for many generations and if local environmental conditions change, it may become beneficial in the new conditions and give rise to a natural breed.

From historical writings, the longhair mutation either arose independently in three separate areas (Russia, Persia (Iran) and Turkey), or it arose in one of those location and spread to neighbouring regions and then further afield with humans. There are multiple mutations of a gene that result in longhair and some modern selectively bred varieties have a mix of those mutations.