Munchkin (cat)

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For other meanings, see Munchkin (disambiguation)

A munchkin cat grooming herself

The Munchkin cat is a relatively new breed created by a random mutation that produced a cat with extremely short legs. Munchkins have short or long coats in a wide variety of colours. Somewhat surprisingly, because of their short stature munchkins are particularly adept at climbing and jumping. They are usually raised as indoor cats, although they are reported to be extremely active, agile and fast runners. Those who have spent time around barns have proven to be extremely good hunters. The mutation only affects the length of the legs.

The breed was begun in 1983 when Sandra Hochenedel found an extremely short-legged black cat living under a trailer in Louisiana. The cat, Blackberry, was pregnant and half of her kittens were born short-legged. One of Blackberry's kittens, a tomcat named Tolouse, became the father of a breeding program and helped establish the breed in North America.

The Munchkin breed is not recognised by all registering associations and is specifically banned by the Fédération Internationale Féline FIFe and other European registries, but it is accepted by The International Cat Association (TICA).

[edit] Genetics

The munchkin gene is an autosomal dominant one. Thus far to date, there have been no viable kittens that are homozygous for the munchkin gene (that is, kittens with two copies of the munchkin gene, one from each parent), possibly because of gene lethality. Kittens that are heterozygous for the munchkin gene (that is, a munchkin gene from one parent and a normal gene from the other) will be 'standard' munchkins.

Because only heterozygous munchkin cats survive to pass on the gene, all litters with at least one munchkin parent have the possibility of having all munchkin kittens, all normal kittens, or a combination of munchkins and normal kittens. A litter with two munchkin parents may be all munchkin kittens, all normal kittens, all non-viable kittens with two copies of the munchkin gene, or any combination of the three.

At one time it was theorized that this short legged trait was due to the same locus of genes that cause achondroplasia in humans, however all attempts to prove this to date, have failed. It is now believed to be the equivalent of hypochondroplasia which is much milder than achondroplasia. Achondroplasia affects more than the long bones of the legs. The munchkin cat is shorter than a standard domestic, but in all other respects it is identical, genetically and in size and overall appearance.

[edit] Punnett squares

Punnett squares, in which the M represents the dominant munchkin gene and the m represents the recessive normal gene, may be used to illustrate the chances of a particular mating resulting in a munchkin cat.

Kittens bearing two copies of the munchkin gene (MM) will not survive. Kittens bearing one munchkin gene and one normal gene (Mm) will be munchkins. Kittens bearing two normal genes (mm) will be normal. Mm munchkin kittens will be able to pass on the munchkin gene to their own offspring. Normal mm kitten will not, as it does not have that gene.

Mating two munchkins:

	M	m
M	MM	Mm
m	Mm	mm

For each kitten born from this mating, there is a 25% chance it will be non-viable, a 25% chance it will be normal, and a 50% chance it will be a munchkin.

Mating a munchkin

with a normal cat:

	M	m
m	Mm	mm
m	Mm	mm

For each kitten born from this mating, there is a 0% chance it will be non-viable (unless it has a different, unrelated condition), a 50% chance it will be normal, and a 50% chance it will be a munchkin.