Short vs. Long Hair:
Cats have 3 types of hair (not counting whiskers).
These are the short, downy
insulating hairs, the middle awn hairs, and the longest, the guard
The length of the hairs is controlled by a gene called L. In shorthaired
cats the gene is the dominant form (the L). L has a mutation,
indicated by a little l. This mutation gives a cat long hair. But
long hair is not the dominate gene.
A cat inherits one set of genes from its mother and one set from its
father. So a cat will have 2 genes for hair length. It might get
an L from its mother and a little l from its father. There are 4
possible combinations, as shown in this table.
|| From the Mother
Combinations of Genes for Hair Length
Because the shorthaired gene form L is dominate, any combination with
L will result in a shorthaired cat: LL, Ll, and lL. But the ll
combination will result in a longhaired cat.
When a cat has long hair, it means that all of its 3 kinds of hair
(excluding whiskers) are longer. Exactly how long, how full, and
how soft is controlled by
other genes that modify the affect of the longhaired gene. These
other genes also affect the length, quality and fullness of the hair
on shorthaired cats.
But the affects of these other genes are more readily seen with long hair.
Long hair is not affected by color genes. So all colors of cat may
appear in either short- or long-haired cats.
Source: A Standard Guide to Cat Breeds,
Richard H. Gebhardt, Grace Pond, and Dr. Ivor Raleigh, Eds.,
McGraw-Hill Book Company, New York, 1979, pp. 23-24.