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Hair length (Coat type L-Locus Dog)

Hair length is a trait in many dog breeds, which is important in the selection of intended matings. There is usually a short coat type and a long coat type.

Which genetic type the dog has, i.e. which coat length it develops, can be determined by a genetic test (FGF5 gene).

This coat structure occurs in many different breeds.


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General Information

  • In the breeds Corgi, Collie, Border Collie, German Shepherd, Miniature Dachshund and other breeds, the mutation of the FGF5 gene could be confirmed as the cause of long-hairedness
  • In these breeds, the test reliably identifies those short-haired animals which, in addition to the predisposition for short-hairedness (dominant), also carry the hidden predisposition for long-hairedness.
  • In breeds with very long coats, such as Afghans, but also in breeds like Akita Inu and Eurasier, the hair length is caused by other genes.

Test Information

Locus Information: L-Locus


This test shows a mutation (FGF5:c.284G>T) in the FGF5 gene.


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Also in the:

Genotype and Lab Report

Inheritance: autosomal recessive

→ Only animals with two copies of the mutation (ll) have a long coat. Animals with only one copy or without mutation show a short coat.




Attention: The nomenclature of the alleles has changed in many laboratories.
The letter 'L' now stands for the shorthair allele, l (small L) for the longhair allele. The reason is the international comparability. In generatio we stick to the conventional nomenclature because of the many old results, but add a corresponding description.


K/K = Two copies for shorthair (new nomenclature: L/L)

The dog is shorthaired. He can only inherit predispositions for 'short-hairedness', so that all offspring will be short-haired.

When bred to a heterozygous shorthaired dog, 50% of the offspring will be carriers of the longhaired trait.


K/L = One copy shorthair and one copy longhair (new nomenclature: L/l)

The dog is shorthaired. It can pass on both the shorthair and the longhair trait to its offspring.

When bred to another heterozygous animal, 25% of the offspring are longhaired. 


L/L = Two copies for longhair (new nomenclature: l/l)

The dog is longhaired. He can only inherit predispositions for 'longhairedness'.

When bred to an animal which is homozygous for 'short-hairedness', 100% of the offspring are carriers of the longhairedness trait.

When bred to an animal which is heterozygous for 'short-hairedness', 50% of the offspring are carriers of the disposition for long-hairedness and 50% of the offspring are long-haired.


Long hair/coat


A dog with a short-haired coat (left) compared to a long-haired dog (right).

Possible genotypes

Left (short hair): K/L, K/K

Right (long hair): L/L


Housley, DJ., Venta, PJ.: The long and the short of it: evidence that FGF5 is a major determinant of canine 'hair'-itability. Anim Genet 37:309-15, 2006. Pubmed reference: 16879338. DOI: 10.1111/j.1365-2052.2006.01448.x.


Cadieu, E., Neff, M.W., Quignon, P., Walsh, K., Chase, K., Parker, H.G., Vonholdt, B.M., Rhue, A., Boyko, A., Byers, A., Wong, A., Mosher, D.S., Elkahloun, A.G., Spady, T.C., André, C., Lark, K.G., Cargill, M., Bustamante, C.D., Wayne, R.K., Ostrander, E.A.: Coat variation in the domestic dog is governed by variants in three genes. Science 326:150-3, 2009. Pubmed reference: 19713490. DOI: 10.1126/science.1177808.


Further information is available at Online Mendelian Inheritance in Animals.

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