OMIA 001216-9796 : Coat colour, roan in Equus caballus

In other species: cattle , pig

Possibly relevant human trait(s) and/or gene(s) (MIM number): 184745

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal

Considered a defect: no

Key variant known: no

Inheritance: Hintz and van Vleck (1979) provided convincing evidence that roan coat colour in Belgian horses is due to heterozygosity for an autosomal gene that is lethal when homozygous.

Mapping: Roan is one of three coat-colour loci that belong to equine linkage group 2: the other two loci are tobiano and chestnut (Extension)(Andersson and Sandberg, 1982; Marklund et al., 1994)

Molecular basis: Building on the results of recent work showing that dominant white coat colour in pigs is due to a mutation at the KIT gene (see OMIA 000209), Marklund (1997) reported very strong evidence that the KIT gene in horses is the gene for roan coat colour: a linkage study revealed zero recombinantion between Roan and KIT, and a 79 bp insertion between exons 1 and 2 of the KIT gene, creating a frameshift mutation, was associated with the Roan phenotype. However, definitive evidence of a causative mutation is still lacking.


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.
2009 Rieder, S. :
Molecular tests for coat colours in horses. J Anim Breed Genet 126:415-24, 2009. Pubmed reference: 19912415. DOI: 10.1111/j.1439-0388.2009.00832.x.
1999 Marklund, S., Moller, M., Sandberg, K., Andersson, L. :
Close association between sequence polymorphism in the KIT gene and the roan coat color in horses Mammalian Genome 10:283-288, 1999. Pubmed reference: 10051325.
1994 Marklund, S., Ellegren, H., Eriksson, S., Sandberg, K., Andersson, L. :
Parentage Testing and Linkage Analysis in the Horse Using a Set of Highly Polymorphic Microsatellites Animal Genetics 25:19-23, 1994. Pubmed reference: 8161016.
1984 Sponenberg, D.P., Harper, H.T., Harper, A.L. :
Direct evidence for linkage of roan and extension loci in Belgian horses. J Hered 75:413-4, 1984. Pubmed reference: 6481131.
1982 Anderson, L., Sandberg, K. :
A linkage group composed of 3 coat colour genes and 3 serum protein loci in horses Journal of Heredity 73:91-94, 1982. Pubmed reference: 7096983.
1979 Hintz, H.F., Van Vleck, L.D. :
Lethal dominant roan in horses Journal of Heredity 70:145-146, 1979.

Edit History

  • Created by Frank Nicholas on 06 Sep 2005
  • Changed by Frank Nicholas on 14 Oct 2011