Plant & Animal Genome V Conference
Town & Country Hotel, San Diego, CA, January 12-16, 1997.
PAG-V: S19 - MOLECULAR COAT COLOR GENETICS IN PIGS AND HORSES
S19
MOLECULAR COAT COLOR GENETICS IN PIGS AND HORSES
ANDERSSON, LEIF
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 597, S-751 24 UPPSALA, Sweden
Coat color genetics in livestock is surprisingly important as breeders often prefer certain coat color variants or simply would like to
ensure that their livestock breed true for color. There is thus a practical as well as a scientific interest for molecular coat color genetics in farm
animals. We have investigated two major coat color loci in pigs (Dominant white and Extension) and two in horses (Roan and Chestnut).
Comparative genomics was used to identify candidate genes for these loci which all have been assigned to the respective linkage map by our
laboratory. The KIT gene encoding the mast/stem cell growth factor was identified as a possible candidate gene for the dominant white color in
pigs. Molecular analysis provided compelling evidence for that pigs with the dominant white color carry a KIT duplication (Johansson Moller
et al. 1996, Mammalian Genome, in press). The roan coat color in horses is controlled by a dominant mutation which is lethal in the
homozygous condition. Comparative mapping suggest also in this case KIT as the major candidate gene. The MC1R gene encoding the
melanocyte stimulating hormone receptor was identified as a candidate gene for both the Extension locus in pigs and the recessive Chestnut
mutation in horses. This conjecture has been confirmed for the horse since sequence analysis of the major part of the single MC1R exon
revealed a missense mutation showing a complete association with the chestnut color; 114 chestnut horses representing 12 different breeds
were all homozygous for this mutation (Marklund et al. 1996, Mammalian Genome, in press).