Discriminant analysis of colour measurements reveals allele dosage effect of ASIP/MC1R in bay horses


https://doi.org/10.17221/105/2017-CJASCitation:Druml T., Grilz-Seger G., Horna M., Brem G. (2018): Discriminant analysis of colour measurements reveals allele dosage effect of ASIP/MC1R in bay horses  . Czech J. Anim. Sci., 63: 347-355.
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Considering the variability of bay coat colour, we aimed to investigate the association of different shades of bay with ASIP and MC1R genotype combinations and we studied the discrimination between the bay and black coat colour. We phenotypically characterized coat colour using a spectrophotometer. The measurements were based upon international standards as defined by the CIE L*a*b* colour system and we phenotyped five different body parts (neck, armpit area, shoulder, belly, croup) of 43 bay and 14 black horses kept under standardized conditions. From the five measuring points a stepwise discriminant analysis revealed that chromacity and luminescence of armpit area and luminescence of the neck were the most important traits to differentiate between black and bay horses, whereas it was shown that the red colour spectrum of neck, luminescence of the neck, and luminescence of the armpit area grouped bay horses according to their ASIP and MC1R genotype combinations. Within the group of bay horses the analyses identified a single ASIP/MC1R genotype combination (A/a E/E) where colour variables differed significantly from the three remaining genotype groups. A/a E/E horses were characterized in all body parts except in the armpit region by significant darker shades (lower luminescence, less chromacity). Regarding classifications of coat colour, we found in the significant cluster of A/a E/E horses the coat colour categories seal brown and dark (mahogany) bay. Overall, we were able to show that the characterization of equine coat colour based upon international standards as defined by the CIE L*a*b* colour system represents a valuable tool for a precise description of colour variation and association analyses.

Curik I., Seltenhammer M., Solkner J. (2002): Quantitative genetic analysis of melanoma and grey level in Lipizzan horses. In: Proc. 7th World Congress on Genetics Applied to Livestock Production, Montpellier, France. (CD-ROM: com. No. 05-09)
Curik Ino, Druml Thomas, Seltenhammer Monika, Sundström Elisabeth, Pielberg Gerli Rosengren, Andersson Leif, Sölkner Johann, Goddard Mike E. (2013): Complex Inheritance of Melanoma and Pigmentation of Coat and Skin in Grey Horses. PLoS Genetics, 9, e1003248-  https://doi.org/10.1371/journal.pgen.1003248
Hurst C. C. (1906): On the Inheritance of Coat Colour in Horses. Proceedings of the Royal Society B: Biological Sciences, 77, 388-394  https://doi.org/10.1098/rspb.1906.0026
Lackner C. (2006): Quantitative approaches in analysing colour traits on the example of the Noriker horse. Thesis, BOKU, Vienna, Austria. (in German)
Marklund L., Moller M. Johansson, Sandberg K., Andersson L. (1996): A missense mutation in the gene for melanocyte-stimulating hormone receptor (MCIR) is associated with the chestnut coat color in horses. Mammalian Genome, 7, 895-899  https://doi.org/10.1007/s003359900264
Munckel H. (1929): Analyses of inheritance of coat colour and white markings in horses. Zeitschrift für Tierzüchtung und Züchtungsbiologie, 16, 1–200. (in German)
Rosengren Pielberg Gerli, Golovko Anna, Sundström Elisabeth, Curik Ino, Lennartsson Johan, Seltenhammer Monika H, Druml Thomas, Binns Matthew, Fitzsimmons Carolyn, Lindgren Gabriella, Sandberg Kaj, Baumung Roswitha, Vetterlein Monika, Strömberg Sara, Grabherr Manfred, Wade Claire, Lindblad-Toh Kerstin, Pontén Fredrik, Heldin Carl-Henrik, Sölkner Johann, Andersson Leif (2008): A cis-acting regulatory mutation causes premature hair graying and susceptibility to melanoma in the horse. Nature Genetics, 40, 1004-1009  https://doi.org/10.1038/ng.185
Reissmann Monika, Musa Lutfi, Zakizadeh Sonia, Ludwig Arne (2016): Distribution of coat-color-associated alleles in the domestic horse population and Przewalski’s horse. Journal of Applied Genetics, 57, 519-525  https://doi.org/10.1007/s13353-016-0352-7
Rieder Stefan, Taourit Sead, Mariat Denis, Langlois Bertrand, Guérin Gérard (2001): Mutations in the agouti (ASIP), the extension (MC1R), and the brown (TYRP1) loci and their association to coat color phenotypes in horses (Equus caballus). Mammalian Genome, 12, 450-455  https://doi.org/10.1007/s003350020017
SAKAMOTO Takahiro, FAWCETT Jeffrey A., INNAN Hideki (2017): Evaluating the potential roles of the <i>Gray</i> and <i>Extension</i> loci in the coat coloration of Thoroughbred racing horses. Journal of Equine Science, 28, 61-65  https://doi.org/10.1294/jes.28.61
Sponenberg D.P. (2009): Equine Color Genetics. Wiley-Blackwell, Hoboken, USA.
Stachurska Anna, Pięta Mirosław, Jaworski Zbigniew, Ussing Anne P., Bruśniak Agnieszka, Florek Mariusz (2004): Colour variation in blue dun Polish Konik and Biłgoraj horses. Livestock Production Science, 90, 201-209  https://doi.org/10.1016/j.livprodsci.2004.04.002
Toth Z., Kaps M., Sölkner J., Bodo I., Curik I. (2006): Quantitative genetic aspects of coat color in horses1. Journal of Animal Science, 84, 2623-2628  https://doi.org/10.2527/jas.2005-704
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