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- Imsland, Freyja, et al.
(författare)
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Regulatory mutations in TBX3 disrupt asymmetric hair pigmentation underlying Dun camouflage colour in horses
- 2016
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 48:2, s. 152-158
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Tidskriftsartikel (refereegranskat)abstract
- Dun is a wild-type coat color in horses characterized by pigment dilution with a striking pattern of dark areas termed primitive markings. Here we show that pigment dilution in Dun horses is due to radially asymmetric deposition of pigment in the growing hair caused by localized expression of the T-box 3 (TBX3) transcription factor in hair follicles, which in turn determines the distribution of hair follicle melanocytes. Most domestic horses are non-dun, a more intensely pigmented phenotype caused by regulatory mutations impairing TBX3 expression in the hair follicle, resulting in a more circumferential distribution of melanocytes and pigment granules in individual hairs. We identified two different alleles (non-dun1 and non-dun2) causing non-dun color. non-dun2 is a recently derived allele, whereas the Dun and non-dun1 alleles are found in ancient horse DNA, demonstrating that this polymorphism predates horse domestication. These findings uncover a new developmental role for T-box genes and new aspects of hair follicle biology and pigmentation.
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| 2. |
- Francois, Liesbeth, et al.
(författare)
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Conformation Traits and Gaits in the Icelandic Horse are Associated with Genetic Variants in Myostatin (MSTN)
- 2016
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Ingår i: Journal of Heredity. - : Oxford University Press (OUP). - 0022-1503 .- 1465-7333. ; 107:5, s. 431-437
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Tidskriftsartikel (refereegranskat)abstract
- Many genes are known to have an influence on conformation and performance traits; however, the role of one gene, Myostatin (MSTN), has been highlighted in recent studies on horses. Myostatin acts as a repressor in the development and regulation of differentiation and proliferative growth of skeletal muscle. Several studies have examined the link between MSTN, conformation, and performance in racing breeds, but no studies have investigated the relationship in Icelandic horses. Icelandic horses, a highly unique breed, are known both for their robust and compact conformation as well as their additional gaits tolt and pace. Three SNPs (g.65868604G>T [PR8604], g.66493737C>T [PR3737], and g.66495826A>G [PR5826]) flanking or within equine MSTN were genotyped in 195 Icelandic horses. The SNPs and haplotypes were analyzed for association with official estimated breeding values (EBV) for conformation traits (n = 11) and gaits (n = 5). The EBV for neck, withers, and shoulders was significantly associated with both PR8604 and PR3737 (P < 0.05). PR8604 was also associated with EBV for total conformation (P = 0.05). These associations were all supported by the haplotype analysis. However, while SNP PR5826 showed a significant association with EBVs for leg stance and hooves (P < 0.05), haplotype analyses for these traits failed to fully support these associations. This study demonstrates the possible role of MSTN on both the form and function of horses from non-racing breeds. Further analysis of Icelandic horses as well as other non-racing breeds would be beneficial and likely help to completely understand the influence of MSTN on conformation and performance in horses.
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