A chromosome inversion near the &lt;i&gt;KIT&lt;/i&gt; gene and the Tobiano spotting pattern in horses

Brooks, Samantha A.; Lear, Teri L.; Adelson, David L.; Bailey, E.

doi:10.1159/000112065

Cited by 98 publications

(102 citation statements)

References 47 publications

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“…The genetic mechanisms involved in several different variations of coloration and patterning in horses have been reported, including chestnut, frame overo, cream, black, silver dapple, sabino-1 spotting, tobiano spotting, and dominant white spotting (Marklund et al 1996;Metallinos et al 1998;Mariat et al 2003;Rieder et al 2001;Brooks and Bailey 2005;Brunberg et al 2006;Brooks et al 2007;Haase et al 2007). The mechanism behind appaloosa spotting, a popular coat pattern occurring in several breeds of horses, remains to be elucidated.…”

mentioning

confidence: 99%

Differential Gene Expression of TRPM1, the Potential Cause of Congenital Stationary Night Blindness and Coat Spotting Patterns (LP) in the Appaloosa Horse (Equus caballus)

Bellone

Brooks

Sandmeyer³

et al. 2008

Genetics

153

156

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The appaloosa coat spotting pattern in horses is caused by a single incomplete dominant gene (LP). Homozygosity for LP (LP/LP) is directly associated with congenital stationary night blindness (CSNB) in Appaloosa horses. LP maps to a 6-cM region on ECA1. We investigated the relative expression of two functional candidate genes located in this LP candidate region (TRPM1 and OCA2), as well as three other linked loci (TJP1, MTMR10, and OTUD7A) by quantitative real-time RT-PCR. No large differences were found for expression levels of TJP1, MTMR10, OTUD7A, and OCA2. However, TRPM1 (Transient Receptor Potential Cation Channel, Subfamily M, Member 1) expression in the retina of homozygous appaloosa horses was 0.05% the level found in non-appaloosa horses (R ¼ 0.0005). This constitutes a .1800-fold change (FC) decrease in TRPM1 gene expression in the retina (FC ¼ À1870.637, P ¼ 0.001) of CSNB-affected (LP/LP) horses. TRPM1 was also downregulated in LP/LP pigmented skin (R ¼ 0.005, FC ¼ À193.963, P ¼ 0.001) and in LP/LP unpigmented skin (R ¼ 0.003, FC ¼ À288.686, P ¼ 0.001) and was downregulated to a lesser extent in LP/lp unpigmented skin (R ¼ 0.027, FC ¼ À36.583, P ¼ 0.001). TRP proteins are thought to have a role in controlling intracellular Ca 21 concentration. Decreased expression of TRPM1 in the eye and the skin may alter bipolar cell signaling as well as melanocyte function, thus causing both CSNB and LP in horses.

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confidence: 99%

Differential Gene Expression of TRPM1, the Potential Cause of Congenital Stationary Night Blindness and Coat Spotting Patterns (LP) in the Appaloosa Horse (Equus caballus)

Bellone

Brooks

Sandmeyer³

et al. 2008

Genetics

153

156

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“…To identify the To gene, DNA was extracted from the roots of mane hairs and tested in the Animal Genetics Laboratory (Truro, Cornwall, UK). In the To test, the chromosomal inversion downstream the KIT gene on ECA3 was analyzed according to Brooks et al (2007). The ratio of non-tobiano (solid-coloured), crypto-tobiano, and tobiano foals born from 36 matings of the studied horses was considered on the basis of data provided by the Polish Horse Breeders Association.…”

Section: Methodsmentioning

confidence: 99%

“…The latest investigation showed a chromosomal inversion on ECA3. One of the inversion breakpoints is approximately 70 kb downstream of the KIT gene (Brooks et al 2007;Rieder 2009). Studies on 204 German horses provided evidence of the inversion being the causative mutation for the tobiano spotting pattern (Haase et al 2008).…”

Section: Introductionmentioning

confidence: 99%

“…The ASIP locus was mapped to ECA22q15 (Rieder et al 2001). The MC1R locus was mapped to ECA3p12 in a group linked with the KIT locus (Marklund et al 1996;Brooks et al 2007;Haase et al 2009a), in the above-mentioned region important for the melanogenesis in horses. Molecular studies performed by Rieder et al (2008) showed a putative major locus mapped to ECA3q at or near the KIT locus.…”

Section: Introductionmentioning

confidence: 99%

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Crypto-tobiano horses in Hucul breed

Stachurska¹,

Jansen²

2015

Czech J. Anim. Sci.

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ABSTRACT:The aim of the study was to verify the hypothesis that the crypto-tobiano horses which do not exhibit the full tobiano white-spotting pattern nonetheless transmit the dominant To gene to the progeny. The study was conducted on the Hucul population. Seven horses with white patches on their limbs, and with or without a small patch on the head, neck or trunk, were selected. At least one of the parents of the horses had to be tobiano or crypto-tobiano. Occasionally such horses produced a tobiano foal from a crossing with a solidcoloured horse. The white patches of the horses used in our study were divided into categories. To identify the To gene, DNA was tested in the Animal Genetics Laboratory (UK). The ratio of non-tobiano, crypto-tobiano, and tobiano foals born from 36 matings of the studied horses was analyzed. The study substantiates the occurrence of crypto-tobiano horses in the Hucul breed. Horses that have patches on their limbs as well as a small white or intermingled patch on the head, neck or trunk, are crypto-tobianos, although crypto-tobianos may have no white on the head, neck, and trunk. The crypto-tobiano pattern occurs in horses which have a tobiano parent or grandparent. The results suggest that the activity of an inhibitor gene suppresses the To allele penetrance in the crypto-tobiano horses. As in the case of many white-spotting patterns, the presence of the To gene in a horse's genotype should be documented by DNA testing or test matings.

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“…DUN (D) locus is mapped to a group of microsatellites on ECA8 (Bricker et al, 2003;Rieder, 2009 (Brooks et al, 2007;Haase et al, 2008Haase et al, , 2009. The tobiano pattern is inherited as a completely dominant trait and can appear in each colour, e.g.…”

Section: Methodsmentioning

confidence: 99%

Allele frequency in loci which control coat colours in Hucul horse population

Stachurska¹,

Brodacki²,

Grabowska³

2012

CZECH J ANIM SCI

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The objective of the study was to determine the frequency of alleles which produce coat colours in Hucul horse population in Poland. The breed is included in the Global Strategy for Management of Farm Animal Genetic Resources, hence its gene pool should remain in unaltered state. Huculs are bay, black, blue dun, yellow dun, tobiano, and chestnut. Grey and chestnut Huculs have always been undesirable. The material consisted of all 1022 matings which resulted in subpopulations recorded in Studbook volumes. The recessive allele frequency was estimated as the square root of recessive genotype frequencies in ASIP (A), MC1R (E), DUN (D), KIT (To region), and STX17 (G) loci. The frequency in A and E loci in total parental generation was also estimated in test matings. Genotype distribution in the population was anticipated according to gamete frequency in sires and dams. Small Wahlund effect, F<sub>ST</sub>and χ<sup>2</sup> values for allele distributions show that division into subpopulations did not influence the population genetic structure significantly. Mean recessive allele frequency in A, E, D, To, and G loci amounted to 0.521, 0.115, 0.878, 0.929, and 0.997, respectively, and in A and E loci it was similar to that assessed in test matings. More bay horses and fewer D diluted horses appeared in offspring than expected. A, e, d, and To allele frequency showed a rising tendency. The genetic structure in Hucul population is not constant and does not comply strictly with the preservation aim. Bay, non-diluted, and tobiano horses are preferred. The linkage between MC1R and KIT loci can make the selection against e allele difficult. Breeders’ preferences may lead to undesired changes in the allele frequency. To avoid such risk, it is recommended to select horses strictly complying with the rules included in the breeding programme and mate the horses randomly from this aspect.  

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A chromosome inversion near the <i>KIT</i> gene and the Tobiano spotting pattern in horses

Cited by 98 publications

References 47 publications

Differential Gene Expression of TRPM1, the Potential Cause of Congenital Stationary Night Blindness and Coat Spotting Patterns (LP) in the Appaloosa Horse (Equus caballus)

Differential Gene Expression of TRPM1, the Potential Cause of Congenital Stationary Night Blindness and Coat Spotting Patterns (LP) in the Appaloosa Horse (Equus caballus)

Crypto-tobiano horses in Hucul breed

Allele frequency in loci which control coat colours in Hucul horse population

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