1
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McFadden A, Vierra M, Martin K, Brooks SA, Everts RE, Lafayette C. Spotting the Pattern: A Review on White Coat Color in the Domestic Horse. Animals (Basel) 2024; 14:451. [PMID: 38338094 PMCID: PMC10854722 DOI: 10.3390/ani14030451] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/12/2024] Open
Abstract
Traits such as shape, size, and color often influence the economic and sentimental value of a horse. Around the world, horses are bred and prized for the colors and markings that make their unique coat patterns stand out from the crowd. The underlying genetic mechanisms determining the color of a horse's coat can vary greatly in their complexity. For example, only two genetic markers are used to determine a horse's base coat color, whereas over 50 genetic variations have been discovered to cause white patterning in horses. Some of these white-causing mutations are benign and beautiful, while others have a notable impact on horse health. Negative effects range from slightly more innocuous defects, like deafness, to more pernicious defects, such as the lethal developmental defect incurred when a horse inherits two copies of the Lethal White Overo allele. In this review, we explore, in detail, the etiology of white spotting and its overall effect on the domestic horse to Spot the Pattern of these beautiful (and sometimes dangerous) white mutations.
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Affiliation(s)
- Aiden McFadden
- Etalon Inc., Menlo Park, CA 94025, USA; (M.V.); (K.M.); (R.E.E.); (C.L.)
| | - Micaela Vierra
- Etalon Inc., Menlo Park, CA 94025, USA; (M.V.); (K.M.); (R.E.E.); (C.L.)
| | - Katie Martin
- Etalon Inc., Menlo Park, CA 94025, USA; (M.V.); (K.M.); (R.E.E.); (C.L.)
| | - Samantha A. Brooks
- Department of Animal Sciences, UF Genetics Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Robin E. Everts
- Etalon Inc., Menlo Park, CA 94025, USA; (M.V.); (K.M.); (R.E.E.); (C.L.)
| | - Christa Lafayette
- Etalon Inc., Menlo Park, CA 94025, USA; (M.V.); (K.M.); (R.E.E.); (C.L.)
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2
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McFadden A, Martin K, Foster G, Vierra M, Lundquist EW, Everts RE, Martin E, Volz E, McLoone K, Brooks SA, Lafayette C. 5'UTR Variant in KIT Associated with White Spotting in Horses. J Equine Vet Sci 2023:104563. [PMID: 37182614 DOI: 10.1016/j.jevs.2023.104563] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/10/2023] [Accepted: 05/10/2023] [Indexed: 05/16/2023]
Abstract
Mutations in KIT, a gene that influences melanoblast migration and pigmentation, often result in mammalian white spotting. As of February 2023, over 30 KIT variants associated with white spotting were documented in Equus caballus (horse). Here we report an association of increased white spotting on the skin and coat with a variant in the 5'UTR of KIT (rs1149701677: g.79,618,649A>C). Horses possessing at least one alternate allele demonstrate phenotypic characteristics similar to other KIT mutations: clear borders around unpigmented regions on the body, face, and limbs. Using a quantitative measure of depigmentation, we observed an average white score of 10.70 among individuals with rs1149701677, while the average score of the control, homozygous reference sample was 2.23 (p=1.892e-11, n=109, t-test). The rs1149701677 site has a cross-species conservation score of 3.4, one of the highest scores across the KIT 5'UTR, implying regulatory importance for this site. Ensembl also predicted a "moderately impactful" functional effect for the rs1149701677 variant. We propose that this single nucleotide variant likely alters the regulation of KIT, which in turn may disrupt melanoblast migration causing an increase in white spotting on the coat. Alternatively, the rs1149701677 variant may be in linkage with another nearby variant with an as-yet-undiscovered functional impact. We propose to term this new allele "Holiday White" or W35 based on conventional nomenclature.
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Affiliation(s)
| | | | | | | | | | | | | | - Erin Volz
- Etalon Inc, Menlo Park, CA 94025, USA
| | | | - Samantha A Brooks
- Department of Animal Sciences, UF Genetics Institute University of Florida, Gainesville, FL 32611-0910, USA
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3
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Patterson Rosa L, Martin K, Vierra M, Lundquist E, Foster G, Brooks SA, Lafayette C. A KIT Variant Associated with Increased White Spotting Epistatic to MC1R Genotype in Horses ( Equus caballus). Animals (Basel) 2022; 12:ani12151958. [PMID: 35953947 PMCID: PMC9367399 DOI: 10.3390/ani12151958] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/19/2022] [Accepted: 08/01/2022] [Indexed: 11/16/2022] Open
Abstract
Over 40 identified genetic variants contribute to white spotting in the horse. White markings and spotting are under selection for their impact on the economic value of an equine, yet many phenotypes have an unknown genetic basis. Previous studies also demonstrate an interaction between MC1R and ASIP pigmentation loci and white spotting associated with KIT and MITF. We investigated two stallions presenting with a white spotting phenotype of unknown cause. Exon sequencing of the KIT and MITF candidate genes identified a missense variant in KIT (rs1140732842, NC_009146.3:g.79566881T>C, p.T391A) predicted by SIFT and PROVEAN as not tolerated/deleterious. Three independent observers generated an Average Grade of White (AGW) phenotype score for 147 individuals based on photographs. The KIT variant demonstrates a significant QTL association to AGW (p = 3.3 × 10−12). Association with the MC1R Extension locus demonstrated that, although not in LD, MC1R e/e (chestnut) individuals had higher AGW scores than MC1R E/- individuals (p = 3.09 × 10−17). We also report complete linkage of the previously reported KIT W19 allele to this missense variant. We propose to term this variant W34, following the standardized nomenclature for white spotting variants within the equine KIT gene, and report its epistatic interaction with MC1R.
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Affiliation(s)
- Laura Patterson Rosa
- Etalon, Inc., Menlo Park, CA 94025, USA; (K.M.); (M.V.); (E.L.); (G.F.)
- Correspondence: (L.P.R.); (C.L.); Tel.: +1-650-380-2995 (C.L.)
| | - Katie Martin
- Etalon, Inc., Menlo Park, CA 94025, USA; (K.M.); (M.V.); (E.L.); (G.F.)
| | - Micaela Vierra
- Etalon, Inc., Menlo Park, CA 94025, USA; (K.M.); (M.V.); (E.L.); (G.F.)
| | - Erica Lundquist
- Etalon, Inc., Menlo Park, CA 94025, USA; (K.M.); (M.V.); (E.L.); (G.F.)
| | - Gabriel Foster
- Etalon, Inc., Menlo Park, CA 94025, USA; (K.M.); (M.V.); (E.L.); (G.F.)
| | - Samantha A. Brooks
- Department of Animal Science, UF Genetics Institute, University of Florida, Gainesville, FL 32610, USA;
| | - Christa Lafayette
- Etalon, Inc., Menlo Park, CA 94025, USA; (K.M.); (M.V.); (E.L.); (G.F.)
- Correspondence: (L.P.R.); (C.L.); Tel.: +1-650-380-2995 (C.L.)
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4
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Patterson Rosa L, Martin K, Vierra M, Foster G, Brooks SA, Lafayette C. Non-frameshift deletion on MITF is associated with a novel splashed white spotting pattern in horses (Equus caballus). Anim Genet 2022; 53:538-540. [PMID: 35672910 DOI: 10.1111/age.13225] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | - Samantha A Brooks
- Department of Animal Science, UF Genetics Institute, University of Florida, Gainesville, Florida, USA
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5
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Esdaile E, Till B, Kallenberg A, Fremeux M, Bickel L, Bellone RR. A de novo missense mutation in KIT is responsible for dominant white spotting phenotype in a Standardbred horse. Anim Genet 2022; 53:534-537. [PMID: 35641888 DOI: 10.1111/age.13222] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 05/04/2022] [Indexed: 12/31/2022]
Affiliation(s)
- Elizabeth Esdaile
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Brad Till
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Angelica Kallenberg
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Michelle Fremeux
- InfogeneNZ, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand
| | - Leslie Bickel
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Rebecca R Bellone
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.,Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA
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6
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Identification of W13 in the American Miniature Horse and Shetland Pony Populations. Genes (Basel) 2021; 12:genes12121985. [PMID: 34946933 PMCID: PMC8702037 DOI: 10.3390/genes12121985] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/07/2021] [Accepted: 12/11/2021] [Indexed: 11/16/2022] Open
Abstract
Coat color is a trait of economic significance in horses. Variants in seven genes have been documented to cause white patterning in horses. Of the 34 variants that have been identified in KIT proto-oncogene, receptor tyrosine kinase (KIT), 27 have only been reported in a single individual or family and thus not all are routinely offered for genetic testing. Therefore, to enable proper use of marker-assisted selection, determining breed specificity for these alleles is warranted. Screening 19 unregistered all-white Shetland ponies for 16 white patterning markers identified 14 individuals whose phenotype could not be explained by testing results. In evaluating other known dominant white variants, 14 horses were heterozygous for W13. W13 was previously only reported in two quarter horses and a family of Australian miniature horses. Genotyping known white spotting variants in 30 owner-reported white animals (25 Miniature Horses and five Shetland ponies) identified two additional W13/N American Miniature Horses. The estimated allele frequency of W13 in the American Miniature Horse was 0.0063 (79 N/N, 1 W13/N) and the allele was not detected in a random sample (n = 59) of Shetland ponies. No homozygous W13 individuals were identified and W13/N ponies had a similar all-white coat with pink skin phenotype, regardless of the other white spotting variants present, demonstrating that W13 results in a Mendelian inherited dominant white phenotype and homozygosity is likely lethal. These findings document the presence of W13 in the American Miniature Horse and Shetland pony populations at a low frequency and illustrate the importance of testing for this variant in additional breeds.
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7
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Patterson Rosa L, Martin K, Vierra M, Foster G, Lundquist E, Brooks SA, Lafayette C. Two Variants of KIT Causing White Patterning in Stock-Type Horses. J Hered 2021; 112:447-451. [PMID: 34223905 DOI: 10.1093/jhered/esab033] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 11/13/2022] Open
Abstract
Over 30 polymorphisms in the KIT Proto-Oncogene Receptor Tyrosine Kinase (KIT) gene have been implicated in white spotting patterns ranging from small areas to full dermal depigmentation in the horse. We performed a candidate-gene exon sequencing approach on KIT and MITF, 2 known causatives of white spotting patterns, within 2 families of horses of unknown white spotting. Family 1 (Fam1, N = 5) consisted of a Quarter Horse stallion and 4 offspring with white spotting pattern ranging from legs, lower ventral, and head regions with jagged borders, to almost complete white. The second family (Fam2, N = 7) consisted of 6 half-sibling American Paint Horse/Quarter Horse and their dam, demonstrating unpigmented limbs with belly spots and an extensive white patterning on the face. This approach resulted in 2 variants significantly associated with familial phenotypes, where Fam1 variant is an indel leading to a frameshift mutation, and Fam2 a non-synonymous SNP. We validated the variants within an unrelated population of horses (Fam2 variant, P = 0.00271944) as well as for protein functional impact with ExPASy, Protter, Phyre2, SMART, PROVEAN, SIFT, and I-TASSER, confirming the reported associations. Fam1 associated variant, deemed W31, alters the protein sequence, leading to an early stop codon truncating the normal amino acid sequence from 972 to just 115 amino acids. Fam2 associated variant, deemed W32, may have a subtle impact on receptor function or could be in linkage with a non-coding or regulatory change creating the mild spotting pattern observed in this family.
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Affiliation(s)
| | | | | | | | | | - Samantha A Brooks
- Department of Animal Science, UF Genetics Institute, University of Florida, Gainesville, FL 32610, USA
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8
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Martin K, Patterson Rosa L, Vierra M, Foster G, Brooks SA, Lafayette C. De novo mutation of KIT causes extensive coat white patterning in a family of Berber horses. Anim Genet 2020; 52:135-137. [PMID: 33111383 DOI: 10.1111/age.13017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2020] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | - Samantha A Brooks
- Department of Animal Science, UF Genetics Institute, University of Florida, Gainesville, FL, 32610, USA
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9
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Grilz-Seger G, Reiter S, Neuditschko M, Wallner B, Rieder S, Leeb T, Jagannathan V, Mesarič M, Cotman M, Pausch H, Lindgren G, Velie B, Horna M, Brem G, Druml T. A Genome-Wide Association Analysis in Noriker Horses Identifies a SNP Associated With Roan Coat Color. J Equine Vet Sci 2020; 88:102950. [PMID: 32303326 DOI: 10.1016/j.jevs.2020.102950] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/28/2020] [Accepted: 01/28/2020] [Indexed: 01/20/2023]
Abstract
The roan coat color in horses is characterized by dispersed white hair and dark points. This phenotype segregates in a broad range of horse breeds, while the underlying genetic background is still unknown. Previous studies mapped the roan locus to the KIT gene on equine chromosome 3 (ECA3). However, this association could not be validated across different horse breeds. Performing a genome-wide association analysis (GWAS) in Noriker horses, we identified a single nucleotide polymorphism (SNP) (ECA3:g.79,543.439 A > G) in the intron 17 of the KIT gene. The G -allele of the top associated SNP was present in other roan horses, namely Quarter Horse, Murgese, Slovenian, and Belgian draught horse, while it was absent in a panel of 15 breeds, including 657 non-roan horses. In further 379 gray Lipizzan horses, eight animals exhibited a heterozygous genotype (A/G). Comparative whole-genome sequence analysis of the KIT region revealed two deletions in the downstream region (ECA3:79,533,217_79,533,224delTCGTCTTC; ECA3:79,533,282_79,533,285delTTCT) and a 3 bp deletion combined with 17 bp insertion in intron 20 of KIT (ECA3:79,588,128_79,588,130delinsTTATCTCTATAGTAGTT). Within the Noriker sample, these loci were in complete linkage disequilibrium (LD) with the identified top SNP. Based upon pedigree information and historical records, we were able to trace back the genetic origin of roan coat color to a baroque gene pool. Furthermore, our data suggest allelic heterogeneity and the existence of additional roan alleles in ponies and breeds related to the English Thoroughbred. In order to study the roan phenotype segregating in those breeds, further association and verification studies are required.
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Affiliation(s)
- Gertrud Grilz-Seger
- Department of Animal Breeding and Genetics, University of Veterinary Sciences Vienna, Vienna, Austria.
| | - Simone Reiter
- Department of Animal Breeding and Genetics, University of Veterinary Sciences Vienna, Vienna, Austria
| | | | - Barbara Wallner
- Department of Animal Breeding and Genetics, University of Veterinary Sciences Vienna, Vienna, Austria
| | | | - Tosso Leeb
- Department of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Vidhya Jagannathan
- Department of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Matjaz Mesarič
- Clinic for Reproduction and Large Animals, University of Ljubljana, Veterinary Faculty, Ljubljana, Slovenia
| | - Markus Cotman
- Department for Preclinical Sciences, University of Ljubljana, Veterinary Faculty, Ljubljana, Slovenia
| | | | - Gabriella Lindgren
- Department of Animal Breeding & Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden; Livestock Genetics, Department of Biosystems, KU Leuven, Leuven, Belgium
| | - Brandon Velie
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Michaela Horna
- Department of Animal Husbandry, Slovak University of Agriculture in Nitra, Nitra, Slovakia
| | - Gottfried Brem
- Department of Animal Breeding and Genetics, University of Veterinary Sciences Vienna, Vienna, Austria
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10
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Genetic heterogeneity of white markings in Quarter Horses. Livest Sci 2020. [DOI: 10.1016/j.livsci.2020.103935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Hug P, Jude R, Henkel J, Jagannathan V, Leeb T. A novel
KIT
deletion variant in a German Riding Pony with white‐spotting coat colour phenotype. Anim Genet 2019; 50:761-763. [DOI: 10.1111/age.12840] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2019] [Indexed: 11/28/2022]
Affiliation(s)
- P. Hug
- Institute of Genetics, Vetsuisse Faculty University of Bern Bern 3001 Switzerland
- DermFocus University of Bern Bern 3001 Switzerland
| | - R. Jude
- RJC Weilerswist 53919 Germany
| | - J. Henkel
- Institute of Genetics, Vetsuisse Faculty University of Bern Bern 3001 Switzerland
- DermFocus University of Bern Bern 3001 Switzerland
| | - V. Jagannathan
- Institute of Genetics, Vetsuisse Faculty University of Bern Bern 3001 Switzerland
- DermFocus University of Bern Bern 3001 Switzerland
| | - T. Leeb
- Institute of Genetics, Vetsuisse Faculty University of Bern Bern 3001 Switzerland
- DermFocus University of Bern Bern 3001 Switzerland
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12
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Shang S, Yu Y, Zhao Y, Dang W, Zhang J, Qin X, Irwin DM, Wang Q, Liu F, Wang Z, Zhang S, Wang Z. Synergy between MC1R and ASIP for coat color in horses (Equus caballus)1. J Anim Sci 2019; 97:1578-1585. [PMID: 30785190 DOI: 10.1093/jas/skz071] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 02/13/2019] [Indexed: 11/13/2022] Open
Abstract
Through domestication and human selection, horses have acquired various coat colors, including seven phenotypes: black, brown, dark bay, bay, chestnut, white, and gray. Here we determined the genotypes for melanocortin-1 receptor (MC1R) and agouti signaling protein (ASIP) in 709 horses from 15 breeds. We found that the EEEE genotype frequency at MC1R decreased from dark to light colors (black = 64.5%, brown = 67.5%, dark bay = 47.0%, bay = 16.5%, and chestnut = 0.0%), whereas the AAAA genotype frequency at ASIP increased as coat color lightened (black = 0.0%, brown = 22.9%, dark bay = 69.2%, and bay = 83.0%). When combined genotypes at MC1R and ASIP were examined, different advantage genotype combinations were found for each color: black EEEE-AaAa (64.5%), brown EEEE-AAAa (47.0%), dark bay EEEE-AAAA, and EEEe-AAAA (36.2% and 33.0%, totally 69.2%), bay EEEe-AAAA (69.6%), and chestnut EeEe-AAAA (62.6%). The χ2 test showed that the phenotypes of horse coat colors were significantly related with the genotypes of MC1R and ASIP (p < 0.001). Furthermore, in contrast to a previous study where AaAa was only found in black, chestnut, and gray horses, we also found this allele in brown, dark bay, bay, and white horses. These results indicated that MC1R and ASIP may synergistically affect the levels of melanin in equine coat colors and that additional genes are likely involved in regulating coat colors, especially for white and gray colors. Our research provides new data for further studies on the synergetic actions of MC1R and ASIP in coat color of horses.
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Affiliation(s)
- Songyang Shang
- Institute of Equine Sciences, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Yan Yu
- Institute of Equine Sciences, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Yuxin Zhao
- Institute of Equine Sciences, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Wanyi Dang
- Institute of Equine Sciences, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Junpeng Zhang
- Institute of Equine Sciences, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Xia Qin
- Institute of Equine Sciences, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - David M Irwin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Qin Wang
- Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Fei Liu
- Shenyang Institute of Animal Husbandry and Veterinary Science, Shenyang, China
| | - Zhenshan Wang
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, China
| | - Shuyi Zhang
- Institute of Equine Sciences, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Zhe Wang
- Institute of Equine Sciences, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
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13
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Henkel J, Lafayette C, Brooks SA, Martin K, Patterson-Rosa L, Cook D, Jagannathan V, Leeb T. Whole-genome sequencing reveals a large deletion in the MITF gene in horses with white spotted coat colour and increased risk of deafness. Anim Genet 2019; 50:172-174. [PMID: 30644113 DOI: 10.1111/age.12762] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2018] [Indexed: 01/18/2023]
Abstract
White spotting phenotypes in horses are highly valued in some breeds. They are quite variable and may range from the common white markings up to completely white horses. EDNRB, KIT, MITF, PAX3 and TRPM1 represent known candidate genes for white spotting phenotypes in horses. For the present study, we investigated an American Paint Horse family segregating a phenotype involving white spotting and blue eyes. Six of eight horses with the white-spotting phenotype were deaf. We obtained whole-genome sequence data from an affected horse and specifically searched for structural variants in the known candidate genes. This analysis revealed a heterozygous ~63-kb deletion spanning exons 6-9 of the MITF gene (chr16:21 503 211-21 566 617). We confirmed the breakpoints of the deletion by PCR and Sanger sequencing. PCR-based genotyping revealed that all eight available affected horses from the family carried the deletion. The finding of an MITF variant fits well with the syndromic phenotype involving both depigmentation and an increased risk for deafness and corresponds to human Waardenburg syndrome type 2A. Our findings will enable more precise genetic testing for depigmentation phenotypes in horses.
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Affiliation(s)
- J Henkel
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland.,DermFocus, University of Bern, 3001, Bern, Switzerland
| | | | - S A Brooks
- Department of Animal Sciences, University of Florida, Gainesville, FL, 32611-0910, USA
| | - K Martin
- Etalon Inc., Menlo Park, CA, 94025, USA
| | - L Patterson-Rosa
- Department of Animal Sciences, University of Florida, Gainesville, FL, 32611-0910, USA
| | - D Cook
- Etalon Inc., Menlo Park, CA, 94025, USA
| | - V Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland.,DermFocus, University of Bern, 3001, Bern, Switzerland
| | - T Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland.,DermFocus, University of Bern, 3001, Bern, Switzerland
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14
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Kumar C, Song S, Dewani P, Kumar M, Parkash O, Ma Y, Malhi KK, Yang N, Mwacharo JM, He X, Jiang L. Population structure, genetic diversity and selection signatures within seven indigenous Pakistani goat populations. Anim Genet 2018; 49:592-604. [PMID: 30229969 DOI: 10.1111/age.12722] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2018] [Indexed: 12/20/2022]
Abstract
Goat farming in Pakistan depends on indigenous breeds that have adapted to specific agro-ecological conditions. Pakistan has a rich resource of goat breeds, and the genetic diversity of these goat breeds is largely unknown. In this study, genetic diversity and population structure were characterized from seven indigenous goat breeds using the goat 50K SNP chip. The genetic diversity analysis showed that Bugi toori goats have the highest inbreeding level, consistent with the highest linkage disequilibrium, lowest diversity and long run of heterozygosity segments. This indicates that this breed should be prioritized in future conservation activities. The population structure analysis revealed four fairly distinct clusters (including Bugi toori, Bari, Black Tapri and some Kamori) and three other breeds that are seemingly the results of admixture between these or related groups (some Kamori, Pateri, Tapri and White Tapri). The selection signatures were evaluated in each breed. A total of 2508 putative selection signals were reported. The 26 significant windows were identified in more than four breeds, and selection signatures spanned several genes that directly or indirectly influence traits included coat colour variation (KIT), reproduction (BMPR1B, GNRHR, INSL6, JAK2 and EGR4), body size (SOCS2), ear size (MSRB3) and milk composition (ABCG2, SPP1, CSN1S2, CSN2, CSN3 and PROLACTIN).
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Affiliation(s)
- C Kumar
- Institute of Animal Science (IAS), Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China.,Directorate of Veterinary Research and Diagnostic Central Veterinary Diagnostic Laboratory, Tando Jam, 70050, Sindh, Pakistan.,Department of Animal Breeding and Genetics, Faculty of Animal Husbandry and Veterinary Sciences, Sindh Agricultural University, Tando Jam, 70060, Sindh, Pakistan
| | - S Song
- Institute of Animal Science (IAS), Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China.,Department of Animal Genetics and Breeding, China Agricultural University, Beijing, 100094, China
| | - P Dewani
- Directorate of Veterinary Research and Diagnostic Central Veterinary Diagnostic Laboratory, Tando Jam, 70050, Sindh, Pakistan
| | - M Kumar
- Department of Animal Breeding and Genetics, Faculty of Animal Husbandry and Veterinary Sciences, Sindh Agricultural University, Tando Jam, 70060, Sindh, Pakistan
| | - O Parkash
- Directorate of Veterinary Research and Diagnostic Central Veterinary Diagnostic Laboratory, Tando Jam, 70050, Sindh, Pakistan
| | - Y Ma
- Institute of Animal Science (IAS), Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China
| | - K K Malhi
- Department of Animal Breeding and Genetics, Faculty of Animal Husbandry and Veterinary Sciences, Sindh Agricultural University, Tando Jam, 70060, Sindh, Pakistan
| | - N Yang
- Department of Animal Genetics and Breeding, China Agricultural University, Beijing, 100094, China
| | - J M Mwacharo
- Small Ruminant Genomics Group, International Center for Agricultural Research in the Dry Areas (ICARDA), P.O. Box 5689, Addis Ababa, Ethiopia
| | - X He
- Institute of Animal Science (IAS), Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China
| | - L Jiang
- Institute of Animal Science (IAS), Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China
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15
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Hoban R, Castle K, Hamilton N, Haase B. Novel KIT variants for dominant white in the Australian horse population. Anim Genet 2018; 49:99-100. [PMID: 29333746 DOI: 10.1111/age.12627] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Rhiarn Hoban
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Kao Castle
- Practical Horse Genetics, Redfern, NSW, 2016, Australia
| | - Natasha Hamilton
- School of Life and Environmental Science, Faculty of Science, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Bianca Haase
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Camperdown, NSW, 2006, Australia
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16
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Holl HM, Brooks SA, Carpenter ML, Bustamante CD, Lafayette C. A novel splice mutation within equine KIT
and the W15
allele in the homozygous state lead to all white coat color phenotypes. Anim Genet 2017; 48:497-498. [DOI: 10.1111/age.12554] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2017] [Indexed: 11/28/2022]
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17
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A Frameshift Mutation in KIT is Associated with White Spotting in the Arabian Camel. Genes (Basel) 2017; 8:genes8030102. [PMID: 28282952 PMCID: PMC5368706 DOI: 10.3390/genes8030102] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/03/2017] [Indexed: 12/04/2022] Open
Abstract
While the typical Arabian camel is characterized by a single colored coat, there are rare populations with white spotting patterns. White spotting coat patterns are found in virtually all domesticated species, but are rare in wild species. Theories suggest that white spotting is linked to the domestication process, and is occasionally associated with health disorders. Though mutations have been found in a diverse array of species, fewer than 30 genes have been associated with spotting patterns, thus providing a key set of candidate genes for the Arabian camel. We obtained 26 spotted camels and 24 solid controls for candidate gene analysis. One spotted and eight solid camels were whole genome sequenced as part of a separate project. The spotted camel was heterozygous for a frameshift deletion in KIT (c.1842delG, named KITW1 for White spotting 1), whereas all other camels were wild-type (KIT+/KIT+). No additional mutations unique to the spotted camel were detected in the EDNRB, EDN3, SOX10, KITLG, PDGFRA, MITF, and PAX3 candidate white spotting genes. Sanger sequencing of the study population identified an additional five KITW1/KIT+ spotted camels. The frameshift results in a premature stop codon five amino acids downstream, thus terminating KIT at the tyrosine kinase domain. An additional 13 spotted camels tested KIT+/KIT+, but due to phenotypic differences when compared to the KITW1/KIT+ camels, they likely represent an independent mutation. Our study suggests that there are at least two causes of white spotting in the Arabian camel, the newly described KITW1 allele and an uncharacterized mutation.
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18
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Dürig N, Jude R, Jagannathan V, Leeb T. A novelMITFvariant in a white American Standardbred foal. Anim Genet 2016; 48:123-124. [PMID: 27592871 DOI: 10.1111/age.12484] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Nicole Dürig
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
- Swiss Competence Center of Animal Breeding and Genetics; University of Bern; Bern University of Applied Sciences HAFL & Agroscope; 3001 Bern Switzerland
| | - Rony Jude
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
- Swiss Competence Center of Animal Breeding and Genetics; University of Bern; Bern University of Applied Sciences HAFL & Agroscope; 3001 Bern Switzerland
- RJC; 53919 Weilerswist Germany
| | - Vidhya Jagannathan
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
- Swiss Competence Center of Animal Breeding and Genetics; University of Bern; Bern University of Applied Sciences HAFL & Agroscope; 3001 Bern Switzerland
| | - Tosso Leeb
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
- Swiss Competence Center of Animal Breeding and Genetics; University of Bern; Bern University of Applied Sciences HAFL & Agroscope; 3001 Bern Switzerland
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19
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Haase B, Jagannathan V, Rieder S, Leeb T. A novelKITvariant in an Icelandic horse with white-spotted coat colour. Anim Genet 2015; 46:466. [DOI: 10.1111/age.12313] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Bianca Haase
- Faculty of Veterinary Science; University of Sydney; Sydney 2006 NSW Australia
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
- Swiss Competence Center of Animal Breeding and Genetics; University of Bern; Bern University of Applied Sciences HAFL & Agroscope; 3001 Bern Switzerland
| | - Vidhya Jagannathan
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
- Swiss Competence Center of Animal Breeding and Genetics; University of Bern; Bern University of Applied Sciences HAFL & Agroscope; 3001 Bern Switzerland
| | - Stefan Rieder
- Swiss Competence Center of Animal Breeding and Genetics; University of Bern; Bern University of Applied Sciences HAFL & Agroscope; 3001 Bern Switzerland
- Agroscope; Swiss National Stud Farm; 1580 Avenches Switzerland
| | - Tosso Leeb
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
- Swiss Competence Center of Animal Breeding and Genetics; University of Bern; Bern University of Applied Sciences HAFL & Agroscope; 3001 Bern Switzerland
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20
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Radke DW, Lee C. Adaptive potential of genomic structural variation in human and mammalian evolution. Brief Funct Genomics 2015; 14:358-68. [PMID: 26003631 DOI: 10.1093/bfgp/elv019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Because phenotypic innovations must be genetically heritable for biological evolution to proceed, it is natural to consider new mutation events as well as standing genetic variation as sources for their birth. Previous research has identified a number of single-nucleotide polymorphisms that underlie a subset of adaptive traits in organisms. However, another well-known class of variation, genomic structural variation, could have even greater potential to produce adaptive phenotypes, due to the variety of possible types of alterations (deletions, insertions, duplications, among others) at different genomic positions and with variable lengths. It is from these dramatic genomic alterations, and selection on their phenotypic consequences, that adaptations leading to biological diversification could be derived. In this review, using studies in humans and other mammals, we highlight examples of how phenotypic variation from structural variants might become adaptive in populations and potentially enable biological diversification. Phenotypic change arising from structural variants will be described according to their immediate effect on organismal metabolic processes, immunological response and physical features. Study of population dynamics of segregating structural variation can therefore provide a window into understanding current and historical biological diversification.
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21
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Hauswirth R, Jude R, Haase B, Bellone RR, Archer S, Holl H, Brooks SA, Tozaki T, Penedo MCT, Rieder S, Leeb T. Novel variants in theKITandPAX3genes in horses with white-spotted coat colour phenotypes. Anim Genet 2013; 44:763-5. [DOI: 10.1111/age.12057] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Regula Hauswirth
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
| | - Rony Jude
- Certagen GmbH; Marie-Curie-Str. 1 53359 Rheinbach Germany
| | - Bianca Haase
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
- Faculty of Veterinary Science; University of Sydney; Sydney 2006 NSW Australia
| | | | | | - Heather Holl
- Department of Animal Science; Cornell University, Ithaca; NY 14853 USA
| | | | - Teruaki Tozaki
- Department of Molecular Genetics; Laboratory of Racing Chemistry; Utsunomiya Tochigi 320-0851 Japan
| | - Maria Cecilia T. Penedo
- Veterinary Genetics Laboratory; School of Veterinary Medicine; University of California-Davis; Davis CA 95616 USA
| | - Stefan Rieder
- Agroscope ALP-Haras; Swiss National Stud Farm; 1580 Avenches Switzerland
| | - Tosso Leeb
- Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
- DermFocus; University of Bern; 3001 Bern Switzerland
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22
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Linderholm A, Larson G. The role of humans in facilitating and sustaining coat colour variation in domestic animals. Semin Cell Dev Biol 2013; 24:587-93. [PMID: 23567209 DOI: 10.1016/j.semcdb.2013.03.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 03/28/2013] [Indexed: 11/27/2022]
Abstract
Though the process of domestication results in a wide variety of novel phenotypic and behavioural traits, coat colour variation is one of the few characteristics that distinguishes all domestic animals from their wild progenitors. A number of recent reviews have discussed and synthesised the hundreds of genes known to underlie specific coat colour patterns in a wide range of domestic animals. This review expands upon those studies by asking how what is known about the causative mutations associated with variable coat colours, can be used to address three specific questions related to the appearance of non wild-type coat colours in domestic animals. Firstly, is it possible that coat colour variation resulted as a by-product of an initial selection for tameness during the early phases of domestication? Secondly, how soon after the process began did domestic animals display coat colour variation? Lastly, what evidence is there that intentional human selection, rather than drift, is primarily responsible for the wide range of modern coat colours? By considering the presence and absence of coat colour genes within the context of the different pathways animals travelled from wild to captive populations, we conclude that coat colour variability was probably not a pleiotropic effect of the selection for tameness, that coat colours most likely appeared very soon after the domestication process began, and that humans have been actively selecting for colour novelty and thus allowing for the proliferation of new mutations in coat colour genes.
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Affiliation(s)
- Anna Linderholm
- Durham Evolution and Ancient DNA, Department of Archaeology, Durham University, Durham, United Kingdom
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23
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Kim NY, Shin KY, Lee CE, Han SH, Lee SS, Park YS, Ko MS, Hong HJ, Yang JH, Jang DJ, Yang YH. Genetic Characterization of Wolla Coat Color in Jeju Horses. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2012. [DOI: 10.5187/jast.2012.54.5.375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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24
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Abstract
During the last decade, coat colouration in mammals has been investigated in numerous studies. Most of these studies addressing the genetics of coat colouration were on domesticated animals. In contrast to their wild ancestors, domesticated species are often characterized by a huge allelic variability of coat-colour-associated genes. This variability results from artificial selection accepting negative pleiotropic effects linked with certain coat-colour variants. Recent studies demonstrate that this selection for coat-colour phenotypes started at the beginning of domestication. Although to date more than 300 genetic loci and more than 150 identified coat-colour-associated genes have been discovered, which influence pigmentation in various ways, the genetic pathways influencing coat colouration are still only poorly described. On the one hand, similar coat colourations observed in different species can be the product of a few conserved genes. On the other hand, different genes can be responsible for highly similar coat colourations in different individuals of a species or in different species. Therefore, any phenotypic classification of coat colouration blurs underlying differences in the genetic basis of colour variants. In this review we focus on (i) the underlying causes that have resulted in the observed increase of colour variation in domesticated animals compared to their wild ancestors, and (ii) the current state of knowledge with regard to the molecular mechanisms of colouration, with a special emphasis on when and where the different coat-colour-associated genes act.
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Affiliation(s)
- Michael Cieslak
- Leibniz Institute for Zoo and Wildlife Research, Research Group of Evolutionary Genetics, Berlin, Germany
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25
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Haase B, Rieder S, Tozaki T, Hasegawa T, Penedo MCT, Jude R, Leeb T. Five novel KIT mutations in horses with white coat colour phenotypes. Anim Genet 2011; 42:337-9. [DOI: 10.1111/j.1365-2052.2011.02173.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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