A missense mutation in PMEL17 is associated with the Silver coat color in the horse.
Abstract: The Silver coat color, also called Silver dapple, in the horse is characterized by dilution of the black pigment in the hair. This phenotype shows an autosomal dominant inheritance. The effect of the mutation is most visible in the long hairs of the mane and tail, which are diluted to a mixture of white and gray hairs. Herein we describe the identification of the responsible gene and a missense mutation associated with the Silver phenotype. Results: Segregation data on the Silver locus (Z) were obtained within one half-sib family that consisted of a heterozygous Silver colored stallion with 34 offspring and their 29 non-Silver dams. We typed 41 genetic markers well spread over the horse genome, including one single microsatellite marker (TKY284) close to the candidate gene PMEL17 on horse chromosome 6 (ECA6q23). Significant linkage was found between the Silver phenotype and TKY284 (theta = 0, z = 9.0). DNA sequencing of PMEL17 in Silver and non-Silver horses revealed a missense mutation in exon 11 changing the second amino acid in the cytoplasmic region from arginine to cysteine (Arg618Cys). This mutation showed complete association with the Silver phenotype across multiple horse breeds, and was not found among non-Silver horses with one clear exception; a chestnut colored individual that had several Silver offspring when mated to different non-Silver stallions also carried the exon 11 mutation. In total, 64 Silver horses from six breeds and 85 non-Silver horses from 14 breeds were tested for the exon 11 mutation. One additional mutation located in intron 9, only 759 bases from the missense mutation, also showed complete association with the Silver phenotype. However, as one could expect to find several non-causative mutations completely associated with the Silver mutation, we argue that the missense mutation is more likely to be causative. Conclusions: The present study shows that PMEL17 causes the Silver coat color in the horse and enable genetic testing for this trait.
Publication Date: 2006-10-09 PubMed ID: 17029645PubMed Central: PMC1617113DOI: 10.1186/1471-2156-7-46Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research explored the genetic causes of a horse coat color called Silver, or Silver dapple, and identified a change in a particular gene, PMEL17, as responsible. The mutation alters black pigment in the horse’s hair, particularly noticeable in the long hairs of the mane and tail, turning them to a mixture of white and gray. The research also included the development of a genetic test for this trait.
Research Methodology
- The study gathered genetic data from one half-sib family – this means a family in which all members share one parent in common. In this case, the family consisted of a heterozygous Silver colored stallion, their 34 offspring, and their mothers who were not Silver.
- 41 genetic markers were studied. These markers were well spread over the horse’s genome, and included one marker close to the PMEL17 gene on horse chromosome 6, which was the gene of interest.
- Statistically significant linkage was found between the Silver color and the marker close to the PMEL17 gene.
Findings
- DNA sequencing of the PMEL17 gene in Silver and non-Silver horses showed a missense mutation. This type of mutation changes one DNA base pair, which alters the genetic code and produces a different amino acid. A specific mutation (Arg618Cys) was associated with the Silver phenotype across multiple horse breeds, meaning all Silver horses tested had this mutation.
- One exception to this was a chestnut colored horse, which had the mutation and several Silver offspring.
- An additional mutation was found in intron 9 of the same gene, which also showed complete association with the Silver phenotype. Despite this, the authors argue that the missense mutation in exon 11 is most likely the causative mutation.
Conclusion
- The research concludes that the cause of the Silver coat color in horses is a missense mutation in PMEL17, and that this result allows for genetic testing to detect the Silver coat color trait in horses.
Cite This Article
APA
Brunberg E, Andersson L, Cothran G, Sandberg K, Mikko S, Lindgren G.
(2006).
A missense mutation in PMEL17 is associated with the Silver coat color in the horse.
BMC Genet, 7, 46.
https://doi.org/10.1186/1471-2156-7-46 Publication
Researcher Affiliations
- Dept of Medical Biochemistry and Microbiology, Uppsala University, SE-751 24 Uppsala, Sweden. a1emmbru@stud.slu.se
MeSH Terms
- Amino Acid Sequence
- Animals
- Chromosome Mapping
- Chromosomes, Mammalian / genetics
- Cloning, Molecular
- Female
- Genotype
- Hair Color / genetics
- Horses / genetics
- Male
- Membrane Glycoproteins / genetics
- Molecular Sequence Data
- Mutation, Missense / genetics
- Phenotype
- Polymorphism, Genetic / genetics
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Skin Pigmentation / genetics
- gp100 Melanoma Antigen
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