MushroomQuick Summary
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Phenotype: Mushroom is a dilute coat color found in Shetland Ponies that results in a distinctive “sepia” toned coat color, often accompanied by a flaxen mane and tail.
Mode of Inheritance: Autosomal recessive
Alleles: N = Normal or non-mushroom, Mu = Mushroom
Breeds appropriate for testing: Shetland Pony, Miniature Horse
Explanation of Results:
- Ponies with N/N genotype will not have this mushroom dilution and cannot transmit this mushroom dilution variant to their offspring.
- Ponies with Mu/N genotype will not have this mushroom dilution, but are carriers. They may transmit this mushroom variant to 50% of their offspring. Matings between two carriers result in a 25% chance of producing a mushroom foal.
- Ponies with Mu/Mu genotype will show a dilute coat color on a red background, and will transmit this mushroom dilution variant to all of their offspring. Matings with other Mu/Mu genotype ponies are expected to produce all mushroom offspring.
Shetland Pony Coat Color Panel
$100 per animal
Sample Collection
Horse DNA tests are carried out using cells from the roots of a hair sample (roughly 20-30 hairs).
1. Grab about 10 hairs at the base.
2. Wrap the hairs around your finger and give it a quick pull.
3. Check the ends to make sure the pulled hairs have roots.
4. Repeat the process until you have collected about 20-30 hairs with intact roots.
5. You can choose different places on the mane or tail. NOTE: For foals, we recommend pulling all hairs from the tail only.
6. Tape the hairs to the submission form and fold the form along the dotted line to protect the sample. Do not use ziploc bags as they can cause condensation that allows mold to grow on the hair.
7. Place the folded form containing the sample in a paper envelope and mail it to the laboratory.
Mushroom is a dilute coat color found in Shetland Ponies that is characterized by a distinctive sepia-toned body hair color, often accompanied by a flaxen mane and tail. The mushroom phenotype shows wide variation in shade and has similarities to cream and silver dilutions, although it is genetically distinct from both. Mushroom dilutes red pigment (phaeomelanin) and thus the dilute phenotype is most obvious on a chestnut base color.
Researchers at the Veterinary Genetics Laboratory and the University of Bern investigated the molecular basis of mushroom color dilution and identified a single nucleotide change in a pigmentation gene that explains this phenotype. Pedigree analysis suggests an autosomal recessive mode of inheritance for mushroom dilution. This means that the phenotype occurs in both males and females but only chestnut ponies with two copies of the mushroom variant have the characteristic mushroom dilute phenotype. Recent work at the Veterinary Genetics Laboratory suggests that bay horses homozygous for the mushroom variant may also have altered pigmentation in the coat. The mushroom mutation is present at a low frequency in Miniature Horses.
Testing for mushroom color dilution helps owners make breeding decisions. If the mushroom phenotype is desired, it is advisable to breed mushroom ponies to each other (e/e, Mu/Mu genotypes). Mating of two chestnut mushroom carriers (e/e, Mu/N genotypes) will result in a 25% chance of producing a mushroom pony. Testing for Mushroom and other coat color genes at the VGL (Agouti, Red Factor, Silver, Dun, Cream) will help owners to distinguish mushroom ponies from similar phenotypes caused by other genes.