A visual guide to equine colors and patterns

The Mushroom Dilution

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Chestnut with the mushroom dilution (Mayflouwer Ester v.d. Toom, Shetland Pony mare). Photo by Anna Gamsgaard Frederiksen.

 

Bay with the mushroom dilution (Kaitlynn of Duke Stable, Shetland Pony mare). Photo by Anna Gamsgaard Frederiksen.

Silver dilutes the black pigment on the body of the horse to a silvery chocolate color, and turns the mane and tail flaxen. This means that black horses show the effect most strongly. Bay horses have their black legs diluted and flaxen mane and tail, but their red body remains unchanged. Because they do not have black hair to dilute, chestnut horses that have the silver dilution do not show the effect. Because chestnuts with the silver dilution can have self-colored manes and tails, it does not appear that silver alters their manes and tails to flaxen. 

Silver-diluted black can vary in color from a pale taupe to a deep chocolate that approaches black. Seasonal changes are common, with winter coats tending to be paler. As they age, the flaxen manes and tails tend to darken, starting at the roots. Black silvers sometimes show dappling. This is especially vivid when the horse is clipped. Paler silvers sometimes have a dark face mask similar to that seen on dun horses. 

When combined with cream, silver-diluted black pigment tends to lose its cool, silvery tones and look more like milk chocolate. Black silvers with cream, sometimes called silver smokies, often lack the contrast in their manes and tails seen in ordinary black silvers. 

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A pale shade of mushroom (Shady Acres Cute Cupcake, Shetland Pony mare). Photo by Anna Gamsgaard Frederiksen. 

 

A dark shade of mushroom (Zilver Sun v.d. Nijkamphoeve, Shetland Pony mare). Photo by Anna Gamsgaard Frederiksen.

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Silver smoky (black silver cream) - notice the warmer tone compared to the two horses above (Positively Charmed, purebred Morgan)

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A clipped black silver showing vivid dappling with longer coat is visible at the base of the tail (Miniature Horse)

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Bay horse with a silver tail
("Gulastra Plume")

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Sooty chestnut with dark legs and mixed flaxen mane and tail (grade pony)

Silver is caused by a mutation to the PMEL17 gene, also known as SILV. Commercial tests to identify silver horses are available. Research on ancient remains suggest that the mutation dates back to at least to the Iron Age. 

The mutation for silver is associated with Multiple Congenital Ocular Anomalies (MCOA), formerly known as Anterior Segment Dysgenesis (ASD). Homozygous silvers are believed to be at higher risk for these eye defects.

None yet!

Frameshift variant in MFSD12 explains the mushroom coat color dilution in Shetland Ponies

Open access

Here are links to some examples of mushroom Shetland Ponies. Be aware that links to individual horses can and do change. If a link no longer works, try searching on the name and breed.

Halstock Shetlands - mushroom breeding program

Halstock Superstar - dark mushroom tobiano stallion

Halstock Sienna - dark mushroom with a self-colored mane minimal tobiano mare

Halstock Swiss Cappucino - very dark mushroom tobiano, dark mane and tail

Twyford Pepsi - mushroom tobiano stallion

Have a link for a mushroom pony with good-quality photos that you would like to share? Just click on the chat button at the lower left of the screen.