The Silver Gene
The Silver gene is a rare color-modifying gene that is pigment-specific. Originally thought to only apply to Shetland Ponies, the gene has been found in a number of other breeds, including the Tennessee Walking Horse, and is becoming more understood. Although called ‘taffy’ in Australia, some breeds use the term ‘chocolate’ to describe the color. You may have heard of this same color as ‘silver dapple.’ Below is found a simple description of the effects of the Silver gene on horse color and new information regarding the testing for the silver gene.
The Silver gene (Z) dilutes only black pigment and will display in some form or other on any horse with black points including black, brown, bay, dun, grullo, and buckskin. A solid black horse presenting this gene will be chocolate colored, ranging in shade from taupe to a rich chocolate brown. The gene tends to dilute the mane and tail much more strongly than the body, often resulting in a silvery-white color, sometimes showing darker roots. The Silver dilution is a simple dominant in that only one Z gene is necessary to give the color trait. In other words, one parent must have the gene in order to pass it on to the foal.
When a horse gets the Z gene any black pigment may be diluted. It is sometimes difficult to tell horses displaying the Silver gene from a red-based horse like a dark liver chestnut. Often the Silver will give a bluish cast rather than a reddish undertone. Also, the silver dilution results in light hair on the lower legs, lightest closer to the hooves. Silver foals usually have distinct striping patterns in their hooves and white eyelashes. Common names for this color on a black horse are ‘classic silver dapple,’ ‘chocolate silver,’ or ‘black silver.’
This picture is “Starbucks Iced Cappuccino” (Cappie). Cappie presents the Silver gene. His base coat is black but the silver dilute makes his body a rich chocolate and his mane and tail white. His mane has an intermixture of dark and light areas which is also very typical of the silver color. Manes and tails often darken with age. Cappie’s color is considered a medium expression of the chocolate silver. A ‘black silver,’ or darker expression of the silver, can be confused with a flaxen dark chestnut although the silver will not have reddish tones. A light chocolate silver with dapples is considered more classic and is often called, ‘silver dapple,’ and can be confused with a chestnut, but again, the horse will lack red tones.
The Silver Gene can also act on a bay base color with the red pigment of the body unaffected. The black on the legs will be diluted but will show darker than a chestnut, ranging from near black to pewter to chocolate brown with lighter hair close to the hooves. The mane and tail display as platinum blonde to a flaxen color, with a silvery color rather than a golden-hued flaxen color. Foals can be distinguished from chestnut foals by the color of the skin with chestnut foals having pink or pinkish skin. Dark skin at birth may be a sign of the silver gene.
The Silver Gene does not act on red pigment. A Chestnut may carry the silver gene but does not display the modifier. A Chestnut can pass the gene to the next generation, therefore appearing as if the gene skips a generation. Also, the effects of other modifiers such as grey, roan, or pinto would combine with the Silver and change the appearance of the Silver on a given horse.
Although quite rare, Silver can be found in a few Tennessee Walking Horses. The color is known to occur in Rocky Mountain Horses, Icelandic, Morgan Horses, Miniatures, and other breeds.
The gene responsible for the Silver dilution (Z) was recently identified by researchers in Sweden and reported in 2006. Therefore, there is a new genetic test for the Silver. Previously, the silver dilution was distinguished by the red-factor test to determine if the horse was black-based. Information on the web from UC Davis provides easily understood genetic information regarding the coat color tests currently available.
The silver gene provides the avid Tennessee Walking Horse enthusiast another option when adding color to a breeding program, mount prospect, or event partner. The Silver gene dilutes the black pigment on a horse with a black base color resulting in a beautiful chocolate with a silvery mane and tail. Although rare, Silver can be found in a few Tennessee Walking Horses and there is a new genetic test to verify the presence of the gene.
References:
Electronic information obtained from The Horse Colors Site on November 6, 2006 at http://www.horsecolor.com/dilutions/silver_dapple.htm
Electronic information obtained from Veterinary Genetics Laboratory at UC Davis was retrieved on December 16, 2006 from http://www.vgl.ucdavis.edu/service/horse/coatcolor.html.
Sponenberg, D. Phillip. (2003). Equine Color Genetics, second edition, Iowa: Iowa State Press.
Sponenberg, D. Phillip (2006). Horse Color Genetics, retrieved on October 31, 2006 from http://members.aol.com/MFTHorses/sponenbg.htm
The Silver gene is a rare color-modifying gene that is pigment-specific. Originally thought to only apply to Shetland Ponies, the gene has been found in a number of other breeds, including the Tennessee Walking Horse, and is becoming more understood. Although called ‘taffy’ in Australia, some breeds use the term ‘chocolate’ to describe the color. You may have heard of this same color as ‘silver dapple.’ Below is found a simple description of the effects of the Silver gene on horse color and new information regarding the testing for the silver gene.
The Silver gene (Z) dilutes only black pigment and will display in some form or other on any horse with black points including black, brown, bay, dun, grullo, and buckskin. A solid black horse presenting this gene will be chocolate colored, ranging in shade from taupe to a rich chocolate brown. The gene tends to dilute the mane and tail much more strongly than the body, often resulting in a silvery-white color, sometimes showing darker roots. The Silver dilution is a simple dominant in that only one Z gene is necessary to give the color trait. In other words, one parent must have the gene in order to pass it on to the foal.
When a horse gets the Z gene any black pigment may be diluted. It is sometimes difficult to tell horses displaying the Silver gene from a red-based horse like a dark liver chestnut. Often the Silver will give a bluish cast rather than a reddish undertone. Also, the silver dilution results in light hair on the lower legs, lightest closer to the hooves. Silver foals usually have distinct striping patterns in their hooves and white eyelashes. Common names for this color on a black horse are ‘classic silver dapple,’ ‘chocolate silver,’ or ‘black silver.’
This picture is “Starbucks Iced Cappuccino” (Cappie). Cappie presents the Silver gene. His base coat is black but the silver dilute makes his body a rich chocolate and his mane and tail white. His mane has an intermixture of dark and light areas which is also very typical of the silver color. Manes and tails often darken with age. Cappie’s color is considered a medium expression of the chocolate silver. A ‘black silver,’ or darker expression of the silver, can be confused with a flaxen dark chestnut although the silver will not have reddish tones. A light chocolate silver with dapples is considered more classic and is often called, ‘silver dapple,’ and can be confused with a chestnut, but again, the horse will lack red tones.
The Silver Gene can also act on a bay base color with the red pigment of the body unaffected. The black on the legs will be diluted but will show darker than a chestnut, ranging from near black to pewter to chocolate brown with lighter hair close to the hooves. The mane and tail display as platinum blonde to a flaxen color, with a silvery color rather than a golden-hued flaxen color. Foals can be distinguished from chestnut foals by the color of the skin with chestnut foals having pink or pinkish skin. Dark skin at birth may be a sign of the silver gene.
The Silver Gene does not act on red pigment. A Chestnut may carry the silver gene but does not display the modifier. A Chestnut can pass the gene to the next generation, therefore appearing as if the gene skips a generation. Also, the effects of other modifiers such as grey, roan, or pinto would combine with the Silver and change the appearance of the Silver on a given horse.
Although quite rare, Silver can be found in a few Tennessee Walking Horses. The color is known to occur in Rocky Mountain Horses, Icelandic, Morgan Horses, Miniatures, and other breeds.
The gene responsible for the Silver dilution (Z) was recently identified by researchers in Sweden and reported in 2006. Therefore, there is a new genetic test for the Silver. Previously, the silver dilution was distinguished by the red-factor test to determine if the horse was black-based. Information on the web from UC Davis provides easily understood genetic information regarding the coat color tests currently available.
The silver gene provides the avid Tennessee Walking Horse enthusiast another option when adding color to a breeding program, mount prospect, or event partner. The Silver gene dilutes the black pigment on a horse with a black base color resulting in a beautiful chocolate with a silvery mane and tail. Although rare, Silver can be found in a few Tennessee Walking Horses and there is a new genetic test to verify the presence of the gene.
References:
Electronic information obtained from The Horse Colors Site on November 6, 2006 at http://www.horsecolor.com/dilutions/silver_dapple.htm
Electronic information obtained from Veterinary Genetics Laboratory at UC Davis was retrieved on December 16, 2006 from http://www.vgl.ucdavis.edu/service/horse/coatcolor.html.
Sponenberg, D. Phillip. (2003). Equine Color Genetics, second edition, Iowa: Iowa State Press.
Sponenberg, D. Phillip (2006). Horse Color Genetics, retrieved on October 31, 2006 from http://members.aol.com/MFTHorses/sponenbg.htm