For Agri-View, written by Lynn Grooms
Wide variation in Icelandic sheep fleeces creates challenges for breeders coding color and pattern when registering their Icelandic sheep. But that same variation is what attracts other breeders, genetics enthusiasts and fiber artists.
Icelandic sheep have two base colors – black and brown; brown is also called moorit. Moorit can range from honey-brown to dark-chocolate, according to the Icelandic Sheep Breeders of North America. The base color is one of three parts of the coding system the association requires breeders to use when registering sheep. The code is used for identifying and recording the phenotype of each animal. It’s also useful when checking a sheep’s parentage and predicting offspring appearances.
Breeders also are required to code the sheep’s pattern. Within that pattern category are six variations – white, gray, badgerface, mouflon, solid and single-gene gray-mouflon. Contributing to the variation is the breed’s dual-coated fleece. The thel or undercoat may be the same or a different color from the long, coarser overcoat. Or the thel can be black or moorit. With the exception of white, all the patterns can be expressed in either black or moorit sheep, Margaret Flowers said. She’s an Icelandic sheep breeder at Trinity Farm near Aurora, New York, and a former professor of biology at Wells College, also in Aurora.
An article titled “The Color Code” is featured on the Icelandic Sheep Breeders of North America website. In the article written by Flowers, she provides examples and photos showing the six patterns. The white pattern is dominant over other patterns, with both tog and thel being white. Solid, in which tog and thel are the same color, is recessive to the other patterns. In gray sheep the thel is gray and the tog expresses the base color.
Badgerface sheep have a dark underside and light back while mouflon sheep show the reverse of badgerface. The single-gene gray-mouflon is likely a mutation of one of the more-common patterns. All four show co-dominance, meaning if two different alleles are present both are expressed, Flowers said.
In addition to color and pattern, breeders must code whether their animal is spotted or not spotted. While some sheep may look all white, it may be just one large white spot.
Stefan Adalsteinsson, who was affiliated with the Agricultural Research Institute in Reykjavik, Iceland, published in 1970 a study about color inheritance. Based on a limited study on the rare pattern, he demonstrated that the gray-mouflon pattern is dominant to solid and recessive to white. He hypothesized that gray-mouflon is likely dominant to gray and mouflon, but that badgerface and gray-mouflon were neither dominant nor recessive to one another but were co-dominant.
Recent breeding data by members of the Icelandic Sheep Breeders of North America demonstrated that single-gene gray-mouflon is recessive to white, and that single-gene gray-mouflon is dominant to solid and co-dominant with badgerface. Sheep that are homozygous for gray are lighter colors than heterozygous sheep. Similarly sheep that are gray-single-gene gray-mouflon are lighter in color than single-gene gray-mouflon sheep. Additional breeding will be needed to confirm inheritance patterns to determine whether an animal that’s single-gene gray-mouflon-mouflon will also express the mouflon trait, Flowers said.
Genetic testing for sheep-color genes isn’t commercially available, said Diane Graves, president of the Icelandic Sheep Breeders of North America. She breeds sheep at her farm, Isafold Icelandics, near Vernonia, Oregon, and is a self-confessed genetics nerd. But some research has been conducted r color traits, such as a study in 2018 by Koseniuk et al and in 2022 by Kalds et al. Currently all sheep-color genetics must be proven empirically with test breedings and by analyzing offspring.
There’s no advantage to the single-gene gray-mouflon pattern from a fiber perspective. For the usable portion of the sheep’s fleece that grows on the body, it’s no different from the gray pattern – which is one of the most common patterns in the Icelandic gene pool. But from a breeding-stock-sales perspective, it’s a desirable trait many buyers are enthusiastic to acquire in their flock, she said.
“A sheep with (single-gene gray-mouflon) usually won’t be priced any higher, but it will be much easier to sell,” she said. “The other reason for interest in (single-gene gray-mouflon) is the ability to play with it in one’s flock. Colors and patterns are like Pokémons; you ‘gotta catch them all.’ Before (single-gene gray-mouflon) appeared in our gene pool, all sheep were limited to two possible patterns that they could visibly display.”
Single-gene gray-mouflon has interested breeders such as Barbara Stinson with Farm of Beauty near Lodi, Wisconsin. She sells as well as knits with yarn produced from her Icelandic-sheep fleeces. Her flock of 21 sheep includes single-gene gray-mouflon animals.
She sells breeding stock to other Icelandic sheep breeders such as Christina Taylor of Driftless Icelandics near Tomah, Wisconsin, and Shana Chapel of Sweet Pasture Pies Farm near Pella, Iowa. The women recently met at Stinson’s farm to trade breeding stock and discuss fleeces.
Taylor started raising Icelandics in 2017 and has a flock of about 20 sheep. She brought four packages of roving to Stinson’s farm to show color variations from a few of her animals. Roving refers to wool fiber that has been processed but hasn’t yet been spun into yarn. She compared one of the roving samples to cinnamon bread. That sample came from Zeus, one of her rams, a possible single-gene gray-mouflon sheep. Zeus is being bred to a sold-black ewe to further test whether he’s indeed single-gene gray-mouflon.
“With each shearing you can see different colors,” she said. “That can be frustrating when trying to code.”
But the sheep-breeders association allows breeders to update their coding, she said.
“Color encoding itself isn’t the easiest thing to master,” said Marjorie Jackson, secretary-treasurer of the Iceland Sheep Breeders Association of North America and an Icelandic sheep breeder near Hermann, Missouri. “Often a breeder will post photos of a lamb for help in determining the correct coding. Some breeders are more adept or interested than others, and some pedigrees are far more helpful than others in determining what might be going on. Since the first documented occurrence of (single-gene gray-mouflon) in the United States in 2010, there has been special interest in this mutation pattern.”
Breeders pay fees to register their sheep. The fees vary based on location – the United States or Canada – as well as age of the animal and membership classification. Most U.S. members pay $9.50 to register a lamb, she said.
Stinson, Taylor and Chapel showed each other their fleece samples when they met recently. Stinson had several bags of fleece from her flock. She has her fleece spun at a mill in Argyle, Wisconsin, and was beginning to knit a striped sweater showcasing the variety of hues from her Icelandic sheep.
In addition to her roving samples, Taylor brought two rams. She traded one, a ram lamb, for one of Chapel’s ewes. Taylor brought an older ram, Leif, to provide company for the ram lamb on the drive from Tomah to Lodi. Leif carries the single-gene gray-mouflon gene.
Chapel showed six samples of fleece from her flock of 15 ewes and six rams. Four of the samples were from her single-gene gray-mouflon sheep. She started raising Icelandic sheep about three years ago, after having had a Shetland-sheep flock.
“Icelandic sheep smell better and their horns are amazing,” she said with a smile.
Icelandic sheep can be raised for meat and milk as well as fiber. And they are useful for clearing brush and invasive species, she said.
Since becoming acquainted with Taylor and Stinson, Chapel has purchased from Taylor three registered ewes. She also bought from Stinson two rams. Ulfhrafn is a moorit gray and Uggi is a black-spotted single-gene gray-mouflon ram. Uggi later produced a single-gene gray-mouflon ram lamb. Intrigued by the genetics, Chapel said she purchased two more single-gene gray-mouflon sheep.
Graves said, “The bottom line is that this is basically intellectual entertainment for color-genetics nerds. It’s fun to think about the possible lamb colors and patterns you could get when deciding on a particular breeding pairing. When the lambs are born, you get to have more fun trying to figure out the colors and patterns that resulted.”
This is an original article written for Agri-View, a Lee Enterprises agricultural publication based in Madison, Wisconsin. Visit AgriView.com for more information.
Below link is from another 2019 Agri-View article
Photo at left is from an earlier article Agri-View, Spice of life woven into Icelandic sheep by Lynn Grooms from Nov. 8, 2019
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