When a farmer in Otago, New Zealand, saw a bizarre-looking lamb in his flock, he first assumed a wild goat had snuck in and impregnated one of his ewes. The newborn had a lamb-shaped body yet was coated with straight, lustrous wool, more like the hair of an angora goat than a typical sheep. News of the “geep” (or sheep-goat hybrid) soon reached the local papers but, when scientists saw photos, they immediately suspected the baby animal was something else. For decades they had been hoping to study a rare woolly mutant called a “Felting Lustre” mutant: a sheep which has straight, fine wool instead of the usual crimped stuff.
Soon farmers from all over New Zealand were phoning the wool researchers and reporting strange lambs
“You can see it when the lambs are born, they have a different sheen,” says Jeff Plowman, a wool researcher at New Zealand’s AgResearch science company. “It doesn’t have a dull look, it’s shiny and bright.” But the naturally occurring mutants often die as lambs because of other genetic health problems with their skin, teeth and lungs. Finding one robust enough to study is difficult. This little “geep” didn’t survive its first winter; however DNA testing before it died confirmed it was 100% sheep – leaving the scientists determined to find others like it. “We started advertising around,” says Plowman.
Soon farmers from all over New Zealand were phoning the wool researchers and reporting strange lambs, only too pleased for a chance to be rid of their unwanted mutants. Even when the lustrous creatures live to adulthood they suffer from chills, and damp, matted coats, making them virtually useless as shearing animals. Eventually Plowman and his team found the sheep they had been waiting for: a mutant so tough she had already survived a winter living in the frigid hills.
Maxine, as she became known, was destined to become dog food unless the scientists saved her. “The farmer said, ‘We’ve found your sheep and, actually, she’s in the dog tucker paddock because the wool is useless’,” says Plowman.
When the scientists mated Maxine with an ordinary merino ram, they found something surprising: her mutation was genetically dominant. She gave birth to Sharon the sheep: a strong, healthy young ewe with silky, straight wool, who researchers are hoping holds vital clues to solving a range of hairy mysteries, from identifying human hair at crime scenes, to designing shinier, softer wool, to uncovering the secret to better hair care products.
Along with producing milk, growing hair is something humans share with all other mammals, including seemingly-distant relations such as echidnas and platypuses, says the wool project leader at AgResearch, Duane Harland. Mammals’ hair comes in a range of textures. A sheep’s wool is much more like ours than, say, the fur of a lab mouse, says Harland. That’s what makes sheep valuable research subjects for studying the structure of human hair (along with the fact that scientists can selectively breed sheep, whereas doing so with humans would be creepy).
Even the basic properties of hair – such as what determines whether it looks straight or curly, or why some people’s is prone to frizz – remain a little mysterious, says Harland. “Of all the biological fibres that exist, for example silk or cotton or other things, hair is one of the most complicated,” he says. “It’s complex enough that we don’t quite understand how things are arranged on a nanometre scale and the way in which the different proteins are combined to define the structure.
“For example, why does some people’s hair frizz up when it’s humid? That’s of a lot of interest to personal care companies because we really don’t quite understand what makes it happen to people. The sheep provide the link,” says Harland.
In the video above produced by AgResearch, Jeff Plowman demonstrates the difference between Sharon’s wool and that of other sheep.
The basic rule with hair is that finer fibres are curlier, while straighter hair is thicker and coarser. Sheep’s wool – especially fine wool, like merino – is many times curlier than even the tightest human afro, which is why fine wool garments feel nice to wear when a jumper made from human hair would scratch you. But mutants like Sharon break the mould by having wool that is both fine and straight. That gives researchers a rare opportunity to study the two properties independently, and perhaps uncover what genes control straightness and other aspects of hair shape.
Sharon the sheep lives in ‘resort-like conditions’ near Christchurch
Like Sharon, the first straight-haired human was probably a mutant, says Harland, but straight-haired humans obeyed the usual rule by having coarser hair than their curly-maned cousins. Straight-haired people also escaped the other health weaknesses often suffered by sheep like Sharon, which may explain why they proliferated. Still, there are human genetic diseases that affect people in similar ways to the mutant straight-wooled sheep, says Harland.
Untangling Sharon’s genes could one day uncover ways to treat those people. “There are human diseases which are pretty much exactly the same as our mutant sheep,” says Harland. “You get people who have skin conditions or problems with their teeth and their hair is also badly affected, and there’s the occasional rare one where a particular keratin gene has been knocked out and families have no hair at all and sometimes no fingernails.”
Meanwhile, in America, other researchers are using human genes to recreate a person’s hair structure. That could help crime scene investigators work out what someone’s hair looks like based on a DNA sample.
More immediately, the New Zealand researchers want to help farmers like the one in Otago who originally found the so-called “geep”. Sheep farmers are struggling to make enough money from ordinary, low-value wool, but when sheep farms convert to high-value dairy cows the more-intensive farming methods can harm the environment.
Plowman and Harland want to let sheep farmers make more profit from keeping fewer, more valuable, animals. That means breeding Sharon’s lustre into tougher sheep varieties. One day Plowman aims to see a fashion model sashaying down a Paris catwalk wearing expensive, shimmering wool created using tricks they learned from studying Sharon. “If you could get a fine, shiny wool, in a sheep that had no [weaknesses like] foot-rot….” muses Plowman. “What we are trying to do is differentiate wool to provide a market and make it viable again.”
In the meantime, Sharon lives in what Harland describes as “rather resort-like conditions” near Christchurch, north of Otago in New Zealand’s South Island. In her first spring, researchers brought her a jacket for warmth and built her a wind shelter made from hay, which Sharon promptly ate. Her carers shear the three-year-old beast regularly to prevent her quirky wool from tangling. They monitor her stress levels.
While their star subject nibbles pasture, Plowman, Harland and others at AgResearch create 3D models of her wool structure using super-powerful microscopes. Soon, they plan to sequence her genome. Ultimately, they hope Sharon will teach them how to breed a hardy sheep with wool that is stronger, softer and shinier, all while teaching us why our own hair appears smooth or frizzy.
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