These rabbits can’t hop. A gene defect makes them do handstands

Mutations in a gene that helps nerve cells work properly rob rabbits of their ability to hop. Instead, the animals use their front paws to move.

These rabbits can’t hop. A gene defect makes them do handstands

A flawed gene might turn some bunnies’ hops into handstands, a new study suggests.

One breed of domesticated rabbit called sauteur d’Alfort has a funny way of walking. To move quickly, they send their back legs sky high and walk on their front paws. That strange gait may be due to a mutation in a gene that helps limbs move. Researchers reported their finding March 25 in PLOS Genetics.

Explainer: What are genes?

The gene is called RORB. And sauteur d’Alfort rabbits aren’t the only animals to adopt an odd scamper if there’s a mutation in this gene. Mice with a mutation in RORB also do handstands if they start to run, says Stephanie Koch. She’s a neuroscientist at University College London. She was not involved with the rabbit work. And even while walking, the mice hike their back legs up to waddle forward like a duck, Koch says.

“I spent four years looking at these mice doing little handstands, and now I get to see a rabbit do the same handstand,” Koch says. She led a 2017 study published in Neuron that explored why mice have the ducklike gait. “It’s amazing.”

Figuring out why the rabbits move in such a strange way could help researchers learn more about how the spinal cord works. The new study is “contributing to our basic knowledge about a very important function in humans and all animals — how we are able to move,” says Leif Andersson. He’s a molecular geneticist at Uppsala University in Sweden.

Sauteur d’Alfort rabbits can’t hop to move fast or cover long distances. They do handstands instead.

A faulty gene appears to drive the funny gait

In the rabbit study, Andersson and his colleagues bred hop-less sauteur d’Alfort male rabbits with New Zealand white female rabbits that can hop. The team then scanned the genetic blueprints of the offspring. They looked in the young bunnies that couldn’t hop for gene differences from ones that could.

A mutation in the RORB gene popped up as a likely suspect for the rabbits’ acrobatic handstands. That change creates faulty versions of the genetic instructions that cells use to make proteins. As a result, there appears to be less of the RORB protein in special nerve cells that have the mutation as compared to cells without it.

Scientists Say: Neuron

Those spinal-cord nerve cells are called interneurons. They help coordinate the left and right side of the body by passing along nerve signals. Properly working interneurons are key for a normal walk or hop, Andersson says. If the special nerve cells don’t have the RORB protein, the rabbits may not be able to coordinate what their hind limbs are doing. That restricts their ability to hop.

While moving slowly from place to place, rabbits with the defective gene can alternate their front and hind legs to walk normally. But to hustle or to travel over long distances, rabbits hop. Hopping requires synchronized hind legs to jump, says study coauthor Miguel Carneiro. He’s a molecular geneticist at Universidade do Porto in Vairão, Portugal.

Without that coordination, all rabbits with a RORB mutation use their front paws to move quickly, Carneiro says. But some hop-less bunnies might do a more drastic handstand than others.

It’s an interesting observation, Koch says. But the study doesn’t reveal much about how interneurons without RORB makes rabbits do handstands. “All they’re looking for is that mutation in one gene and how that gene is affecting the spinal cord.” In fact, she notes, “it could be affecting everything in the rabbit. We have no idea.”

Uncovering how that genetic defect affects the body more broadly could be important for understanding the way animals move. Even people can’t run without harmonized movements of our four limbs. “If you look at the 100-meter sprint — [by] Usain Bolt or someone like that — there’s super coordination between limbs,” Andersson says. “If you lack the coordination between arms and legs … you could never compete for a gold medal.”

These handstand rabbits wouldn’t grab any golds either. But they could help researchers develop ways to repair the body when RORB defects cause disease, Koch says.

Source : Science News for Students More   

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Explainer: What are cicadas?

There are more than 3,000 species of cicadas, but the best known in North America are periodical cicadas, which emerge every 13 or 17 years.

Explainer: What are cicadas?

Those who live in many parts of the eastern United States will experience an odd phenomenon every 13 or 17 years. Depending on where you live, insects called cicadas emerge from the ground in huge numbers. But don’t worry. They don’t hurt people or pets. They’re just here to party.

It’s one of the loudest insect parties you’ll ever see — or hear. When large numbers of the adult insects convene, the collective noise made by males can approach 90 decibels. That’s about the same as a gas-powered lawn mower.

Explainer: Insects, arachnids and other arthropods

“Where the cicadas emerge, it will be spectacular,” Michael Raupp in 2013. He’s an entomologist at the University of Maryland in College Park. Across some small areas, cicada concentrations may approach 1 trillion insects per square mile. That’s like having nearly 4 million cicadas emerge from a patch of ground the size of your bedroom floor (but not all at once, of course).

There are more than 3,000 species of these insects. The best-known species in North America are periodical cicadas. These 5-centimeter- (2-inch-) long insects typically emerge from the ground once every 13 or 17 years. There are 15 different cicada broods, which emerge in a specific region of the country and are identified by a Roman numeral. The 2021 group, a 17-year variety, is called “Brood X.”

There are 15 broods of periodical cicadas that emerge in different areas of the eastern United States during different years.Courtesy of the U.S. Forest Service

Periodical cicadas spend more than 99 percent of their life underground. There, they slurp nutrient-rich fluids from the roots of certain trees and shrubs. These underground young are known as nymphs. This immature stage resembles adults.

While latched onto roots, nymphs track the passage of time by noticing chemical changes in their meals. Early in the final springtime of their lives, the nymphs burrow escape tunnels to the surface. Then each insect will return to root level until the soil temperature reaches roughly 64° Fahrenheit (about 18° Celsius). At that point, the nymphs will surface again, climb out and promptly ascend the nearest tall object. There each molts one last time, becoming an adult.

“You see the insects in a mad, desperate dash for the trees so they can survive and mate,” Raupp said. “Birds and squirrels will be eating them. It’s life. It’s death. It’s romance. It’s a massive display of Mother Nature’s wonder — in my opinion, at its best.”

Adult cicadas live for only two to four weeks. During that brief time, they mate and then the females lay eggs in the tender young branches of trees. Those eggs hatch after a few weeks. The young drop to the ground. At once, each tiny nymph begins burrowing down to find plant roots to feed on.

You might think that large numbers of parasites slurping nutrients from the roots of trees and shrubs for an extended period would harm plants. And Raupp said, “It’s a wonder that we don’t see more damage.” But to date, research has not shown that the underground activities of cicadas cause significant damage to their hosts.

Overall, in fact, cicadas probably help the environment, not hurt it. Their burrowing churns up the ground, loosening the soil, noted Raupp. That not only helps air reach plant roots but also helps water percolate deeply.

Big and noisy, cicadas frighten especially squeamish people. “But chill out,” Raupp cautioned. Learn as much about them as you can. People should realize that they aren’t going to harm children or pets.

Source : Science News for Students More   

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