Category: Genetics

Hopping Ahead of Climate Change

3/14/2023

Sneed B. Collard III

Connecting Scientists and Kids

Earth’s temperatures are getting warmer. In fact, sixteen of the seventeen hottest years on record have occurred since the year 2000. These warmer temperatures are driving larger, long-term changes in our planet’s weather and climate. Scientists refer to these changes as “climate change.”

In a few places, climate change might be welcome, but around the world, warmer temperatures and other changes are leading to a host of problems from rising sea levels to more extreme weather events and the spread of harmful human diseases.

Professor Scott Mills, from the University of Montana, wanted to see how climate change might be affecting one particular animal called the snowshoe hare.

Snowshoe hares live in regions of North America that receive snow every winter. The hares, in fact, change their coat color from brown to white and back again every year. This helps camouflage them against their background—and hides them from the eyes of lynx, owls, and other hungry predators.

  Here’s the thing: snowshoe hares can’t choose when they molt, or change their coat color. Molt timing is controlled by their genes, which are part of the DNA inside their bodies. If a hare’s genes make it molt to white in October, but snow doesn’t fall until December, the hare will stick out like a light bulb against the brown earth. And that’s a problem. Why? Because almost everywhere on earth, the length of time with snow on the ground is growing shorter and shorter.

  To find out if shorter winters might harm hare populations, Scott and his team spent three years tagging and following hares. They measured how many were born, how many died, and what they died from. They also recorded whether the hares were matched or mismatched against their backgrounds.

  They discovered that predators killed mismatched hares significantly more often than hares whose coats match their backgrounds. Scott and his team also calculated that over the next one hundred years, this greater mortality, or death rate, could lead to the decline or disappearance of many snowshoe hare populations.

  The good news? Different hares molt at different times. This may help some hare populations adapt to shorter winters and longer periods without snow.

  Hares are not the only animals affected by shorter winters. More than twenty species of animals including lemmings, weasels, hamsters, and Arctic foxes change their coat colors every year. Scott’s research helps us predict what might happen to these animals—and decide what we can do to protect them.

Scott’s discoveries about Montana snowshoe hares, together with experts’ predictions about our future climate, indicate that hares will be mismatched between 5-½ and 10 weeks by the end of this century.

Before tagging and putting a radio collar on a snowshoe hare, Professor Mills and his team must weigh and measure it.

This snowshoe hare has been tagged and fitted with a radio collar—and is now ready to help scientists learn more about snowshoe hare survival.

Even from a great distance, a mismatched hare stands out like a glowing light bulb. (Photo Courtesy of L. Scott Mills research laboratory)

Besides serving as popular prey for predators, snowshoe hares are irresistibly cute. This is a young hare, also called a leveret.

Sneed B. Collard III is the author of more than eighty award-winning books, many focusing on science and the natural world. His entertaining memoir Snakes, Alligators, and Broken Hearts—Journeys of a Biologist’s Son recounts his challenges and adventures growing up as the son of divorced biologist parents, and the experiences that would one day lay the foundation for his writing career. He is a dynamic speaker and offers school and conference programs that combine science, nature, and literacy. To learn more about him and his talks, visit his website, www.sneedbcollardiii.com.
This book was reviewed by Vicki Cobb in the Huffington Post: "The Cheeseburger of the Forest".

MLA 8 Citation
Collard, Sneed B., III. "Hopping Ahead of Climate Change." Nonfiction Minute, iNK Think Tank, 15 Nov. 2017, www.nonfictionminute.org/hopping-ahead-of-climate-change.

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Amazing Maize

11/23/2022

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Dorothy Hinshaw Patent

Nature's Animal Ambassador

If I asked you what grain is the most harvested in the world, you’d probably answer either wheat or rice. But the answer is actually corn, more accurately called ‘maize.’ This nutritious crop that originated in Mexico feeds not only people but also animals around the world. We’re used to the wonderfully tender sweet corn harvested in late summer and early autumn, but most maize is actually field corn, more starchy than sweet and used as animal feed or to make cornmeal and flour.

For a long time, biologists puzzled about the origins of this important crop. There is no wild plant that looks anything like modern corn, which is actually a giant grass. The closest relative is a scrawny branching plant with hard dark seeds called teosinte. It seems a huge jump from teosinte to corn, yet geneticist George Beadle found in the 1930s that corn and teosinte have the same number of chromosomes and could be crossbred to produce hybrids. With the limited tools available at that time, Beadle deduced that only about five genes were involved in creating the differences between teosinte and corn.

Fast forward to modern times, when scientists can look directly at DNA and analyze every detail of its structure. We now know that Beadle came very close to the truth—about five regions in the DNA seem to control the major differences between teosinte and corn. For example, these two plants look so very different, yet just one single gene turns a branched plant into a single stalk, like a stalk of corn. Another single gene controls one of the most dramatic and certainly most important traits for farmers—the nature of the seeds and their stalk. In teosinte, each seed has a hard covering. Just one gene eliminates the hard covering and produces a stalk bearing exposed seeds, like an ear of corn.

Scientists now use maize as a perfect example of two major ways evolution happens. One way is through major sudden jumps, like the change from a branching plant to a single stalk. The other is the more gradual kind of change that has led to the thousands of different kinds of maize grown by farmers today. There are probably hundreds of varieties of sweet corn and thousands of varieties of field corn. Think about that the next time you bite into a nice crunchy taco made from a corn tortilla.

Here you can see the major differences between a teosinte plant and a corn plant. Credit:TeosinteCornUOR

Corn was a very important crop for homesteaders in the American West, used both to feed themselves as well as their animals. Read about it in Homesteading: Settling America's Heartland, revised and expanded edition, Mountain Press, 2013.

Dorothy Hinshaw Patent is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.

MLA 8 Citation
Patent, Dorothy Hinshaw. "Amazing Maize." Nonfiction Minute, iNK Think Tank, 8
June 2018, www.nonfictionminute.org/the-nonfiction-minute/Amazing-Maize.

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The Flaw in the Seedless Banana

1/18/2022

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Dorothy Hinshaw Patent
Nature’s Animal Ambassador

You can see how little fruit is inside a wild banana.

You probably eat bananas at least once a week—they are the most popular of all fruits, even surpassing the apple. But have you ever noticed that bananas have no seeds? Probably not. You just peel them and enjoy their soft, seedless flesh without even thinking about seeds.

If you’d been strolling through a tropical forest in New Guinea thousands of years ago and reached up to pluck a wild banana snack, you wouldn’t have wanted to eat it. The banana ancestors had big hard seeds surrounded by a small amount of sweet flesh, not worth peeling. Sometimes, however, plants appeared with fruit that had no seeds. Over time, people cherished these seedless fruits and grew the plants for their own use.

The banana plant sends up a central stalk surrounded by very large leaves, then flowers at the tip. The flowers produce a heavy load of bananas without being pollinated. Then the stalk dies. Meanwhile, the stalk sends out side shoots that become new plants. That’s a form of cloning, meaning that all of a banana plant’s progeny are genetically identical, both to their parent and to one another.

The ancestors of the modern banana could reproduce in the usual way, so their seeds contained mixtures of DNA from the mother plant and DNA from another plant’s pollen. This “sexual reproduction” allows for the genes of the plants to be combined in new ways. If a disease came along, it might kill most of the plants, but some others could have natural resistance and survive.

Because it lacks seeds, the banana has gotten into trouble. Back in the 1950s, an especially sweet and tasty variety called the Gros Michel was the commercial banana. But a devastating fungus came along and killed the plants and contaminated the soil. Growers then chose another variety, Cavendish, which resisted the disease. But now a wilt called Panama disease has shown up that kills the Cavendish plants. And because bananas lack genetic diversity and because they don’t develop seeds that mix up their genes, the Cavendish has no way of defending itself.

Banana growers are doing what they can to stop the spread of the disease, however, and up to now they have been successful. But don’t be surprised if in a few years the bananas you buy look and taste different. Luckily, there are other varieties out there, like small “finger” bananas and larger red-skinned fruits, that you can already buy in places like Hawaii.

These bananas are ready for harvest.

The banana flower cluster is huge. You can see the bananas beginning to form in the upper right of the photo.

Here are just a few kinds of bananas, from left to right—plantains, which are starchy rather than sweet; red bananas; finger bananas; and Cavendish bananas

Dorothy Hinshaw Patent's new nonfiction picture book about horses has a fresh focus: how people over the ages have decorated horses in special ways. Organized into three categories—warfare and hunting, performance and competition, performance, and ceremony—the book introduces horses such as the chariot-pulling war horse of the Persians to the rose-decorated winner of the Kentucky Derby. For more information, click here.

Dorothy Hinshaw Patent is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.

MLA 8 Citation
Patent, Dorothy Hinshaw. "The Flaw in the Seedless Banana." Nonfiction Minute, iNK Think Tank, 21 Dec. 2017, www.nonfictionminute.org/ the-nonfiction-minute/The-Flaw-in-the-Seedless-Banana. Accessed 21 Dec. 2017.

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Hopping Ahead of Climate Change

Amazing Maize

The Flaw in the Seedless Banana

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