Genetics lesson takes root

Science teachers use the American chestnut to teach pupils about breeding methods

Education beat

December 04, 2005|By KATIE MARTIN | KATIE MARTIN,SPECIAL TO THE SUN

When teaching genetics to his seventh-grade science classes, Jobe Mikalauskas likes to use the American chestnut tree as an example.

The pupils learn about genetic traits as Mikalauskas describes to them how researchers are using breeding methods to try to increase traits that will improve the disease resistance of the tree, which has been devastated by a fungus over the past century.

Eventually, the Mount Airy Middle School teacher hopes to plant a chestnut orchard near the school that pupils can study.

"You don't see chestnuts anymore because they only get to be so tall before they succumb to the blight," Mikalauskas said.

The American chestnut has become the focus of projects in numerous middle and high schools throughout Carroll County.

A weeklong unit about the tree and breeding methods was recently added to this year's curriculum for Mikalauskas' and other seventh-grade science classes.

The projects are based on a partnership formed several years ago with ThorpeWood, an environmental education center in Thurmont that has a chestnut orchard of nearly 400 trees.

The center is supporting the American Chestnut Foundation's efforts to restore the once-abundant trees to the region.

"We're trying to get students excited about the project because eventually you are going to begin to hear about the reforestation, and they are going to be able to say, `Yeah, I worked on that,'" Mikalauskas said.

He and other teachers have been using the project to explain genetics to pupils for the past few years.

"We're teaching about the history behind the American chestnut, the backcross breeding method, and about traits," he said. Classes also discuss the restoration efforts when studying ecology.

Researchers are using backcross breeding - a method of cross-breeding plants to give them a particular trait - to develop hybrid, disease-resistant chestnut trees, Mikalauskas said.

"The timber that comes from the American chestnut is some of the best you can get. It's rot-resistant, it lasts forever, and it grows very fast," Mikalauskas said.

He said his classes do identification activities, distinguishing the American chestnut from the Chinese chestnut, and then they explain how to use the backcross method to breed in or breed out a trait to resist an imaginary bug.

Students at other schools have planted chestnut trees on school grounds as part of the awareness program.

Shelby Sawyers, a science teacher at Northwest Middle School, said his pupils took field trips to ThorpeWood.

"They actually get the trees out of the nursery and transplant them into a larger nursery so they have more room to grow," Sawyers said. "One year, we put up a safety fence to keep animals out of the orchard."

The middle-school projects give pupils an introduction that teachers hope leads into more in-depth involvement during high school.

"They'll be able to take what they learned here and then, when they get to high school, they will know the history of the chestnut and then think about these projects and what they want to study," Mikalauskas said. "It brings up a little bit of ownership in the project."

Sawyers encouraged his pupils, their parents and member of the community to attend an event at ThorpeWood last spring where several South Carroll High School students explained their research projects related to the blight fungus.

"It was cool for my kids to see what they could do when they get to high school," Sawyers said.

The event featured a tour of ThorpeWood and a look at the effect of the blight fungus on chestnut trees.

"They could see the canker [caused by the fungus] and see what preventative measures scientists are taking to get the trees back to where they should be - 200 feet tall and 6 feet around at the base," Sawyers said.

Westminster High School biology students got involved with the chestnut tree project by participating in two days of hands-on research facilitated by Maryland Bio-Lab.

Using the stations inside the organization's mobile lab - a tractor-trailer - students examined a virus that attacks the fungus, said Judy Plaskowitz, a biology teacher at Westminster High.

"They used DNA technology to isolate and identify a virus that attacks the chestnut blight," Plaskowitz said. "Blight is a fungus that invades chestnut trees and basically clogs up their plumbing so they can't send water to the leaves and food down to the roots."

Plaskowitz said students had background on how dominant the chestnut tree was on the East Coast to give them some idea of the devastation blight brought about.

"I think the thing that really impresses them is that they get the opportunity to work with state-of-the-art equipment," she said.

Plaskowitz said she is planning to do the lab again this year, as she hopes it gives pupils the message that it is possible to save endangered species.

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