Sixth-graders get a lesson in strawberry DNA

(Republished with permission from the St. Louis Post-Dispatch. This article originally ran in the Science & Medicine section on Monday, April 28, 2008)

By Andrew Simon St. Louis Post-Dispatch

DNA sequencing has led scientists to map the human genome and could take them to huge advancements in medicine — possibly diagnosing and preventing disease.

But Alex Heerman just wanted to create some deadly fruit.

Heerman and his fellow McKinley Middle School sixth-graders learned how to extract DNA from strawberries Thursday, during a demonstration conducted by Latricia Wallace, the outreach coordinator for Washington University Medical School’s Genome Sequencing Center.

“Can we take this DNA and make a super-strawberry of death?” Heerman asked Wallace, who was at McKinley a day before National DNA Day to help students gain a better understanding of genetic science.

Genome sequencing may help save lives, but many of the students were more concerned with using their newfound knowledge to create everything from killer fruit to a super-powered baby.

When they pulled the stringy white clumps of DNA from their cups of strawberry mixture, many stared at the results in disbelief.

When Wallace had asked the students before the demonstration if they thought it was possible to see DNA with the naked eye, only about half raised their hands.

“I had no idea you could actually look at DNA,” Eddie Cadamey said. “I thought it was too small.”

A single strand of DNA is much too tiny to be seen with the naked eye, but DNA is viewable without a microscope if thousands of strands are stuck together.

When dealing with strawberries, the process of extracting this DNA involves mashing up the fruit, adding detergent, salt, water and alcohol, and filtering the mixture. The result is a liquid with a layer of DNA on the top.

“This is very raw and crude DNA that’s not down to the molecular level,” Wallace said. “If you’re actually sequencing the DNA, you need a much more advanced process.”

This process, even aided by a new generation of robots, can take several months.

But the payoff could be enormous.

Once scientists are able to sequence enough individual genomes, the variations in order that cause diseases like cancer should become apparent, Wallace said. When the technology improves to the point where sequencing somebody’s genome is routine, doctors could screen patients to find out if they are predisposed to serious conditions.

The day when this is feasible is still a long way off, but researchers in the Human Genome Project are getting closer.

In the meantime, Wallace and others are working to increase awareness of their field.

“You can pretty much do this with anything,” Wallace told the students. “We can sequence bacteria, a platypus, mustard seeds. … We’ve even found that about 50 percent of our DNA is the same as a banana’s.”

Copyright 2008 St. Louis Post-Dispatch, Inc.