photo by Ginger Yarrow

With the help of Dr. Oliver Pergams, Whittier 4th/5th grade students in Ms. McDaniels’ class used
their own cheek cells to extract samples of their own DNA.

Dr. Pergams began the session by asking the kids what they know about DNA. One student offered, “It’s
who you are with your genes.” Dr. Pergams is a professor of evolutionary and conservation biology who
works and teaches at several local institutions, including the Field Museum. He has worked with OPEF’s
Global Village* program for 9 years.

In order to get at their DNA, students scraped their cheeks with their teeth while swishing Gatorade in
their mouths. Gatorade has a lot of salt in it so cells won’t burst and the DNA will stay intact. In a less
than savory moment, the students then spit the Gatorade back into the cup, hopefully with some cheek
cells somewhere within it.

Nathan D. said, “Not everyone knows what DNA is, so this is kind of nice to learn the basics of DNA, the
letters [proteins] that make up DNA.”

The next step was to add a “cell lysis” buffer to the Gatorade. This solution is basically a detergent that
breaks down the cells so you can get at the DNA which is now floating in the solution freely with all the
other cell contents in a sort of soup called the “cell lysate.”

To isolate the DNA strands and render them insoluble, ethyl alcohol is added on top of the solution.
When the alcohol meets the cell lysate soup, the DNA rises up out of the solution and into the ethyl
layer. As Dr. Pergams explained, “That white stuff floating around in there? That’s your DNA.”

Emma S. said the experiment was “interesting and it’s cool that you can see your own DNA and that you
can easily get it without hurting yourself!”

Students then transferred the suspended DNA into a plastic pendant which they strung with thread to
make a necklace! The kids were engaged and despite the “ick” factor were truly eager to see evidence
of their own basic genetic make-up.

Brian G. was impressed: “it was cool to figure out how to separate out your own DNA. I didn’t know you
had DNA inside your mouth!”

Dr. Pergams will be back in Ms. McDaniels classroom again after spring break. He plans to teach about
evolution, using teeth in a variety of local mammal skulls, followed by an owl pellet dissection. He will
also do a lesson on invasive species, followed by a field trip to a local natural area.

Dr. Pergams views these field trips with Global Village* as particularly important. “We are becoming
increasingly videophilic, with our children spending 5-10 hours per day in front of screens and only 20
minutes per week in unstructured play outside. Each year fewer and fewer students have been in the
woods before.” With Dr. Pergams, students will take their classroom learning into the woods where
they will remove samples of invasive species.

Click here to see photos by OPEF reporter Ginger Yarrow.


* The program is now named “Science Alliance”