Experimenting with DNA in Honors Biology

Upper School students in Mrs. Hajem's honors biology class are using PCR or Polymerase Chain Reaction to conduct labs on DNA. The PCR method was created in the 1970s to copy DNA for further study such as when investigating a crime scene to identify and match DNA left behind, or check the paternity of a child. PCR can also be used to "edit" DNA and change it, or test to see if someone carries a certain gene.

In this lab, students are testing their own DNA to see if they carry a "tasting" gene for PTC - a chemical found in broccoli and asparagus. With the PCR machine, students can makes copies of their DNA, as well as heat it up to cause a reaction that cuts the DNA with enzymes. "Once the students' isolate the gene region, they will run a gel electrophoresis on it," said Mrs. Hajem. "The gel electrophoresis will allow us to see the bands of DNA to determine if we carry the gene for PTC tasting," she explained.

Prior to starting the lab, Mrs. Hajem asked her students who likes or dislikes the taste of broccoli and asparagus. One student in particular answered with a resounding "I despise it!" to the question. The class hypothesized that the one student who doesn't like it will show the band of DNA that carries the trait for tasting PTC. As a follow up, they will also use PTC paper (which has PTC on it) which will allow the students to taste it right away. The lab is ongoing and the students are eager to find out the answer to the PTC question and more as they continue their study of DNA.

Future labs will include testing for GMOs, CRISPR and gene editing, and the DNA identification of mushrooms.