A couple weeks ago, a fellow graduate student and I participated in NC DNA Day, which is a yearly event to promote science education in public schools. The UNC School of Medicine sponsors this day of outreach as well as a mini-festival and 5k race this coming weekend. Scientists from NC universities and biotech companies are invited to travel across the state and give hour long presentations on DNA with some interactive activities. The DNA Day organizers make the process completely turnkey – all you have to do is pick up your bag of materials, download the PowerPoint files, and you’re ready to teach.
We traveled to Southern Vance High School in Henderson, NC. The students were just about to start a unit on genetics, so our lesson would be a good primer for the content that was to follow. We opted to teach a standard-level, sophomore biology class as well as an honors biology class in the same grade. The honors class took in the information more readily and we ended up with 20 minutes left over at the end of our unit, but the standard-level students seemed more engaged with the larger picture of the material and the moral dilemmas posed by gene therapy. Both classes of students were cooperative and respectful, with a couple of class clowns that were pretty easy to handle.
Of the four modules offered, we were assigned “Genes and Disease: Cystic Fibrosis,” which covers basic genetic inheritance, pedigrees, the Central Dogma, and mutations. The first major activity for the students was to demonstrate the random chance involved with inheritance. To illustrate this point, fuzzy balls were placed into a paper bag, each representing one allele of a particular gene. For instance, heterozygotes (carriers) would have one red ball and one white ball, whereas people affected with a recessive disease (such as cystic fibrosis) would have two red balls in their bag. Students then drew the alleles that were passed on to the next generation, and this information was filled in on a pedigree at the front of the room. This activity was quite fruitful as students picked up on the stochastic nature of inheritance.
The second activity was having the students figure out the genotypes of family members in a pedigree. A couple of individuals were known to have cystic fibrosis, and others were normal individuals who were (somehow) known to not be carriers. From this information, students were able to assign genotypes to all individuals in this family. One point of contention between our activity and the classroom was with one individual in the pedigree who could have been homozygous dominant or heterozygous. The classroom teacher emphasized that on the End of Course exams, these students would not have an ambiguous case such as this. We had to concede that it was “likely” that the individual in question was homozygous dominant (having birthed three homozygous dominant children).
The final activity asked students to transcribe two DNA sequences (the two alleles in the above heterozygous individuals) into RNA and then translate this into a protein sequence. Students then compared the protein sequences to a reference sequence to reveal a silent mutation and a missense mutation. This coding activity removed some of the complications of teaching the process of translation (ribosomes, codons, etc.) so that students could focus on what a DNA mutation does.
In all, the students responded well to these lessons, and most seemed to have a better grasp of the material by the end of the class. Hopefully, this introduction will give these classes a leg up with their genetics unit. We told the teacher that she could contact us in the future if she wanted more information from us, or even if she wanted us to Skype into the class as a guest expert.
I highly recommend that any interested scientists participate in next year’s NC DNA Day. It is a very fulfilling outreach activity with minimal effort required. Please look at their website and peruse the other modules that are available.