Strawberry DNA extraction with third graders

On June 11th, Gramene's project manager and outreach, education and training coordinator, Dr. Marcela Karey Tello-Ruiz of Cold Spring Harbor Laboratory, visited third graders at Bayville Intermediate School in New York to guide them through a DNA extraction from strawberries using household ingredients like soap, salt and alcohol.

Students had previously learned about the importance of DNA in all living organisms and about nucleotide basepairing while making DNA models with gummy candy, so they were able to quickly grasp concepts about its location inside the cells, its molecular "twisted ladder" structure, as well as the importance of isolating DNA.  Students were told about several interesting applications of the knowledge gained from studying DNA. These include genetic testing, analysis of forensic evidence, uncovering marketing fraud, preserving biodiversity, and helping people produce more food, medicines or useful substances without doing so much damage to other life forms by using biotechnology. 

Prior to the actual DNA extraction, Dr. Tello-Ruiz explained each step of the protocol so that the students were able to visualize that 1) crushing the strawberries breaks open many cells to facilitate release of the DNA into the solution, 2) soap causes breaking down the fatty membranes of cells and nuclei further releasing DNA into the solution, 3) salt and ice cold alcohol help DNA stick together and precipitate, and is separated from proteins and other debris.

Students also learned about domestication, selection and breeding.  They were intrigued to learn that many fruits and vegetables that we eat today are very different from their ancestors.  They also learned that extracting DNA from strawberries was facilitated by the presence of lots of enzymes in ripe strawberries and also because of the multiple sets of chromosomes (polyploid genome) of large cultivated strawberries compared to their much smaller diploid wild ancestors.  Also surprising for them was learning that plant crops that look very different like broccoli, cabbage, kale, and brussels sprouts are actually the same plant (species), just like different dog breeds are the result of selecting for specific looks and propose.  Our journey concluded with children coming up with their own ideas of what they could do with the DNA they had just extracted.

This outreach educational activity was made possible through National Science Foundation award #1127112 to the Gramene Project.

Visit Gramene's Facebook page for other outreach and educational activities that Gramene has brought to K-12 students in past years to celebrate Fascination of Plants Day or FoPD.