Exploring Your Universe: Strawberry DNA

I had a fantastic time volunteering at the “Exploring Your Universe” event at UCLA this Sunday. Allison Fritts-Penniman and Johnathan Chang organized two great booths for the EEB department: a strawberry DNA extraction using soap and rubbing alcohol and a marine invertebrate touch-tank. During my shift, I taught children ages 4-18 about the concepts of DNA and the genetic code and led them through the simple extraction process. For some of the younger kids, the concept of DNA was a bit too abstract, but they still enjoyed getting to do some hands-on science by adding dish soap to strawberry puree, then watching the DNA precipitate into the isopropanol. Older children were more engaged with the actual concepts; one ten year old boy asked increasingly insightful questions as he began to understand the importance of DNA in heredity and evolution, and I was able to talk him through how DNA is an indicator of relatedness between individuals and of phylogenetic relatedness between species.

The best thing about the strawberry DNA protocol is that it can easily be done at home, and so I suggested that parents and their children carry out experiments to see what else they can extract DNA from (onion, banana, cheek swabs, etc.). The main advantage of using store-bought strawberries is that they are octoploid (eight copies of their chromosome set, as opposed to our two copies) making the quantity of DNA extracted very high and therefore easy to visualize, so I warned participants that other organisms they try to extract DNA from may not give such generous yields.

I highly recommend this simple DNA extraction protocol for teachers and parents — when I was in middle school, I carried out this protocol on a piece of onion at a family science workshop and became deeply fascinated with DNA and genetics. Hopefully some of the kids on Sunday were just as inspired!