Deoxyribonucleic Acid: Fun with Strawberries

In which you see DNA with your own eyes…

Sisters Science Symposium (S3), hosted at Sisters High School by Sisters Science Club, became a gathering of curious inquirers from a small Oregon community.  It snowed that morning and you wondered if this sudden assertion of Pacific Northwest winter would deter people from attending.  Not so…the school commons resembled a cell membrane with protein ion channels allowing our charged comings and goings: our attracting, learning, and informing.

You did not wake that morning expecting you would soon be pulverizing a strawberry in a plastic sandwich bag.  But you did, and you assisted others, as young as toddler Annika and as seasoned as the organizer of the event, Cal.

A high school freshman or sophomore guides you through the procedure.  The ultimate goal is to extract DNA from a whole strawberry.

You mash a strawberry up one minute, delighting in a joy which is similar to eating but more like a food fight.  Thus rendered a red mess, you add 10 ml of a buffer consisting of water, dish soap, salt, and a dash of meat tenderizer.  This tincture facilitates the  movement of proteins, carbohydrates, lipids and ion changes in the strawberry’s DNA.  Last, you filter 4ml of the strawberry goop through cheese cloth and pour 5ml of cold ethanol.  The ethanol helps the DNA precipitate from the goop. Amazing!

When you hold it up to the winterlight in the windows you can see, with your very strawberry-lover eyes, DNA floating in the cold, clear ethanol.  Unbelievable!  They look like little stars in an aquatic outerspace.

The last part of the procedure is the actual extraction of your DNA stars.  You reach into the vial with a wooden stirstick and swish them around.  They collect, like honest-to-goodness snot, around your stick.  You remove it, and while putting it in a sample container, you recall that you have similar stuff inside of you too.  You are not too far off from the species of strawberry, or juniper, or monarch, or lemur.

The building blocks of life in ten minutes…or as a fifth grader informs you: “We have books inside of us.”  And so does the strawberry.

-Carrie Anne Ebner

(Special thanks to Rima Givot, science teacher, for the corrections on science terminology and the procedure.)


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