Molecular Genetics is NOT Rocket Science–Just Roll Up Your Sleeves

I typically start talking to students about molecular genetics by pointing out that while we share 98% of our genome with chimps, we share around 60% with bananas. So what’s the significance of either of those numbers? What I’m getting at, in part, is that all living things share DNA & that what makes us different, to a great extent, is not that 2% or that 40% but how those genes are regulated & put to work. When I teach undergrads, I lecture on this stuff & we set up lab activities to help reinforce these principles & connect the dots. But when I teach grad students, my purpose is more to help guide them in learning how to learn what they need or want to know.  So by & large, they do the presentations of the material & we (the whole class) help clarify things that remain obscure & connect the dots between the material. I challenge each of them to keep their presentations dynamic, to take on the challenge of being a teacher to their peers, to break out of the mold of just summarizing articles & walking thru bullet sheets of those summaries.  I have been thrilled to see them rise to the challenge by bringing hands-on activities into our classroom.  I am fond of how David Sloan Wilson discusses presents science as a roll-up-your sleeves practice that anyone can do in his book Evolution for Everyone. We talk a lot of theory, but whether you’re an undergrad, grad student, professor, lay person, or whatever, it’s always easier to build up from what you already know & can touch with your hands than to fathom theory in the abstract.

This week’s readings included somewhat intensive readings in genetic principles (see summaries here & here), so our presenters helped us connect the dots by teaching us how to extract DNA from strawberries. I am not sure how much DNA we share with strawberries, but it can’t be that different from bananas.

 This can all be found online, including proper measurements (here, for instance). First, a mixture is made of dish soap & salt. The dish soap will dissolve the walls & organelles of the eukaryotic cells. The salt will break down the bonds of the polypeptide chains.

Waiting for the chemistry explosion
Emma & Becca waiting for the chemicals to explode

The strawberries are pulzerized in a plastic bag then the dishsoap/salt solution is added to do its work.  The strawberry solution is then strained thru cheesecloth into a waiting receptacle.

Sieving the squished strawberries
Elizabeth strains the squished strawberry solution

Cold alcohol is slowly poured on top of the strawberry solution.

Pouring the cold ethanol on top
Elise carefully pouring in the alcohol (& wishing I would go away with the camera)

 The strawberry DNA precipitates up to the alcohol & congeals between the layers of strawberry solution & alcohol.

Looking for DNA
Emma looking for the DNA to congeal

And there it is (looking, as the students pointed out, like snot)! 

Strawberry DNA!
Strawberry DNA!

What does all this mean for anthropology? It means that the principles & methods underlying life &, thus, the human experience are graspable–literally! Using our holistic & interdisciplinary approach, we have the tools to take the necessary steps to address the questions that interest & compel us, not matter how fuzzy or messy or technically intimidating they may at first seem to be.

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