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.
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.
Cold alcohol is slowly poured on top of the strawberry solution.
The strawberry DNA precipitates up to the alcohol & congeals between the layers of strawberry solution & alcohol.
And there it is (looking, as the students pointed out, like snot)!
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.