Monthly Archives: December 2015

Through the DNA Looking Glass

There is an allure to making the invisible visible, especially when it is about us. We carry many things around with us every day, beneath the surface: stories, histories, thoughts, and beliefs. Our bodies also carry around a total of several trillion copies of our genome, two per cell  and these, too, remain invisible to us. (Also invisible to me, as an undergraduate biology major, unable to work a microscope: “All I see is clear liquid!”)

There is a popular science fair and classroom experiment where, with nothing more than a few household ingredients, you can extract and make visible some of your own DNA (usually from a sample of cheek cells). I’ve seen this experiment done where you can put your own DNA in a vial of liquid and wear it as a necklace. Some of you may think this is a “vial” proposition, and granted the DNA usually looks a bit like snot, but many people get into it. There is just something cool about being able to turn some of your cells inside out and spill the hidden contents, the “secret code” that drives the cellular machinery of your body.

The first time I saw physical evidence of my own genome was while studying abroad in college, at Deakin University in Melbourne, Australia. I was taking a Human Genetics course and some folks from the local public health department came in to use our class as guinea pigs for a new genetic screening program. (Historically, Australia has been a bit ahead of the curve in terms of thinking population level applications of genetic information.) The program they were piloting was to test everyone for genetic variants that cause a disease called hereditary hemochromatosis, which is characterized by a buildup of excess iron in the body.

Hemochromatosis is an excellent candidate for population level screening. First, the genetic basis is well understood and easy to test for. Second, it’s pretty common, so you’re not wasting a lot of resources by just testing everyone for it like you might for a rarer condition. Third, there is an inexpensive and straightforward treatment: give blood. Though it was the go-to “treatment” for many diseases from ancient times up to the late 1800’s, bloodletting is usually a bad idea – except for treating hemochromatosis. A final reason that genetic screening makes sense is that, if left untreated, the effects can be pretty serious. So: easy to detect + easy to treat + bad to overlook = reasonable population genetic screening program. Which is likely why these Aussies wanted to try it out.

So I gave a sample, probably signed a form, and a few weeks later got a letter in the mail (a letter, isn’t’ that quaint?) with my results. There, on the paper, was my genotype for two of the most common hemochromatosis variants. I had two normal copies of both variants tested, meaning I was not expected to have the disease or to pass on a risk variant to my child. I felt relief, for sure, but more than that I just felt a sense of awe. I wasn’t wearing a pendant with my own viscous DNA molecules, but I was holding in my hand some tangible piece of information about my own genome. Granted it was only two positions out of the 3 billion in my whole genome, but that 0.000000067% was neato to see, hold, and then fold back into that envelope for safe keeping.

It’s not necessarily rational or logically defensible to feel the allure of the DNA mystique, to get transfixed in the DNA looking glass. But it happens to people – it has happened to me and I think it will continue to happen to people in the future. Understanding what all those A’s, C’s, T’s and G’s actually do is one laudable and long-term goal, but even just holding a few letters in your hand and watching them glint in the sunlight is – I think – pretty cool.

Alice through the looking glass
John Tenniel sketch from “Alice through the looking glass” 1871; Public domain, via Wikimedia Commons