In a recent Op-Ed, Olivia Judson sounds puzzled by the fact that far from revealing what actually defines each of us, many genetic differences “appear to be more or less irrelevant” (“Testing genes, solving little“, IHT, Aug 18, 2008).
In practice, leaving aside the gender and a hint of the genetic ancestry of the person, a genetic analysis cannot be used to understand almost anything. And yet, all our traits are written in our genes, are they not?
Ms Judson hypothesizes two solutions to this riddle. Either “huge numbers of genes affect most traits” or “variants of a few genes do have a substantial effect but they are too rare to have been discovered yet“. But there is another much more plausible solution, via the science of Epigenetics.
Very simply, Epigenetics is the study of genes’ expression, i.e. of the actual activity of each gene and of its changes over time.
Much as functional Magnetic Resonance Imaging (fMRI) has enabled scientists to probe the actual workings of the brain, instead of being limited to its physical aspect as visible through static MRI, so Epigenetics is opening up the possibility of understandings the genes as they truly act, and not simply as bits of DNA that happen to reside in our cells.
After all, the very definition of life implies a continuous change.
It would be pretty hard to understand the world if all we could see were static images, losing out on everything that happens dynamically.