The streets and squares of this university town ooze culture, history and atmosphere but its demeanour is curiously ordered, reserved and discrete. An efficient taxi service takes me right to the front door of my first interviewee. Susan Gasser (Friedrich Miescher Institute) recently took charge of one of the world’s leading centres for biomedical research. I’m fortunate to catch her on a Saturday, winding down from a busy week. Perching on her veranda overlooking the river we watch Dutch barges and Rhein ferries in a flurry of activity.

“For me epigenetics is the memory of the cell,” she says. “A cell has to know where it came from and where it’s going to in a multicellular organism.” Skin cells need to make more skin cells, and liver more liver cells, and so on. “Highly differentiated tissues share the same genetic raw material yet know that they are different. To me, epigenetics is a kind of memory that allows a cell to know what it is or what it’s going to be tomorrow.” Fascinated, I ask her how cells could have a memory. “This memory is established by posttranslational modifications on proteins and DNA, basically,” she pauses, “or else structure. It’s both a temporal and spatial, and a modification-based memory,” she clarifies.

“Genetics is the hardware, the architects plan, what must be. Epigenetics has an element of chance that’s not hardwired.” Susan’s work focuses on the spatial element of epigenetic memory, the way our chromosomes are arranged inside the tiny nuclear domain. Her research team use fluorescence techniques to probe and track nuclear components as they assemble in yeast cells. I quiz her about the implications of this research.

“It’s not so important that my grandmother understands epigenetics. But it’s important that everyone under 18 be aware that we have the capacity to sequence any gene from any individual. Then they should also understand that even knowing the sequence of an entire genome is not sufficient to know who you are or what you are, or whether you will be sick or not,” she reassures. “Your identity is not programmed in the raw sequence of your genome, but has a lot to do with this memory thing. It’s very plastic and a lot will depend on how you live. Or in the case of a cell, on what the cell has been through. ”

“Ten years ago I would have said I think it’s important that people just understand a gene, but now, although I still think it’s important, understanding a gene is barely the beginning. There’s a tremendous amount of unpredictable variability, aspects of inheritance, aspects of the environmental impact on cells, which do not change the fundamental genetic information but change its expression or manifestation. Basically the stochastic part gives us variety in life.” Susan’s words of wisdom are reassuring in an age when genetic information could become the property of corporations. But because DNA sequences alone cannot suffice as accurate predictors of our fate, corporations greedy for information will have to think more carefully.