The Case for INTERdependence Day: Hearing Ourselves, in Epigenetic Echoes

Yes, we have just celebrated Independence Day here in the US. And yes, throwing off the yoke of foreign tyranny is cause for collective acclaim, if not tanks on flat-bed trucks.

But declaring and defending independence from foreign monarchs is not the signature matter of our time. The signature matter of our time is: interdependence. 

Here we all are- English and American, Aboriginal and Inuit, French and Finnish, Indonesian and Nepalese- on this precarious, cosmic speck of common ground with the common cause of preserving it. We are one species, one kind, one extended family- and we have but one, common home.

As Europe bakes, Anchorage simmers, Mexico climbs over mountains of hail, and Indian cities ration water- we are hearing a declaration of interdependence.

As families are sundered and dis-united at the southern border of these United States, it is the neglect of interdependence that will torment the mind and haunt the spirit for years and lifetimes. The young children being taken from their parents’ arms and sent to traumatizing squalor are an indelible emblem of every family’s interdependence. Any parent should be able to imagine these children as our own. Any parent should feel the stirrings of rebellion against the tyranny of disregard for a child’s fear, a family’s desperation.

Reverberating from us, to us, and out in all directions to the indifferent stars from this small beleaguered globe are the echoes of our interdependence.

They echo within us as well. We are interdependent to the depths of our entwined DNA strands.

I am half put together from genes assembled in the womb of my maternal grandmother. This does not make me strange or special; so, too, are you. We are, with exceedingly rare exception, each the product of the genetic endowment of a single egg and a single sperm.

That egg formed in our mother’s ovary. That ovary formed inside our mother. Our mother formed inside her mother’s womb. And when our mothers were born, those fully formed eggs already resided in waiting for fate, inside those fully formed ovaries.  Half of my genetic endowment, and half of yours, were fully formed within the body and living experience of our mothers’ mothers.

That is already a bounty of interdependence across a span of three generations, but it is the least of what the genome has to say on the subject. Only about 5% of genetic real estate is genes. The remainder- the vast tracts between active genes, arching along the course of that elegant double helix- is the epigenome. Like the tracks and stations and switches all around any given train, these direct the behavior of a gene. Change the settings of the epigenome, and a gene will do more, or less, or nothing at all- just as any given train can be sped up, slowed down, redirected, or brought to a standstill. 

But whereas our genes, like any given train, are a relatively fixed, constructed thing- the epigenome is attentive, reactive, and responsive.  The levers and switches of the epigenome determine the innumerable course corrections in genetic expression warranted over a lifetime in response to triumph, disaster, and every variant of fortune in between.

So the eggs that made us carried not just the fixed genes imparted there by our grandmother’s biology via the nascent biology of our mothers; they carried, too, an imprint of our grandmothers’ life experience. Happy or sad; loved or lonely; affluent or indigent; threatened or secure- our grandmothers imparted to us their tales of joy and sorrow, reverie and rage in the settings of our epigenome.  We can write over these- they are forever revisable- but we were born with the tales of grandmothers inscribed on our identities.

What of the paternal line?  This is a tale of fathers and grandfathers, too. True, our fathers were not born with bodies yet owning the sperm that made us. Those formed years later, after puberty, and were then replaced sequentially ever after by machinery in the testes committed to their manufacture. 

Any given sperm is formed only shortly before it makes its one fateful journey. But a new study in the prestigious journal, Cell, that likely presages a Nobel Prize in medicine, tells of the cross talk between neurons and germ cells (eggs and sperm). The researchers effectively eavesdropped on conversations between the nervous system and gametes- explaining how shifts in psychological state could in turn alter the epigenetic configurations in a given cohort of sperm. The epigenetic imprint imparted by our fathers is forever subject to the revisions of their own every-changing psyches.

To appreciate the significance of all this, imagine a man exposed to radiation, genetic damage ensuing. Those mutations would be packaged into sperm, and passed on to plague the next generation. Now, just imagine instead, suffering not a bath of toxic radiation, but a trauma; violence; betrayal; destitution. We now know these are similarly transmitted, just via the epigenome rather than genes. 

We- mothers and fathers, grandmothers and grandfathers- pass along epigenetic echoes of our own life experiences to our progeny. Their own experiences can reset the switches, but their predispositions are born of the slings and arrows of our own outrageous fortunes.

And so we are interdependent now, all among us. And we are interdependent, too, across an expanse of generations. In a child we traumatize today are already the inchoate echoes of some enigmatic mental illness two generations forward.

Countries around the world celebrate Independence Days. These remind us that freedom is not free; that independence has a price. But they look back more than ahead. They tell us little about what freedom is for, what best to do with hit; how best to imbue it with the full measure of its worth.

That tale may ride the many echoes of our connections, from sea to sea, and gene to gene, and generation to generation. That tale may warrant more reflection on where we go from here together, whatever reverence we may direct at our separate paths through the past to now.

Now would be not a moment too soon to begin celebrating: Interdependence Day.

-fin

Dr. David L. Katz;  founder and president, True Health Initiative; author, The Truth about Food; 2019 James Beard Foundation Award finalist in health journalism.