
A recent book review in New Scientist opened my eyes to something completely new to me – microchimerics. I’m pretty sure I’ve never come across the word before. Here’s the introductory paragraph of the review, which, I believe, captures the essence of the book –
“We now know that during pregnancy, fetal cells cross the placenta into the mother, embedding themselves in every organ yet studied. Likewise, maternal cells, and even those that crossed from my mum to me, can make their way into my kids. And things might get even more chimeric – I have older sisters, so their cells, having passed into my mum during their own gestation, might have then found their way into me and, in turn, into my kids. This fascinating idea – that we are a holobiont, composed not only of human cells and microbes but also fragments of others – and its implications sit at the heart of Hidden Guests: Migrating cells and how the new science of microchimerism is redefining human identity by Lise Barnéoud.”
I’ve long been aware of the discoveries of Lynn Margulis, who back in the 1960s published “On the origin of mitosing cells”, from which she developed the theory that the component parts of our cells evolved from separate unicellular life forms collaborating and incorporating – in other word, “symbiosis”. We humans are perhaps the most complex of all multicellular organisms ever discovered, and, it seems, multicellular organisms evolved by separate, unicellular ones co-operating and collaborating.
I was taught in Medical School, that each of us is composed of many more cells which aren’t of “human origin”, than we are of our “own” family ones. Whole communities of micro-organisms live on and inside our bodies. We’ve come to think of these communities are “biomes”, and the gut biome in particular has been shown to be crucially important in everything from our immune defences, to our emotions and, even, cognition. Quite simply, we couldn’t live without them.
Another thing I was taught in Medical School was that all of our cells die off and are replaced, so that many times over the course of the average lifetime, we find ourselves with a complete set of cells which we didn’t have when we were younger. In many ways it’s best to think of ourselves, not as discrete, separate, fixed entities, but rather as flows – flows of cells, of chemicals, of substances, energies and information.
So, at a biological level, we do indeed “contain multitudes”, as Whitman wrote so beautifully in his poem, “Song of Myself”.
These latest findings about microchimeric cells are only the latest discovery into this reality….we aren’t just creatures with many facets, or features, we are creatures containing multitudes.
All of this resonates with Miller Mair’s theory of mind which I’ve long found convincing – “instead of viewing any particular person as an individual unit, I would like you to entertain, for the time being, the ‘mistaken’ view of any person as if he or she were a ‘community of selves.’ I found this metaphor, of a community of selves, rather than a single self, to be incredibly useful in understanding both my patients and myself. It is the psychological equivalent of the biological one of “biomes”.
The “community of selves” idea came back to my mind recently when I read a post on social media where the writer said that when their father died, they lost not just him, but a part of themselves. I hadn’t really thought about that before, but it strikes me as very true. Because each of these “selves” which we experience arises within particular relationships, and we can become aware of how certain selves are only present within those particular relationships. Miller Mair describes how some of the “selves” in our “community” are short lived, whereas others persist and become more integral, or core, to who we are. I’m sure that’s the case with those who we love most, those about whom we care the most. So, there is, indeed, a part of ourselves which will be diminished, or even lost, when a loved one dies.
I don’t know if you’ve ever encountered the story of the “air telephone” in the garden of a survivor of the 2011 earthquake and tsunami in Japan. It’s an incredibly moving story. You can read it here – https://observer.co.uk/style/how-we-live/article/wind-phone-japan-grief and it’s beautifully told in the “This American Life” podcast in this episode – https://www.thisamericanlife.org/597/one-last-thing-before-i-go-2016
The telephone box, containing a telephone which wasn’t connected to anything, became a place to grieve, by allowing survivors to spend some time speaking to their dead loved ones. This story came back to my mind the other day when I was watching the final scene of the final episode of DCI Banks, where the detective builds a small cairn up on a hill, as a place to go where he could speak to his dead loved one.
Culturally, we’ve shifted away from graveyards filled with the headstones of those who have passed, to cremations, with the remains scattered in places of meaning, or, sometimes, behind a plaque, but, whatever we do, we need to find the special places to connect, to share some time and space, not just to mourn, but to keep alive the unique parts of our selves which those loved ones created with us.
We do, indeed, contain multitudes. In so many ways. We are woven from such complex threads of DNA, of cells, of families, societies and cultures. We are not separate, and we are not alone.








