the web site of Austin-based writer Eileen Mcginnis.


a blog about caregivers + creators throughout history.


“One is the Loneliest Number”: Evolutionary Biologist Lynn Margulis and the Murky Boundaries of the Parental Self

I don’t know if I can define myself anymore, now that I’m your mother. You’ve consumed me.

-       Camille T. Dungy, Guidebook to Relative Strangers


“Hello, Self. I am a self.”

About a year ago, One Bad Mother co-host Theresa Thorne offered listeners a telling anecdote. With two kids under six plus a newborn, Thorne described feeling like a conglomeration of appendages Doing Things for her three children all day long—nursing, packing lunches, picking up toys. So, as odd moments of the day she would pause to remind herself, out loud, that she was, in fact, a self.

While confessing to this tragi-comic exercise on the podcast, Thorne delivered the line Hello, Self in a humorless monotone. She sounded like a robot rebooted into consciousness. Her voice was stiff, unconvincing. Doubt had crept in.

This mantra from my favorite podcast came to mind over the winter holidays, when I was out at breakfast catching up with some grad-school friends. While my son was briefly occupied, one of them turned to me and asked about…me. I froze. In that moment, my mind conjured up a white wall of ice between her good-natured inquiry and the information I was seeking. What have I been up to lately? Who am I again?

But the dilemmas we have about selfhood as parents—about maintaining the integrity of the self, or reconnecting with a lost self—go deeper than a lack of time for self-care or introspection.

The more I read up on the latest areas of scientific inquiry, from the vast microbiome in our gutsto the renegade fetal cells that inhabit our bodies long after pregnancyto the approximately 8% of human DNA acquired from ancient viral interlopers, the more I grow convinced of this: the independent self that I’ve been hunting for since giving birth was never really there to begin with.

As Valentine’s Day approaches, I come bearing a message that is perhaps comforting, perhaps terrifying:  

You are not alone. Because whatever tricks mind and memory may play on you, you are not a self.



In 1967, a 29-year-old scientist and single mother of two published a paper that exploded the standard evolutionary narrative.  

Building on earlier, largely speculative currents at the margins of her discipline, she put forth the first rigorous case for endosymbiosis (symbiosis in which one organism lives inside the other) as a driving force in the evolution of multicellular life. Specifically, she “surmised that mitochondria, chloroplasts, and other cellular organelles might be descended from bacteria that had been devoured by other single-celled organisms and somehow survived within the organisms’ bodies.”  

In other words, the structures that today are so integral to powering the cells of animals (mitochondria) and plants (chloroplasts) were at one time independent beings, alien hitchhikers from elsewhere.

“Origin of Mitosing Cells” might sound a bit dry, but make no mistake: this paper, like its author, had hutzpah. Her title echoed the language of Darwin’s On the Origin of Species, in order to argue that evolutionary novelty is not derived primarily from natural selection on random mutations, as Darwin had claimed; rather, it often occurs through sudden acts of fusion, synthesis. Surreptitious mergers, more so than bloody struggles, make the world go ‘round.

The byline on this bold pronouncement of our fused evolutionary histories? Lynn Sagan. The name was a vestige of a less successful entanglement of selves: the marriage of Lynn Alexander (later Margulis) and the astrophysicist and science popularizer Carl Sagan.

Lynn and Carl on their wedding day.

Lynn and Carl on their wedding day.

When the two met on The University of Chicago campus in the early 1950s, Sagan was a cocky 19-year-old graduate student in astronomy; Lynn Alexander, a 15-year-old prodigy starting her freshman year as a liberal-arts undergraduate.

Margulis would later describe their union, which lasted from 1957 until 1965, as “a torture chamber shared with children.” The couple had argued and broken up constantly even before their marriage. These tensions were exacerbated by a gender imbalance in their caregiving:

As one visitor remembers it, [their son] Dorion, in another room, would scream at the top of his lungs. Lynn would bolt to see what was the matter. Carl would finish his sentence, unperturbed…. He expected Lynn to handle all the duties of a 1950s housewife, from washing dishes to paying the household bills. Unlike most housewives, Lynn was trying to juggle two infants and a demanding husband with getting a doctorate.

Despite the unsustainability of these competing demands, Margulis was…prolific. She earned a Master’s in zoology and genetics from The University of Wisconsin at Madison in 1960; a Ph.D. in genetics from UC Berkeley in 1965. She gave birth to two boys: Dorion and Jeremy, in 1959 and 1960, respectively. And by the time her controversial paper came out in the Journal of Theoretical Biology in late 1967, she was remarried, to the crystallographer Thomas Margulis (they divorced in 1980, after having two children together).

In Symbiotic Planet, Margulis writes rather cryptically of that time. She glosses over the particulars of her personal struggles to linger on the larger evolutionary drama.

There are glimpses, though, of her domestic life and attitudes. Margulis admits that “More than husbands, I had always wanted children.” She would later choose motherhood, and science, over marriage: “I quit my job as a wife twice. It’s not humanly possible to be a good wife, a good mother, and a first-class scientist.” Margulis knew her priorities.

Margulis’s eldest child, Dorion Sagan. Margulis and her son would later author several books together, including the influential  Microcosmos  (a dig at Carl Sagan’s  Cosmos  perhaps?)

Margulis’s eldest child, Dorion Sagan. Margulis and her son would later author several books together, including the influential Microcosmos (a dig at Carl Sagan’s Cosmos perhaps?)

While pregnant on extended bedrest in 1969, gestating a fourth child (daughter Jennifer), Margulis also hatched the idea for her first book, on what she termed serial endosymbiosis theory (SET). She recalls late-night and pre-dawn writing sessions, “even earlier in the morning than the voices of children.” But her manuscript was returned unceremoniously five months later, her contract with Academic Press broken due to hostile peer reviews.

Through clever wordplay, Margulis links her experience of working motherhood in the 1950s and ‘60s to her wide-ranging, synthetic approach to science:*

I was no more constitutionally inclined to focus monomaniacally on the cell nucleus than I was to be a satellite wife in a nuclear family; my attentions, like that of many women, were divided. My friend Mary Catherine Bateson describes modern women as ‘peripheral visionaries.’ A woman must be almost octopoid in her attentions if she is to survive. Holding the infant in one arm, Bateson points out, she stirs the pot with another, while she watches the toddler.

This idea of mothers as peripheral visionaries—outsiders with a view from the margins—suits Margulis’s sense of herself as a scientific provocateur. Aside from ‘synthesizer,’ she might well describe herself with another word: iconoclast.**


Textbooks today present endosymbiosis as a dry, factual inevitability. There is no drama in the telling. No hint of the 15 rejection letters that Margulis received before her landmark article was accepted.

I want to grab those textbooks by the shoulders and shake them!*** We—that is, all multicellular life—owe our much-vaunted complexity to so-called ‘lowly’ bacterial ancestors! Who, rather than being digested, somehow survived to reproduce, trading their autonomy for longevity. Yet, as Margulis discovered, they still retained their own separately heritable DNA, a faint marker of their former independence.

From the very first, then, our destinies have been intertwined not only with those of vastly different species, but with entirely different kingdoms of life.

Margulis’s body of work in theoretical biology thrives on these unlikely pairings. She writes, for example, about how partnerships between plants and fungi enabled life to make its precarious journey from the sea to the land, which, 500 million years ago, was a dry, nutrient-poor, inhospitable place.

Then, there’s her research on the Gaia hypothesis, first proposed by the English chemist James Lovelock in the early 1970s. Although dismissed as a science-meets-New Age version of the Earth Mother, the Gaia hypothesis does not propose that our planet is a single organism. Instead, it suggests that, through complex interactions, the living matter on earth is able to maintain the planet’s temperatures and atmospheric composition at life-sustaining levels.

The Gaia hypothesis

The Gaia hypothesis

Even though the Gaia hypothesis does not posit ‘selfhood’ for the planet, it does argue for a new perspective on life’s interconnectedness—with itself, and even with the planet’s inorganic matter.

Not just on the micro but on the macro scale, life refuses to be contained, packaged into neat binaries of self and other.



When I was younger, my mom would hug me close and whisper, “You and me, we’re the same person. We’re the same.” In the throes of teenaged differentiation from my parents, I found this sentiment cloying, claustrophobic.

Now, I have a better idea of where she was coming from. The emotional tug, the craving whenever I’m away from my son for too long, after that initial celebratory surge of freedom wears off. The sense of incompleteness, like some vital part of me—a limb, a lung—has gone roaming.

I also have a better understanding of the literalness of her claim. Despite inhabiting different bodies, my mom and I remain tethered on the biochemical level: the mitochondrial DNA I’ve inherited only through my mother; the bits of my fetal self that continue to circulate in her, nearly 40 years after giving birth.

That, and more: our very existence as placental mammals, with the capacity to grow young inside our bodies, began with a viral infection.

Retrovirus genes became incorporated into the placental DNA of mammals not once, but multiple times in evolutionary history. In viruses, these genes fuse cells together into a protective envelope; in mammals, they function to build one layer of the placenta, which mediates between the mother’s blood and that of the fetus. Without these ‘envelope genes,’ this crucial boundary between placenta and fetus is weakened. The fetus does not survive.

We mammals needed genes from a virus to make it safe to hold mother and child, self and other, in a risky new configuration inside the body.

The crucial role of viruses in the evolution of placental mammals gives a new perspective on the humble partnerships that played out, over time, to make us ‘us.’ Behind the scenes, these viral symbionts were modestly driving the evolution of that messy / longed-for / unwanted / magical / draining / heart-wrenching / brutal / intimate / invasive / utterly bizarre phenomenon we call pregnancy.

As Margulis puts it, “We can no more be cured of our viruses than we can be relieved of our brains’ frontal lobes: we are our viruses.”


I started researching this essay with a hypothesis: that Lynn Margulis’s early experience of motherhood, of being intertwined with other lives in that uniquely intimate way, might have shaped her ideas about symbiosis’s role in the evolution of life.

The data never really confirmed my hunch (to call it what it is). Margulis got interested in cytoplasmic DNA before she became a mother. At the time, the spotlight in her field was on DNA in the nucleus, and she felt dissatisfied with the prevailing notion that the other parts of the cell were unimportant, mere junk collected along the way. She also balked at the Balkanization, as it were, of the sciences, finding in theoretical biology an appealing opportunity to synthesize findings in evolutionary theory and microbiology.

So, rather than project onto her, let me admit this: symbiosis is a compelling metaphor for my own dissolution, engulfment, after parenthood.

New motherhood breaks down those supposedly sacrosanct boundaries. Faced with the urgent demands of a ravenous infant, I’ve casually exposed my breasts in front of my father-in-law. With a baby, then toddler attached to me at the hip, I’ve had to unlearn the deeply ingrained belief that the bathroom should be a private space.

As if in compensation for that lost sense of myself as an individual, parenthood has offered instead a different awareness of life’s interdependence. Like our viral and bacterial ancestors, I’ve traded autonomy for longevity. My child has permanently altered my connection to the planet, to mortality, to the life cycle.

In a recent email, my brother-in-law Tim, who is also the father of a 9-month-old baby, echoed some of these existential musings. He had borrowed my copy of Kurt Vonnegut’s novel Galapagos, which imagines how a population bottleneck might have affected our species’ evolution over the next million years.

Tim’s meditation on the book captured this paradox of new parenthood: how a laser-like focus on a small organism requiring your constant care can also generate a mind-altering expansiveness. A sense of connection across space and time, without the aid of ‘shrooms:

In a way a book considering a million years of human evolution is a check on how much we can agonize about decisions in our lives. (Eeeek!) On the other hand, it’s sort of beautiful just being a mammal on this earth and sharing time with other mammals. I’m holding a little mammal now as she goes back to sleep— she needs things that mammals need: closeness, warmth, food, a cozy place to sleep, etc. And soon she’ll be asking questions that your slightly bigger mammal wrestles with. (Mommy, are you going to die?) Yes, we all will, someday, and a thousand generations of us will after that if we’re lucky, but some part of us won’t, or maybe by that point it won’t matter….

Long story short, it’s really fun getting to be alive with you all, sharing this tiny slice of evolutionary history. 

Tim’s comment, and Margulis’s example, give me the courage to get comfortable with a more expansive, evolutionary perspective. Not to shrink in terror from our symbiotic nature, but instead to meet it with curiosity. To be open to the peripheral visions that emerge once we stop clinging so tightly to a narrow definition of selfhood.

To embrace, in a word, “awe.”****

Lynn Margulis.

Lynn Margulis.

For more un-Valentine’s posts, check out last year’s essay “Love and Cruelty,” about primatologist and father Harry Harlow.



*In yet another synthesis of science and motherhood, Margulis learned about her first pregnancy while at the lab: “One day, while Lynn was in her biology lab pipetting a solution of amoebas, she fainted. When she came to, she was on the floor, the pipette still in her mouth. She instantly knew she must be pregnant.”

**Some of Margulis’s provocative ideas push boundaries in less satisfying ways, especially her conviction that 9/11 was an inside job.

***Margulis is similarly peeved. She writes in Symbiotic Planet, “Today I am amazed to see a watered-down version of SET taught as revealed truth in high school and college texts. I find, to my dismay if not to my surprise, that the exposition is dogmatic, misleading….Unlike the science itself, SET now is uncritically accepted. So it goes.”

****Margulis again: “Our deep connections, over vast geological periods, should inspire awe, not repulsion.”

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