Is DNA Alive?

No, it’s not alive…mostly. The only sense in which a DNA molecule is a living thing is that it makes copies of itself, although it can’t even do that on its own. Otherwise, DNA fails all the tests: it doesn’t process anything in order to maintain its state, it doesn’t grow and develop, so it has no energized activity that starts or ends—in other words, it’s not born and it doesn’t die.

Somewhere along the line in reading general science I picked up the impression, even though I think I knew better, that DNA strands are alive. They are such vital keys to living organisms, and I read so many descriptions of what DNA does and of “selfish” genes, that although I knew they were blueprints of a sort, they came to seem like living blueprints.

DNA and seed (kew.org)

DNA and seed
(kew.org)

One image that took shape in the back of my mind was that DNA was a kind of seed, and seeds, I thought, are alive. But no, seeds are not fully alive either. They are not active and, until they germinate, they don’t change or develop. (Another familiar item that may seem alive but that doesn’t meet all the criteria are viruses. Viruses are bundles of DNA that become active only when they are inside a cell, at which point they take over the cell and give us the flu.)

It shouldn’t be surprising that some familiar biological components do not, by themselves, meet all the criteria for the complex condition we call “being alive.” Still, surprised I was about DNA. Perhaps because we humans are so fully aware that we are alive, it is easy to think that there must be a fully living seed or even a soul at the root. It is almost more than we can imagine that the liveliness we feel is the product of a complexity of non-living parts. It’s an astounding thing.

Hope Jahren’s ‘Lab Girl’ and the Dramatic Life of Plants

Much as people admire plants, it is difficult to relate to them. It takes a unusual focus to sympathize with a plant’s struggles, to identify with it, to understand its idiosyncrasies. We have an immense range of words and images for capturing our own inner experiences—fear, exhaustion, revulsion, joy, thirst and so forth—but a mere handful for even the most prominent stages of plant life—growing, blooming, wilting, and a few others. This distance isn’t surprising. Plants are different from us in the most basic ways. They are anchored to the ground, they don’t have faces, and they make their own food. We acknowledge them as members of the family of life, but they also seem alien.

blog.plos.org

The poverty of our understanding of plants contributes, I believe, to our uneasiness about the meaning of our lives. We’re prone to feeling that being alive is either an exclusively human pleasure or a lonely human struggle. It’s easy to lose touch with the reality that plants along with animals have been passing through the experiences of growing, struggling, fending off threats, and sometimes flourishing, for hundreds of millions of years and by the billions. We might feel more at home in our own skins if our imaginations could take in the  lives of plants a little more readily.

Hope Jahren helps us do so. Lab Girl, her memoir, traces her life through the rigors of becoming an established research scientist and her workaholic triumphs and disappointments in labs and in the field. The bristling autobiographical chapters alternate with brief essays about how plants function and survive. It’s these plant chapters that most caught my attention. Here are excerpts:

      No risk is more terrifying than that taken by the first root. A lucky root will eventually find water, but its first job is to anchor—to anchor an embryo and forever end its mobile phases, however passive that mobility was. Once the first root is extended, the plant will never again enjoy any hope (however feeble) of relocating to a place less cold, less, dry, less dangerous. Indeed, it will face frost, drought, and greedy jaws without any possibility of flight. ….The root grows down before the shoot grows up, and so there is no possibility for green tissue to make new food for several days or even weeks. Rooting exhausts the very last reserves of the seed.  The gamble is everything, and losing means death. The odds are more than a million to one against success.
But when it wins, it wins big. If a root finds what it needs, it bulks into a taproot—an anchor that can swell and split bedrock, and move gallons of water daily for years.  (52)

     A cactus doesn’t live in the desert because it likes the desert; it lives there because the desert hasn’t killed it yet. Any plant you find growing in the desert will grow a lot better if you take it out of the desert. The desert is like a lot of lousy neighborhoods: nobody living there can afford to move…. A desert botanist is a rare scientist indeed and eventually becomes inured to the misery of her subjects. Personally, I don’t have the stomach to deal with such suffering day in and day out.   (142)

     Here’s my personal request to you: if you have any private land at all, plant one tree on it this year. If you’re renting a place with a yard, plant a tree in it and see if your landlord notices. If he does, insist to him that it was always there….
Once your baby tree is in the ground, check it daily, because the first three years are critical. Remember that you are your tree’s only friend in a hostile world. If you do own the land that it is planted on, create a savings account and put five dollars in it every month, so that when your tree gets sick between ages twenty and thirty (and it will), you can have a tree doctor over to cure it, instead of just cutting it down….
At the end of this exercise, you’ll have a tree and it will have you. You can measure it monthly and chart your own growth curve. Every day, you can look at your tree, watch what it does, and try to see the world from its perspective. Stretch your imagination until it hurts: what is your tree trying to do? What does it wish for? What does it care about? Make a guess. Say it out loud.    (282)

Jahren’s language seems at first to personify plants heavily and maybe excessively, but she’s careful. She parallels our own emotional experiences with similar situations that plants experience in whatever way they experience them. Putting down the first root really is an all-or-nothing risk even if the seed doesn’t go through the sleepless nights that we would. Desert plants really do “suffer” in that they function minimally in their near-lethal environment. In this way Jaren brings us closer to aspects of plants’ lives that we cannot easily think about. Most people are more inclined to imagine what it is like to live on the moon than what it must be like for the tree in the backyard to be bracing for winter. We can’t know for sure how a plant experiences events, but we can, as she urges us, “stretch [our] imagination until it hurts.”

And then there’s “you’ll have a tree and it will have you.” Considering the world’s deteriorating environment, Jahren argues, if one tree can rely on you, that tree is well off. I would add that the benefit is mutual; we ourselves are better off if we can share and feel, even faintly, the life of any plant.

Oliver Sacks and the Comforts of Metal

Oliver Sacks and Robin Williams on the set of Awakenings (brainpickings.org)

Oliver Sacks and Robin Williams on the set of the film Awakenings
(brainpickings.org)

I was first aware of Oliver Sacks with the publication in 1985 of his book The Man Who Mistook His Wife for a Hat. The descriptions of his mentally ill patients were as intriguing as the title. A few years later, Robin Williams played Sacks in Awakenings, the story of the kind and idealistic doctor who finds a drug that revives his catatonic patients at a hospital in the Bronx.

Sacks died of cancer in 2015. He had been writing for a few months for the New York Times about his struggle. One of these wrenching and beautiful pieces is “My Periodic Table.” In it, Sacks describes three aspects of nature in which he sees different sides of himself.

“Times of stress throughout my life have led me to turn, or return, to the physical sciences, a world where there is no life, but also no death.” With death approaching, “I am again surrounding myself, as I did when I was a boy, with metals and minerals, little emblems of eternity.” These include element 81, Thalium, a souvenir of last year’s 81st birthday; Lead, 82, for the birthday just celebrated; and Bismuth, 83. “I do not think I will see my 83rd birthday, but I feel there is something hopeful, something encouraging, about having ‘83’ around.”

(Reading this touched off my own memory of how, as a boy, I tried with my father’s help to collect all 92 natural elements. In a display case on the wall over my bed I placed some sulfur and carbon from my chemistry set, small bottles of hydrogen, nitrogen and other gases that I had made, and bits of lead, iron, and other metals. Bringing together in my room the building blocks of nature felt like a commanding achievement, though the final display came to only about 20 items.)

While Sacks finds consolation in the basic metals, he responds differently to the stars. About viewing the starry sky one night, he writes that “It was this celestial splendor that suddenly made me realize how little time, how little life, I had left. My sense of the heavens’ beauty, of eternity, was inseparably mixed for me with a sense of transience—and death.”

Lastly, when he “wanted to have a little fun” before beginning immunotherapy, he visited the lemur research center in North Carolina. “Lemurs are close to the ancestral stock from which all primates arose, and I am happy to think that one of my own ancestors, 50 million years ago, was a little tree-dwelling creature not so dissimilar to the lemurs of today. I love their leaping vitality, their inquisitive nature.”

A lively ancestor, mortality among the stars, deathless birthday metals—a sacred trinity of sorts, Sacks’ selection of holy companions. We select from nature according to our joys and fears. The chemical elements mean little to me now and I don’t have thoughts one way or the other about metals and their durability. But I share sometimes Sacks’ sense of feeling belittled by the stars; they do inspire awe, but in contemplating my life and death, I’m in need of something friendlier. For me, Sacks’ lemurs are on a better track. I find consolation by including myself among the mass of organisms of all kinds—not just humans—living and dying now, the wave of rising and falling life as the current of beings sweeps on, out of its billion-year past.