Cosmic Apprentice: Dispatches from the Edges of Science (4 page)

WEIRD DALLIANCES AND UNEXPECTED SPECIATIONS

In an unexpected textbook example of speciation, the Columbia University geneticist Theodosius Dobzhansky selected fruit flies for their ability to withstand heat and cold. Dobzhansky found that after two years the heat-adapted flies could no longer successfully fertilize cold-living ones. The two separated populations of
Drosophila paulistorium
now conformed to the traditional zoological definition of new animal species. They had been reproductively and geographically isolated, and were now only able to breed with their own kind.

However, Wolfgang Miller of the University of Vienna Medical School, Austria, later found that the “cold-fertile fly population” had retained a symbiont widely distributed in certain tissues, whereas the “hot-fertile flies” had been “cured” of the symbiont. In fact, Dobzhansky’s flies evolved as a result of the presence or absence of “mycoplasma,” now recognized to be in the aforementioned genus of
Wolbachia.
In other words, the presence or absence of a bacterium, not neo-Darwinism’s much-vaunted but still theoretical gradual accumulation of random genetic variations, correlated with what is, besides the Jeon experiments, perhaps the only real-time observed example of a speciation event.

Humanity’s discovery of and battle with pathogenic microbial strains has misled us to think that microbes are generally extraneous to our bodies and health. But increasingly scientists are realizing that we have, we in part are, an adaptive microbiome, the endogenous collection of often “smart” microbes that is not only negatively connected to sickness but positively correlated to warding off obesity, asthma, allergies, and other maladies. Tel Aviv University’s Eugene Rosenberg found that
Drosophila pseudoobscura
fruit flies would mate only with others on the same diet; antibiotics removed their dietary pickiness, leading to promiscuity and suggesting that possession of specific gut microbes can be like membership in a special club, leading to selective mating and ultimately speciation. And it is likely not just insects. Our symbiotic bacteria are connected to digestion, sense of smell, immunity, and other aspects of physiology. Prokaryotes are part of the hologenome; they are not just hangers-on but genetic actors.
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Such are the new facts—factishes—of life. As genes are not selves, the notion of the selfish gene remains a trope. Selves are materially recursive beings with sentience, and the minimum self seems to be a cell. Because life is an open thermodynamic system, as well as an open informational one, genomic transfer is rampant.

Leaflike green slugs (recently shown to manufacture chlorophyll themselves)
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and underwater snails with rows of green plastids feeding them show how plants and animals can merge.
Convoluta roscoffensis
does not eat but burrows under the sand of the beaches of Brittany out of harm’s way when the surf pounds (or a research scientist stomps his wading boots); when the danger passes, the animated algae, the green worms, then reemerge into the sunlight. The “planimal” is fed by the green building of its body, the living architecture that it gardens and which feeds it from within.

It seems unlikely that any cosmic deity arranged for the partners that are
C. roscoffensis
to come together, but they did, partly of their own accord, and they probably would have looked odd anyway on Noah’s Ark.

Identifiable new behaviors, combined skills and physiologies, and even multigenome personalities also affect us. Human gut microbiota are not simply hangers-on but influence the timing of maturation of our intestinal cells, our internal nutrient supplies and distribution, our blood vessel growth, our immune systems, and the levels of cholesterol and other lipids in our blood.
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They also—partly because of the presence of neurons in the mammalian intestinal tract, and the communication between gut and brain—influence human mood. Lab work with
Campylobacter jejuni
shows that this bacterium increases anxiety in mice, whereas the soil bacterium
Mycobacterium vaccae
inside them cheers them up. In people it has been suggested that yogurt with live cultures, for example with bifidobacteria, improves our sense of well-being.

TOXO

Toxoplasma gondii
is a protist notorious for infecting pregnant mothers who may contract it from kitty litter. From the mother
Toxoplasma
moves to the fetus, often devouring it and leading to a miscarriage.
Toxoplasma gondii
sexually reproduces in bodies of members of the Felidae family, notably house cats. But mice, usually afraid of cats, lose their fear when their brains become infected with
Toxoplasma.
Also, and curiously, they become sexually attracted to feline urine.

Toxoplasma
also infects large numbers of humans. Even though a possessor of
Toxo
may not know it’s there, he or she can be affected by it.
Toxoplasma
infection in men correlates with enhanced risk taking and jealousy. An index of the risk-taking behavior is provided by the fact that males in car and motorcycle accidents are more likely to test
Toxoplasma
-positive.
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Toxo
-men are more likely to be unfriendly, unsociable, and withdrawn. Even if bereft of obvious symptoms, men who carry
Toxoplasma
are less likely, relative to controls, to be found attractive to women.

Women are another story. Women with
Toxoplasma
are more likely to be judged outgoing, friendly, and conscientious—and promiscuous. There is, of course, the complication of the stereotype of the woman who lives alone with all the cats. The caricature of such a woman is not of someone outgoing. Perhaps
Toxo
’s effects alter with age.

However confounding,
Toxo
’s effects seem real.
Toxoplasma
makes enzymes (tyrosine hydroxylase, phenylalanine hydroxylase) that alter brain levels of the neurotransmitter dopamine. Dopamine is a neurotransmitter involved in attention, sociability, and sleep. Cocaine and amphetamines work in large part by blocking the reuptake of dopamine in the brain. Dysfunctional dopamine regulation is theorized to be linked to schizophrenia, and several antipsychotic drugs target dopamine receptors. Up to one-third of the world population is thought to be infected with
Toxo,
with an estimated infection rate of almost 90 percent in France—a result perhaps of their love of rare beef, steak tartare or
saignant,
“bleeding.” More alarmingly still, the Czech scientist Jaroslav Flegr found via MRI scans that twelve of forty-four schizophrenia patients showed significant shrinkage of the cerebral cortex, but that the reduction in gray matter of the schizophrenics was almost completely correlated with those who tested positive for
T. gondii.
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Toxo,
accounting for a range of effects and affects from increased sexual attractiveness and feelings of well-being to full-on mental dysfunction, appears to be a facultative part of our more-than-human hologenome.

We have other “inner aliens.”
Candida albicans
is the yeast fungus that causes vaginal infections and perlèche, a cracking at the corners of the lips. It thrives on easily digestible sugars and carbohydrates such as those found in beer, wine, cracker crumbs, and confections. It was perhaps spread among the wine-drinking revelers of Provence, troubadours who sang and jested, and who may have used makeup as a way to cover cracked lips that literally hurt when they smiled.
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Spirochetes are a stranger case still. Disease species cause Lyme disease and syphilis, and also other conditions. Spirochetes can go into hiding and form “round bodies,” becoming virtually undetectable in cells. Friedrich Nietzsche and others are thought to have been infected by syphilis, whose “tertiary stage” is sometimes marked by a strange clarity of expression and artistic genius as well as madness.

ALFRED NORTH WHITEHEAD ON FACTS

I have talked about how the “facts” of symbiogenesis can in some sense be considered superior to the theory of neo-Darwinism. But since I am speaking about scientific facts to anthropologists,
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I should probably be careful, as there is always the possibility that I am projecting cultural ideas onto the data and that all that we see or seem is but a culturally refracted dream.

According to Alfred North Whitehead, science is the bastard offspring of “irreducible and stubborn facts” (a phrase he took from William James in a letter to his brother, Henry) and the Greek genius for lucid theorizing.
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Whitehead argues that, far from mental gymnastics, an “anti-intellectualist” strain was crucial for science’s development—to protect it from the insular hyperconceptualization of mere academic thought.
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Science had to move away from the mannerist overdeveloped rational architecture of philosophy. While the Greeks had developed a remarkable ability to think boldly and clearly, and proceed through precise logic, the medieval scholastics, following Aristotle, expanded reason into a self-perpetuating empire out of touch with the real world. And the antidote was not more thinking but engagement with the real world. Of course, for natural science, engagement did not mean observation of other people, their thoughts or practices, but rather of things and organisms.

Whitehead traces this antischolastic attentiveness, which first developed among some Europeans but belongs to anyone who will have it, in part to, of all things, Greek tragedy—whose essence he says is “not unhappiness [but] the remorseless working of things. This inevitableness of destiny . . . This remorseless inevitableness,” which in human dramas “involves unhappiness” but which “pervades scientific thought.”
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In short, for Whitehead the tragic realm of cause and effect has, if not a happy ending, a promising development: the development of modern science.

Closely observed by attention to facts, the inner workings of fate become reformulated as the laws of physics.

Interestingly, the Greeks—indeed the same Greek, Empedocles—came up with both symbiogenesis
and
natural selection thousands of years before Darwin. Empedocles had this great idea: In prehistory, organs, on their own, roamed the earth and recombined with one another. In other words, they symbiotically merged and were naturally selected. Those that persisted made copies of themselves, messily evolving.

Although Aristotle dismissed Empedocles because his mixed beings suggested irrational Greek myths, and Darwin dismissed Aristotle because Aristotle lumped natural selection with Empedocles, in retrospect Empedoclean biology looks good. If you substitute cells for organs, Empedocles intuited both natural selection and symbiogenesis.

Alas, he did not engage the empirical. To Aristotle, the wacky misbegotten organs that arose on their own and coalesced to make bodies, the less fit ones dying out, must have smacked of passé myth, the mating of Olympians and humans, chimeras and immortals. For Aristotle, Empedocles’s Dionysian imagination must have seemed a return to chaos, with no respect for observation or classification. The fifth century BCE philosopher of Acragas (now Sicily) was loopy. And for Darwin, who knew Aristotle was aware of natural selection because he mentioned it dismissively in connection with Empedocles, both Empedocles and Aristotle were wrong.

Yet as the spiral of science turns, what was once recognized as myth sometimes becomes re-cognized as science. This is the case with symbiogenesis. Strong evidence exists that all eukaryotes evolved suddenly by symbiosis and that many other organisms such as lichens, which combine fungi and algae or fungi and cyanobacteria, did also. We speak of brotherhood, but maybe we should speak of “otherhood.” Others come together in aggregates of expanded energy use, economies of scale, and diverse assemblages where combined skills and redundancies prefigure additional developments. Together mingling beings find energy and the substances they need to live. Corals reefs require photosynthetic symbionts. “White ants,” or termites, cannot digest wood without the living hordes in their guts whose visualization Joseph Leidy compared to the outpouring of a “crowded meeting-house.” Cows, “four-legged methane tanks,” collectively add enough of that gas, unstable in the presence of oxygen, into the atmosphere that aliens, outfitted with spectroscopic devices, might be able to tell that there was life on this planet from the presence of microbially produced methane alone. And that’s no bull, though it’s close, literally. (See
chapter 10
.)

It is hilarious to contemplate that the methanogens releasing gas in the specialized symbiotic cow stomachs called rumens could signal—with no help from humans—the presence of complex life on this planet. But this point that the archaean nonequilibrium chemistry of our atmosphere could serve as a beacon to aliens is serious, too. And it serves as a nice segue into related facts of life I want to talk about now.

SENTIENT FLAMES

Let me turn now briefly to what I consider another evidence-based discourse, a new set of life—and death—facts that may be even less well-known to you than symbiosis but which I consider equally important to understanding life.
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I don’t think it’s possible to understand life without understanding the role of energy. Life is a complex thermodynamic system. Like a whirlpool or flame, the shape alone stays stable as energy is used and matter is cycled. It absolutely depends on the energy and matter. Deprive a storm system of its atmospheric pressure gradient, an autocatalytic chemical reaction of its chemical gradient, or convection of its temperature gradient, and these disappear: their form is dependent on their function—not necessarily their only function, but their basic one. And the same is, elegantly, true of life: if you deprive cyanobacteria or purple sulfur bacteria or plants of their solar energy gradient, or animals of their food-oxygen gradient, they disappear. The big difference with life is that it has found a way, via the recursive DNA-RNA-protein system, to restart the flame.

It is a thermodynamic fallacy that we are destined to die because of wear and tear and inevitable entropic dissolution connected to thermodynamics’ second law. In fact, life’s signal operation, as well you know, is to resist normal wear and tear. While writing this essay, I saw a little kid’s face light up when his parents pointed at a Starbucks and pronounced the magic word, “cookie.” He recognized that sugar gradient much as a bacterium swimming toward sweetness or a sunflower following the light. Of course he is much more evolved than a bacterium or a sunflower: He is human. More to the point, taking a break from writing this essay, in the shower, I rubbed my eye and it swelled and reddened something awful. “Miraculously,” however, it restored itself.