In 1970, the biologist Lynn Margulis applied for a grant from the National Science Foundation. Three years prior, a small scientific journal had published Margulis’ paper in which she outlined a provocative theory about the evolution of life. She had hoped to continue that work with funding from one of the major federal agencies to support science and engineering research.
In a 1998 interview, she recalled what an NSF grant officer had told her: “There are some very important molecular biologists who think your work is shit.” According to Margulis, the officer also said her work appealed to “small minds” in biology. His message was clear: Your application is rejected, and don’t bother applying again.
At first, Margulis didn’t know where to turn for support, but there was a major new organization in science that offered promise: The National Aeronautics and Space Administration, or NASA for short, had been founded just 12 years earlier, mere months after the Soviet Union had launched Sputnik, the world’s first artificial satellite. Eager to do work on the origin of life, a NASA scientist approached Margulis in 1971 and agreed to provide seed funding for her research.
“This was a key moment in modern biology,” said Robert Hazen of the Carnegie Institution for Science in an interview this year.
Up until then, many scientists embraced “neo-Darwinism,” a view of evolution in which change happens slowly and is driven by small, random genetic mutations that benefit an individual organism — be it a finch, a giant tortoise, an orchid, or a barnacle. Over time, these changes may lead to the creation of new forms of life. It’s a process that can be viewed in the fossil record. For example, just two years after Charles Darwin published his classic text, “On the Origin of Species,” a now-famous fossil was discovered of a creature with teeth, a long bony tail, and wings. Known as an Archaeopteryx, it is believed to represent a transitional form between dinosaur and bird.
But with NASA’s support, according to James Strick (co-author of “The Living Universe”), and others, scientists began to study life from a completely different perspective. Rather than only using fossils hidden in rock layers to study evolution, some scientists turned to the wide variety of living bacteria. What they produced in the ensuing decades was a new, microbial view of the evolution of life — one that today, according to Jan Sapp, a professor of biology and history at York University in Toronto, forms the foundation for evolutionary biology as it is routinely taught in classrooms across the world. It is a line of inquiry that has been buoyed by the emergence of advanced genetic sequencing tools that have allowed biologists to reconstruct, in increasingly exquisite detail, the steps taken over millennia of evolutionary change.
And all of that leaves NASA — an agency associated largely with feats of technology and engineering, nominally devoted to interstellar exploration, and born of a bitter, militaristic, geopolitical space race — as the unlikely catalyst for a revolution in, of all things, biology.
On a Friday afternoon, October 4, 1957, a satellite went up and by evening, the news had travelled around the world. “The success of Sputnik seemed to herald a kind of technological Pearl Harbor,” wrote Pulitzer Prize-winning journalist David Halberstam, echoing an observation from physicist Edward Teller. “Suddenly, it seemed as if America were undergoing a national crisis of confidence,” Halberstam wrote in his 1993 book “The Fifties.” It was the Cold War, with Russia and the U.S. competing to lead the world into the future. Sputnik declared at a stroke that the Russians were winning the race. A book called “Why Johnny Can’t Read — and What You Can Do About It” suddenly became a smash bestseller. Life magazine printed an article called “Arguing the Case for Being Panicky.” And in government, the White House and Congress shifted gears. Science was suddenly front and center.
Within 11 months of Sputnik’s launch, President Dwight D. Eisenhower had created the job of presidential science adviser, Congress had increased federal education funds by more than a billion dollars, and NASA was founded with a $100 million annual budget. The work NASA was founded to do was to put American astronauts into space. But scientists, led by Nobel Prize winner Joshua Lederberg, saw additional opportunities. In the weeks after Sputnik, Lederberg wrote memos to senior scientists around the country. A few months later he formalized those memos into an article for Science magazine.
In a 1998 interview, Margulis recalled what a grant officer had told her: “There are some very important molecular biologists who think your work is shit.”
Lederberg had seen Sputnik in the sky while on an academic trip in Australia. He was both exhilarated and frightened by what it portended for biology. Space had been breached. Much more would follow. Knowing a bit of history, he realized that humans had thoughtlessly contaminated every place they had visited on Earth. Now humans would soon be travelling to moons and planets. “Since the sending of rockets to crash on the moon’s surface is within the grasp of present technique, while the retrieval of samples is not, we are in the awkward situation of being able to spoil certain possibilities for scientific investigation for a considerable interval before we can constructively realize them,” he wrote in Science.
As Lederberg and other scientists saw it, this was humanity’s first chance to look for life, or even for pre-life chemistry, beyond Earth. That meant, first, that spacecraft had to be sterilized in order not to be sampling their own waste. And second, it meant trying to figure out what to look for. Water, carbon, other basic chemicals? What would life look like if it were just getting started? What would it look like where there were few resources?
NASA had been created with distinctly political and military ambitions. But scientists like Lederberg worked hard to insert science — in particular origin of life research — into the agency’s mission and to make the program civilian. Ultimately, NASA appointed a 40-year-old biologist, Richard S. Young, to lead a program devoted to exobiology, a term coined by Lederberg to refer to scientific work on extraterrestrial life.
It was clear to Young that exobiology did not fit comfortably inside the traditional biology of the great institutions of the National Science Foundation and the National Institutes of Health, and so Young recruited the first generation of exobiologists from people of mixed backgrounds, including Lederberg, Margulis, and a University of Illinois professor, Carl Woese.
When Margulis arrived in graduate school, the University of Wisconsin had just built a huge electron microscope, among the most powerful in the world. Through it, she could see things that had previously been invisible. Most notably, she observed tiny structures called mitochondria. There are hundreds, on average, inside each cell in a complex organism, and their function is to convert food into energy.
Looking into the microscope, Margulis seized on an idea that had been floated much earlier but had never gained much currency: that these mitochondria — found in the cells of complex organisms from humans, to horses, to honeybees — are remnants of once free-living bacteria. Even more important, the origin of eukaryotic cells — of all the “higher organisms” — came with the merging somewhere back in evolutionary history, of two simpler single-celled organisms. This symbiosis had become a new, more complex creature altogether. Margulis was soon on the path to showing how central that merger was, not just to individuals, but to evolution as a whole. After all, in this scenario, evolution occurred not gradually, but through a big, sudden change.
Many biologists found the notion of symbiosis hard to accept. The writer David Quammen asked a scientist whether Margulis was “perceived back then as being radical or flakey?”
“Uh-huh,” the scientist said, “Right from the beginning I think.”
But her ideas were proved right by the methods of another odd man out in science who was also funded by NASA: Carl Woese. A biophysicist and microbiologist, Woese felt himself an outsider in biological science, unappreciated and on the sidelines. Francis Crick, James Watson, and a few others were the stars in the field. “I differed from the whole lot of them,” Woese wrote. While others obsessed about the grand molecule that carries the information of life, DNA, Woese instead fell in love with the skinny, single-stranded ribosomal RNA that took the rich information stored in DNA and made it into working molecules — the proteins of the living cell.
This molecule is the most conserved of all those in biology, meaning it can be found in every living thing and is likely to have existed for all the four billion years of life on Earth. If you were going to compare creatures to determine which came before and which were most similar, this would be the part to compare. For big animals, comparing necks and limbs and other features worked pretty well, but for the rest of living things — which are microscopic and basically round or oblong — that approach was useless. So, Woese and his team began to extract RNA from living organisms. They strung it out in bits on a sheet of wet plastic so that they could eventually compare the genetic sequences of microbes.
As Lederberg and other scientists saw it, space exploration was humanity’s first chance to look for life, or even for pre-life chemistry, beyond Earth.
Woese thus pressed forward a new kind of “fossil record” — one that marked similarities and differences between certain key molecules. In diving into this record, he discovered an entirely new form of life, with genetic sequences unlike bacteria and unlike the eukaryotes that made up bigger creatures in biology. He eventually called the unknown creatures Archaea.
Margulis had worked, not with molecular fragments of creatures, as Woese had, but up to her elbows in the slimy creatures themselves. Margulis and Woese were something of opposite characters. She was warm and social. Woese was somewhat reclusive and shy; he studied medicine for two years, then quit after the first two days of his rotation in pediatrics. He could party with a few very close friends, but rarely. The two each had a bit of disdain for the other’s specialty. Margulis thought of molecular biology as sterile and divorced from real life. Woese thought of the creatures of biology as messy and confusing, not at the intellectual center of things.
But when it came to proving Margulis’ hypothesis that the mitochondria in humans and all other animals and plants were bacterial, it was Woese’s methods that gave the initial proof.
W. Ford Doolittle, a NASA-funded biologist at Dalhousie University in Halifax, was intrigued by Margulis’ work. “Her ideas didn’t seem all that flakey to me because there was some work already out there, even though it had come along decades before we had been born,” he said. With advances in gene sequencing technology, he spotted an opportunity to answer the open question of whether mitochondria evolved from free-living bacteria. All a scientist needed to do was pinpoint the genetic sequence of mitochondrial RNA and then compare it with the sequences of bacterial RNA and of nuclear RNA. Which was it more like?
In the early 1970s, one of Woese’s lab members arrived in Halifax and joined Doolittle’s group. Linda Bonen was an expert in the new sequencing techniques and in the ensuing years, her skills, along with help from another researcher, Michael Gray, would make such genetic comparisons possible. The work resulted in a number of papers, including one published in 1977 showing that the RNA in wheat mitochondria doesn’t resemble the RNA inside wheat’s nucleus. Instead, it resembles the RNA of bacteria. Essentially, years of doubt and debate ended at once. Margulis’ hypothesis was demonstrated correct. In 1983 she won membership in the National Academy of Sciences, the single badge that in America says you are a top-ranking scientist. She later won the highest honor in American science, the National Medal of Science.
It all came in a string of work by outside-the-mainstream scientists working with fresh NASA money made possible by Sputnik. They remade the central theme of biology.
Years of doubt and debate ended at once. Margulis’ hypothesis was demonstrated correct.
“There is a new biology,” said Doolittle, in a telephone interview from Nova Scotia. “It’s microbially-oriented, rather than just animal- and plant-oriented.” As a student, Doolittle learned about animals and plants. “We thought of bacteria as an afterword,” he said. “Now it’s clear that the world is microbial,” and this shift, says Doolittle, is due to the pioneering work of scientists like Margulis and Woese.
All of this has put new opportunities before students. Biology students now range all over the world, many to extreme environments, to seek out new bacteria and learn how they survive. One of the biggest projects in all of biology, the Deep Carbon Observatory, has completed its first 10 years exploring relations between bacteria and the planet, with more than 1,200 scientists in 55 nations.
The wider public has caught on, too. Margaret McFall-Ngai, an animal physiologist and biochemist at the University of Hawaii, illustrates it this way: “If, getting on a plane, I make the mistake of saying I work on microbiology and human health,” she says, her seatmate will inevitably ask about the human microbiome. The subfield — devoted to the bacteria that live on and inside of us — is one of many with roots in the new biology. And McFall-Ngai can predict how the conversation will go: “I’ll be in for two hours of questions.”
Philip J. Hilts is a journalist and author, and formerly the director of the Knight Science Journalism Program at MIT.