Microcosm_ E. Coli and the New Science of Life - Carl Zimmer [90]
With the invention of yogurt an entire ecosystem of bacteria evolved. Yogurt was first developed by nomadic herders in the Near East about five thousand years ago. They probably happened to notice one day that some milk had turned thick and tangy, and that it also proved slow to turn rancid. Plant-feeding bacteria had fallen into the milk and had altered its chemistry as they fed on it. The herders found that adding some of the yogurt to normal milk transformed it into yogurt as well. The bacteria in those cultures became trapped in a new ecosystem, and they adapted to it, evolving into better milk feeders and jettisoning many of the genes they no longer needed.
For thousands of years, humans continued to tinker with animals, plants, and microbes in this same semiconscious way. But as the microbial world unfolded beginning in the nineteenth century, scientists discovered new ways to manipulate nature. The first attempts were simple yet powerful. Louis Pasteur demonstrated that bacteria turned wine sour and contaminated milk. Heat killed off these harmful microbes, leaving children healthier and oenophiles happier.
As microbiologists discovered microbial alchemy, they searched for species that could carry out new kinds of useful chemistry. Chaim Weizmann, the first president of Israel, originally came to fame through his work in biotechnology. Living in Britain during World War I, he discovered bacteria that could manufacture acetone, an ingredient in explosives. Winston Churchill quickly took advantage of it by building a string of factories to breed the bacteria in order to make cheap acetone for the Royal Navy. The next generation of microbiologists began manipulating genes to make them even more efficient. By bombarding the mold that makes penicillin, scientists created mutants with extra copies of penicillin genes, allowing the mold to make more of the drug.
As scientists discovered how to manipulate life, they wondered what sort of world they were creating. In a 1923 essay, the British biologist J.B.S. Haldane indulged in some science fiction. He pretended to be a historian of the future looking back on the 1940 creation of a new strain of algae that could pull nitrogen from the air. Strewn on crops, it fertilized them so effectively that it doubled the yield of wheat. But some of the algae escaped to the sea, where it turned the Atlantic to jelly. Eventually it triggered an explosion in the population of fish, enough to feed all humanity.
“It was of course as a result of its invasion by Porphyrococcus that the sea assumed the intense purple colour which seems so natural to us, but which so distressed the more aesthetically minded of our great grandparents who witnessed the change,” Haldane wrote. “It is certainly curious to us to read of the sea as having been green or blue.”
For the next fifty years, hope and dread continued to tug scientists in opposite directions. Some hoped that biotechnology would offer an alternative to a polluted nuclear-powered modern world, a utopia in which poor nations could find food and health without destroying their natural resources. Yet the notion of rewriting the recipe for life sometimes inspired disgust rather than wonder. It might well be possible to create an edible strain of yeast that could feed on oil. But who would want to eat it?
Aside from scientists, few people took these speculations very seriously. For all the progress biotechnology made up until 1970, there was no sign that life would change anytime soon. And then, quite suddenly, scientists realized they had the power to tinker with the genetic code. They could create a chimera with genes from different species. And they began their transformation