Under a White Sky: The Nature of the Future

Marine biologist Ruth Gates began studying coral reefs in the 1980s. Threats to corals have multiplied from development, to overfishing and pollution, to rising ocean temperatures, to marine heat waves that lead to bleaching. After noticing that some coral reefs were able to recover from damage, Ruth pursued research on what she called “super corals,” studying whether corals that survived artificially stressful conditions could be crossbred, and ultimately “to seed the reefs of the future” (94).

While Gates died prematurely, her research—now known as “assisted evolution”—continued in Australia, where a marine heat wave in 2016 affected 90% of the Great Barrier Reef, making finding solutions even more urgent. Kolbert explores some of those solutions at a lab in Townsville, where the conditions of the ocean are recreated for corals that live in tanks that spawn in concert with wild corals. The goal of the super coral team is to use the gametes released in this spawning event to breed more resilient corals that could survive in future oceans.

To replicate the diversity and ecological significance of the Great Barrier Reef, assisted evolutionary measures would have to be fast and widespread, a stark contrast to the naturally slow process of evolution that formed the real Reef: “it was natural selection—indifferent, but infinitely patient—that had given rise to life’s astonishing diversity” (109). Given that even a basketball-sized chunk of reef can contain as many as two hundred and thirty species of crustaceans alone, it’s unlikely that if the Reef were to be lost, it could be meaningfully recreated, even through large-scale application of combined techniques.

At the conclusion of the chapter, Kolbert describes witnessing the coral spawning; as the corals in tanks released their gametes, volunteers collected them in buckets, painstakingly mixing them by hand because the facility lacked the ocean waves that would normally break up the bundles.

CRISPR is a gene editing software “that allows its users to snip a stretch of DNA and then either disable the affected sequence or replace it with a new one” (116). This rewriting of the basic building blocks of life is relatively simple: Kolbert describes using a CRISPR kit she bought for $209 to create a new organism, an antibiotic-resistant E.coli. At the high-security Australian Animal Health Laboratory, Kolbert witnesses a larger gene-editing experiment to control the cane toad, an invasive species introduced in a failed biocontrol measure.

Cane toads, which can be the size of a dinner plate, were introduced to Australia to control a grub that was affecting sugar cane in the early 20th century. Over subsequent decades, the toxic toads quickly spread across the country, poisoning native species as they went; this trajectory was accelerated by a process of rapid evolution, whereby toads generated longer front legs to speed to their progress. Despite various traps and citizen brigades, the toads have continued to spread. One gene-editing solution would change the gene that makes the toads poisonous: Released into the wild, such toads would make predators sick without killing them, training those predators not to eat the fully toxic cane toads. Another option is tinkering with the genetic code to make toad eggs impossible to fertilize.

Gene editing would have species-level implications, manipulating the process of inheritance though synthetic gene drives, meaning that the altered genes are passed down more than 50% of the time, even when the traits are disadvantageous to the species. This capacity has caught the attention of organizations like the Genetic Biocontrol of Invasive Rodents, which wants to use suppression drives—spreading a trait harmful to survival through a population—to control invasive mice. “Mathematical modeling suggests than an effective suppression drive would be extremely efficient; a hundred gene-drive mice released on an island could take a population of fifty thousand ordinary mice down to zero within a few years” (133). People have spread rats and mice across much of the globe, which has had devastating impacts on island species. The standard tool for controlling rodent populations is poison, which can end up poisoning the very species it’s meant to protect. There may be unforeseen consequences to gene editing, but there are few alternatives—and in the meantime, thousands of species are at risk. Nonetheless, the history of biological interventions is fraught with miscalculations.