杏吧原创

KAKAPOS are fat New Zealand ground parrots that have stared into the abyss of extinction for decades. Conservationists have laboured to raise numbers from the moribund low 50s to a still ultra-critical 160 or so today.

Once a species becomes so depleted, however, a lack of genetic diversity can hinder its long-term salvation. A geneticist once told me of a crazy idea that might save the kakapo. He said that there are more stuffed kakapos in European museums than there are living birds. If we could extract DNA from those dead parrots, from a time when their numbers were large, we could genetically engineer the living birds to mimic the once healthy species by changing single letters of genetic code.

There are a lot of 鈥渋fs鈥� here, but the modification of DNA itself 鈥� even at the level of precision this mad scheme would require 鈥� is eminently possible, thanks to a technology known by the acronym CRISPR. Ten years ago, identifying, characterising and modifying a gene then getting it back into an organism was a process that took weeks, months or years. With CRISPR you can perform the same process in days.

Incredibly, it looks as though CRISPR will live up to its hype, transforming every aspect of biology as genetic engineering did from the 1970s on. Tweaking individual letters of genetic code, it takes just hours to finely edit what evolution fashioned over billions of years. All aspects of the science of life are within CRISPR鈥檚 reach: disease, conservation, synthetic cellular manufacture.

CRISPR鈥檚 complex origins as a gene editing tool can reasonably be credited to a few key players: Jennifer Doudna is one of them. With her former colleague Samuel Sternberg, she has written a detailed account of the story so far. It may well end up being compared with the book that inspired a 12-year old Doudna in the first place: James Watson鈥檚 The Double Helix.

But while Watson鈥檚 iconic account of his and Francis Crick鈥檚 discovery of the structure of DNA is dramatic and myth-making, bitchy and sexist, A Crack in Creation is thoughtful and thorough. Packed with amazing female scientists, it is thrilling, generous and no less personal. It鈥檚 a good tale of how science works, tracing all the meandering paths that lead to discovery: meetings, chance encounters, ceaseless discussions, and the endless beavering of lab life.

鈥淐oncern about genetically modifying people may once have seemed overheated. That鈥檚 about to change鈥�

A Crack in Creation is quite technical at times, and a touch bogged down with the clinical specifics of the many diseases that CRISPR may one day fix. The journey from the days of gene therapy to the first human CRISPR studies in China is no amble, either. Following these early Chinese studies, Doudna recommended an instant moratorium on human CRISPR experimentation. Similar moratoriums were called for in the first days of genetic engineering in the 1970s, and in recent years, following the experimental modification of virulent flu viruses.

Public concern about the genetic modification of people may have seemed overheated while we lacked the scientific chops to do anything significant. But that is about to change: CRISPR is powerful and potentially scary. Doudna鈥檚 own ethical position comes into focus in the final chapter. It鈥檚 a nuanced account, but she definitely inclines towards excising conditions like cystic fibrosis and Huntington鈥檚 disease from the human germ line.

A Crack in Creation touches the surface of these issues. It doesn鈥檛 delve deep, but one book cannot do everything. Genetics has been in perpetual revolution for several decades now. Since the 1990s, when the Human Genome Project ground into action, there have been so many advances in our understanding of genetics and our ability to manipulate DNA that it鈥檚 hard to keep up. Doudna accounts for the many cracks in creation in the 21st century: developing RNAi, where genes can be silenced with tiny bits of ingested genetic code; the building of giant chromosomes to help us clone larger genes; and the manipulation of stem cells. All of these achievements resulted in Nobel prizes 鈥� Doudna鈥檚 must surely come soon.

We need scientifically informed public conversations about what we should do next with these powers, and Doudna鈥檚 book is a good place to begin. The first gene engineers of the 1970s framed their discoveries by actively engaging with the ethical, legal and political ramifications of genetic engineering. So must we. 鈥淎s I write this,鈥� says Doudna, 鈥渢he world around us is being revolutionized by CRISPR, whether we鈥檙e ready for it or not.鈥� So strap in and get up to speed, because these days, the science of modifying life moves pretty fast.

This article appeared in print under the headline 鈥淭his changes everything鈥�