CRISPR has ruffled feathers, but it may be capable of saving species

Frans Lanting/National Geographic Creative

By Adam Rutherford

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 ifs here, but the modification of DNA itself even at the level of precision this mad scheme would require 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 CRISPRs reach: disease, conservation, synthetic cellular manufacture.

CRISPRs 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 Watsons The Double Helix.

But while Watsons iconic account of his and Francis Cricks 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. Its 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.

Concern about genetically modifying people may once have seemed overheated. Thats about to change

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. Doudnas own ethical position comes into focus in the final chapter. Its a nuanced account, but she definitely inclines towards excising conditions like cystic fibrosis and Huntingtons disease from the human germ line.

A Crack in Creation touches the surface of these issues. It doesnt 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 its 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 Doudnas must surely come soon.

We need scientifically informed public conversations about what we should do next with these powers, and Doudnas 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. As I write this, says Doudna, the world around us is being revolutionized by CRISPR, whether were ready for it or not. 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 This changes everything

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How the living world was changed, by the woman who changed it - New Scientist

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