Five years ago, when researchers first discovered that bacterial immune systems could be hijacked to edit DNA in living creatures, it was big news. The technology, called CRISPR, allowed scientists to more easily than ever cut and paste all those As, Cs, Ts and Gs that make up the base pairs of DNA and encode the world's living things. With CRISPR, scientists could use genetic engineering to tackle problems from disease to famine.
A scientist cuts a DNA fragment under UV light for DNA sequencing. Image: AP
But gene editing with CRISPR is so 2017.
Recently, scientists have begun exploring new uses for the technology. This week alone, pioneers of CRISPR have unveiled three of them. CRISPR works by precisely targeting small snippets of DNA, and then cutting and pasting them. This, it turns out, has a lot more value than correcting a disease-causing genetic mutation or cutting out the gene that makes a mushroom brown.
In one study released yesterday, Jennifer Doudna's UC Berkeley lab used CRISPR as a sort of DNA detective to identify snippets of DNA that might signal a viral infections, cancer or even defective genes - a diagnostic tool. In that study, CRISPR's ability to identify specific genetic codes and attack was used to zero in on cancer-causing HPV and send out a glowing signal when it was present in human cells.
In another study released yesterday, by researchers from MIT and Harvard's Broad Institute, the CRISPR system was used to locate tumour DNA in blood samples of lung cancer patients. And in yet another Broad Institute study, scientists used CRISPR to create a sort of "black box" for cellular data, recording events inside individual human and bacterial cells by programming CRISPR to, in essence, make edits when significant cellular events occur. That sort of insight into the inner-workings of cells could help us better understand ageing and disease.
CRISPR's new tricks have come from making slight tweaks to its underlying system. In some cases, it means working with a different enzyme to actually doing the molecular cutting - usually the system relies on an enzyme called Cas9, but several recent CRISPR innovations have relied on other enzymes, such as Cas12a. In other cases, it's giving CRISPR upgrades, like the ability to send out a glowing signal when it detects something noteworthy.
All this adds up to the potential of CRISPR as not just a gene-editing powerhouse, but a multifunctional tool that also works as a biosensor, a medical detective, and an invaluable instrument for basic research.