Big Tech supports social media, the stock market, insurance companies, scientific research, financial transactions, mass surveillance and monitoring, the ‘Internet of things’, ‘smart city’ sensors and grids, and mobile communications for Internet users writ large. By most industry accounts, data centres – and the cloud infrastructure that undergirds it – has become the most important sociotechnical system of our time, but also the least sustainable. Interestingly, one of the alternatives to these water- and energy-intensive data storage solutions has emerged from advancements in synthetic DNA technologies, now touted by the industry as a safer, greener and more efficient alternative. But how did we get here? How might ideas of 'sustainability' and 'efficiency' function in this context? In conversation, Mél Hogan and Deb Verhoeven discuss the idea of ‘Sustainable DNA’ – in its various instantiations – as an object of critical media studies.