We are indebted to Lynn J. Rothschild for debunking, in Journal Club, some microbial myths (Nature 443, 249; 2006 doi:10.1038/443248a). Her prime concern is that many microbiologists have simply given up trying to culture many of the more recalcitrant microbes living in the natural environment, in favour of resorting to DNA-sequencing methods.

There is a lingering and widespread presumption that DNA-sequence information will make a huge difference to our knowledge of microbes in the natural world, but we, like Rothschild, beg to differ. She argues for a greater effort to learn how to culture the 'unculturable' microbes. We would go further, and suggest that, having done so, we should devote greater effort to describing species by their phenotypic properties. Characterization of the phenotype, rather than the genetic sequence, is the key to gaining deeper and better understanding of microbial diversity in the natural world.