A study by researchers in Spain suggests that current metagenomic analyses of the microbiome can yield erroneous results, largely due to the incomplete databases that are used to identify microbial DNA sequences. A team led by Clemente Fernández Arias and Federica Bertocchini at the Centro de Investigaciones Biológicas Margarita Salas, Madrid, evaluated current microbiome analysis techniques on computer simulations of microbial communities in a report published on Feb. 8 in PLOS ONE.