On Thursday morning, Ian visited the Vega Thurber lab at Oregon State University. The Vega Thurber lab works on viral (and bacterial) ecology of invertebrates, notably corals, so there is much synergy between our research groups. After breakfast, we talked about common problems associated with metavirome annotation, specifically the presence of many contaminants in reagents, which can cause problems for one-off metaviromes prepared without corresponding blanks. It’s a pervasive problem in the field of metagenomics. Despite huge efforts to clean reagents and make them DNA- or RNA-free, it is still quite possible to amplify rare viruses and bacteria from essentially nothing. This was first brought to light by Ian’s postdoc adviser, Jon Zehr, who noted that a huge number of heterotrophic nitrogenase sequences in the non-redundant database at GenBank were, in fact, easily amplified in blanks. Our group’s observations of both blank metaviromes (including those prepared with/without corresponding blank DNA…