Even though recent microbiome studies have been aiming to characterize the full spectrum of microbes, archaea have often been overlooked, writes Sarah Zhang at the Atlantic. That's because, she adds, they've been tricky to study, both historically in culture as well as with newer sequencing techniques.
Indeed, Zhang points to a new study from researchers at the University of Texas and Yale University that found that some 90 percent of the diversity of archaea might have gone unnoticed in recent gut microbiome studies
Texas's Howard Ochman and his colleagues reported in mSphere in February than when they used archaea-specific 16S rRNA primers, they could detect an increased number of archaea in in the gut microbiomes of great apes, as compared to universal primers. For instance, Zhang notes that the researchers uncovered 71 archaea in bonobos using the specific primers, but just six with the universal primers.
Zhang notes that even metagenomic techniques might overlook archaea because there are few reference genomes for them. But, to that end, Joint Genome Institute's Tanja Woyke and others are working on beefing them up through the Microbial Dark Matter project.