Utility of carrier genomic DNA for ultra-low biomass metagenome sequence library preparation

Best practices for making shotgun metagenome sequence libraries from ultra-low biomass specimens have yet to be fully resolved. In this study, we address the utility of spiking in carrier genomic DNA into library preparation protocols to get to minimum input requirements recommended by protocols. Mock microbial genomic DNA (an established mixture of DNA from 8 different bacterial species and 2 fungal species) was mixed together with carrier DNA (lambda DNA) at different ratios and at different input levels starting at 50 pg and decreasing below 1 pg. This study was performed as part of the NASA Planetary Protection Analysis Working Group.