The DOE Joint Genome Institute offers metagenome quantitative stable isotope probing (Metagenome – qSIP) capabilities to investigate metabolic activity of metagenome-assembled genomes (MAGs). The JGI Metagenome – qSIP workflow begins with users carrying out isotope enrichment culturing and DNA extractions which are sent to the JGI for sample processing. Once received, DNA is fractionated and synthetic DNA spike-ins are added for downstream analysis. Sequenced fractions are co-assembled, annotated, and binned before estimating DNA isotope incorporation of MAGs, expressed as atom fraction excess (AFE).