Very few microbiome characterizations have focused on our commensal fungi. The researchers in this paper addressed this question by sequencing fungal ribosomal DNA as well as directly visualizing fungi via colonic tissue staining. They recovered fungi from the feces of rats, guinea pigs, dogs, mice, and humans, suggesting that commensal fungal populations are widespread. In total they found over 100 species in mouse intestines which represent at least 50 genera. They assessed the impact on mouse health by inducing Colitis, a mysterious GI inflammatory disorder that has been linked with an altered microbiome, with a chemical DSS. Following DSS treatment and Colitis induction, they found antibodies specific to the commensal fungi. Provided that commensal fungi are recognized by Dectin-1, they used Dectin-1 knock out mice to test the fungi's influence on Colitis. Since Dectin-1 KO mice were shown to have a more inflamed gut and therefore more severe Colitis-like symptoms, collectively, their results suggest that the ability to control fungi in the gut is crucial to Colitis prevention (in mice).