Animals are hosts to microbial ecosystems that have diverse impacts on host phenotype. These microbiomes contain organisms from all domains of life, including bacteria, archaea, and eukaryotes. Eukaryotic microbes, including protists and fungi, are emerging as key members of the microbiome that interact with the host and with other microbes in multifaceted ways. The factors that differentiate negative and positive interactions with a human host, and mechanistically how eukaryotic microbes accomplish these impacts, are largely unknown. The Lind lab studies commensal gut eukaryotes, considering several questions: 1) how microbial eukaryotes interact with gut microbiota and with the animal host to influence host phenotype and 2) how commensal gut eukaryotes have evolved. The lab addresses these questions using tools from comparative and functional genomics approaches combined with mechanistic experiments using defined cultures.