PT - JOURNAL ARTICLE AU - Carlotta De Filippo AU - Monica Di Paola AU - Irene Stefanini AU - Lisa Rizzetto AU - Luisa Berná AU - Matteo Ramazzotti AU - Leonardo Dapporto AU - Damariz Rivero AU - Ivo G. Gut AU - Marta Gut AU - Mónica Bayés AU - Jean-Luc Legras AU - Roberto Viola AU - Cristina Massi-Benedetti AU - Antonella De Luca AU - Luigina Romani AU - Paolo Lionetti AU - Duccio Cavalieri TI - Population genomics of <em>Saccharomyces cerevisiae</em> human isolates: passengers, colonizers, invaders AID - 10.1101/001891 DP - 2014 Jan 01 TA - bioRxiv PG - 001891 4099 - http://biorxiv.org/content/early/2014/01/17/001891.short 4100 - http://biorxiv.org/content/early/2014/01/17/001891.full AB - The quest for the ecological niches of Saccharomyces cerevisiae ranged from wineries to oaks and more recently to the gut of Crabro Wasps. Here we propose the role of the human gut in shaping S. cerevisiae evolution, presenting the genetic structure of a previously unknown population of yeasts, associated with Crohn’s disease, providing evidence for clonal expansion within human’s gut. To understand the role of immune function in the human-yeast interaction we classified strains according to their immunomodulatory properties, discovering a set of genetically homogeneous isolates, capable of inducing anti-inflammatory signals via regulatory T cells proliferation, and on the contrary, a positive association between strain mosaicism and ability to elicit inflammatory, IL-17 driven, immune responses. The approach integrating genomics with immune phenotyping showed selection on genes involved in sporulation and cell wall remodeling as central for the evolution of S. cerevisiae Crohn’s strains from passengers to commensals to potential pathogens.