PT - JOURNAL ARTICLE AU - Patrick Smith AU - David Willemsen AU - Miriam Popkes AU - Franziska Metge AU - Edson Gandiwa AU - Martin Reichard AU - Dario Riccardo Valenzano TI - R<span class="sc">egulation of</span> L<span class="sc">ife</span> S<span class="sc">pan by</span> <span class="sc">The</span> G<span class="sc">ut</span> M<span class="sc">icrobiota in</span> T<span class="sc">he</span> S<span class="sc">hort</span>-L<span class="sc">ived</span> A<span class="sc">frican</span> T<span class="sc">urquoise</span> K<span class="sc">illifish</span> AID - 10.1101/120980 DP - 2017 Jan 01 TA - bioRxiv PG - 120980 4099 - http://biorxiv.org/content/early/2017/04/06/120980.short 4100 - http://biorxiv.org/content/early/2017/04/06/120980.full AB - Gut bacteria occupy the interface between the organism and the external environment, contributing to homeostasis and disease. Yet, the causal role of the gut microbiota during host aging is largely unexplored. Here, using the African turquoise killifish (Nothobranchius furzeri), a naturally short-lived vertebrate, we show that the gut microbiota plays a key role in modulating vertebrate life span. Recolonizing the gut of middle-age individuals with bacteria from young donors resulted in life span extension and delayed behavioral decline. This intervention prevented the decrease in microbial diversity associated with host aging and maintained a young-like gut bacterial community, characterized by overrepresentation of the key genera Exiguobacterium, Planococcus, Propionigenium and Psychrobacter. Our findings demonstrate that the natural microbial gut community of young individuals can causally induce long-lasting beneficial systemic effects that lead to life span extension in a vertebrate model.