Clerissi C. auteur aut IRD Touchon M. auteur aut IRD Capela D. auteur aut IRD Tang M. X. auteur aut IRD Cruveiller S. auteur aut IRD Parker M. A. auteur aut IRD Moulin Lionel auteur aut IRD Masson-Boivin C. auteur aut IRD Rocha E. P. C. auteur aut IRD text journalArticle eng text/pdf reformatted digital access The emergence of symbiotic interactions has been studied using population genomics in nature and experimental evolution in the laboratory, but the parallels between these processes remain unknown. Here we compare the emergence of rhizobia after the horizontal transfer of a symbiotic plasmid in natural populations of Cupriavidus taiwanensis, over 10 MY ago, with the experimental evolution of symbiotic Ralstonia solanacearum for a few hundred generations. In spite of major differences in terms of time span, environment, genetic background, and phenotypic achievement, both processes resulted in rapid genetic diversification dominated by purifying selection. We observe no adaptation in the plasmid carrying the genes responsible for the ecological transition. Instead, adaptation was associated with positive selection in a set of genes that led to the co-option of the same quorum-sensing system in both processes. Our results provide evidence for similarities in experimental and natural evolutionary transitions and highlight the potential of comparisons between both processes to understand symbiogenesis. specialized 084 9 art. 2264 [13 ] [+ Corrigendum 4641 du 02 nov. 2018] 2018 2041-1723 https://www.documentation.ird.fr/hor/fdi:010073111 10.1038/s41467-018-04778-5 2041-1723 [F B010073111] https://www.documentation.ird.fr/hor/fdi:010073111 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers18-06/010073111.pdf IRD - Base Horizon / Pleins textes 2018-07-03 2026-07-21 fdi:010073111 fre