biostudies-literatureFloriano AMEuropean Commission1120-1126https://www.ebi.ac.uk/biostudies/studies/S-EPMC5905368biostudies-literatureUnknown10(4)"Candidatus Fokinia solitaria" is an obligate intracellular endosymbiont of a unicellular eukaryote, a ciliate of the genus Paramecium. Here, we present the genome sequence of this bacterium and subsequent analysis. Phylogenomic analysis confirmed the previously reported positioning of the symbiont within the "Candidatus Midichloriaceae" family (order Rickettsiales), as well as its high sequence divergence from other members of the family, indicative of fast sequence evolution. Consistently with this high evolutionary rate, a comparative genomic analysis revealed that the genome of this symbiont is the smallest of the Rickettsiales to date. The reduced genome does not present flagellar genes, nor the pathway for the biosynthesis of lipopolysaccharides (present in all the other so far sequeGenome biology and evolutionThe Genome Sequence of "Candidatus Fokinia solitaria": Insights on Reductive Evolution in Rickettsiales.PMC5905368FP7-PEOPLE-2009-IRSES247658Berendonk TUFloriano AMBazzocchi CPetroni GSassera DKrenek SCastelli MfalseThe Genome Sequence of "Candidatus Fokinia solitaria": Insights on Reductive Evolution in Rickettsiales."Candidatus Fokinia solitaria" is an obligate intracellular endosymbiont of a unicellular eukaryote, a ciliate of the genus Paramecium. Here, we present the genome sequence of this bacterium and subsequent analysis. Phylogenomic analysis confirmed the previously reported positioning of the symbiont within the "Candidatus Midichloriaceae" family (order Rickettsiales), as well as its high sequence divergence from other members of the family, indicative of fast sequence evolution. Consistently with this high evolutionary rate, a comparative genomic analysis revealed that the genome of this symbiont is the smallest of the Rickettsiales to date. The reduced genome does not present flagellar genes, nor the pathway for the biosynthesis of lipopolysaccharides (present in all the other so far seque2018-01-01T00:00:00Z2018 Apr2026-04-08T02:45:55.227Z2019-03-26T23:31:42ZS-EPMC59053682965980710.1093/gbe/evy072