Lateral gene exchanges shape the genomes of amoeba-resisting microorganisms

• Main Authors: Claire eBertelli, Gilbert eGreub
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2012-08-01
• Series: Frontiers in Cellular and Infection Microbiology
• Subjects: evolution; Intracellular bacteria; horizontal gene transfer; Free-living amoebae; Horizontal transfer; Lateral gene transfer
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fcimb.2012.00110/full

Based on Darwin’s concept of the tree of life, vertical inheritance was thought to be dominant, and mutations, deletions and duplication were streaming the genomes of living organisms. In the current genomic era, increasing data indicated that both vertical and lateral gene inheritance interact in space and time to trigger genome evolution, particularly among microorganisms sharing a given ecological niche. As a paradigm to their diversity and their survival in a variety of cell types, intracellular microorganisms, and notably intracellular bacteria, were considered as less prone to lateral genetic exchanges. Such specialized microorganisms generally have a smaller gene repertoire because they do rely on their host’s factors for some basic regulatory and metabolic functions. Here we review events of lateral gene transfer (LGT) that illustrate the genetic exchanges among intra-amoebal microorganisms or between the microorganism and its amoebal host. We tentatively investigate the functions of laterally transferred genes in the light of the interaction with their host as they should confer a selective advantage and success to the amoeba-resisting microorganisms.