Major gene influxes in prokaryote genome evolution - Lateral gene transfer and origin of archaeal higher taxa

<strong>School of Computational and Integrative Sciences (SC&amp;IS)</strong> <strong>Dr. Shijulal Nelson-Sathi</strong> Institute of Molecular Evolution Heinrich-Heine-Universitaet Duesseldorf Universitaetsstr.1 40225 Duesseldorf Germany Date : <strong>December 8, 2015</strong> Title : <strong>Major gene influxes in prokaryote genome evolution - Lateral gene transfer and origin of archaeal higher taxa</strong> <strong>Abstract : </strong>Prokaryotic genome evolution entails both tree-like components generated by vertical inheritance and network-like components generated by lateral gene transfer (LGT). Even though both these processes are widely accepted, its relative contribution during the formation of prokaryotic species is the subject of intense debate. While it is clear that LGT within prokaryotic lineages such as cyanobacteria, proteobacteria, or halophiles is an important factor for genome evolution, its role, if any, at the origin of such groups still remain as an open issue. To investigate the role of vertical and lateral evolutionary processes underlying the origin of higher taxa in archaea, we have performed phylogenomic analysis of 134 archaea in the context of their homologues from 1,847 reference bacterial genomes. Our results show origins of archaeal higher taxa unexpectedly correspond to thousands of archaeal lineage-specific gene acquisitions from bacteria. Interdomain gene transfer is highly asymmetric, transfers from bacteria to archaea are more than 5-fold more frequent than vice versa These findings uncover a pivotal role for lateral gene transfer in major evolutionary transitions among prokaryotes and implicate bacterial gene acquisitions as key innovations en route to the origin of archaeal higher taxa. In a similar analysis with additional 55 eukaryote genomes, we found that gene inheritance in eukaryote is more vertical, lineage-specific lateral gene transfer from bacteria is extremely rare, bacterial genes in eukaryotes corresponds to the origin of chloroplasts or mitochondria. References : 1. Nelson-Sathi S et al. Proc. Natl. Acad. Sci. USA 109, 20537-20542 (2012) 2. Nelson-Sathi S et al. Nature 517 7532, 77-80 (2015) 3. Nelson-Sathi S et al. Proc. Natl. Acad. Sci. USA 112, 10139-46 (2015) 4. Ku C, Nelson-Sathi S et al. Nature 524, 427-32 (2015)