biological consequences of ancient gene acquisition and duplication in the large genome of candidatus solibacter usitatus ellin6076古代生物的后果大基因组的基因收购和重复candidatus solibacter usitatus ellin6076.pdf

Biological Consequences of Ancient Gene Acquisition and Duplication in the Large Genome of Candidatus Solibacter usitatus Ellin6076 1 1 2 2 1 1 Jean F. Challacombe *, Stephanie A. Eichorst , Loren Hauser , Miriam Land , Gary Xie , Cheryl R. Kuske 1 Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America, 2 Genome Analysis and Systems Modeling Group, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America Abstract Members of the bacterial phylum Acidobacteria are widespread in soils and sediments worldwide, and are abundant in many soils. Acidobacteria are challenging to culture in vitro, and many basic features of their biology and functional roles in the soil have not been determined. Candidatus Solibacter usitatus strain Ellin6076 has a 9.9 Mb genome that is approximately 2–5 times as large as the other sequenced Acidobacteria genomes. Bacterial genome sizes typically range from 0.5 to 10 Mb and are influenced by gene duplication, horizontal gene transfer, gene loss and other evolutionary processes. Our comparative genome analyses indicate that the Ellin6076 large genome has arisen by horizontal gene transfer via ancient bacteriophage and/or plasmid-mediated transduction, and widespread small-scale gene duplications, resulting in an increased number of paralogs. Low amino acid sequence identities among functional group members, and lack of conserved gene order and orientation in regions containing similar groups of paralogs, suggest that most of the paralogs are not the result of recent duplication events. The genome sizes of additional cultured Acidobacteria