HORIZONTALLY TRANSFERRED GENES ARE OFTEN SHARED BETWEEN CLOSELY RELATED BACTERIAL SPECIES

Evgeni Bolotin Ruth Hershberg

Rachel & Menachem Mendelovitch Evolutionary Processes of Mutation & Natural Selection Research Laboratory, Department of Genetics and Developmental Biology, The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa

Horizontal gene transfer (HGT) is a major contributor to the evolution of bacterial gene content. In this study we used a pangenome based approach to identify genes that were horizontally transferred into four closely related species belonging to the Enterobacteriaceae family. This analysis enabled us to show that a surprisingly high percent of the horizontally transferred genes are shared between these species. Furthermore, we demonstrate significant differences between horizontally transferred genes that are shared between more than one species and those that are not. Specifically, acquired genes shared between the four analyzed species tend to be conserved in a larger number of additional species, and are better optimized for expression in their host genomes. Combined, these results demonstrate the existence of a large pool of horizontally transferred genes that are shared between species and that these genes display unique characteristics that differentiate them from other horizontally transferred genes.