A Novel Family of Genomics Islands Across Multiple Species of Streptococcus

Abstract

The genus Streptococcus is one of the most genomically diverse and important human and agricultural pathogens. The acquisition of genomic islands (GIs) plays a central role in adaptation to new hosts in the genus pathogens. The research presented here employs a comparative genomics approach to define a novel family of GIs in the genus Streptococcus which also appears across strains of the same species. Specifically, we identified 9 Streptococcus genomes out of 67 sequenced genomes analyzed, and we termed these as 15bp Streptococcus genomic islands, or 15SGIs, including i) insertion adjacent to the 3 end of ribosome l7/l12 gene, ii) large inserts of horizontally acquired DNA, and iii) the presence of mobility genes (integrase) and replication initiators. We have identified a novel family of 15SGIs and seems to be important in species differentiation and adaptation to new hosts. It plays an important role during strain evolution in the genus Streptococcus.