Shaping a bacterial genome by large chromosomal replacements, the evolutionary history of Streptococcus agalactiae.

ABSTRACT: Bacterial populations are subject to complex processes of diversification that involve mutation and horizontal DNA transfer mediated by transformation, transduction, or conjugation. Tracing the evolutionary events leading to genetic changes allows us to infer the history of a microbe. Here, we combine experimental and in silico approaches to explore the forces that drive the genome dynamics of Streptococcus agalactiae, the leading cause of neonatal infections. We demonstrate that large DNA segments of up to 334 kb of the chromosome of S. agalactiae can be transferred through conjugation from multiple initiation sites. Consistently, a genome-wide map analysis of nucleotide polymorphisms among eight human isolates demonstrated that each chromosome is a mosaic of large chromosomal fragments f

SUBMITTER: Brochet M 

PROVIDER: S-EPMC2572952 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature