Functionally structured genome architectures in Lactobacillus – insights into their variability and evolution
(English)Manuscript (preprint) (Other academic)
Bacterial genome architectures evolve in response to selective pressures on the interplay between replication and gene expression. Several genomes contain a higher fraction of genes coding for proteins involved in information processes near the origin of replication, which is thought to be due to selection for rapid growth. We recently described a novel type of genome architecture in Lactobacillus kunkeei (Tamarit, et al. 2015). In this genome, vertically inherited genes encoding proteins with roles in translation and replication have accumulated in the chromosomal half surrounding the terminus of replication, while species-specific genes, and genes encoding proteins with metabolic and transport functions have accumulated in the chromosomal half around the origin of replication. Here, we show that this pattern is present also in the closest relatives of L. kunkeei, and similar but not identical biased genome architectures are present in other groups within the Lactobacillaceae. Thus, the biased genome structure in L. kunkeei has emerged from an ancestral clustering of vertically inherited genes around the terminus of replication, while horizontally acquired genes have been inserted near the origin of replication. The genome bias has been lost independently in several groups due to insertions of mobile elements near the terminus of replication and/or major genome rearrangements. We propose chromosomal structuring in macrodomains in the Lactobacillaceae, and suggest that further exploration of its functional consequences and generality will provide valuable insights into the forces that shape genome organization in bacteria.
genome organization, replication axis
Research subject Biology with specialization in Molecular Evolution
IdentifiersURN: urn:nbn:se:uu:diva-301781OAI: oai:DiVA.org:uu-301781DiVA: diva2:955251