Selection on horizontally transferred and duplicated genes in sinorhizobium (Ensifer), the root-nodule symbionts of medicago

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Structural variation, including variation in gene copy number and presence or absence of genes, is a widespread and important source of genomic variation. We used whole-genome DNA sequences from 48 strains of Sinorhizobium (recently renamed Ensifer), including 20 strains of Sinorhizobium melilotiand 12 strains of S. medicae thatwere the focus of the analyses, to study the fitness effects of new structural variants created by duplication and horizontal gene transfer. We find that derived duplicated and horizontally transferred (HT) genes segregate at lower frequency than synonymous and nonsynonymous nucleotide variants in S. meliloti and S. medicae. Furthermore, the relative frequencies of different types of variants are more similar inS. medicaethan in S. meiloti, the specieswith the larger effective population size. These results are consistent with the hypothesis that most duplications and HT genes have deleterious effects. Diversity of duplications, as measured by segregating duplicated genes per gene, is greater than nucleotide diversity, consistent with a high rate of duplication. Our results suggest that the vast majority of structural variants found among closely related bacterial strains are short-lived and unlikely to be involved in species-wide adaptation.

Original languageEnglish (US)
Pages (from-to)1199-1209
Number of pages11
JournalGenome biology and evolution
Volume6
Issue number5
DOIs
StatePublished - May 2014

Keywords

  • Fitness effects
  • Mutation
  • Pangenome
  • Purifying selection
  • Structural variation

Fingerprint Dive into the research topics of 'Selection on horizontally transferred and duplicated genes in sinorhizobium (Ensifer), the root-nodule symbionts of medicago'. Together they form a unique fingerprint.

Cite this