The extent of genome flux and its role in the differentiation of bacterial lineages.
Genome Biol Evol
; 6(6): 1514-29, 2014 Jun 12.
Article
em En
| MEDLINE
| ID: mdl-24923323
ABSTRACT
Horizontal gene transfer (HGT) and gene loss are key processes in bacterial evolution. However, the role of gene gain and loss in the emergence and maintenance of ecologically differentiated bacterial populations remains an open question. Here, we use whole-genome sequence data to quantify gene gain and loss for 27 lineages of the plant-associated bacterium Pseudomonas syringae. We apply an extensive error-control procedure that accounts for errors in draft genome data and greatly improves the accuracy of patterns of gene occurrence among these genomes. We demonstrate a history of extensive genome fluctuation for this species and show that individual lineages could have acquired thousands of genes in the same period in which a 1% amino acid divergence accrues in the core genome. Elucidating the dynamics of genome fluctuation reveals the rapid turnover of gained genes, such that the majority of recently gained genes are quickly lost. Despite high observed rates of fluctuation, a phylogeny inferred from patterns of gene occurrence is similar to a phylogeny based on amino acid replacements within the core genome. Furthermore, the core genome phylogeny suggests that P. syringae should be considered a number of distinct species, with levels of divergence at least equivalent to those between recognized bacterial species. Gained genes are transferred from a variety of sources, reflecting the depth and diversity of the potential gene pool available via HGT. Overall, our results provide further insights into the evolutionary dynamics of genome fluctuation and implicate HGT as a major factor contributing to the diversification of P. syringae lineages.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Genoma Bacteriano
/
Evolução Molecular
/
Transferência Genética Horizontal
/
Pseudomonas syringae
Idioma:
En
Revista:
Genome Biol Evol
Assunto da revista:
BIOLOGIA
/
BIOLOGIA MOLECULAR
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Reino Unido