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The evolution of domain-content in bacterial genomes

Molina, N. and van Nimwegen, E.. (2008) The evolution of domain-content in bacterial genomes. Biology Direct, Vol. 3. p. 51.

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Official URL: http://edoc.unibas.ch/dok/A5259623

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Abstract

BACKGROUND: Across all sequenced bacterial genomes, the number of domains nc in different functional categories c scales as a power-law in the total number of domains n, i.e. nc proportional n(alpha)c, with exponents alpha(c) that vary across functional categories. Here we investigate the implications of these scaling laws for the evolution of domain-content in bacterial genomes and derive the simplest evolutionary model consistent with these scaling laws. RESULTS: We show that, using only an assumption of time invariance, the scaling laws uniquely determine the relative rates of domain additions and deletions across all functional categories and evolutionary lineages. In particular, the model predicts that the rate of additions and deletions of domains of category c is proportional to the number of domains nc currently in the genome and we discuss the implications of this observation for the role of horizontal transfer in genome evolution. Second, in addition to being proportional to nc, the rate of additions and deletions of domains of category c is proportional to a category-dependent constant rho(c), which is the same for all evolutionary lineages. This 'evolutionary potential' rho(c) represents the relative probability for additions/deletions of domains of category c to be fixed in the population by selection and is predicted to equal the scaling exponent alpha(c). By comparing the domain content of 93 pairs of closely-related genomes from all over the phylogenetic tree of bacteria, we demonstrate that the model's predictions are supported by available genome-sequence data. CONCLUSION: Our results establish a direct quantitative connection between the scaling of domain numbers with genome size, and the rate of addition and deletions of domains during short evolutionary time intervals.of domain numbers with genome size, and the rate of addition and deletions of domains during short evolutionary time intervals.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Computational & Systems Biology > Bioinformatics (van Nimwegen)
UniBasel Contributors:van Nimwegen, Erik
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:BioMed Central
ISSN:1745-6150
Note:Publication type according to Uni Basel Research Database: Journal article
Last Modified:22 Mar 2012 14:23
Deposited On:22 Mar 2012 13:33

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