title: Estimating the size of the bacterial pan-genome.
abstract: The 'pan-genome' denotes the set of all genes present in the genomes of a group of organisms. Here, we extend the pan-genome concept to higher taxonomic units. Using 573 sequenced genomes, we estimate the size of the bacterial pan-genome based on the frequency of occurrences of genes among sampled genomes. Using gene- and genome-centered approaches, we characterize three distinct pools of gene families that comprise the bacterial pan-genome, each evolving under different evolutionary constraints. Our findings indicate that the pan-genome of the bacterial domain is of infinite size (the Bacteria as a whole have an open pan-genome) and that approximately 250 genes per genome belong to the extended bacterial core genome.
authors.affiliation: University of Connecticut Biotechnology Center, 91 North Eagleville Road, Storrs, CT 06269-3149, USA. pascal.lapierre@uconn.edu
authors.forename: Pascal
authors.initials: P
authors.lastname: Lapierre
authors.forename: J Peter
authors.initials: JP
authors.lastname: Gogarten
mesh_terms: D000595:Amino Acid Sequence; D019143:Evolution, Molecular; D005787:Gene Frequency; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid