Chemoreceptor gene loss and acquisition via horizontal gene transfer in Escherichia coli

摘要: ABSTRACT Chemotaxis allows bacteria to more efficiently colonize optimal microhabitats within their larger environment. in Escherichia coli is the best-studied model system, and a large number of E. strains have been sequenced. The Escherichia/Shigella genus encompasses great variety commensal pathogenic strains, but role chemotaxis association with host remains poorly understood. Here we show that core genes are lost many, not all, nonmotile well preserved all motile strains. encoding Tar, Tsr, Aer chemoreceptors, which mediate broad spectrum chemical physical cues, also nearly uniformly conserved In contrast, clade extraintestinal apparently underwent an ancestral loss Trg Tap sense sugars, dipeptides, pyrimidines. range time estimated for these (1 3 million years ago) corresponds appearance Homo.