Trends and barriers to lateral gene transfer in prokaryotes

Gene acquisition by lateral gene transfer (LGT) is an important mechanism for natural variation among prokaryotes. Laboratory experiments show that protein-coding genes can be laterally transferred extremely fast among microbial cells, inherited to most of their descendants, and adapt to a new regulatory regime within a short time. Recent advance in the phylogenetic analysis of microbial genomes using networks approach reveals a substantial impact of LGT during microbial genome evolution. Phylogenomic networks of LGT among prokaryotes reconstructed from completely sequenced genomes uncover barriers to LGT in multiple levels. Here we discuss the kinds of barriers to gene acquisition in nature including physical barriers for gene transfer between cells, genomic barriers for the integration of acquired DNA, and functional barriers for the acquisition of new genes.

► Gene acquisition by lateral gene transfer (LGT) among prokaryotes is frequent. ► The percolation of acquired DNA among populations and across generations is rapid. ► Phylogenomics reveal that LGT has a substantial impact on genome evolution. ► Barriers to LGT in the species, and habitat levels are becoming increasingly apparent. ► Prokaryote genome evolution comprises vertical and lateral components.