title: Evolutionary implications of horizontal gene transfer.
abstract: The flow of genes between different species represents a form of genetic variation whose implications have not been fully appreciated. Here I examine some key findings on the extent of horizontal gene transfer (HGT) revealed by comparative genome analysis and their theoretical implications. In theoretical terms, HGT affects ideas pertaining to the tree of life, the notion of a last universal common ancestor, and the biological unities, as well as the rules of taxonomic nomenclature. This review discusses the emergence of the eukaryotic cell and the occurrence of HGT among metazoan phyla involving both transposable elements and structural genes for normal housekeeping functions. I also discuss the bacterial pangenome, which provides an important case study on the permeability of species boundaries. An interesting observation about bdelloid rotifers and their reversion to asexual reproduction as it pertains to HGT is included.
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, University of California, Davis, California 95616, USA. msyvanen@ucdavis.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Syvanen
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics*; D019295:Computational Biology; D004251:DNA Transposable Elements; D056890:Eukaryota / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D051456:Gene Flow; D022761:Gene Transfer, Horizontal; D016680:Genome, Bacterial; D044404:Genomic Islands; D009154:Mutation; D010802:Phylogeny; D012098:Reproduction / Q000235:genetics; D012641:Selection, Genetic
chemical_list: D004251:DNA Transposable Elements