title: Evidence for the evolution of bdelloid rotifers without sexual reproduction or genetic exchange.
abstract: The Class Bdelloidea of the Phylum Rotifera is the largest metazoan taxon in which males, hermaphrodites, and meiosis are unknown. We conducted a molecular genetic test of this indication that bdelloid rotifers may have evolved without sexual reproduction or genetic exchange. The test is based on the expectation that after millions of years without these processes, genomes will no longer contain pairs of closely similar haplotypes and instead will contain highly divergent descendants of formerly allelic nucleotide sequences. We find that genomes of individual bdelloid rotifers, representing four different species, appear to lack pairs of closely similar sequences and contain representatives of two ancient lineages that began to diverge before the bdelloid radiation many millions of years ago when sexual reproduction and genetic exchange may have ceased.
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: D
authors.initials: D
authors.lastname: Mark Welch
authors.forename: M
authors.initials: M
authors.lastname: Meselson
mesh_terms: D000818:Animals; D001426:Bacterial Proteins; D001483:Base Sequence; D005075:Biological Evolution; D004268:DNA-Binding Proteins / Q000235:genetics; D017238:Genes, Helminth; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011995:Recombination, Genetic; D012100:Reproduction, Asexual / Q000235:genetics*; D012403:Rotifera / Q000145:classification* / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D012808:Sigma Factor / Q000235:genetics; D013045:Species Specificity; D035181:TATA-Box Binding Protein; D014157:Transcription Factors / Q000235:genetics; D014305:Triose-Phosphate Isomerase / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C074510:HSP82 protein, S cerevisiae; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D029701:Saccharomyces cerevisiae Proteins; D012808:Sigma Factor; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; C401931:rpoI protein, Rhizobium leguminosarum; D014305:Triose-Phosphate Isomerase