title: Spontaneous zygogenesis, a wide-ranging mating process in bacteria.
abstract: Spontaneous zygogenesis (or Z-mating) in Escherichia coli, unlike F-mediated conjugation, promotes formation of complete zygotes. Most Z-mating products have proven to be phenotypically unstable, losing part of the phenotype for which they were selected. Persistent Z-mating products appear as stable genetic recombinants or yield subclones of two types: either both parental types or one of them plus a recombinant type, and the ability to promote spontaneous zygogenesis can appear in all emerging types. Here it is shown that spontaneous zygogenesis-promoting E. coli strains can Z-mate with strains of Shigella flexneri, Salmonella enterica Serovar Typhimurium and Serratia marcescens, giving rise to products that behave like those of homospecific Z-matings. When genetic recombination was prevented in products of Z-mating between E. coli and S. enterica or S. marcescens, phenotype switching was observed in purified isolates exhibiting a single phenotype, thus providing further evidence of interspecies genotypic mixing. The presence of two distinct replicons within a cell introduces a new situation that contrasts with classical conjugation between heterologous strains, where the partially transferred chromosomal segment is subject to restriction, is unable to replicate and is limited in genetic recombination.
authors.affiliation: Laboratory of Phage Typing and Bacterial Genetics, Pasteur Institute of Brussels, Rue Engeland 642, B-1180 Brussels, Belgium. jpgratia@yahoo.fr
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Gratia
mesh_terms: D003227:Conjugation, Genetic; D003433:Crosses, Genetic; D004926:Escherichia coli / Q000235:genetics*; D011995:Recombination, Genetic; D012486:Salmonella typhimurium / Q000235:genetics*; D012706:Serratia marcescens / Q000235:genetics*; D012763:Shigella flexneri / Q000235:genetics*