title: Mosaic structure of large regions of the Lactococcus lactis subsp. cremoris chromosome.
abstract: Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris are closely related phenotypically and genetically. Here we report that certain regions of their chromosomes diverge considerably more than others. Conserved regions differ by less than 20%, whilst variable regions differ by more than 60%. This mosaic structure may have arisen by horizontal gene transfer from distantly related bacteria since in a particular region of the L. lactis subsp. cremoris chromosome the G+C content and the codon bias are not typical for lactococci. Such an exchange, which conserves the function of the gene and cannot be achieved under selective pressure, may be of considerable importance in the evolution of bacteria.
authors: Laboratoire de Génétique Microbienne, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
authors: C
authors: C
authors: Delorme
authors: J J
authors: JJ
authors: Godon
authors: S D
authors: SD
authors: Ehrlich
authors: P
authors: P
authors: Renault
mesh_terms: D000595:Amino Acid Sequence; D000597:Amino Acids, Branched-Chain / Q000096:biosynthesis; D001483:Base Sequence; D002876:Chromosomes, Bacterial / Q000235:genetics*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004926:Escherichia coli / Q000235:genetics; D005815:Genetic Code; D014644:Genetic Variation; D006639:Histidine / Q000096:biosynthesis; D013294:Lactococcus lactis / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014364:Tryptophan / Q000096:biosynthesis
chemical_list: D000597:Amino Acids, Branched-Chain; D006639:Histidine; D014364:Tryptophan