title: Evolutionary coorigin of the RNA polymerase sigma factor and the lambda repressor inferred from gene nucleotide sequence homologies.
abstract: The lambda phage cI gene and E. coli rpoD gene encoding the lambda repressor and sigma factor, respectively, were aligned with each other based on the internal homologies found in the rpoD gene. Statistical evaluations for these intragenic and intergenic base sequence homologies in the corresponding alignments have conclusively demonstrated that the rpoD gene must have evolved by repeated gene duplications from a primitive gene closely similar to and co-ancestral to the cI gene.
mesh_terms: D010582:Bacteriophage lambda / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D005814:Genes, Viral; D012097:Repressor Proteins / Q000235:genetics*; D012234:Rho Factor / Q000235:genetics*; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000235:genetics*; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D012234:Rho Factor; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D012321:DNA-Directed RNA Polymerases