title: Variable arrangement of 5S ribosomal genes within the ribosomal DNA repeats of arthropods.
abstract: The polymerase chain reaction and hybridization to genomic blots were used to investigate whether the previously observed inclusion of 5S ribosomal RNA genes in the 28S-18S ribosomal DNA intergenic regions of some crustacean species (copepods) could also be detected in other arthropods. Such an arrangement was found not only in other calanoid copepod species but also in a cirriped, an euphausid, and a spider. It is interesting that species from two different calanoid copepod genera do not have this type of arrangement. We conclude that the inclusion of 5S ribosomal RNA genes within the ribosomal DNA repeats has probably occurred repeatedly during the evolution of arthropod species and that the mechanism(s) responsible for these insertions could also be responsible for their loss.
authors.affiliation: Department of Biology, University of Ottawa, Ontario, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Drouin
authors.forename: J M
authors.initials: JM
authors.lastname: Sévigny
authors.forename: I A
authors.initials: IA
authors.lastname: McLaren
authors.forename: J D
authors.initials: JD
authors.lastname: Hofman
authors.forename: W F
authors.initials: WF
authors.lastname: Doolittle
mesh_terms: D000818:Animals; D001181:Arthropods / Q000235:genetics*; D001483:Base Sequence; D015139:Blotting, Southern; D004275:DNA, Ribosomal / Q000235:genetics*; D008040:Genetic Linkage; D007438:Introns; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012339:RNA, Ribosomal, 28S / Q000235:genetics; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S; D012341:RNA, Ribosomal, 5S