title: srRNA evolution and phylogenetic relationships of the genus Naegleria (Protista: Rhizopoda).
abstract: A rapid RNA sequencing technique was used to partially sequence the small-subunit ribosomal RNA (srRNA) of four species of the amoeboid genus Naegleria. The extent of nucleotide sequence divergence between the two most divergent species was roughly similar to that found between mammals and frogs. However, the pattern of variation among the Naegleria species was quite different from that found for those species of tetrapods characterized to date. A phylogenetic analysis of the consensus Naegleria sequence showed that Naegleria was not monophyletic with either Acanthamoeba castellanii or Dictyostelium discoideum, two other amoebas for which sequences were available. It was shown that the semiconserved regions of the srRNA molecule evolve in a clocklike fashion and that the clock is time dependent rather than generation dependent.
authors.affiliation: Evolutionary Biology Unit, South Australian Museum, Adelaide.
authors.forename: P R
authors.initials: PR
authors.lastname: Baverstock
authors.forename: S
authors.initials: S
authors.lastname: Illana
authors.forename: P E
authors.initials: PE
authors.lastname: Christy
authors.forename: B S
authors.initials: BS
authors.lastname: Robinson
authors.forename: A M
authors.initials: AM
authors.lastname: Johnson
mesh_terms: D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D009253:Naegleria / Q000235:genetics*; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013997:Time Factors
chemical_list: D012335:RNA, Ribosomal