Comparison of Sequence Differences in a Variable 23S rRNA Domain among Sets of Cryptic Species of Ciliated Protozoa

ABSTRACT Studies were undertaken to discover the relative molecular distances separating some familiar forms of ciliated protozoa, and the genetic species they include. Sequences of 190 bases of the D2 domain of the large ribosomal nucleic acid molecule were obtained by polymerase chain reaction fro...

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Bibliographic Details
Published in:The Journal of eukaryotic microbiology 1998-01, Vol.45 (1), p.91-100
Main Authors: Nanney, David L., Park, Chaeryung, Preparata, Rosamaria, Simon, Ellen M.
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Ciliophora - classification
Ciliophora - genetics
Colpidium
Colpoda
D2 domain
Dexiostoma
Evolution, Molecular
Fundamental and applied biological sciences. Psychology
Genetic Variation
Glaucoma
Lambornella
Paramecium
Paramecium - classification
Paramecium - genetics
PCR
PHYLOGEN string analysis. rRNA (large subunit
Phylogeny
Protozoa
RNA, Ribosomal, 23S - genetics
Sequence Homology, Nucleic Acid
Systematics. Geographical distribution. Morphology. Cytology
Tetrahymena
Tetrahymena - classification
Tetrahymena - genetics
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Summary:ABSTRACT Studies were undertaken to discover the relative molecular distances separating some familiar forms of ciliated protozoa, and the genetic species they include. Sequences of 190 bases of the D2 domain of the large ribosomal nucleic acid molecule were obtained by polymerase chain reaction from protists of three distinctive groups of ciliated protozoa‐Colpoda, Paramecium and Tetrahymena. Evolutionary trees were constructed for each set of sequences using the PHYLOGEN 1.0 string programs. All three groups of ciliates manifested large molecular diversity among strains difficult or impossible to distinguish morphologically. The largest single evolutionary distance within a group was the 75 differences separating Tetrahymena paravorax from the other tetrahymenids. The largest mean distance for a group was the 21.2 for the colpodids. In all the protist groups the large molecular diversity is obscured by morphological conservatism associated with constraints of ancient designs. The molecular diversity within morphotypes argues for long evolutionary coexistence of species differentiated from each other in significant physiological, ecological, or nutritional ways.
ISSN:1066-5234
1550-7408
DOI:10.1111/j.1550-7408.1998.tb05075.x