Small-subunit ribosomal RNA sequences from selected dinoflagellates: testing classical evolutionary hypotheses with molecular systematic methods

1997 ◽  
pp. 237-259 ◽  
Author(s):  
G. W. Saunders ◽  
D. R. A. Hill ◽  
J. P. Sexton ◽  
R. A. Andersen
Keyword(s):  
Ribosomal Rna ◽  
Small Subunit ◽  
Molecular Systematic ◽  
Rna Sequences ◽  
Small Subunit Ribosomal Rna ◽  
Ribosomal Rna Sequences

Phylogenesis of pit-plug-associated features in the Rhodophyta: inferences from molecular systematic data

1997 ◽  
Vol 75 (9) ◽  
pp. 1436-1447 ◽  
Author(s):  
Gary W. Saunders ◽  
J. Craig Bailey
Keyword(s):  
Ribosomal Rna ◽  
Sequence Data ◽  
Algal Species ◽  
Small Subunit ◽  
Future Research ◽  
Molecular Systematic ◽  
Rna Sequences ◽  
Small Subunit Ribosomal Rna ◽  
Cap Layer ◽  
Red Algal

Small-subunit ribosomal RNA sequence data are presented for Rhodogorgon carriebowensis Norris et Bucher (Rhodogorgonales, Rhodophyta) and Galaxaura marginata (Ellis et Solander) Lamouroux (Nemaliales, Rhodophyta). Data for these species were included in a matrix consisting of small-subunit ribosomal RNA sequences for 70 taxonomically diverse red algal species. Distance, parsimony, and maximum-likelihood analyses of these data all strongly support (100% of bootstrap replicates for distance and parsimony) a close alliance between the Rhodogorgonales and Corallinales. Our alignment includes 19 species representing six florideophyte orders (Acrochaetiales, Batrachospermales, Corallinales, Nemaliales, Palmariales, Rhodogorgonales) in which pit plugs are characterized by two cap layers. Distance and parsimony analyses resolve a monophyletic lineage including all "two-cap-layer" species. Our parsimony-derived molecular phylogeny was used to test a published hypothesis of pit-plug evolution. Four aspects of Pueschel's hypothesis are consistent with the results of our molecular systematic study: (i) "naked" plugs represent the ancestral type, (ii) outer cap layers are homologous structures, (iii) domed outer caps are ancestral to plate-like outer caps, and (iv) cap membranes are a derived feature within the two-cap-layer lineage. Directions for future research are discussed. Key words: Acrochaetiales, Batrachospermales, Corallinales, molecular systematics, Nemaliales, Palmariales, phylogeny, pit plug, Rhodogorgonales, Rhodophyta.

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