title: Isolation and molecular phylogenetic analysis of actin-coding regions from Emiliania huxleyi, a Prymnesiophyte alga, by reverse transcriptase and PCR methods.
abstract: Reverse transcriptase and polymerase chain reaction methods were used to amplify and clone actin cDNAs from the chlorophylls a + C-containing unicellular alga, Emiliania huxleyi (Prymnesiophyta). Actins in E. huxleyi are defined by a gene family containing at least six distinct coding regions that were derived from relatively recent gene duplications. Five of the coding regions (types 1, 2, and 4-6) varied only among synonymous codons. A nonsynonomous change in a sixth coding region (type 3 actin) produced a serine-to-phenylalanine replacement. The G + C composition of third positions in E. huxleyi actin genes is 98%, which contrasts with the mean value of 50% G + C content for first and second positions. Distance-matrix and parsimony analyses of actin genes identified the prymnesiophytes as a photosynthetic lineage that is not already related to other eukaryotic algal groups.
authors.affiliation: Center for Molecular Evolution, Marine Biological Laboratory, Woods Hole, Massachusetts 02543.
authors.forename: D
authors.initials: D
authors.lastname: Bhattacharya
authors.forename: S K
authors.initials: SK
authors.lastname: Stickel
authors.forename: M L
authors.initials: ML
authors.lastname: Sogin
mesh_terms: D000199:Actins / Q000235:genetics*; D000595:Amino Acid Sequence; D001482:Base Composition; D001483:Base Sequence; D015139:Blotting, Southern; D004247:DNA; D056890:Eukaryota / Q000235:genetics*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010802:Phylogeny; D010839:Phytoplankton / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D012194:RNA-Directed DNA Polymerase; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000199:Actins; D009838:Oligodeoxyribonucleotides; D004247:DNA; D012194:RNA-Directed DNA Polymerase