title: Phylogenetic affiliations of mesopelagic acantharia and acantharian-like environmental 18S rRNA genes off the southern California coast.
abstract: Incomplete knowledge of acantharian life cycles has hampered their study and limited our understanding of their role in the vertical flux of carbon and strontium. Molecular tools can help identify enigmatic life stages and offer insights into aspects of acantharian biology and evolution. We inferred the phylogenetic position of acantharian sequences from shallow water, as well as acantharian-like clone sequences from 500 and 880 m in the San Pedro Channel, California. The analyses included validated acantharian and polycystine sequences from public databases with environmental clone sequences related to acantharia and used Bayesian inference methods. Our analysis demonstrated strong support for two branches of unidentified organisms that are closely related to, but possibly distinct from the Acantharea. We also found evidence of acantharian sequences from mesopelagic environments branching within the chaunacanthid clade, although the morphology of these organisms is presently unknown. HRP-conjugated probes were developed to target Acantharea and phylotypes from Unidentified Clade 1 using Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) on samples collected at 500 m. Our CARD-FISH experiments targeting phylotypes from an unidentified clade offer preliminary glimpses into the morphology of these protists, while a morphology for the aphotic acantharian lineages remains unknown at this time.
authors.affiliation: Department of Biological Sciences, University of Southern California, 3616 Trousdale Pkwy AHF 301, Los Angeles, CA 90089-0371, USA. igilg@bigelow.org
authors.forename: Ilana C
authors.initials: IC
authors.lastname: Gilg
authors.forename: Linda A
authors.initials: LA
authors.lastname: Amaral-Zettler
authors.forename: Peter D
authors.initials: PD
authors.lastname: Countway
authors.forename: Stefanie
authors.initials: S
authors.lastname: Moorthi
authors.forename: Astrid
authors.initials: A
authors.lastname: Schnetzer
authors.forename: David A
authors.initials: DA
authors.lastname: Caron
mesh_terms: D002140:California; D016000:Cluster Analysis; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020459:Genes, rRNA; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D010802:Phylogeny; D016053:RNA, Protozoan / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D056901:Rhizaria / Q000235:genetics* / Q000302:isolation & purification*; D012623:Seawater; D017422:Sequence Analysis, DNA
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D016053:RNA, Protozoan; D012337:RNA, Ribosomal, 18S