Presentation Detail

Systematics and Inferred Phylogenies

Brugler, Mercer R. [1], Lara, Adolfo [2], González Muñoz, Ricardo [3], Rodriguez, Estefania [4].

Evaluation of novel nuclear introns within shallow and deep-water sea anemones (Cnidaria: Anthozoa: Hexacorallia: Actiniaria).

Sea anemones (actiniarians) are among the most diverse members of the subclass Hexacorallia and are considered an emerging model system, as they represent a basal eumetazoan lineage that serves as an outgroup to studies analyzing the origin and evolution of bilaterian animals. However, simple body plans reduce the number of morphological characters available to define a species or provide phylogenetic information. Mosaics of characters currently distinguish anemones, and proposed evolutionary relationships have been largely based on an absence of features. In addition to slow mitochondrial sequence evolution, there are currently no nuclear markers in the actiniarian molecular toolkit other than the ribosomal cistron (18S-ITS1-5.8S-ITS2-28S). Defining species boundaries and deeper phylogenetic relationships is imperative and represents a critical step in advancing our understanding of sea anemone taxonomy and systematics. Utilizing EPIC (exon-priming, intron-crossing) primers, in addition to non-standard PCR profiling conditions, we obtained a total of 10 nuclear introns (AK [Arginine Kinase], CaM [Calmodulin], i2 [Calpain], Enolase [2-Phospho-D-Glycerate Hydrolase], G3PDH [Glyceraldehyde 3-Phosphate Dehydrogenase], Nck [Nck Associated Protein 1 Homolog], Pes [Pescadillo Homolog], SRP54 [Signal Recognition Particle 54-kDa Subunit], i50 [Transferase] and VATPSB [Vacuolar ATP Synthase Subunit B]). Six introns were used to evaluate intraspecific variation within Phymanthus crucifer, a shallow-water anemone collected from the Gulf of Mexico and Caribbean. Additionally, seven introns (three of which overlapped with those used for Phymanthus) were used to evaluate intra- and interspecific variation within the deep-sea / Antarctic sea anemone genus Actinostola. In particular, we analyzed variation among A. chilensis, A. crassicornis, A. georgiana, A. sp.1 (small specimen) and A. sp.2 (large specimen). Variability within these novel nuclear introns as compared to mitochondrial rns, rnl and cox3, as well as nuclear 18S and 28S, will be discussed. Variable nuclear markers will ultimately determine which external / internal morphological characters of a sea anemone are species-specific. PCR products of all nuclear introns were cloned to determine copy number. Although the literature suggests that ploidy within anemones ranges from 2n = 18 (Anthopleura midori and A. kurogane), 30 (Nematostella vectensis) to 32 (Haliplanella luciae and Aiptasiomorpha sp.), our data revealed upwards of 14 different copies of an intron within a single individual. While high copy number was an issue for many introns, some introns were indeed single copy.

1 - American Museum of Natural History, Sackler Institute for Comparative Genomics, Division of Invertebrate Zoology, Central Park West at 79th Street, New York, NY, 10024, USA
2 - University of Houston - Downtown, Department of Natural Sciences, One Main Street, Room 813-North , Houston, TX, 77002, USA
3 - Universidad Nacional Autónoma de Mexico
4 - American Museum Natural History, Invertebrate Zoology, Central Park West at 79th street, New York, NY, 10024, USA

Keywords:
Anthozoa
Actiniaria
Sea Anemone
Single Copy Nuclear Loci
Phymanthus
Actinostola
species delimitation
EPIC Primers
ploidy
Cloning.

Presentation Type: Regular Oral Presentation
Session: 92
Location: Rendezvous B/Snowbird Center
Date: Sunday, June 23rd, 2013
Time: 4:30 PM
Number: 92005
Abstract ID:858
Candidate for Awards:Ernst Mayr Award