MOLECULAR SYSTEMATICS OF Oithona nana (COPEPODA, CYCLOPOIDA) OFF THE BUENOS AIRES PROVINCE

CEPEDA G. D.; VIÑAS M. D.; SALERNO G. L.; BERÓN C. M.

Villa Carlos Paz, Argentina

Congreso; XLIV Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Oithona nana is one of the dominant  copepod species in coastal waters of the Argentine Sea. In order to confirm its taxonomic identity, molecular analysis was performed, comparing the 28S sequences of specimens from the type locality (Gulf of Naples) and the Buenos Aires province (“EPEA Station”, 38º 28’S, 57º 41’W, and “El Rincon” area). The 5´ end of the large subunit (28S) is appropiate to distinguish between closely related taxonomic groups such as genera and species. O. nana females were obtained and preserved in 95% ethanol. Each specimen was squashed in a PCR tube and a DNA fragment corresponding to 28S ribosomal was PCR amplified using universal primers P63 and R635. The product was cloned and sequenced. A phylogenetic tree was constructed using the software package MEGA. Three groups corresponding to different cyclopoid families were well-resolved (high bootstrap values). Within the Oithonidae family, O. nana sequences from Buenos Aires province were closely related to that from the type locality (less than 5% distance) showing a strong agreement between the morphological and molecular taxonomy of O. nana from the Argentine Sea. The obtention of the 28S “reference sequence” of O. nana constitutes an important advancement towards its specific confirmation, and contributes to strengthen the public databases.