GENETIC-EVIDENCE FOR 3 SPECIES WITHIN PSEUDOTERRANOVA-DECIPIENS (NEMATODA, ASCARIDIDA, ASCARIDOIDEA) IN THE NORTH-ATLANTIC AND NORWEGIAN AND BARENTS SEAS

• Published in: International Journal for Parasitology
• Main Authors: PAGGI, Lia, NASCETTI, Giuseppe, CIANCHI, Maria Rossella, MATTIUCCI, Simonetta, D'AMELIO, Stefano, BULLINI, Luciano, P. Orecchia, B. Berland, J. Brattey, J. W. Smith
• Other Authors: Paggi, Lia, Nascetti, Giuseppe, Cianchi, Maria Rossella, P., Orecchia, Mattiucci, Simonetta, D'Amelio, Stefano, B., Berland, J., Brattey, J. W., Smith, Bullini, Luciano
• Format: Article in Journal/Newspaper
• Language: English
• Published: PERGAMON-ELSEVIER SCIENCE LTD 1991
• Subjects: morphology; pseudoterranova-decipien; norwegian sea; north atlantic; p-decipiens a; b and c; genetic variation; biochemical taxonomy; geographical distribution; multilocus electrophoresi; host specie; barents sea; codworms; Barents Sea; Norwegian Sea; common seal; North Atlantic; North East Atlantic; Phoca vitulina
• Online Access: http://hdl.handle.net/11573/409025; https://doi.org/10.1016/0020-7519(91)90010-5; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=A1991FN86000008&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a; http://www.scopus.com/inward/record.url?eid=2-s2.0-0025859523&partnerID=65&md5=c036da4498d0b272339e6849b9810508

Genetic variation of 1017 specimens of codworm, Pseudoterranova decipiens, collected from fish and seals at 23 sampling locations in the North Atlantic and Norwegian and Barents Seas, was analysed on the basis of 16 enzyme loci. Three reproductively isolated species, provisionally designated P. decipiens A, B and C, were detected, showing distinct alleles at the following loci: Mdh-1, 6Pgdh, Np, Pgm, Est-2 (between species A and B); Mdh-3, 6Pgdh, Np, Sod-1, Adk, Pgm, Est-2, Mpi(between A and C); Mdh-1, Mdh-3, Sod-1, Adk, Pgm, Est-2, Mpi(between B and C). One F1 hybrid was observed between P. decipiens A and B, but this apparently does not lead to any gene exchange between the two species, which do not show any evidence of introgression. No hybrids or introgressed individuals were observed between P. decipiens C and either A or B. Genetic distances among conspecific populations were low (average Nei's D 0.001-0.005), even though they were collected thousands of kilometres apart, indicating high levels of gene flow within each of the three species. The values of Nei's index D were 0.44 between P. decipiens A and B, 0.57 between B and C, and 0.79 between A and C. Estimated evolutionary divergence times, using Nei's formula, range from 2 to 4 million years. Differences between P. decipiens A, B and C were also found with respect to genetic variability, morphology, geographical distribution and hosts. Mean heterozygosity values of 0.08, 0.05 and 0.02 were obtained for P. decipiens A, B and C, respectively. Preliminary morphological examination of adult males, previously identified by multilocus electrophoresis, revealed differences in the relative size and pattern of caudal papillae. P. decipiens B is widespread in the study area, whereas P. decipiens A was found only in the North-East Atlantic and Norwegian Sea. In this area P. decipiens A is most common in the grey seal, Halichoerus grypus, while the common seal, Phoca vitulina, is the main host for P. decipiens B. In Canadian Atlantic waters, where P. decipiens A ...