Relations phylogénétiques chez les Euphausidés de la Mer de Ross et des régions adjacentes de l'Océan Austral. La Mer de Ross abrite une grande concentration de krill antarctique (Euphausia superba Dana, 1850) et de krill de glace (Euphausia crystallorophias Holt & Tattersal, 1906) qui ont une grande importance écologique (Azzali & Kalinowski, 1999; Sala et al., 2002). L'objectif de cette étude était d'approfondir notre compréhension de la distribution et la phylogénie des espèces de krill qui ont été recueillis dans le la mer de Ross au cours de la XIXème expédition PNRA . Des individus de 33 échantillons au filet ont été examinés par séquençage de portions de deux gènes mitochondriaux; 530 pb du gène 16S sur un total de 20 individus et 938 pb de NADH sur 200 individus. Des analyses (BIO-ENV) ont montré que la distribution de ces espèces est mieux corrélée avec la température de l'eau qu'avec la profondeur ou la présence de glace. Des analyses moléculaires de variance (AMOVA) réalisées à partir des données de NADH ne mettent pas en évidence de différences de diversité nucléotidique au sein de chaque espèce: E. superba (n = 100, h = 0,97533 ± 0,0472, pi = 0,53433 ± 0,17212), E. crystallorophias (n = 100, h = 0,81762 ± 0,07431, pi = 0,88567 ± 0,46825). La plus grande part de la variabilité est associée au niveau individuel et peut dépendre du polymorphisme élevé de l'espèce. Les analyses AMOVA entre les échantillons n'ont montré aucune différence significative chez aucune espèce.
Ross Sea supports a large concentration of Antarctic krill (Euphausia superba Dana, 1850) and Ice krill (Euphausia crystallorophias Holt & Tattersal, 1906) that have a great ecological significance (Azzali & Kalinowski, 1999; Sala et al., 2002). The aim of this study was to further our understanding of the distribution and phylogeny of krill species that were collected in the Ross Sea during the XIX PNRA expedition. Krill from 33 net samples were examined by sequencing parts of two mitochondrial genes; 530 bp of the gene 16S from a total of 20 specimens and 983 bp of NADH from 200 specimens. BIO-ENV analysis showed that the distribution of these species correlated best with water temperature than bottom depth and the ice presence. AMOVA analysis, conducted using the NADH data among geographic populations, revealed no significant differences of nucleotide diversity within the two Euphausia species: E. superba (n = 100, h = 0.97533 ± 0.0472, pi = 0.53433 ± 0.17212), E. crystallorophias (n = 100, h = 0.81762 ± 0.07431, pi = 0.48578 ± 0.46825). Most of the variability is associated with individuals and may depend on the high polymorphism of the species. AMOVA analysis between net samples showed no significant differences in all species.
Phylogenetic relationships of the Antarctic euphausiids inhabiting the Ross Sea and the adjacent regions of Southern Ocean
Daniela GIORDANO;Paola RINELLI;Antonello SALA;Laura GIULIANO;Ermanno CRISAFI;
2011
Abstract
Ross Sea supports a large concentration of Antarctic krill (Euphausia superba Dana, 1850) and Ice krill (Euphausia crystallorophias Holt & Tattersal, 1906) that have a great ecological significance (Azzali & Kalinowski, 1999; Sala et al., 2002). The aim of this study was to further our understanding of the distribution and phylogeny of krill species that were collected in the Ross Sea during the XIX PNRA expedition. Krill from 33 net samples were examined by sequencing parts of two mitochondrial genes; 530 bp of the gene 16S from a total of 20 specimens and 983 bp of NADH from 200 specimens. BIO-ENV analysis showed that the distribution of these species correlated best with water temperature than bottom depth and the ice presence. AMOVA analysis, conducted using the NADH data among geographic populations, revealed no significant differences of nucleotide diversity within the two Euphausia species: E. superba (n = 100, h = 0.97533 ± 0.0472, pi = 0.53433 ± 0.17212), E. crystallorophias (n = 100, h = 0.81762 ± 0.07431, pi = 0.48578 ± 0.46825). Most of the variability is associated with individuals and may depend on the high polymorphism of the species. AMOVA analysis between net samples showed no significant differences in all species.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.