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Genetic diversity of eukaryotic picoplankton in Astan (Roscoff) by SSU rRNA gene cloning and sequencing. Khadidja Romari, Fabrice Not & Daniel Vaulot Station biologique de Roscoff. DNA extraction. Extracted nucleic acid. PCR. Amplified rDNA. Cloning. rDNA clones. Sequencing.
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Genetic diversity of eukaryotic picoplankton in Astan (Roscoff) by SSU rRNA gene cloning and sequencing Khadidja Romari, Fabrice Not & Daniel Vaulot Station biologique de Roscoff
DNA extraction Extracted nucleic acid PCR Amplified rDNA Cloning rDNA clones Sequencing Phylogenetic identification rDNA sequences Comparative sequence analysis rDNA database Environmental sample (pre-filtration and filtration)
PCR on the white colonies M M 1 2 3 4 5 6 7 8 9 10 11 12 . . . . . . . . . . . 1800 bp Fig.1: Agarose gel electrophoresis showing 18S rDNA PCR product of clones from environmental sample (RA000412). M: Smart Ladder Librarie clones screening
RFLP : Restriction Fragment Lenght Polymorphism 600 bp Fig.2: Agarose gel electrophoresis showing the restriction profiles of 18S rDNA fragment of clones environmental sample(RA000412) obtained using the enzyme HaeIII. M’: molecular mass marker 100bp M’ M’ M’ 1 2 3 5 6 8 9 10 11 12
Alveolata Perkinsea Fungi Neighbor-joining dendrogram of the picoeukaryote groups found in the four libraries
Clones Distribution of the picoeukaryote groups during the four seasons Ex: RA000412 = station of the cruise, year, month, day
Photosynthetic group Heterotrophic group April 2000 December 2000
Alveolata Perkinsea Fungi Neighbor-joining dendrogram of the picoeukaryote groups found in the four libraries clones
0.10 Part of tree extracted from ARB indicating a position of the He000427.214 group
SSU rDNA phylogenetic relationshipps (Parcimony ML tree) between 13 clones of He000427.214 group
Alveolata Perkinsea Fungi Neighbor-joining dendrogram of the picoeukaryote groups found in the four libraries clones
0.10 Part of tree extracted from ARB indicating a position of the LKM 74 group
SSU rDNA phylogenetic relationshipps (Parcimony ML tree) between 13 clones of LKM 74 group
Alveolata Perkinsea Fungi Neighbor-joining dendrogram of the picoeukaryote groups found in the four libraries clones
Part of tree extracted from ARB, indicating a position of the clone RA000609.30
Conclusion • The phylogenetic diversity in each library was rather large • Low redundancy • Of a total of 224 eukaryal clones, 85 affiliated with algal class and 79 • clones are affiliated with clearly heterotrophic group • The spring clone library is largely dominated by the phototrophic • group : Prasinophyte and chryptophyceae
Conclusion • Some sequences are found identical in both Helgoland and Roscoff • clone libraries • Two novel group appeared : • He000427.214 (13 clones) • LKM 74 (9 clones)