Overlap and discrepancies between ecotypes, genotypes and morphotypes of Antarctic and Arctic nanofauna
Zusammenfassung der Projektergebnisse
The polar regions offer the unique opportunity to compare spatially separated populations of protists. We studied whether acanthoecid choanoflagellates forming well defined and distinguishable morphospies due to their siliceous lorica show different genotypes within the same morphotype based on SSS rDNA. We were able to establish a high number of strains from different populations and to cultivate them. This is unique worldwide since choanoflagellates are thought to be very difficult to cultivate. We tested their autecological tolerances regarding temperature and salinity and found that there was no intraspecific variation of the examined SSU rDNA gene within one population and a very low divergence between the populations from both polar regions. Regarding the SSU rDNA there were no detectable speciation processes between species from the temporal and spatially separated sampling regions. Whether there is a permanent exchange of organisms through deep sea currents remains un-answered at the moment. We also showed, that non acanthoecid morphospecies like the craspedid Codosiga botrytis is hiding a species complex with a huge genetic diversity but a very low morphological variance. Additionally our results helped to resolve the phylogeny of choanoflagellates by clearly showing that the former large families of Salpingoecidae and Codosigidae are redundant as they are not monophyletic. Furthermore we showed that the V4 region of the SSU rDNA is a suitable marker region for choanoflagellate species due to the low intraspecific variance.
Projektbezogene Publikationen (Auswahl)
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(2012) CBOL Protist Working Group: Barcoding eukaryotic richness beyond the animal, plant and fungal kingdoms. PLoS Biology, 10 (11): e1001419
Pawlowski, J., Audic, S., Adl, S., Bass, D., Belbahri, L., Berney, C., Bowser, S.S., Cepicka, I., Decelle, J., Dunthorn, M., Fiore-Donno, A., Gile, H.G., Holzmann, M., Jahn, R., Jirků, M., Keeling, J.P., Kostka, M., Kudryavtsev, A., Lara, E., Lukeš, J., Mann, G.D., Mitchell, A.D.E., Nitsche, F., Romeralo, M., Saunders, W.G., Simpson, G.B.A., Smirnov, V.A., Spouge, J., Stern, F.R., Stoeck, T., Zimmermann, J., Schindel, D., de Vargas, C.
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(2011) Higher level taxonomy and molecular phylogenetics of the Choanoflagellatea. Journal of Eukaryotic Microbiology 58: 452- 462
Nitsche, F., Carr, M., Arndt, H. and Leadbeater, B.S.C.
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(2012) Cryptic diversity within the choanoflagellate morphospecies complex Codosiga botrytis – phylogeny and morphology of ancient and modern isolates. European Journal of Protistology, 48: 263-273
Stoupin, D., Kiss, A.K., Arndt, H., Shatilovich, A.V., Gilichinski, D.A. and Nitsche, F.
