Limnological Institute, SB RAS, Irkutsk
Head of the Institute:
M.A.Grachev, Professor
Tel: +7 (3952) 46 05 04
Fax:+7 (3952) 46 04 05
email: grachev@lin.irk.ru
Principal researchers:
D.Yu.Sherbakov, Dr.
Project objectives
The ability of any ecosystem to meet various environmental challenges directly depends on its complexity, which includes not only species composition of its biota, but also genetic variability of the species. Therefore it is essential to develop an estimate which would take into account the both characteristics. Currently there are many different approaches to quantify species diversity, but estimates of genetic variability although widely used in population and evolutionary studies, still escape application at the ecosystem level. On the other hand, recent progress in technology of DNA sequencing made it possible to obtain sufficient amounts of data, which would allow taking into account genetic diversity while describing an ecosystem.
Thus in framework of current project we propose to collect both sets of data (species content and genetic diversity) for several different ecosystems concentrating at benthic invertebrate communities, obtain an information on their genetic diversity by amplifying and sequencing ca 600BP long fragment of mitochondrial gene Cox I and compare traditional numerical characteristics of an ecosystems based on species content only with several kinds of the new ones taking into account genetic diversity. By comparing the data obtained to the existing qualitative knowledge on the processes going on the model ecosystems we expect to estimate the usability of different methods of numerical descriptions of ecosystem and obtain more adequate tool for uniform description of biodiversity in different ecosystems.
Background and significance of objectives
At the Limnological Institute in course of molecular phylogenetic studies ca 700bp long fragment of mitochondrial gene coding for the first sub unit of cytochrom c oxydase have been successfully used to analyze evolutionary relationships within amphipods, 3 families of molluscs and oligochaets. Currently it is well accepted, that this fragment is usefull for evolutionary studies at different levels including the population one: in spite of relatively high evolutionary robustness of its amino acid composition, the accumulation rate of synonymous base substitutions, especially transitions, is still very high. “Universal” primers allow seemless inclusion of representatives of different animal groups into the same study, thus allowing comparison of the results, which already have been done in course of evolutionary studies.
On the other hand, considerable experience of taking of quantitative probes and analyzing species content and abundance there had been accumulated in course of detailed ecological studies of benthic communities at Lake Baikal.
Well established and wide network of international collaboration with different European laboratories of similar profile (Royal Belgian Institute of Natural Sciences, Drs. Goddeeris, Marens, Verheyen; Bulgarian Institute of Fisheries, Dr. Uzunova; the Helsinki University, Dr. Va inola and several other German, British and Dutch groups) will enable the analysis of different ecosystems ranging both by biodiversity and extent of human impact.
Therefore the program of the program of the study proposed (flow chart is given at Fig.1) will consist of the following major stages performed for at least two model communities at Lake Baikal and Black Sea:
- Collection of quantitative representative samples of benthic organisms
- Species identification (wherever possible: usually such probes contain large amounts of juveniles, identity of which is always a problem).
- Amplification and sequencing of Cox I fragment from well identified individuals first, then from other animals. Additional species identification of juveniles may be performed at this stage basing on nucleotide sequences. The amount of sequence information sufficient for further analysis will be determined by recurrent test.
- Information on species composition and abundance will be processed in standard way to obtain all possible estimators of biodiversity, and they will be compared to estimators of genetic diversity calculated from DNA sequence data. Utility of different approaches to combine both sets of data will thus be tested.
Expected results
- For several model communities of benthic invertebrates will be thoroughly studied both from faunistic and genetic points of view. Unlike many studies of this kind, considerable information on species identity of juveniles will be obtained;
- Comparative data on population structure (genetic polymorphism) in the most abundant species will enable one to address questions about possible parallelisms in population processes taxa interacting within the same ecosystem;
- An approach to formal characterization of biodiversity of higher predictive value will be developed together with the guidelines for its application to other ecosystems.
List of publications of participants related to the project
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Sherbakov D. Yu. Molecular phylogenetic studies on the origin of biodiversity in Lake Baikal // Ecology & Evolution. – 1999. – Vol. 14, ą 3 (153). – P. 92-95.
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Vainola R., Kamaltynov R. Allozime studies on the evolutionary diversity of Baikalian amphipode crustaceans, and their relationship to European escapee species Pallasea quadrispinosa. – 1995
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in The second Vereshchagin Baikal Conference (Abstr.) (5-15 October 1995), pp 40-41, Irkutsk, Russia.
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Ogarkov O.B. et al. Phylogenetic relatedness of the Baikal Lake endemic amphipods (Crustacea, Amphipoda) deduced from partial nucleotide sequences of the cytochrome oxidase subunit III genes // Mol. Biol. – 1997. – ą 31. – P. 24-29.
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Zubakov D.Yu., Sherbakov D.Yu., Sitnikova T.Ya. Analysis of phylogenetic relationships of Baikalian endemic molluscs fam. Baikaliidae, Kleissin 1878 (Gastropoda, Pectinibranchia) based upon partial nucleotide sequences of mitochondrial gene CO I. // Mol. Biol. – 1997. – ą 31. – P. 1097-1102.
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Weinberg I.V., Kamaltynov R. M. Zoobenthos communities on stony beach of Lake Baikal. 1.Fauna // Zool. Journal. – 1998. – Vol. 77, ą 2. – P. 158-165.