Untersuchungen über die Eignung beiochemischer und molekulargenetischer Marker für eine Identifizierung von verschiedenen Störarten und deren Hybriden

by Ingo Manfred Jenneckens
Doctoral thesis
Date of Examination:1999-07-08
Date of issue:2001-11-07
Referee:Prof. Dr. Gabriele Hörstgen-Schwark
Referee:Prof. Dr. Dr. Bertram Brenig
Persistent Address: http://dx.doi.org/10.53846/goediss-1723

 

 

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Abstract

English

The goal of this thesis was to explore the potential of different biochemical and molecular markers to discriminate different sturgeon species. Blood samples were collected from the Eurasian sturgeons Acipenser baerii (n = 125), A. gueldenstaedtii (n = 91), A. ruthenus (n = 38), A. stellatus (n = 42) and Huso huso (n = 72). Additionally four samples of A. persicus as well as two samples of A. naccarii and Polyodon spathula were available Furthermore, blood samples of the hybrids A. baerii x A. ruthenus, H. huso x A. gueldenstaedtii, H. huso x A. ruthenus and (H. huso x A. ruthenus) x A. gueldenstaedtii have been at disposal. Alltogether 13 different biochemical markers occuring in the blood were investigated at A. baerii, A., gueldenstaedtii, A. ruthenus, A. stellatus and H. huso. Of these solely the allozyme system phosphoglucomutase (PGM) was characteristic for one sturgeon species, A. stellatus. Specimens of this species were fixed at allele c not observed in individuals of the other four sturgeon taxa. Several different molecular methods were investigated in this study, like AFLP, inter-SSR PCR, RAPD and SINE-PCR. Furthermore, microsatellite loci as well as the mitochondrial cytochrome b gene have been examined. Solely the microsatellite locus LS-39 was identified as diagnostic nuclear marker for A. stellatus. All specimens as well as an analyzed caviar lot of the species were fixed at the allele of 111 bp. This allele was not observed in other sturgeons investigated. With respect to the experimental conditions the techniques AFLP, inter-SSR PCR and SINE-PCR were unabel to identify the invstigated species A. baerii, A. ruthenus, A. stellatus and H. huso or A. ruthenus, A. stellatus and H. huso, respectively. On the other hand neither a discrimination of sturgeon hybrids nor the assignment of hybrids to parental species was possible. Marked sequence differences were observed among the species A. ruthenus, A. stellatus, A. transmontanus, H. huso, P. spathula and the sisterspecies encomprised within the genus Scahirhynchus at the mitochondrial cytochrome b gene. Due to the well known occurence of natural variability of nucleotide sequences among specimens within species, statements concerning interspecific conserved nucleotide substitutions could not be drawn. The use of these nucleotide substititions as diagnostic features has to be proven at a larger number of wild specimens originating from different locations. However, the fact that mitochondrial DNA is inherited maternally has the disadvantage that hybrids could not be identified. Furthermore, new aspects on the ploidy level of different acipenseriform species were retrieved and a closer view on the systematics of Acipenseriformes was obtained by reconstructed molecular phylogenies.
 
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