Genetic differentiation of two diploid-polyploid complexes of spined leach, genus Cobitis (Cobitidae), in the Czech Republic, involving C-taenia, C-elongatoides, and C. spp.: Allozyme interpopulation and interspecific differences

Altogether 375 individuals, sampled at eight localities from the Elbe R. an d Danube R. basins in the Czech Republic were studied electrophoretically t o detect protein variability at population and specific levels in order to identify the spined leach species occurring on the territory A further 64 i ndividuals of C. taenia sensu Va s i l e v & Va s i l e v a (1994) from thr ee localities in northern Europe were analysed as comparative material. The products of 11 loci out of 18 analysed were found to be polymorphic. Analy ses of the electrophoretic patterns in individual loci and intensity ratios of respective bands showed that at several localities, both in the Elbe R. and the Danube R. basins, the diploid, triploid and tetraploid forms occur sympatrically suggesting the presence of two different hybrid diploid-poly ploid complexes. In Psovka (Elbe R. basin), the hypothesis of the hybrid origin of such poly ploid individuals was confirmed by the present electrophoretic data using a nalyses of loaches from diploid populations of C. taenia (north-western and northern Germany, north-eastern Poland) and C. elongatoides (upper Elbe R. and upper Dyje R. basins). The species-specific alleles in several loci th at distinguished the genomes of the species involved were identified, and d iploid contribution of C. elongatoides and haploid contribution of C. taeni a was confirmed. In the Dyje R. (Danube R. basin), one species involved was again C. elongat oides constituting always the diploid part of triploid and tetraploid indiv iduals. together with the haploid or diploid contribution of another specie s still unidentified (designated as Cobitis sp.). Contribution of a third s pecies to the genome of some tetraploid individuals is supposed but it coul d not be identified surely because of the very complicated electrophoretic patterns in most loci of polyploid genomes, which did not allow the individ ual variants to the respective species to be assigned. Two species involved in the origin of hybrid / polyploid individuals in bot h complexes, viz. C. taenia and C. sp., showed nearly identical protein mar kers in nearly all loci, irrespective of the fact that the karyotype of the latter apparently does not correspond to that of C. taenia. The results co nfirmed the previous hypothesis on the presence of two different hybrid dip loid-polyploid complexes: C. elongatoides and C. taenia in the Psovka Creek (Elbe R. basin), and C. elongatoides and C. sp. in the Dyje R. at its conf luence with the Morava R. (Danube R. basin).