Ráb, P., M. Rábová, J. Bohlen & S. Lusk
Genetic differentiation of the two hybrid diploid-polyploid complexes of loaches, genus Cobitis (Cobitidae), involving C. taenia, C. elongatoides and C. spp. in the Czech Republic. Karyotypes and cytogenetic diversity
Folia Zoologica 49 Suppl. 1: 55-66
Folia Zool. 49 (Suppl. 1): 55-66 (2000)
Genetic differentiation of the two hybrid diploid-polyploid complexes of loaches, genus Cobitis (Cobitidae) involving C. taenia, C. elongatoides and C. spp. in the Czech Republic: Karyotypes and cytogenetic diversity
- RÁB, M. RÁBOVÁ, J. BOHLEN & S. LUSK
Abstract
The karyotype and cytogenetic diversity of the spined loaches of the genus Cobitis in the Czech Republic was surveyed using conventional Giemsa-staining, Ag-staining, C-banding, CMA3-fluorescence and fluorescence in situ hybridization (F.I.S.H.) with 28S DNA probe. C. elongatoides Bacescu et Maier, 1969 was identified as a diploid loach species inhabiting both Elbe and Danube basins of the Czech Republic. This species has 2n = 50 and a karyotype composed of 15 pairs of meta- (m), 8 pairs of submeta-(sm), 1 pairs of subtelo- (st) and 1 pair of acrocentric (a) chromosomes. The complex specific NOR-phenotype included one medium m, one small and large sm pair. The structural polymorphism of the presence and/or absence type regarding the ribosomal sites was observed with the number of NORs ranging from one to four. In the middle Elbe R. bas in, the hybrid diploid/polyploid complex of this species occurred with C. taenia sensu Vasil’ev & Vasil’eva (1994). This species has 2n = 48 and a karyotype identical to that described by Vasil’ev’s team from Moscow region. The NOR-bearing chromosome pairs include one medium sized srn pair with NORs covering entire short arms. The identical karyotype found in the individuals from Weser R. basin (northwestern Germany), Kleiner Ploner See {northern Germany) and Klawój Lake (northeastern Poland) confirmed such a conclusion. In the middle Danube basin, triploid and tetraploid individu~1s occur. Besides the diploid karyotype of C. elongatoides, the karyotypes of triploid individuals also contained a haploid chromosome set with 8 m, 13 sm and 4 st – a chromosomes, while in tetraploid individuals to those two previous ones, an additional haploid set with 16 m and 8 srn chromosomes could be identified. The NOR-bearing chromosomes of tetraploids include at least one large st and one large m. Those two haploid chromosome sets could not be assigned to any of the species of the genus Cobitis karyotyped so far.