Cobitis Elongatoides Research Articles

Ice age cloning – comparison of the Quaternary evolutionary histories of sexual and clonal forms of spiny loaches (Cobitis; Teleostei) using the analysis of mitochondrial DNA variation

Recent advances in population history reconstruction offered a powerful tool for comparisons of the abilities of sexual and clonal forms to respond to Quaternary climatic oscillations, ultimately leading to inferences about the advantages and disadvantages of a given mode of reproduction. We reconstructed the Quaternary historical biogeography of the sexual parental species and clonal hybrid lineages within the Europe-wide hybrid complex of Cobitis spiny loaches. Cobitis elongatoides and Cobitis taenia recolonizing Europe from separated refuges met in central Europe and the Pontic region giving rise to hybrid lineages during the Holocene. Cobitis elongatoides due to its long-term reproductive contact with the remaining parental species of the complex--C. tanaitica and C. spec.--gave rise to two clonal hybrid lineages probably during the last interglacial or even earlier, which survived the Würmian glaciation with C. elongatoides. These lineages followed C. elongatoides postglacial expansion and probably decreased its dispersal rate. Our data indicate the frequent origins of asexuality irrespective of the parental populations involved and the comparable dispersal potential of diploid and triploid lineages.

Evolutionary history of asexual hybrid loaches (Cobitis: Teleostei) inferred from phylogenetic analysis of mitochondrial DNA variation.

Reconstruction of the evolutionary history of asexual lineages undermines their suitability as models for the studies of evolutionary consequences of sexual reproduction. Using molecular tools we addressed the origin, age and maternal ancestry of diploid and triploid asexual lineages arisen through the hybridization between spiny loaches Cobitis elongatoides, C. taenia and C. tanaitica. Reconstructions of the phylogenetic relationships among mitochondrial DNA (mtDNA) haplotypes, revealed by sequence analyses, suggest that both hybrid complexes (C. elongatoides-taenia and C. elongatoides-tanaitica) contained several asexual lineages of independent origin. Cobitis elongatoides was the exclusive maternal ancestor of all the C. elongatoides-tanaitica hybrids, whereas within the C. elongatoides-taenia complex, hybridization was reciprocal. In both complexes the low haplotype divergences were consistent with a recent origin of asexual lineages. Combined mtDNA and allozyme data suggest that the triploids arose through the incorporation of a haploid sperm genome into unreduced ova produced by diploid hybrids.

Annual dynamics of the fish stock in a backwater of the River Dyje

AbstractCanalization of the lower reaches of the River Dyje included the isolation of its meanders. One of these meander lakes remained connected at its downstream end with the River Dyje at river kilometre (r. km) 4.44. The meander lake was 500 m long, with a width varying from 30 to 50 m, and a surface area of 1.2–2.0 ha depending on the water level in the river. In 1997–1999 we studied the temporal changes in the species composition of the fish stock, using gill nets and electrofishing. We found 38 fish species in the backwater under study. Cyprinid fishes were most common, especially Rutilus rutilus, Alburnus alburnus, Abramis brama, A. ballerus, Blicca bjoerkna, Carassius auratus. We also caught rare species such as Abramis sapa, Pelecus cultratus and Gymnocephalus schraetser, or species new to the Czech Republic, Sander volgense, Gymnocephalus baloni and Proterorhinus marmoratus. In addition to the cyprinid species mentioned above, we also found Esox lucius, Sander lucioperca, Perca fluviatilis and Gymnocephalus cernuus spawning in the backwater. There was also a permanent population of Cobitis elongatoides. The fish stock in the backwater was highly variable. Species diversity, size structure and abundance varied over the course of the year. It was markedly affected by the water discharge in the River Dyje. The results obtained document the importance of river backwaters for the fish communities inhabiting the river channel. Copyright © 2001 John Wiley & Sons, Ltd.