Diversity of European spined loaches (genus Cobitis L.): an update of the geographic distribution of the Cobitis taenia hybrid complex with a description of new molecular tools for species and hybrid determination

Abstract

Although the unique features of asexual reproduction and hybridization among European spined loaches (genus Cobitis) have recently attracted the attention of conservation biologists, faunists and evolutionary biologists, the research has suffered from uncertain identification of specimens and their genomes because of the extreme morphological similarity of all the species within the hybrid complex. In this article, a Europe-wide study is reported, which was performed on samples collected by several research teams. Several complementary methodologies, such as allozyme analysis, karyotyping, flow cytometry and DNA sequencing allowed us to confirm or reject the existence of all previously reported species and their hybrids as well as to uncover several new hybrid biotypes. The biogeography of all the known biotypes, that is, parental species and hybrid biotypes, has been summarized here and the taxonomic position of two undescribed putative species mentioned in previous publications has been established. New polymerase chain reaction restriction fragment length polymorphism markers for species determination have further been developed and applied, which would allow the unambiguous identification of parental species and their genomes in the known hybrid biotypes within the complex.

Gene mapping of 28S rDNA sites in allotriploid Cobitis females (Pisces: Cobitidae) from a diploid-polyploid population

“…It means that the genome of these triploid fish raised as a consequence of hybridization process among three following species: Cobitis elongatoides, C. taenia and C. taurica. The same genome constitution of triploid hybrids from the Bug River (Poland) has been previously reported also by Janko et al (2007), and then it has been confirmed in investigations conducted by Maciak et al (2011).…”

“…Most of the studies published so far contain data on the chromosome number and karyotype of Cobitis taxa. In a few recent papers there are data on the chromosome structure of some Cobitis species obtained by classical chromosome banding and/or by molecular methods (Boroń 1999;Boroń & Kotusz 1999Ráb et al 2000;Rábová et al 2001Rábová et al , 2004Saitoh 2003;Janko et al 2005Janko et al , 2007Boroń et al 2006). However, little cytogenetic information is available for polyploid Cobitis taxa (Boroń & Danilkiewicz 1999;Rábová et al 2004;Boroń et al 2006).…”

“…However, C. tanaitica has not been observed so far in the Bug River (Boroń 2001(Boroń , 2003. Molecular investigation showed that the genome composition of triploid hybrids from the Bug River came from three following species: C. elongatoides, C. taenia and C. taurica (ETTau) (Janko et al 2007). …”

Molecular Biodiversity Inventory of the Ichthyofauna of the Czech Republic

“…It concerned 11 orders, 17 families and 72 species. The selection of collection localities covered the main distribution areas of the studied taxa according to comprehensive surveys and the most recent taxonomic and phylogenetic studies (Baruš & Oliva, 1995;Hanel & Lusk, 2005;Kottelat & Freyhof, 2007;Janko et al, 2007;Mendel et al, 2008d, etc). The collection of samples was divided into three levels: -classification of the first level is based on the hydrologic position of the Czech Republic ( Fig.…”

Reproductive Potentials of Diploid and Polyploidy Representatives of the Genus Сobitis (Cypriniformes, Cobitidae)

“…C. elongatoides and C. tanaitica hybridize downstream (Mezhzherin, Pavlenko, 2007) and in middle reaches (Janko et al, 2007). In the case of hybrids of C. elongatoides × C. tanaitica backcrossing, triploid biotypes C. 2 elongatoides -tanaitica and C. elongatoides -2 tanaitica occur, while triploid biotypes C. elongatoides -tanaitica -taenia and C. elongatoides -tanaitica -2 taenia form upstream in the basin at the point of contact of C. elongatoides and С. taenia (Janko et al, 2007). Th erefore, it is quite correct to consider the Danube to be the place of origin of most European triploid biotypes of spined loaches, from where they have begun to invade other European river systems.…”