engleski

Chromosome number and structure, and organization of rDNA in loaches of Adriatic watershed in Croatia

Rivers in Croatian Adriatic watershed are geologically very old. Their main feature is they are short, isolated and due to that many endemic fishes have developed in them. Those rivers inhabit three species of the genus Cobitis: C. narentana in Neretva, C. dalmatina in Cetina and a separate species in Zrmanja, whose taxonomic status is uncertain but it had shown some morphological similarities to Italian species C. bilineata. Until recently, those species were considered as one species and their chromosome complements have not yet been investigated. We assessed cytogenetic analysis of loach populations from Croatian Adriatic watershed to reveal differences among them. A total number of 90 specimens was collected from three rivers: Neretva (Cobitis narentana), Cetina (Cobitis dalmatina) and Zrmanja (Cobitis sp.). Cytogenetic analysis of their gill cells evinced chromosome number and morphology according to the centrornere position in all three species and revealed differences between them. Staining with fluorochromes and silver as well as fluorescent hybridization in situ (FISH) showed position of nucleolar organizing region (NOR) in each of the three species. This chromosome marker revealed similarities between related species. The intra- and interspecies variations among the investigated loaches are discussed.

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