Karyological and molecular analysis of three endemic loaches (Actinopterygii: Cobitoidea) from Kor River basin, Iran

This study provides new data on chromosomal characteristics and DNA barcoding of three endemic loaches of Iran: spiny southern loach Cobitis linea (Heckel, 1847), Persian stream loach Oxynoemacheilus persa (Heckel, 1848) and Tongiorgi stream loach Oxynoemacheilus tongiorgii (Nalbant & Bianco, 1998). The chromosomes of these fishes were investigated by examining metaphase chromosome spreads obtained from epithelial gill and kidney cells. The diploid chromosome numbers of all three species were 2n=50. The karyotypes of C. linea consisted of 4M + 40SM + 6ST, NF=94; of O. persa by 20M + 22SM + 8ST, NF=90 and of O. tongiorgii by 18M + 24SM + 8ST, NF= 92. Sex chromosomes were cytologically indistinguishable in these loaches. Maximum likelihood-based estimation of the phylogenetic relationships based on the COI barcode region clearly separates the three Iranian loach species of the Kor River basin. All species distinguished by morphological characters were recovered as monophyletic clades by the COI barcodes. The obtained results could be used for population studies, management and conservation programs.