Cytogenetic characteristics of endemic Squalius cappadocicus Özuluğ and Freyhof, 2011 in Türkiye

In this study, a detailed chromosome analysis of the endemic Cappadocian Chub, Squalius cappadocicus in Melendiz Stream (Aksaray) was performed. The standard Giemsa staining, C-banding (CBG and CB-DAPI), and Ag-NOR technique were applied. The diploid chromosome number was 50; its karyotype formula was 14M + 16Sm + 10St + 10A. Heteromorphic sex chromosomes weren’t detected in the karyotype of the studied specimens. The number of all chromosomal arms (NF) was 90. In the standard C-banded and CB-DAPI karyotype of the species, dark C-bands were observed in the centromeric region of some bi-armed and acrocentric chromosomes, while slightly centromeric or pericentromeric C-bands were detected in some chromosomes. Three different active Ag-NORs, which were hemizygous, were detected in all samples examined. Two of these active NORs were detected in the bi-armed and the other in the acrocentric chromosome short arm. The Ag-NOR number of this species was evaluated as a feature that distinguishes it from other Squalius species in Türkiye.