Banded Karyotypes and ZZ/ZW Sex Chromosome System of Endemic Squalius recurvirostris (Leuciscinae, Cyprinidae) in Turkey

In this study, detailed cytogenetic properties of the endemic Ak?ehir chub, Squalius recurvirostris, distributed in basin Ilg?n (Çavu?çu) Lake was investigated by applying standard Giemsa staining, C-banding and Ag-NOR technique. Diploid chromosome number is (2n) 50. A pair heteromorphic chromosomes detected karyotype females. However, difference not observed males. Therefore, it determined that females were ZZ/ZW sex chromosomes. The Z large acrocentric, W medium-sized submeta/subtelocentric. all chromosomal arms (NF) 90, fundamental autosomal (NFa) 88 karyotyped individuals studied. Some bi-armed acrocentric have centromeric C-bands set. slightly or pericentromeric are some chromosomes, while other pairs C-negative. studied two active NORs detected. Both these hemizygous associated with a C-heterochromatin region. One on entire long arm submetacentric short another pair.