Comparative Cytogenetics of Two Squalius Bonaparte, 1837 Species (Cypriniformes: Leuciscidae)

Abstract

The karyotypes and other chromosomal characteristics of Anatolian endemic species Squalius carinus Özuluğ and Freyhof (Ichthyol Explor Freshw 22(2):107–148, 2011) and S. fellowesii (Günther, 1868) (Cypriniformes: Leuciscidae) were analysed by means of sequential Giemsa staining, C-banding and silver staining. The diploid chromosome numbers were invariably 2n = 50; their karyotypes were composed of 12 pairs of metacentric, ten pairs of submetacentric and three pairs of subtelo-acrocentric chromosomes in S. carinus, whereas ten pairs of metacentric, ten pairs of submetacentric and five pairs of subtelo-acrocentric chromosomes in S. fellowesii. No heteromorphic sex chromosomes were detected. The largest chromosome pair in their karyotypes was a subtelo-acrocentric chromosome. C-positive heterochromatins were observed on the pericentromeric regions of most of the chromosomes in the studied species. In addition, heterochromatic blocs were observed in the karyotype of S. carinus. The nucleolus organizer regions were detected terminally on the short (p) arms of single submetacentric chromosome pair in both species. Our study thus confirmed overall conservatism of leuciscin karyotypes. © 2020, Shiraz University.