Chromosomal studies of three vulnerable marine fishes from west coast of India

Abstract

Cytogenetic profiling was carried out in three vulnerable marine ornamental fishes, namely Thalassoma lunare, Zanclus cornutus and Arius subrostratus, using silver nitrate, chromoycin A3 CMA3 staining and C- banding techniques to study the variation in localization of NORs and C-bands. Karyotype analyses of these species revealed a diploid chromosome number of 48, all acrocentrics, in T. lunare and Z. cornutus. In A. subrostratus, however, the diploid chromosome number was found to be 58 consisting of 22 metacentric, 16 submetacentric, 10 subtelocentric and 10 telocentric chromosomes with fundamental arm number of 96. The silver stained NORs were observed on 3 pairs of chromosomes in T. lunare, whereas other two species possessed NOR on single pair of chromosome. Within the species, there was complete concordance in number and position of NORs as detected by AgNO3 and CMA3 staining. Prominent constitutive heterochromatic bands were detected on 4, 2 and 3 pairs of chromosomes, respectively, in T. lunare, Z. cornutus and A. subrostratus. There was variation found in the number and position on NORs and C-bands among these species, which could be used as species-specific markers. This study describes for the first time the cytogenetic profiling in Z. cornutus and A. subrostratus.