CYTOGENETIC ANALYSIS OF GLOBAL POPULATIONS OF MUGIL CEPHALUS (STRIPEDMULLET) BY DIFFERENT STAINING TECHNIQUES AND FLUORESCENT IN-SITU HYBRIDIZATION

The present paper reports the results of cytogenetic analysis carried out on several scattered populations of the striped mullet, Mugil ceph alus, the most widespead among mugilid species. The karyotype was inve stigated through Ag-staining, C-banding, fluorochrome-staining (chromo mycin A(3)/DAPI) and fluorescent in situ hybridization with rDNA genes . All populations showed the same chromosome number and morphology and no changes were detected in heterochromatin and NORs. Therefore, neit her population- nor sex-specific marker chromosomes were identified. I n some of the specimens, NOR size heteromorphism was detected. Results are discussed with respect to karyotype and ribosomal cistrons organi zation and to cytotaxonomic implications.