Exploring Fish Miscellany from Biodiversity Hotspot Region of Northeast India Through Chromosome Profiling

North Eastern states of India are blessed with extensive ecoclimatic conditions and much of India’s endemic flora and fauna. This region is rich in fish diversity with plenty of species of ornamental importance, including model species zebrafish. Among the potential ornamental fishes, Ctenops nobilis is designated as Near Threatened and Danio dangila is included in the Least Concern list by IUCN. Cytogenetic profiling was undertaken here to provide complementary data for precise species identification and to study genetic inheritance, genome organization and evolution of the species. The cytogenetic analyses revealed diploid chromosome numbers 44 and 50 with karyotype formula 8m+20sm+10st+6t (FN=72) and 20m+24sm+6st (FN=94), respectively, in C. nobilis and D. dangila. The staining of nucleolar organizer regions revealed the presence of Ag-NORs, CMA₃ sites and 18S rDNA probe signals on one pair sub-telocentric chromosome and one pair sub-metacentric chromosome in C. nobilis and D. dangila, respectively. These biomarkers are an important resource for molecular taxonomy, evolutionary/phylogenetic studies and conservation genetics of C. nobilis and D. dangila.