Karyological Analysis and Nucleolar Organizer Region of Benh's damselfish, Neoglyphidodon nigroris (Perciformes, Pomacentridae)

Abstract

Karyotype and nucleolar organizer regions (NORs) in the pomacentrid fish Neoglyphidodon nigrolis were studied. The specimen collected from the Andaman Sea (Thailand). We conducted conventional cytogenetic and Ag-positive NORs analyses in N. nigrolis. The chromosome number was observed to be 2n=48, the fundamental number was 84, and the karyotype consisted of 8 metacentric, 26 submetacentric, 2 acrocentric and 12 telocentric chromosomes with a large number of bi-armed chromosomes, where multiple pericentric inversions played a significant role in the karyotype organization. The Ag-NOR banding exhibited that a single pair of NORs was presented on telomeric regions of the short arms in a large acrocentric chromosomes pair 18. Basic knowledge on cytogenetics of damselfish would be applied for support on breeding, conservation and chromosome evolution in this fish. The karyotype formula of N. nigrolis is as follows: L_m² + L_sm¹⁰ + L_a² + L_t⁴ + M_m⁶ + M_sm¹⁶ + M_t⁸ or 8m+26sm+2a+12t