Chromosome mapping using genomic DNA and repetitive DNA sequences as probes for somatic chromosome identification in Nibea albiflora

Yellow croaker Nibea albiflora is a species of commercial important fish. However, chromosome identification is still difficult in yellow croaker for lack of cytogenetic markers. Hence, we analyzed the characteristics of chromosome in yellow croaker by using Giemsa staining, fluorescence staining, genomic in situ hybridization(GISH), and fluorescence in situ hybridization (FISH) with repetitive DNA sequences to assist chromosome identification. According to the distribution mode of fluorescent signal of self-GISH, 24 pairs of chromosomes could be distinguished and paired. FISH with 18S rDNA resulted in one pair of 18S rDNA signals distributing at the interstitial region of chromosome 1, which colocated with the secondary constriction after Giemesa staining, the negative band after DAPI staining, and the highlighted area after DPI staining. Whereas 5S rDNA FISH resulted in two pairs of signal with different intensity. The strong one was located on the centromere of chromosome 1, and the weak one was located on the distal position of chromosome 4. The signals of telomeric sequence were located on both termini of all chromosomes, although the signals of some chromosomes were weak. These results enriched the cytological genetic markers for chromosome identification in N. albiflora, and provided basic data for studying the chromosome evolution of Sciaenidae.