Chromosomal aberration and genetic differentiation of Oreochromis niloticus affected by heavy metals from an iron ore mine area

Abstract

The concentrations of As, Cd, Cr, Pb and Fe in water, sediment and Oreochromis niloticus tissues and the chromosomal aberrations, genetic differentiation and genomic template stability (GTS) of O. niloticus in 2 reservoirs near iron ore mine and one reference reservoir were investigated. Genetic differentiation and %GTS were evaluated by inter simple sequence repeat analysis. The As, Cd and Cr concentrations in fish from 2 mine reservoirs exceeded the standards. Seven types of chromosomal aberrations were found in fish from the iron ore mine: single chromatid gap, iso chromatid gap, centromere gap, dicentric chromosome, fragmentation, deletion, and ring chromosome. The average percentages of aberrant chromosomes in the cells of O. niloticus from mine reservoirs 1, 2 and the reference reservoir were 23.6, 16.8 and 2.2, respectively. Genetic differentiation and subsequent dendrogram analysis separated O. niloticus into 3 clusters, corresponding to the 2 mine reservoirs and the reference reservoir. The %GTS ranges of O. niloticus were 68.75–83.75, 71.88–85.19 and 83.58–97.01, respectively. Metals accumulations in O. niloticus could induce the occurrence of chromosomal aberrations and genetic differentiation.