The Effect of Magnesium Ions on Chromosome Structure: Insights from G-Banding

Magnesium ion (Mg 2+ ) plays a fundamental role in the chromosome condensation which is important for genetic material segregation. Studies about the effects of Mg 2+ on the overall chromosome structure have been reported. Nevertheless, its effects on the distribution of heterochromatin and euchromatin region have yet to be investigated. This study was aimed to evaluate the effects of Mg 2+ on the banding pattern of the chromosome structure. Chromosome analysis was performed using the GTL-banding technique on synchronized HeLa cells. The effect of Mg 2+ was evaluated by subjecting the chromosomes to three different solutions, namely XBE5 (5 mM Mg 2+ ) as a control, XBE (0 mM Mg 2+ ), and 1 mM EDTA as cations chelator. The results showed a condensed chromosome structure with a clear banding pattern when it was treated with a buffer containing 5 mM Mg 2+ . In contrast, chromosomes treated with a buffer containing no Mg 2+ and those treated with an ions chelator showed an expanded and fibrous structure with the lower intensity of the banding pattern. Elongation of the chromosome caused by decondensation resulted in the band splitting. The results of this study further emphasized the role of Mg 2+ on chromosome structure and gave insights into Mg 2+ effects on the banding distribution.