Journal of Forensic Medicine ›› 2022, Vol. 38 ›› Issue (1): 119-126.DOI: 10.12116/j.issn.1004-5619.2021.410801

Special Issue: 水中尸体研究专题

• Techniques and Applications • Previous Articles     Next Articles

Improved Glass Bead-Vortex Oscillation Method for DNA Extraction from Diatom

Jie CAI1(), Bo WANG1, Sun-lin HU2, Yi-hong QU1, Tao SONG1, Jian-hua CHEN1(), Jian-qiang DENG1()   

  1. 1.Hainan Province Tropical Forensic Engineering Research Center, Department of Forensic Medicine of Hainan Medical University, Haikou 571199, China
    2.Shenzhen M&M Scientific Co. , Ltd. , Shenzhen 518103, Guangdong Province, China
  • Received:2021-08-04 Online:2022-02-25 Published:2022-02-28
  • Contact: Jian-hua CHEN,Jian-qiang DENG

Abstract: Objective

To examine the effect of improving diatom DNA extraction by glass bead - vortex oscillation method.

Methods

The DNeasy PowerSoil Pro kit was used as control, two plant DNA extraction kits with different principles (New Plant genomic DNA extraction kit and Plant DNA Isolation kit) and one whole blood DNA extraction kit (whole blood genomic DNA extraction kit) were selected to extract diatom DNA from lung tissue and water sample of the same drowning case. The combination of mass ratio of glass beads with different sizes and vortex oscillation time was designed, and the optimal DNA extraction conditions were selected with the addition of glass beads oscillation. The extracted products of the conventional group and the modified group were directly electrophoretic and detected by diatom specific PCR. Finally, all the extracts were quantified by qPCR, and the Ct values of different groups were statistically analyzed.

Results

When the frequency of vortex oscillation was 3 000 r/min, the optimal combination of DNA extraction was vortex oscillation for 4 min, and the mass ratio of large glass beads to small glass beads was 1∶1. The DNeasy PowerSoil Pro kit was used as a reference, and the Ct value of 10 mL water sample was greater than that of 0.5 g tissue. The Ct values of the other three kits used for plant DNA extraction decreased after the glass beads-vortex oscillation method was used, and the Ct values of the tissues before and after the improvement were statistically significant (P<0.05). The whole blood genomic DNA extraction kit used in this study could successfully extract diatom DNA, the extraction of water samples was close to DNeasy PowerSoil Pro kit, after the modified method was applied to tissue samples, the difference in Ct value was statistically significant (P<0.05). However, when the three kits were used to extract diatom DNA from water samples, Ct values before and after the improvement were only statistically significant in New Plant genomic DNA extraction kit group (P<0.05).

Conclusion

The improved glass bead-vortex oscillation method can improve the extraction efficiency of diatom DNA from forensic materials, especially from tissue samples, by plant and blood DNA extraction kits.

Key words: forensic pathology, drowning, DNA extraction, diatom, glass bead-vortex oscillation improving method

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