Determination of Place of Residence Using the Gene Information of Plants Carried by the Human Body / 法医学杂志

Objective To identify the plant species using the DNA sequence of plant pollen from lung tissues of a unidentified body, infer the possible long-term places of residence of the deceased according to the distribution area of the pollen in the lung tissues, therefore narrow the scope of criminal investigation and provide clues for case solving. Methods Lung tissues were extracted from the deceased, total DNA was extracted by the mCTAB method. Gene fragments of the two plant DNA barcodes, matK and rbcL, were acquired using specific primers for amplification, then sequenced. The DNA sequences of target gene fragments were acquired through bioinformatics analysis. The sequences were combined with reference sequence data. Phylogenetic analysis was made to identify the species that the DNA sequences belonged to. The places where the deceased could have lived for a long time were inferred, according to the distribution information of plant species. Results Gene fragments of 32 plant species which belonged to 31 genera of 27 families were in the lung tissues of the deceased. Among them, plants of 9 genera that had certain indicative function were mainly endemic plants from Hainan, Guangdong, Guangxi and Yunnan. These results showed that the deceased may have stayed in these areas for a long time before death. After further investigation, the victim was confirmed to have come from a county in southern Guangxi, which was in accordance with the research results. Conclusion The method of using gene information of plants from lung tissues of human bodies to infer places of residence can assist inference of the places where the deceased could have lived for a long time. The present study may also provide new ideas for locating sources of the corpses in cases with unidentified victims.

Establishment of DNA Genetic Marker Identification System for Plant Evidence / 法医学杂志

Objective To establish a species identification system based on DNA genetic markers for plant evidence. Methods Two hundred common plants in Shanghai were collected and identified by mor-phological characteristics. The primers of gene segments rbcL, matK, and ITS were designed and amplified. The PCR amplicon was detected by agarose gel electrophoresis. After the sequencing, the universality and the identification capacity of the three markers were evaluated. Results The success rate of amplifi-cation was in order of rbcL (99.5％) >matK (92.5％) > ITS (86.0％). The identification capacity of the combination of rbcL and matK was better than that of rbcL or matK, by which most plant species could be identified to the genus or higher. ITS was not suitable to be a unique marker because of its unstable result, but it still could be a powerful supplement. The identification capacity of the combination of rbcL, matK and ITS was higher than that of rbcL and matK, by which most plant species could be identified to the genus or lower. Conclusion The identification system with the combination of rbcL, matK and ITS as markers has excellent universality for plant evidence, which can distinguish most plant species to the genus or lower.