ABSTRACT
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.