The invention belongs to the technical field of forensic
medicine and biological
medicine, discloses a method for forensic
medicine identification of corpses in
water based on
metagenomics markers and application, and aims to solve the problems that existing drowning diagnosis is insufficient in accuracy and the deduction of post-death submerging time (PMSI) is limited. The method comprises the following steps: collecting a corpse
lung tissue in water and a
water sample in a corresponding
water area, and obtaining a
microbial DNA sequence by adopting a metagenome sequencing technology; the method comprises the following steps:
processing data through
bioinformatics analysis (such as fastp
quality control, host sequence removal by KneadData and Kraken2 species
annotation), and selecting and screening
species level microbial markers in combination with a
random forest algorithm and Boruta characteristics; and respectively establishing a drowning diagnosis model and a PMSI
inference model based on the screened markers, and verifying the performance of the models through indexes such as AUC and MAE. Complete microbial communities of
bacteria, eukaryotes (including fungi),
archaea and viruses in
lung tissues of corpses in water are comprehensively analyzed for the first time, 17 bacterial markers and 9
eukaryote markers are screened out for drowning diagnosis (
verification experiment bacterial model AUC = 1, the accuracy rate is 89.29%,
eukaryote model AUC = 0.95, the accuracy rate is 87.5%), and 17 markers are screened out for PMSI
inference (integrated model MAE = 0.66 days). According to the method, the species resolution reaches the
species level, the method is not influenced by
amplification bias, the method is suitable for different
water area environments, and an efficient and objective forensic medicine tool is provided for identifying the cause of the
dead body in water and deducing the submerged time after the
dead body.