A study on detecting chlorophyll-related genes of plankton in the diagnosis of death by drowning / 中国法医学杂志

ABSTRACT

Objective To evaluate the value of detecting chlorophyll related genes of plankton in the diagnosis of drowning. MethodsEighteen rabbits were divided randomly into three groups death by drowning (n=10), postmortem submersion (n=6) and control (n=2). The heart blood, lung, liver, kidney and brain tissues were taken from every rabbit. After isolated plankton from tissues with percoll and extracted their DNA, the chlorophyll-related genes, including EG (EG1 and EG2) and SK (SK1 and SK2), were detected using PCR technique. Meanwhile, diatom test was also performed from lung and liver tissues by nitric acid digestion method. ResultsFor the drowning group, the specific amplification products for EG1 were detected from 9 samples in heart blood, 10 samples in lung, 9 samples in liver, 7 samples in kidney and 8 samples in brain. The products for EG2 were detected from 8 samples, 10 samples, 7 samples, 5 samples and 7 samples accordingly. There were a small number of positives in heart blood, lung and kidney with SK1 and SK2 (≤2). For the postmortem submersion group, only one case was positive from heart blood and lung tissue respectively for EG1. No amplified product was detected for EG1 and EG2 in various tissues in control group, and also no product was detected for SK1and SK2 in other groups. In addition, diatoms were detected from 9 lung and 3 liver tissues in drowning group with the nitric acid digestion, and only one sample of lung was positive in the postmortem submersion group. ConclusionThe detection rate of the chlorophyll-related gene EG with PCR method was higher than that of diatom with nitric acid digestion method in drowning victims, and it can be used as a potentially useful tool for diagnosing drowning.