Animals and plants can also be tested for paternity and non-human DNA to reveal the origin of sharks
Original plants and animals can also do “paternity” non anthropogenic DNA unrael the mysteries of shark story – our correspondent dong-ming yu – “the rule of law and news” reporter Huang Haodong – our correspondent RuanJuan peak at 10 containers of shark’s fin, forensic festa unbearable frowned, after all, from so many shark fin to find “endangered species of wild shark fins is like looking for a needle in a haystack.In January, the coast Guard commissioned the Academy of Forensic Science (CAS) to conduct a species identification of a recently seized shipment of smuggled shark fins to determine whether it contained fins from endangered wild sharks, in a bid to better combat crime.The reporter learned that the forensic Forensic Science Laboratory of the Academy of Forensic Sciences had already arranged non-human DNA identification five years ago, and had completed the scientific research, technological breakthroughs and equipment configuration of relevant projects, until the establishment of non-human DNA identification laboratory.From 2020, “non-human DNA identification” will be included in the routine business scope of forensic evidence identification for the first time.”Non-human DNA identification involves identification, species identification and kinship identification of non-human samples from animals, plants, microorganisms, etc. It is similar to ‘paternity testing’ for animals and plants.”Zhang Suhua is a top-notch young talent in the industry. Her team is also a leading team of scientific and technological innovation, with strong research strength and outstanding technology tackling ability.According to the arrangement of the research team, she is mainly responsible for the technical research and specific identification business of non-human DNA identification.Through several years of exploration, she has accumulated rich working experience.However, deposit festa and colleagues rushed to the seizure of smuggled the scene saw shark’s fin, snakeskin bag full of shark fin discrete pile in ten big container, due to long time of hna transport, the vast majority of shark fin has been bad, some serious corruption even maggots crawling, the strong stench is each container, even wore masks, protective clothing,We are still smoked not light, the smell of the body a few days do not send out.Shark’s fin is a prized ingredient that has been sought-after since ancient times, but the fins are cut from a live shark, and losing their fins is almost a death sentence.Looking at the 10 containers of shark fins in front of her, Zhang Suhua, who always loves nature and animals, decided to find out the “origin” of these shark fins and crack down on those criminals according to law.”It is impossible to fully identify such a large number of shark fins, so our team decided to sample them after consultation.”With the help of coast guard officers, Zhang said, she and her colleagues moved the fins out of the container, a process that lasted nearly two hours.It was bleak and cold in January, but Zhang and her colleagues were sweating.After weighing and counting, the seized fins weighed about 4 tons and were packed in 137 snakeskin bags.Zhang and her colleagues decided to take two samples from each bag and send them back to the forensic Institute for identification.It was not easy to complete the count of shark fin, but there was trouble in sampling.”The amount of biological cells in shark fins is very low, and most of them have deteriorated, so sampling needs to be more careful, otherwise the secondary damage will make it impossible to extract valid DNA properly.””Compared with other parts, shark fin cartilage contains more cells and is the easiest part to extract DNA information.After careful examination, we decided to take a sample from this area.”Extracting shark fin cartilage is a delicate task. Zhang and her team sterilize and clean all the fins before soaking them before sampling them.Shark fin cartilage is so delicate that it took them almost a full day to sample all the fins.With a usable sample, the next step is formal species identification.”Species identification usually starts from the appearance or DNA, but this sample is only a small part of shark fin, so it is difficult to distinguish from the appearance. Only through DNA comparison can we get relatively accurate results.”Zhang suhua said they chose to amplify two mitochondrial genes in shark fin tissue by PCR.PCR amplification is a molecular biological technology used to amplify and amplify specific DNA fragments. Its biggest characteristic is that it can greatly amplify trace DNA, even if it is only a little DNA, which can be amplified by PCR. It is very suitable for the identification of shark fin.Using this technique, Zhang and his team were able to extract comparable gene sequences from 135 samples.After extracting the gene sequence, the next step is sequence alignment.”Sequence alignment is based on the sequence structure in biology. If both the nucleic acid sequence and the protein primary structure are regarded as strings, the similarity between sequences can be detected through the alignment of strings.”When it comes to her major, Zhang Suhua knows everything.They used software to compare the DNA sequences of the samples with shark sequences recorded in the database of the internationally recognized National Center for Biotechnology Information in the United States. The results showed that the DNA sequences of the samples matched those of a species of shark called the big-eyed Thresher shark.The large-eyed thresher shark, also known as the deep-sea thresher shark, is found in tropical waters off the coast of Taiwan, China, and was listed as vulnerable by the IUCN in 2018 and as an appendix to the Convention on International Trade in Endangered Species of Wild Fauna and Flora.In order to enhance the scientific rigor of sequence alignment results, Zhang suhua et al. also provided support for identification by “phylogenetic tree” analysis.”Phylogenetic trees are bioinformatics’s way of describing the relationships between different organisms.By constructing a phylogenetic tree, it is possible to trace a gene sequence.”Through experiments, Zhang Suhua found that the gene sequences of the samples were homologous with those of the big-eyed Thresher shark, which further verified the results of software comparison.By comparison, Zhang and her colleagues were able to determine that 97 of the 135 samples identified belonged to the bigeye thresher shark.After the conversion, the forensic Academy issued an appraisal report, concluding that about 71.8 percent of the total four tons of shark fins seized by the coast Guard belonged to this species.Shanghai police have filed a case on suspicion of smuggling endangered species.Since non-human DNA identification was included in the scope of forensic evidence identification, Zhang Suhua has participated in the identification of Chinese sturgeon species, individual identification and kinship identification of pigeon racing, pig and cattle paternity identification and other judicial identification cases, and gained a profound understanding of this new field of judicial identification.Identification materials from animals and plants are very different from human tissue, and these differences often make identification more difficult.Zhang Suhua recalls a wood species identification case she attended in the past, when she had to identify a wooden furniture chair and confirmed the origin of the wood used to make the chair.Because the wood is highly processed, it is very difficult to extract plant DNA, and the whole identification process takes a lot of time and energy.In addition, non-human DNA identification as a new identification project, the lack of industry standards and authoritative data is also a major difficulty in identification work.Zhang suhua admitted that the comparison of non-human DNA is largely dependent on information recorded in foreign public databases. Once there is a species not recorded in the database, the identification work will become unreliable and difficult to carry out.In this regard, the ACADEMY has also taken active measures.This year, the Institute of Forensic Examiners completed the establishment of industry standards for the identification of cannabis plant species and individuals, which are currently being promulgated. The standards define the appropriate areas for identification of cannabis plants and the corresponding detection and analysis methods, providing the first reference for the identification of this kind of plants.In addition, THE CAS has set up its own DNA barcoding database including hallucinogenic plants and poisonous mushrooms to provide a basis for comparison of gene sequences of these species.”At present, we are also working on establishing a forensic non-human DNA database to fill the data gap of non-human forensic identification in China.”Zhang suhua said that there is no end to scientific exploration. Only by constantly updating and optimizing facilities and establishing a sound database of data and information can more mysteries be solved for mankind.