The DNA extraction system is the first link of the forensic DNA laboratory system solution. The system must realize the extraction, purification and enrichment of genomic DNA in biological samples. The quality and quantity of the extracted DNA will directly determine the success or failure of the final inspection. The PCR amplification system plays a connecting role in the entire DNA laboratory system, connecting two subsystems. That is, it is necessary to perform specific in vitro amplification of the genome obtained by the extraction system (obtain billions of copies of target DNA in a short time), so as to reach the detection limit of the genetic analyzer, and realize the fluorescence detection and screening of PCR products. Get the final DNA typing. The fluorescent DNA screening and detection system is the final link of the DNA laboratory system solution. The products obtained by the above-mentioned DNA extraction and amplification system must be used to obtain the final test results and realize the output. The three subsystems complement each other and are indispensable, and are interlocked throughout the inspection process.
According to the requirements of the "Public Security Organization DNA Laboratory Grade Evaluation Method (Trial)", DNA laboratories implement hierarchical management, from high to low divided into first, second, and third levels, of which the third-level DNA laboratory is the most basic DNA laboratory. The basic laboratory layout needs to have an acceptance area, a preparation area, a DNA extraction area, a amplification area, a detection area, a DNA database work area, a reagent preparation area, a physical evidence and sample storage area, and an office area.
Level 3 DNA Laboratory
In addition to meeting the above-mentioned areas, the third-level DNA laboratory also requires an area of no less than 130 square meters, and the interval, function, decoration, cleanliness and necessary auxiliary facilities of each area meet the requirements of industry technical standards. The layout of the entire laboratory is reasonable, and the inspection and identification process flows in one direction.
According to the functional requirements, the laboratory should have facilities such as fireproof, shockproof, anticorrosion, moistureproof, antistatic, constant temperature and drainage.
Tertiary DNA laboratories can be widely promoted in county-level public security agencies. This is mainly because the public security agencies with DNA laboratories in my country are mainly concentrated in provinces, regions, and prefecture-level cities. Normally, county-level public security agencies need to The collected DNA material evidence shall be sent to the DNA laboratory of the public security organ of the prefecture-level city where it belongs for material evidence inspection. However, in recent years, due to the important role of DNA inspection technology in the investigation and solving of cases by public security organs, the collection of DNA-related material evidence has been increasing year by year. This undoubtedly increases the workload of DNA inspectors in prefectural public security organs and leads to long-term inspections. Overworked, resulting in a large backlog of cases and low efficiency in handling cases. In view of the above situation, it is necessary for county-level public security agencies to establish DNA laboratories that can detect suspect samples and other high-quality materials. This will greatly reduce the labor intensity of higher-level public security agencies, and improve the system for overcoming difficult inspections and amplifications. The combination of DNA testing system. Due to the large amount of samples, the PCR direct amplification system needs to include amplification reagent distribution equipment, punching equipment, scanning equipment, PCR amplification equipment, amplification reagents, and DNA testing mostly uses 16-channel or 24-channel genetic Analyzer.
Secondary DNA laboratory
In addition to meeting the requirements of the third-level DNA laboratory, the second-level DNA laboratory must have a laboratory area not less than 300 square meters, of which the laboratory room area must not be less than 200 square meters. The laboratory's on-site biological sample DNA inspection and personnel sample DNA inspection are set up in different regions. In addition, the laboratory needs to have an access control system and independent exhaust facilities. The secondary DNA laboratory shall undertake the DNA inspection capability of large quantities of personnel samples from the DNA database within its jurisdiction, and shall have the capability of DNA inspection for the identification of unknown corpses such as large regional cases (incidents), natural disasters, accidents, etc., and shall have special biological capabilities. The DNA testing capabilities of samples (such as bones, teeth, nails, contact testing, trace biological samples), and DNA testing capabilities are among the advanced in this province.
Level 1 DNA laboratory
In addition to meeting the requirements of the second-level DNA laboratory, the first-level DNA laboratory needs to have a laboratory area of not less than 800 square meters, of which the area of the experimental room is not less than 600 square meters. Special areas for special biological inspection materials, routine biological inspection materials, and personnel biological samples for DNA inspection and DNA database management applications are required. The functional areas of the laboratory are reasonably laid out, physically isolated, and equipped with constant temperature and humidity, air purification, negative pressure interval, biological safety and other facilities. There are on-site survey equipment room, dressing room, multimedia room and reference room.
In addition to meeting the requirements of routine biological material testing, database construction, and difficult material testing, first-level DNA laboratories must also have research results on new technologies and methods for DNA testing. Therefore, first-level DNA laboratories are equipped with conventional DNA extraction and amplification. In addition to the testing equipment, there should also be automated DNA testing workstations that meet the needs of scientific research.