NGS (Next Generation Sequencing) technology has become one of the most important tools in the life science field today. With the rapid development of genomics, the principle of NGS detection not only helps scientific researchers reveal the complexity of gene sequences, but also has achieved significant applications in many fields such as clinical diagnosis and precision medicine.
1. Basic PrincipleThe basic principle of NGS technology is to read sequence information by using the signals sent by some chemical markers when the base is inserted into the DNA strand when the base is inserted into the DNA strand. These signals can be optical signals or H+ stream signals. By capturing and analyzing these signals, the sequence of DNA can be determined.
2. Technology Platforms and MethodsNGS is based on a variety of different technical platforms, such as sequencing while synthesis, ligation sequencing, etc. The following is an example of synthesis and sequencing: Sequencing at the same time: This method is sequenced by adding fluorescently labeled nucleotides under the action of DNA polymerase. During the sequencing process, after the DNA template strand is bound to the primer, four deoxynucleotides (dATP, dTTP, dCTP, dGTP) with different fluorescent labels are added in sequence under the catalysis of DNA polymerase. Whenever a nucleotide is added to the extended DNA strand, a specific fluorescence signal is emitted. By capturing and analyzing these fluorescent signals, the species of added nucleotides can be determined, thereby inferring the sequence of DNA.
3. Sequencing process and stepsNGS detection usually includes the following steps: 1. DNA extraction: Extract high-quality DNA from the sample as a template for sequencing. 2. Library preparation: Fragment the extracted DNA and add specific linker sequences to both ends to form a sequencing library. 3. On-machine sequencing: Load the prepared sequencing library onto the sequencer for high-throughput parallel sequencing. The sequencer captures and analyzes the fluorescent signal emitted by each DNA fragment to determine its sequence. 4. Data analysis: Process and analyze a large amount of original data obtained from sequencing, including removing low-quality sequences, aligning to the reference genome, detecting variants, etc., and finally obtain reliable sequencing results.
4. Technical characteristics and advantages1. High throughput: NGS technology can simultaneously perform sequence measurements of hundreds of thousands to millions of DNA molecules, greatly improving the throughput and efficiency of sequencing. 2. High Depth: NGS can achieve high-deep sequencing, repeat sequencing of the target region or the entire genome multiple times, and can more accurately detect low-frequency variation. 3. High sensitivity: NGS technology can detect extremely low concentrations of DNA molecules and is suitable for sequencing of trace samples. 4. Rich information: NGS technology can provide a large amount of sequence information, which helps discover new genetic mutations and disease-related sites.
The NGS detection principle is based on high-throughput parallel sequencing technology to determine the DNA sequence by capturing and analyzing the fluorescent signals emitted during DNA synthesis. This technology has the characteristics of high throughput, high depth, high sensitivity and rich information, and has broad application prospects in clinical diagnosis, scientific research and other fields.