Disadvantages: the chip density is lower than the mask method, and it must have a good preservation design. This method can be divided into point method and printing method. The point method is a small-scale production or lab-made low-density chip that uses a steel needle on a robotic arm with a fine score of capillary action to place a solution of nucleic acid probes on a slide or polyester fiber film. Low cost, suitable for a small number of probes or manufacturing demand is not large.
defect is that the sequencing set of sample DNA concentration value and purity is relatively high, the technical standard of the experimental process is relatively high, and only one domain or one coding sequence is tested in each experiment. withIn contrast to PCR and FISH technology, high-throughput sequencing technology can immediately load the 3 billion base sequences of DNA molecules, which has the characteristics of high-throughput sequencing and large amount of information. Among them, second-generation high-throughput sequencing is the most popular technique for genetic examination nowadays.
The principle of the gene chip is base pairing. The sample is hybridized by one or more nucleic acid probes labeled with known sequence, and the sample sequence can be determined by detecting the hybridization result. The advantage is that a large number of samples can be analyzed at one time, but the disadvantage is that it is easy to appear false positive. The principle of gene sequencing is the dideoxy chain termination method, which uses instruments to determine a DNA sequenceThe advantage is that the accuracy is high, there are no false positives, but the flux is slightly lower.
And morphological identification characteristics can lead to species identification errors due to convergence and variation. By establishing a DNA barcode database, a large number of samples can be quickly identified at once. The new research results of taxonomists will be continuously added to the database and become permanent information, thus promoting the rapid and in-depth development of taxonomy. Disadvantages: At present, it is not perfect enough to be popularized, and it can only be tested in the field of plants.
Disadvantages If whole-gene testing is widespread, information about people with genetic defects will fall into the employer of the person being testedHands, will have a bad effect on his life. And gene sequencing without uncertainty is the only basis for personalized therapy, along with other technical foundations such as gene therapy.
1, the main process of DNA microarray technology: ① chip preparation: DNA chip preparation methods include light-guided in-situ synthesis, chemical injection method, contact spot coating method, in-situ DNA controlled synthesis, non-contact micromechanical printing method TOPSPOT and soft lithography replication. So far we've been able to combine 400,000 differentThe DNA molecule is placed on a 1 cm2 chip.
2, the term microarray is interpreted as gene chip. DNA microarray (DNA microarray) is also known as DNA array or DNA chip, and the more commonly used name is gene chip.
3. Donnel et al. 1992, Pease et al. 1994, Yershow et al. 1996, Wallraff et al. 1997 all reported the use of DNA microarray technology for DNA sequence analysis. Most researchers use the first synthetic oligonucleotide sequence to produce microarraysThe array is then hybridized with the labeled unknown DNA sequence, and the data is obtained through fluorescence confocal microscope scanning and computer software analysis. Some researchers will also hybridize and sequence the array of DNA fragments under test with the labeled oligonylate as the probe.
4. DNA microarray, a scientific and technological treasure sprouting in the 1980s and bright in the 1990s, is like a precision probe in the biological world, revealing the secrets of genes by high-throughput detection. In contrast to the traditional approach of Southern and Northern hybridization, the gene chip can read the dynamics of many genes at once, like a miniatureA genetic laboratory that does not perform complex mathematical operations, but can reveal the complexity and diversity of life.
The emerging microarray chip technology is a highly organic combination of molecular biology technology and computer technology, small size, high experimental efficiency, can save manpower, material resources and time, is an important supplement to the traditional molecular biology research methods and clinical detection methods. In the practical application of microarray technology, data analysis plays an important role, which has not been applied to the existingVarious statistical models have been comprehensively evaluated.
The advantage of microarray chips is that they can simultaneously scan a large number of genes of interest, but this is also the bottleneck of their research. An experiment will produce a large amount of data, and how to analyze these data and draw biologically meaningful conclusions is an important topic for the further development and perfection of microarray chip technology. In this respect, computer technology and a variety of statistical methods are needed.
Complementary pairing principle. DNA microarray technology (microarray) is a technique used to rapidly detect the expression status or discovery of multiple genes at the same timeThe basic principle of new genes, rapid detection of DNA sequence mutations, mapping of SNP genetic linkage, and new technologies for DNA sequence analysis is based on the principle of complementary pairing, DNA samples are extracted and labeled, and then added to the microarray chip, and each probe on the chip is complementary paired with a specific gene sequence.
The term microarray is interpreted as a gene chip. DNA microarray (DNA microarray) is also known as DNA array or DNA chip, and the more commonly used name is gene chip.
In general, microarray technology