The principle of extracting dna by ctab method

The principle of extracting dna by ctab method is as follows:

Principle of CTAB method CTAB (cetyltrimethyl ammonium bromide) is a cationic detergent, which has the characteristics of precipitating nucleic acids and acidic polysaccharides from low ionic strength solutions.

In the solution with high ionic strength (>: 0.7mol/LNaCl), CTAB forms a complex with protein and polysaccharide, but cannot precipitate nucleic acid. Protein, polysaccharide, phenol and other impurities can be removed by organic solvent extraction, and then ethanol is added for precipitation to separate nucleic acids.

Introduction to dna:

DNA paternity used the theories and techniques of forensic medicine, biology and genetics to analyze the genetic characteristics and judge whether the relationship between parents and children is biological or not according to the similar characteristics of their offspring and parents in morphological structure or physiological function. DNA paternity: Also called paternity test, it is an important part of forensic material evidence examination.

DNA typing is the most commonly used method to identify parent-child relationship. Human blood, hair, saliva, oral cells and bones can all be used for paternity testing, which is very convenient. There are three main types of people in paternity testing. One is the family crisis, and the marriage is not harmonious. The second is the identification of single parents, that is, it is mainly because the man suspects that he is taking the children alone.

There is also an immigrant. If you get married and have children in the mainland according to the relevant regulations of the state, you must do paternity test. According to the national regulations, paternity test needs to fill in the judicial appraisal book. Judicial expertise has legal effect and can be recognized by courts, judicial organs and law firms. Then fill in the Application Form for DNA Entrusting Identification and the Power of Attorney, collect blood or blood mark samples, and enter the DNA testing procedure.

DNA fingerprint:

Dna fingerprinting refers to DNA polymorphism with complete individual specificity, and its individual recognition ability is comparable to that of finger fingerprints, hence the name. It can be used for personal identification and paternity test, and hybridize with the restricted fragment of human nuclear DNA to obtain hybridization bands with different lengths composed of alleles at multiple sites. This pattern is rarely the same between two people, so it is called "DNA fingerprint".

Because DNA fingerprint has high variability and stable heredity, and it is still inherited in a simple Mendelian way, it has become the most attractive genetic marker and can be widely used in paternity testing.