Routine Sample Collection and DNA Background Introduction
31.Routine sample collection
1.1Mantacc oral swab collection
1) Do not eat, smoke, drink water, drink alcohol or chew gum, etc. 1h before sampling.
2) Prepare a glass of water and rinse the mouth fully for about 10s and then spit it out to remove the food residues etc. from the mouth.
3) extend the swab into the left side of the mouth so that the head of the swab fully touches the mucosa of the upper and lower dental bed of the left cheek, and rub up and down with the same intensity as brushing, while rotating the swab so that the head of the swab fully touches the oral mucosa.
4) the same method was used for the 2nd swab at the mucosa of the inner right cheek/right upper and lower dental bed.
5) One swab for each of the left and right oral cavity, and after the collection is completed, put back into the collection tube with the sample number written on the wall of the tube, and send it at room temperature within 24-48h.
1.2 Mantacc saliva collection kit
1) 1h before sampling, do not eat, drink, drink alcohol, smoke or chew gum, and it is recommended to take samples in the morning.
2) Subjects need to secrete and collect saliva in the mouth for at least 1 min. open the sterile saliva collector and collect saliva This process needs to be repeated several times to collect up to 2-5 mL of saliva (without the foam part).
2. DNA background introduction
DNA is the carrier of genetic information, an important bioinformatic molecule, and the main object of molecular biology research. In order to perform experiments such as sequencing, hybridization, gene expression, and library construction, obtaining genomic DNA with high molecular weight and high purity is a very important prerequisite, so the extraction of genomic DNA is also one of the important and basic operations in molecular biology experimental techniques. To extract DNA from tissues, different material processing methods are adopted depending on the source of the material. The tissues are dispersed into individual cells, and then the cytosolic and nuclear membranes are broken to release the chromosomes, while histones and non-histones bound to DNA are removed.
3. Principles of genomic DNA extraction
3.1 Ensure the integrity of the primary structure of nucleic acids (because all genetic information is stored in the primary structure of nucleic acids, so the complete primary structure is the basis for ensuring the structure and function of nucleic acids to be studied).
3.2 Exclude contamination by other molecules (e.g. proteins, polysaccharides, lipids, organic solvents, etc.) so that downstream experiments can proceed smoothly.
3.3 Organic solvents and high concentrations of metal ions that inhibit enzymes should not be present in the nucleic acid sample.
3.4 The extracted DNA fragments need to be tested in terms of molecular quality, concentration, purity, etc., so as to judge the quality of DNA, and only DNA that meets the quality requirements can be continued for subsequent biological experiments.
3.5 The main factors affecting the quality of DNA extraction include the source of material, the method of taking material, storage temperature, extraction method, etc.