Triggers of nonallergic rhinitis symptoms vary and can include certain odors or irritants in the air, changes in the weather, some medications, certain foods, and chronic health conditions. A diagnosis of nonallergic rhinitis is made after an allergic cause is ruled out.
DNA extraction. For the various methods, see Nucleic acid methods. DNA isolation is a process of purification of DNA from sample using a combination of physical and chemical methods. The first isolation of DNA was done in 1869 by Friedrich Miescher. Currently it is a routine procedure in molecular biology or forensic analyses.
Restriction enzymes are enzymes that can cut DNA. You can think of restriction enzymes as molecular scissors. DNA ligase is an enzyme that can join two DNA molecules. You can think of DNA ligase as molecular glue. DNA ligase joins two DNA molecules together by forming a phosphodiester bond between the two molecules.