DNA gel electrophoresis is a process used to separate proteins and nucleic acids in molecular biology. The gel is usually composed of a crossed-linked polymer and acrylamide which aid in separating and analyzing different parts of a DNA molecule. DNA gel electrophoresis is commonly used in forensics to determine the specific sequence of DNA to help find the leading suspect. It is also commonly used in genetics and the fields of molecular biology and biochemistry.
Nucleic acids and proteins carry either a positive or negative charge. When placed in an electric chamber in DNA gel electrophoresis, each electrical charge will move toward either end of the chamber. The negative electrical charged molecules will move to the positive end of the chamber, while the positive electrical charged molecules will move to the negative end. The gel separates each of these molecules so they evenly spread throughout the reading. The gel is composed of long fibers which prevent the molecules from moving to aid in analyzing the individual molecules.
Southern blotting is a technique used in DNA gel electrophoresis to determine the presence or absence of a specific nucleotide sequence in a DNA molecule. Northern blotting is a different technique used to identify gene expression in the presence of RNA, or ribonucleic acid. Eastern blotting is used to determine the presence of lipids, proteins and carbohydrates in a DNA sequence. To simply detect proteins in a DNA sequence, the technique of western blotting is used in the electrophoresis chamber through gel isolation.
Zymography is also an approach to detect certain biological functions through DNA gel electrophoresis. It is mainly used to study extracellular matrix-degrading enzymes, which catalyze the destruction of the matrix outside the cell, as well as the basement membrane of a cell. The use of polyacrylamide gel aids in separating the enzymes, which are proteins, by using a protein substrate such as gelatin or casein. This technique is used to measure the amount of degradation activity occurring outside the cell.
DNA gel electrophoresis is used quite often in forensics. It is used to separate blood proteins and DNA found at a crime scene to determine correlations with the available suspects. Gel electrophoresis is also used to determine a specific inheritance within genetics, as certain DNA and proteins are associated with different races. It is also used to solve paternity cases to determine the relative relationship between individuals.