DNA isolation is a process that deals with the purification of DNA from a given sample with the help of physical and chemical methods. According to -, DNA was first isolated by Friedrich Miescher in 1869. Of recent, it is a routine procedure used in both molecular biology and forensic analyses. In regards to the chemical method, there are many different kits used for extraction. PCR sensitivity detection is considered to show the variation between the commercial kits. There are various methods that are involved in isolating and extracting DNA, such methods include the organic extraction, the chelex extraction and solid phase extraction.
There are several steps involved in the organic extraction of DNA. The first step involves lysis of the cell. There is disruption of he cell and the nucleus in order to release that DNA stored inside. A lysis solution ca be used, as well as mechanical disruption using a tissue homogenizer, as well as the use of enzymes such as Proteinase K and detergents. The second step of DNA isolation and extraction is precipitation. After lysis, the DNA needs to be separated from some mashed up cell parts and certain proteins. Precipitation helps in separating DNA from this cellular debris. The ZR BashungBead helps in this separation. Futhermore, the Zymo-Spin Ⅳ Spin Filter has a positive charge that attracts the negatively charged DNA. Alcohol such as isopropanol can be used to precipitate the DNA out of the aqeous solution. Lastly, the DNA has to purified. This can be done by rinsing it with alcohol.
Once the DNA has been separated and extracted, it can be differentiated by size and weight through gel electrophoresis. This method separates DNA fragments based on their size. This method involves running a current through a gel containing the DNA. The DNA molecules will then travel through the gel in various directions, at different speeds which allows them to be seoarated from one another based on their size. One can see how many different DNA fragments are found in a sample and how large they are relative to one through gel electrophoresis. The gel is a matrix made of agarose molecules which are tightly held together by hydrogen bonds and form tiny pores. At one end, the gel has pocket-like indentations known as well which are where the DNA samples are placed.
Before loading the DNA, the gel is placed in a gel box. On one end of the box is a positive electrode, with a negative electrode on the other side of the gel box. The gel box is then filled with a salt-containing buffer solution whose function is to conduct current. Ethidium bromide is also added to the gel box. It is a molecule commonly used to visualize DNA. It does this by binding to to DNA and it fluoresces under UV light. It is also known as an intercalating agent. It has a flat structure tha allows it to insert itself between the nitrogenous bases of a DNA molecule. Thus this molecule provides both a means of tagging DNA molecules and a means of visualizing them. DNA bands are formed once the gel starts running. These bands can either be short or long depending on their size and density. The shorter DNA fragments will travel through the gel matrix faster than the long ones.