Simplified Explanation for DNA Extraction
For sure, you’ve heard about DNA or sometimes called as the Blueprint of Life or Genetic Code. All living organisms including bacteria, plants, animals and us Humans have DNA found in their cells. DNA is the long molecule that is made up of nucleotides chain while the order of these nucleotides made these organisms similar to other species and yet, makes them unique to each other. Genes are the section within long DNA molecules are found.
For the study to begin, the DNA has to be extracted out of the cell first. In eukaryotic cells like plants and human cells, DNA is in an organized chromosome in the organelle which is referred as nucleus. The bacterial cells have none of this and so, their DNA is organized either in circular plasmids or rings which are found in cytoplasm. The process for DNA extraction frees the DNA from cells and separating it from cellular fluid as well as proteins. Through this, the DNA in its purest form is what’s left.
Lysis, Precipitation and Purification are the three basic procedures when carrying out a DNA extraction. These steps are thoroughly discussed in the next lines.
Step number 1. Lysis – in this step, the cell and the nucleus are broken open to be able to release the DNA inside. As a matter of fact, there are a couple of methods that scientists do to perform this and it’s by mechanical disruption and Lysis. In mechanical disruption, it is breaking open the cells which are done with tissue homogenizer, with a pestle or mortar or by cutting tissues in smaller pieces. This procedure is crucial especially when plant cells are used since they have tougher cell walls.
When lysis is used, detergents and enzymes such as Proteinase K are always part of the process to free up DNA and at the same time, to dissolve cellular proteins.
Step number 2. Precipitation – when lysis step is done, DNA is now free from its nucleus but, there’s another challenge which is the fact that it’s mixed up with mashed up cells. Using precipitation will then separate DNA from the cellular debris. To make the DNA molecules become less water soluble and more stable, sodium is applied to neutralize the negative charges. Next, alcohol either isopropanol or ethanol is added and makes the DNA to precipitate out of the solution as it isn’t soluble in alcohol.
Step number 3. Purification – when the DNA is separated from the aqueous phase, it’ll be rinsed using alcohol. Unwanted materials and remaining cellular debris will be removed in this process. It’s at this point when the purified DNA will be re-dissolved in water.