DNA Extraction Simplified
Probably, you have heard of the Blueprint of Life or Genetic Code, both of which refer to our DNA. DNA is found in cells of any living organisms whether it is bacteria, plants, animals and us Humans. DNA is long molecules that are made up of nucleotides chain while the order of nucleotides have made organisms to come from the same species but with a different appearance. Genes on the other hand are sections in the long DNA molecules.
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. Bacterial cells have none of this and for that, its DNA is organized either in a circular plasmid or ring which can be found in cytoplasm. The process of doing DNA extraction is intended to free up the DNA from the cells and separate it from the cellular fluid and also, protein. After this, what is left often is the purest form of the DNA.
The truth is, there are three basic procedures when doing DNA extraction and these include Lysis, Precipitation and Purification. Read on if you’re interested to know about these steps.
Step number 1. Lysis – for this step, the nucleus and the cell are broken open in order to release 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 relation to mechanical disruption, it breaks open cells which are done using a 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 – the DNA is freed from the nucleus upon the completion of lysis step but it is often mixed up with mashed up cells. Using precipitation will then separate DNA from the cellular debris. Sodium will be used first in neutralizing the negative charges that are present on DNA molecules and make them less water soluble and more stable. The DNA isn’t soluble in alcohol like isopropanol or ethanol and for that, it’s used to trigger precipitation.
Step number 3. Purification – alcohol will be used to rinsed the DNA after it has been separated from aqueous phase. 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.