The extraction and purification of nucleic acid is the first step in most molecular biology studies and in all recombinant DNA techniques. DNA extraction is a process of isolating genomic DNA from RNA, proteins, and lipids. Basically, a genome is the entire genetic content in the chromosomes of eukaryotes and prokaryotes or in the RNA and DNA of viruses. The genome is the total haploid set of genes in an organism (Campbell, Reece, Taylor, Simon, & Dickey, 2011). The purpose of DNA extraction is to obtain DNA in a relatively purified form that can be used for further investigations such as PCR and DNA sequencing. There are many different methods available for isolating genomic DNA. Modification and optimization of DNA extraction methods are usually performed for different cell types (Dhaliwal, 2013). Cetyltrimethyl ammonium bromide (CTAB) is a preferable method that can be used to isolate genomic DNA. There are four important steps in the animal tissue DNA extraction protocol which are enzymatic digestion of cellular proteins, DNA precipitation, DNA washing and DNA hydration (refer to Figure 1 in Appendix 1 ). First, the cellular protein is digested through the enzymatic process. At this stage, the animal tissue is ground until it becomes small enough. This is important for breaking down the cell wall since DNA is found within the nucleus in eukaryotic organisms. Then, 600 µL of CTAB buffer is pipetted into the eppendorf tube and mixed well with the ground tissue. CTAB (hexadecyltrimethyl ammonium bromide) buffer acts as a detergent that helps lyse the cell membrane (Herzer, 2001). Additionally, 15 µl of Proteinase K is also added to the eppendorf tube. Proteinase K is used to digest contaminating proteins. According to Kim (2013), it is possible that the enzyme in the center of the paper is completely dry and 20 µl of distilled water is added into the eppendorf tube. The function of distilled water is to redissolve the DNA pellet. Next, the eppendorf tube together with the DNA solution is placed in a 4°C freezer. The DNA is stored in the DNA freezer and is taken out of the freezer when you want to use the DNA to further any suitable DNA-related studies. Works Cited Campbell, Reece, Taylor, Simon, and Dickey (2011). Biology. Petaling Jaya, MYS: Pearson Custom Publishing.Dhaliwal A. (2013). DNA extraction and purification. Mater Method, 3, 191.Herzer S. (2001). DNA purification. Retrieved from http://biologya.ifsc.usp.br/biomplcel1/outros/DNA%20purification.pdf.Kim J. (2013). 10 Questions You Want to Ask About Protein Kinase K. Retrieved from http://info.agscientific.com/blog/bid/158711/10-Question-you-want-to-ask-about-PROTEINASE-K