Practical report on DNA Extraction Biological Science Assignment

Practical report on DNA Extraction Biological Science - Assignment Example This proved to be a successful method to extract DNA from a Kiwi fruit in a quantity that permit visualization without a high-power microscope. INTRODUCTION DNA (deoxyribonucleic acid) is the basic structure of all living organisms (plants, animals, humans, microbes) and is present in the cells, especially in the cell nucleus. They are made from simple units known as ‘nucleotides’. Genes, which carry all information (structure, behavior, functions) of a cell or an organism, are made from long strands of DNA and this DNA is copied and inherited through generations from parent to the offspring. Hence, DNA is used in producing genetically modified plants and animals, in identifying variations/similarities of plant types, in medical research and in forensic medicine and in manufacturing pharmaceuticals (Jie, 2011). Isolated DNA from a tissue of a plant, animal, microbe or a human is therefore very useful since it provide much information about the individual, its characters and genetic background. There are many protocols of DNA extraction from an organism. Advanced techniques are needed to isolate DNA in a more pure form and require sophisticated equipment and specific chemicals. However, all these methods are based on three basic steps; i.e. separation and opening of cells chemically or mechanically to release DNA, purify DNA by removing proteins and other cell debris and finally, precipitation of DNA using an alcohol (Hoyle, 2011). If these basic steps are practiced, it should be possible to isolate DNA by following simple means and hence the objective of this study was to extract DNA from a Kiwi fruit using household items. MATERIALS AND METHODS A fruit of Kiwi (Actinidia deliciosa), otherwise known as ‘Chinese gooseberry’, was used to extract DNA. Outer skin of the fruit was peeled off and the fruit was chopped into small pieces using a knife. These pieces were put into a jar and mashed thoroughly to break open cells and enhance relea se of DNA. The Extraction buffer (Table 1) was added into fruit pulp and continued further mashing to enhance release of more DNA. Table 1. Composition of the extraction buffer Component Quantity Washing up liquid 5g Salt 2g Tap water 100ml All components were mixed and stirred slowly until salt was completely dissolved. This Kiwi - buffer mixture was then incubated at 600 C for 15 min. by carefully immersing the jar in a water bath. The water bath was prepared by filling a large basin with approximately equal volumes of normal tap water and boiling water from a kettle. The precise temperature was maintained by using a thermometer. After 15 minutes, the jar was removed from the water bath and the content was filtered through a fine sieve (coffee filter) into a fresh jar to separate Kiwi DNA from other cellular debris. Ice-cold alcohol was pre-prepared by freezing methylated spirit for a minimum of 30 min period and this was carefully poured down the inside of the jar containing Kiwi DNA suspension. RESULTS A yellow-green colored filtrate was observed after filtering the incubated mixture of fruit pulp and buffer. When ice-cold alcohol was added into this filtrate, a transparent layer was formed on top of the Kiwi mixture as alcohol has lesser density than the mixture. Gradually, a white substance began to appear at the bottom of the ice cold alcohol layer where it met the Kiwi DNA suspension. This white substance was Kiwi DNA and could be collected using a small spatula made from a curved paper clip. DISCUSSION Since all living