DNA extraction methods for living organisms

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An experiment was conducted to determine if DNA could be extracted from the leaf of a common weed. It was hypothesized that following proper procedures with this leaf sample would prove successful, and this hypothesis was confirmed.

DNA testing is used for a variety of applications today. DNA tests on humans are used to establish paternity during lawsuits and in other disputes (the Maury show accounting for a substantial percentage of these paternity tests), and can also be used to establish lineage to a much greater degree, even tracing individuals back to specific regions of ancestry (Fuller 2010). This use of DNA has brought a greater sense of identity to many individuals, including those whose answers were forcibly removed form their homelands, as is the case with many African-Americans.

This is not the only use for DNA, however. Forensic scientists and law enforcement can also use DNA testing to identify victims and suspects of crime (HGP 2010). Blood, hair, and even saliva can all be used to extract and identify DNA, which can be a major assistance to law enforcement in helping to solve crimes (HGP 2010). Identifying plant DNA could potentially be as useful in certain circumstances, insofar as providing clues to crime and establishing plant lineages -- the applications are virtually endless. This experiment will help to demonstrate the enormous ease with which DNA knowledge and clues can be obtained.

Materials and Methods:

In addition to a single leaf from a common garden weed (a dandelion), the necessary supplies for this experiment included a small quantity of salt (less than 1 mL), 200 mL of cold water, 30 mL of common liquid detergent, a bottle of contact lens solution (fewer than thirty drops in all were used), and approximately 300 mL of isopropyl alcohol. Five test tubes, a common kitchen blender, a glass beaker, a strainer, and several cotton sticks were also utilized.

The experiment was conducted as follows: first, the water, salt, and leaf were combined in a blender until smooth. This mixture was strained into the beaker where the detergent was mixed in and the mixture was allowed to sit before being poured into the five test tubes, with (roughly) equal amounts of the mixture in each tube. Four to six drops of contact lens cleaning solution was added to each test tube and gently stirred with a cotton swab. Alcohol was then slowly poured down the side of the test tube, until an amount roughly equal to that of the underlying mixture rested at the top portion of the tube.

Results:

As expected, DNA precipitated in the border region where the water mixture met the alcohol in each test tube. This DNA material appeared as white clumps of strands in the test tubes, and was removed using cotton sticks. Substantial amounts of the DNA formed in each of the test tubes.

Discussion: