The Evolution of DNA

Man has sought answers to the meaning of life trying to understand the fundamentals of our existence. Over the past couple of decades we have been able to uncover a substantial amount of knowledge pertaining to the instructions that allow life to continue. DNA or deoxyribonucleic acid has been identified in all forms of life. We have discovered that the human genome, are the codes for manufacturing proteins, which carry out the necessary tasks to ensure the stability of life. DNA is made up of 3 components; a phosphate group, nitrogenous base, and a five-carbon sugar. Together these components form nucleotides, which in turn are bound together forming segments called genes. A gene is a sequence of base pairs coding for a specific trait or characteristic.

Essentially DNA is the blue print for life. Having identified these instructions, scientists are now intrigued by the possibilities of which this new area of research is generating. Applications of this knowledge range from the simplest forms of cloning, treating hereditary illness as well as biological warfare. The pursuit of this research has raised many questions regarding ethical issues that will play a key role in any further developments. Currently the Federal Bureau of Investigation is developing techniques designed to link criminals to crime scenes. In October of 2000 they unveiled The National DNA Index System, which catalogues every U.S resident’s DNA sequence. This will allow authorities across the country to match criminals to crime scenes using remarkably little evidence. Another booming area of this field involves genetic manipulation. Within the next 10 to 20 years scientists predict that through laboratory breakthroughs we will have sufficient knowledge to select desired characteristics to be displayed in our offspring. The applications and issues previously mentioned as well other hot topics of discussion will be covered in greater detail throughout this report.
 DNA fingerprinting was first developed as an identification technique in 1985. Originally used to detect the presence of genetic diseases, DNA fingerprinting soon came to be used in criminal investigations and forensic science. This method of identification compares fragments of the suspects DNA and any DNA found at a particular crime scene. This procedure has proved to be the most reliable means of identification because no two persons in the world, excluding identical twins, have a matching sequence. A DNA fingerprint is constructed by extracting a DNA sample from body tissue or fluid such as hair, blood, or saliva. A process called electrophoresis creates a detailed mold of the DNA sample. Electrophoresis is the phenomenon of the movement of electrically charged particles through a gas or liquid as a result of an electric field formed between electrodes immersed in the medium. In an emulsion of rubber latex in an aqueous medium, for example, the rubber droplets tend to acquire an electrical charge opposite to their own. If this electrode has a particular shape, the rubber particles deposited on it will coalesce to form an article of this shape. The DNA fragments have a slight negative charge, so they move towards the trays positive end. (As with magnets, opposite poles attract.) But the medium acts like a strainer: Smaller DNA fragments travel through easily and thus travel farther towards opposite electrode. Radioactively labeled probes (pieces of DNA) are applied to the system. The probes attach themselves to the DNA fragments. X-ray film is applied. The radiations from the probes, which are now present at only a few locations, expose corresponding areas on the X-ray film. Scientists in coordination with the National Institute of Justice are now developing credit card sized chips that will have the ability to analyze DNA right at the crime scene. Essentially the cops go to the crime scene pick up the evidence, drop it into a cartridge and stick it into their portable reader. This tool in a matter of minutes performs the whole process of electrophoresis mentioned previously. This process is so incredibly efficient that police will not have time for a coffee, before the DNA profile is completed. This device is still being developed and is expected to be completed and ready for used within the next five years. In most cases, courts have readily accepted the reliability of DNA testing as an accurate method for acquiring evidence. However DNA fingerprinting is controversial in a number of areas: the accuracy of the results, the costs of testing, and the possible misuse of the technique.
The possibility of providing our children with genetic enhancements is becoming ever closer. Scientists have hypothesized many possibilities. They include ideas such as: appearance, slowing down aging, resistance to viruses and diseases as well as intelligence. For example, the risk of heart disease depends on the levels of HDL, the good cholesterol, being present in higher levels is better. In the human body, a gene called ap0-A1 makes a major piece of HDL. In mice, it’s possible to acquire basically any HDL level required by introducing more copies of this gene. Theoretically this could be applied to humans. Another example of how resistance of illness can be obtained is: Those who are born with two defective copies of a gene called CCR5 can escape HIV infection despite numerous encounters. The reason is that CCR5 makes a protein that the AIDS virus locks onto when it invades white blood cells. If the there is no CCR5 protein on protruding from the cells membrane then the virus cannot infect. Essentially, scientists predict that these alterative enhancements will be available possibly within the next 10 to 20 years.
After experimenting with rodent’s intelligence through genetic engineering, scientists claim that results from the genetic enhancement suggest that an increase of mental and cognitive attributes such as intelligence and memory in mammals is feasible. For example the hippocampus, found inside the brains of mice and humans, is crucial to learning. It is here where short-term memory is transformed into long-term memory. The gene NR2B helps build a protein called NMDA, which acts as a receptor for specific chemical signals. These chemical signals train brain cells to fire in repeating patterns. They are what we experience as memories. Again, through introducing the desired genes into a freshly fertilized egg, the genetic information will be made their own and passed on through future generations.
The future of this field of research looks promising. In addition to the potential to cure disease and prolong life – the use in the criminal justice system will surely continue to produce results with pinpoint accuracy. Once the backlog associated with the lengthy amount of time in which it takes to process DNA evidence is addressed it will enable the courts to clear many outstanding criminal cases. Continued research will eventually assist courts in rendering verdicts that are without controversy. As with any other form of science it may never be perfected, but its use in criminal investigations and the improvements in quality of life will far exceed any current gene mapping theory currently available.

1.         Haney, Daniel Q. Popular Science Online. “Building a better baby.”
2.         Lander, Dr. Eric S. “Uses of DNA in identification”.
3.         Lemonick, Michael D. Time Magazine: Canadian Edition. “Smart Genes?”. September 13, 1999. Page 40.
4.         Microsoft Encarta Online Encyclopedia 2001. “Electrophoresis.”
5.         Sinha, Gunjan. Popular Science Magazine. “DNA Detectives”. August 1999. Page 48.
6. Bennett, Wayne W. and Hess, Karen M., Criminal Investigation (8th Ed), 2007. Pages 133-138.