This document is about understanding the technology of DNA Testing. The topic of DNA is very complicated and not easy to understand, so a very easy to understand language would be used which would help the readers to understand the concept and technology of DNA testing. In easy words, DNA is determines the individual characteristics of a person which identifies and differentiates him from other people on medical basis. DNA technology is not new to the human being, it is there since very old times but the scientists have identified and named it quite later after the advancements in the technology.
BODY – “THE TECHNOLOGY OF DNA TESTING”
The discovery of DNA is one of the most fascinating and useful discoveries and events in the world and more importantly, for the twentieth century. Almost everyone among us is aware of this term but most of us are unaware of the importance and the real meaning or concepts of DNA (File, 1997, p399). Deoxyribonucleic Acid – DNA: DNA is fundamentally the abbreviation of the term deoxyribonucleic acid which actually is the genetic unique design and blueprint which authenticates and verifies the biological characteristics of a particular individual person.
DNA of every person is very unique and different and not every person in the world has the same design, however, the genes of a blood family would contain similar designs which determine that they are members of that specific family group. DNA is very small in size and cannot be tested from naked eye. It basically is found in the blood cells of the human body. DNA is present in shape of long strands in the blood cells of human body. Structure of DNA: (File, 1997, p399) DNA is the substance which contains the inheritance influence of bone density, blood cells, stature, and eye color pattern or hair structure.
It is said to be human body’s blueprint forever till he lives. The size of DNA could be packed normally into a space which could be equivalent to a cube 1/millionth of an inch on one side. It is because of the reason that it let the cells to come close and form a cooperative group and form an organism. Our body comprises of many type cells overall; there are blood cells, kidney cells, brain cells, liver cells, sperm cells, muscle cells and many more.
Each part and organ of our body comprises of billions and trillions of these tiny cells and each cell contains a complete sample or specimen DNA which is very similar to every other cell in the body. But there exists some exceptions, such as, the red cells present in our body contains less amount of DNA because of the fact that blood itself can be categorized because of the DNA present in the white cells of our body (USA, 1990, p19). (West Group, 1994, p147) DNA is present not only in human body but also exists in animals, plants and bacteria. It is basically made up of four bases which are: • Guanine
• Cytosine • Adenine • Thymine Diagrams of DNA Structure showing a) the different parts present in the DNA pattern; and b) the overall design of a DNA structure Technology of DNA Testing: (Fay, 1993, p237) The technology of DNA testing is also known as genetic fingerprinting, genetic blueprint, DNA typing, and DNA profiling. All these names refer to the same technology which refers to the technology being used to differentiate between people and individuals of the same species or families by using their DNA samples. It investigates and analyzes the basic design and inheritance structure of DNA.
(Butler, 2005, p30) The results of the DNA test are fully dependent on the quality and quantity of the sample provided to the analyst. The technology of DNA testing has two major methodologies or components which are explained in the following points: 1. The molecular biological procedure which allows the scientists or analysts to examine the DNA sample directly without any problem. 2. The population genetics which allows the DNA samples to be interpreted and measure the degree through which different samples are attached. This helps in getting the analytical work examining. The DNA Methodologies:
(Fay, 1993, p237) There are basically two common kinds of analytical methodologies of DNA which are gradually present in a normal forensic environment, which are used to identify the polymorphic DNA in human samples. These two different types of DNA methodologies are briefly explained as under: 1. Polymerase Chain Reaction Technique (PCR) Analysis: A PCR-based analysis or testing technique looks around and tries to identify the existence particular alleles (alleles are the alternative type of genes which are present in different individuals), and verifies very particularly different genetic characteristics of humans.
2. Restriction Fragment Length Polymorphism (RFLP) Analysis: This analysis methodology of RFLP searches out and verifies segments and fragments of DNA chain which covers the polymorphic particles and segments, and then it measures the total length of those particular fragments. Short Tandem Repeats (STR) Analysis: (Butler, 2005, p30) STR is said to be the most prevailing method of DNA testing used nowadays which is entirely based on PCR. This methodology makes use of high polymorphic areas which consists of short repeated sequences of DNA.
Normally, the average calculated value is 4 bases, but due to different kinds of DNA characteristics, it could be in other lengths such as, 3 or 5 as well. This difference is because every person’s DNA is different from the other and different individuals may contain different units. Amplified Fragment Length Polymorphism (AmpFLP): (Fay, 1993, p237) This practice was identified and came into practice in the 1990s decade. It is a very modernized technique which gives results better than RFLP and uses PCR to amplify the DNA samples and presents verified results.
Mitochondrial Analysis: (Butler, 2005, p30) This methodology is used in the cases where neither the quality nor the quantity of the DNA sample is satisfactory and when then it is impossible to make the complete profile of the DNA sample. It makes the extra copy present in the nuclear DNA and uses one of the copies of mitochondrial DNA (mtDNA) which are present in the sample. Y-Chromosome: (Fay, 1993, p237) This technique is present in the inherited paternal.
Normally known as Y-STR, it lets the pledge of mixed DNA samples from the male or female; or even in cases when differential extraction is not happening or not possible at all. CONCLUSION (Riley, 2005) DNA testing is the basis to recognize the positive unique identification which is present in the sample of a particular individual. This examination could be taken from blood, saliva, hair, semen or organ sample taken from a human. DNA testing is very crucial at times and needs highly adapted scientific knowledge and education to do that.
At present, DNA testing has modernized very much and people including the governments have laid great importance to it. DNA testing is increasing day by day to recognize and identify paternity; and yet, especially it has been deliberately increased to be used in forensic situations in identifying suspects or criminals from the crime scene. In addition, DNA testing is used in genetic disease research, and most of the times, in determining AIDS, bone marrow transplants, and anthropological investigations.
References
Facts on File, Inc, 1997, Issues and Controversies, File By Facts on File, Inc. , pg 399. 1990, Genetic witness: forensic uses of DNA tests, DIANE Publishing – Washington, Government of USA, pg 19. West Group, Bancroft-Whitney Company, Lawyers Cooperative Publishing, Lawyers Co-operative Publishing Company; 1994, American Jurisprudence Trials: An Encyclopedic Guide to the Modern Practices, Lawyers Co-operative Pub. Co. , pg 134-167. John Fay, 1993, Encyclopedia of Security Management: Techniques and Technology, Butterworth-Heinemann, pg237.