The "hot Hot" Topic of DNA Testing

Deoxyribonucleic acid (DNA) testing has revolutionized the process of identification, of proving beyond reasonable doubt whether or not a person is of interest in a criminal case or in establishing biological relationship. DNA testing is now used extensively to establish paternity, maternity, to confirm or rule out a suspect in a crime, to establish distant biological relationships and to even test for infidelity! Prenatal testing is also done to check for genetic defects. DNA testing is common scene on CSI Miami and various murder mystery type shows, it was talked about endlessly in connection to Anna Nicole Smith for months but do we really understand the procedure?
Let me explain in simplified terms how DNA contains all the tell tale signs needed for paternity testing or criminal investigations. First let us brush up on some basics in Biology. Our bodies are made up of cells which are the building blocks of life, just like houses are made up of bricks or stones put together. Each cell contains DNA that contains huge amount of information in them. DNA has genes interspersed within it that code for proteins that carry out every possible function in one's body and determine every characteristic trait of an individual. Every person has a unique set of genes just as unique as their fingerprints. Remember, DNA is the only permanent human record that lasts a lifetime. When an embryo is formed after the fusion of a sperm and an egg, the embryo, now a new individual has a distinct, unique identity of his/her own and contains half of the DNA from the mother and the other half from the father. The children of the same two sets of parents will have several genetic markers in common; however they will not have the exact same set of genes or genetic markers. The only exceptions to this rule are identical twins that have the same set of genes but their outward appearances differ and so do their finger print patters.
The principle of paternity testing is that the child's DNA is compared for certain genetic markers against that of the dad's DNA. If they match then he is the biological father of the child, if not then he is not. DNA testing of persons of interest in a crime is done in much the same way. Evidence such as sperm, hair follicles, blood, nails of the victim containing the criminal's skin cells or any source of cells from which DNA can be extracted, are collected. The DNA is extracted and compared against genetic markers of the suspect's to find a match. If the suspect's DNA is not in the database a simple cheek swab can be used to collect cells and compare it to DNA from the crime scene. However, if there is not the faintest idea who the suspect is and if the suspect's DNA is not on the database then there is nothing to compare the DNA from the crime scene to.
DNA testing is an invaluable tool that can be used for good or evil. It can point out the malefactor and set an innocent suspect free. It can reveal truth in a paternity case although the consequences of the results could have long term damaging effects on individuals and families. It can be used to help unite long lost siblings or family members. Finally but sadly, it is being used to test for genetic defects in embryos and at the parents' wish to kill embryos that don't pass the test.