DNA Basics

• Adenine, cytosine, guanine and thymine are the four chemical bases that make up DNA. The bases match up with each other to form pairs, and there are about 3 billion bases in human DNA. Much like the manner in which alphabetical letters create words when they appear in a specific order, the order of the chemical bases provides a blueprint or code for constructing an organism. Every organism has its own unique DNA with a set of instructions that is then passed down from adults to their children during reproduction. An organism's genome is its full set of nuclear DNA.
  
  

Effects on Medicine

• The discovery of DNA has had a great impact on science and medicine. The ability to identify genes that are involved in different diseases has lead to better diagnosis of disease. Scientists are able to determine if people have a genetic predisposition to a disease, and preventative measures can be taken in certain cases. The discovery of DNA has also led to breakthroughs in the treatment of some diseases, and gene therapy offers hope to many who suffer from diseases that were previously considered untreatable.
  
  

Effects on Crime Solving

• The discovery of DNA has had an effect on crime scene investigations and convictions. Every person's DNA is unique, and this makes it an important tool much like fingerprinting. DNA gathered at a crime scene can be analyzed and then used to rule out certain suspects or it may confirm that a suspect was at the crime scene. It can also be used to compare evidence from different crime scenes and find connections between them. Forensic experts collect DNA that can be stored and used to help solve crimes that occurred in the past.
  
  

Identifying the Wrongly Convicted

• DNA has played an important role in proving the innocence of people who have been wrongly convicted of a crime. Testing of DNA after a conviction has been used both in cases in which no DNA testing was done as well as in cases where the use of the latest technological advances in DNA analysis could result in evidence that may exonerate someone of a crime. In postconviction testing of DNA much attention is focused on the way the DNA evidence has been collected and preserved to ensure the DNA has not been contaminated.