The use of DNA evidence in the courtroom has not only become widespread due to advancing technologies but it has become widely misunderstood because of several popular television programs. DNA analyses have become powerful tools that have the potential to convict criminals and exonerate the innocent. They have even been used to exonerate criminals who were convicted decades ago through efforts such as the Innocence Project. However, the sensitivity of the tests and an undercurrent of misinformation serve to confuse jurors and complicate the criminal justice system.
Over the course of one week, students will isolate and analyze DNA using methods commonly employed in forensic laboratories. While doing so, they will learn about the strengths and limitations of DNA evidence, be introduced to population genetics, probability, and the ‘real’ life of a CSI. The week will culminate in a mock trial involving a case created, developed and tried by students in the class.
What are good sources of DNA? Students will identify good sources of DNA and isolate their own DNA for analysis. We will also explore DNA stability under different conditions and determine the effect of various environmental conditions on the value of DNA in the forensic laboratory.
How does DNA distinguish among individuals? Students will explore population genetics, allele frequencies, probabilities and other quantitative measures commonly used to make DNA valuable in forensic investigations. Of course, we will also see how those measures can be used, misused and abused in the courtroom.
What are the strengths and limitations of DNA in forensic investigations? Without a doubt, DNA analyses are sensitive and powerful tools for crime scene investigations. We will consider the contributions that DNA profiles have made to solving crimes, study the current limitations of their interpretation, and discuss ethical and social issues related to the increased use of DNA profiles to solve crime. Recently scientists have demonstrated that DNA is stable for at least 700,000 years. This finding impacts the interpretation of DNA evidence found at crime scenes because we cannot determine when it was left there. Another development involves the use of commercial software to interpret mixtures of DNA in the forensic laboratory. The controversy surrounding that software leaves questions about its value unanswered.