READ: Structure of DNA

Introduction

 DNA is the genetic code of life. What makes us "human" is the number and sequence of nucleotides in our genome. The human genome, as well as the genome of many other species has been sequenced. While 99.9% of the genes in every human are the same, the 0.1% variation makes each individual unique. When these small but unique parts of an organisms genome is known, it is possible to identify an unknown species by comparing the DNA sequence of the unknown to the known and make a match.

Essential Questions

1. How is DNA evidence analyzed?

2. What makes DNA evidence unique?

3. How can old or degraded samples be analyzed for DNA?

4. How are DNA profiles stored?

Module Minute

DNA analysis is very useful in Forensic Science to both implicate and exclude persons of interest in a crime. DNA analysis is unique in that each person, with the exception of identical twins, has their own individual DNA that can be used to identify them from the other 7 billion people on the planet. In addition, DNA can be extracted from sources many years later in many cases, which means that many formerly "cold cases" can be re-opened and possibly solved with newer technologies. DNA profiles are stored in a large database known as "CODIS" for the purpose of comparing unknown to known DNA samples at different points in time. While DNA evidence does not always lead to a suspect, it is one of the very best tools in the Forensic Investigator tool belt because of the amount of individual evidence it provides.

Georgia Virtual, DNA Analysis, CC BY-NC-SA 3.0