DNA and molecular biology has advanced by leaps and bounds. It has found use in pharmacology, genetic engineering in disease prevention, in increasing agricultural growth, in detection of disease and crime (forensics) etc.
Some fields that have shown remarkable growth due to advances in DNA technology include:
- pharmacology and nanotechnology
- archaeology and anthropometry
DNA technology in forensics
DNA is unique. Because it is unique, the ability to examine DNA found at a crime scene is a very useful forensic tool. The common methods used to identify and describe the DNA profile includes – Restriction fragment length polymorphism (RFLP) and Short tandem repeat profiling (STR).
Restriction fragment length polymorphism (RFLP)
In RFLP, the DNA is cut into segments of varying lengths by an enzyme, then the segments are separated out on the basis of size using a technique called electrophoresis.
The DNA fragments of a particular length are transfered to a nylon membrane. They are matched up with radioactively labelled fragments of DNA in such a way that only fragments that are identical stick together.
The excess radioactive fragments are washed away and an x-ray of the remaining fragments taken.
Electrophoresis is essentially applying positive and negative currents to a gel base and letting the DNA migrate to the positive pole (since it is negatively charged). The labelled fragments separate out based on their size. This gives a picture of which of the labelled fragments.
Short tandem repeat profiling (STR)
Short tandem repeat profiling (STR) involves use of an enzyme to make many copies of a small section of the DNA. This section is then cut into pieces by another enzyme, and separated by electrophoresis. The fragments are then visualised with a silver stain, with the pattern of light and dark bands seen being characteristic for an individual.