Indmedica Home | About Indmedica | Medical Jobs | Advertise On Indmedica
Search Indmedica Web
Indmedica - India's premier medical portal

Journal of the Academy of Hospital Administration

Facilities required to set up the DNA Fingerprinting Laboratory for Forensic Purposes

Author(s): Anupama Raina and TD Dogra *

Vol. 15, No. 1 (2003-01 - 2003-06)

Keywords : DNA Fingerprinting, Forensic

Introduction

DNA Fingerprinting, the latest technique developed in the field of Forensic Medicine is widely used presently all over the globe. It has advantages over the conventional techniques as it has tremendous discriminating power and stability. DNA is more stable to environmental degradation, which includes temperature, time, humidity (which leads to the growth of microorganisms), and exposure to UV, sunlight and various chemical substances. Moreover, DNA is somatically stable which means, it generates the same genetic pattern irrespective of the biological material used like hair, seminal stain, fresh blood, soft tissue, hard tissue etc. In fact, this unique feature of DNA makes it a powerful tool, particularly in forensic identification. This technology came into existence in 1985 Prof. Alec Jeffrey's, while studying the myoglobin gene, a protein that stores oxygen in the muscle, discovered that certain regions of DNA showed variations in the number of tandem repeats which are known as, Variable Number of Tandem Repeats (VNTR). It was observed that these VNTR's appear as repeated over and over again next to each other and the number of these repeated sequences present in a sample differs from an individual to individual, thus producing unique patterns like fingerprints, named it as DNA fingerprint. DNA fingerprints are actually genetic pattern determined from an individuals genetic material i.e. DNA and are transmitted from parents on the theory based on Mendelian law of inheritance. According to this law, half of the genes are transmitted from the father and rest half from the mother. This helps in identifying the individual when compared with the samples of his/her parents with full proof. Actually, over 99% of all 3 billion nucleotides in human DNA which one inherits from one's parents are identical among all individuals but for every 1000 nucleotides there is a site of variation of polymorphism in the population which makes one individual different form another except monozygotic twins.

DNA technology has helped to isolate and amplify and analyze minute amounts of human DNA.

DNA fingerprinting test establishes the identity of an individual. It also helps to investigate the possibility that two or more biological samples originate from the same individual (or species). It has become a popular courtroom tool all over the world.

Common type of Biological samples encountered

Many different types of evidences are forwarded to the laboratories for DNA analysis. The following is the list:

  • Fresh Blood and blood stains
  • Semen and seminal stains
  • Tissues (Soft)
  • Bones (Hard tissues)
  • Hair (roots)
  • Nails
  • Saliva, urine

Applications

DNA fingerprinting, a novel method to identify an individual has following applications:

  1. Criminal and civil case
    1. Rape
    2. Murder
    3. Kidnapping
    4. Exchange of babies
    5. Disputed paternity
    6. Immirgration
    7. Identification of the nearest relation to claim compensation in Mass disaster
  2. Population genetics
  3. Animal genetics

Facilities Required

  1. Sequencer, preferably Automated: To run the isolated DNA samples for analysis
  2. PCR machine: To amplify the DNA samples
  3. Gel documentation: To visualize the DNA samples for quality and quantity estimation
  4. Refrigerated and non refrigerated centrifuge: To maintain the temperature during the process of isolation of DNA
  5. Gel apparatus, both horizontal and vertical along with power supply: To run the DNA samples for quality and quantity estimation
  6. Water purification system: Contamination free water
  7. Uninterrupted power supply: So that the temperature of the equipments is maintained while power break up
  8. Deep freezer: To store the samples for long duration
  9. 20°C and 4°C: To store the fine chemicals and solutions respectively
  10. Water Bath: Used during the process of isolation of DNA

Precautions to be taken

DNA labs should be restricted to people working in this laboratory. The latest technique used i.e. PCR is highly sensitive. The care has to be taken that no other sample or cells get mixed with the samples handled which leads to problem while analyzing the case. Moreover, all the samples should be handled with extra care by using gloves and sterile instruments like scissors, forceps and glass wares. Other contaminants like grease, dirt, some fabric dyes (dye in denim jeans) seriously compromise the DNA analysis process.

* Department of Forensic Medicine and Toxicology, AIIMS

Access free medical resources from Wiley-Blackwell now!

About Indmedica - Conditions of Usage - Advertise On Indmedica - Contact Us

Copyright © 2005 Indmedica