EVEN A NANOGRAM OF DNA CAN SOLVE A CRIME; BRIEF ABOUT TOUCH DNA

 

AUTHOR – ARUNKUMAR R, SEM IV, M.SC. FORENSIC SCIENCES, NATIONAL FORENSICS SCIENCES UNIVERSITY, GOA CAMPUS

INTRODUCTION

     DNA (Deoxyribose Nucleic Acid) is an essential molecule that present in all the living organisms which results in replication and growth of the organism it contains the genetic information which is passed generation after generation. DNA is made of phosphates, Deoxyribose sugar, nucleobases are formed into a double helix structure. The ability of DNA to carry information about the ancestors are applied in the Forensic science for crime solving. Touch DNA also refers to as ‘Trace DNA’ these are the less amount of DNA as 1ng that collected from a crime scene which may transferred from the skin cells of fingerprints because of handling or touching some object and the collected DNA is used to sequencing of gene STR(Short Tandem Repeats) analysis. Less amount of sample is only required.

METHODOLOGY 

     The process begins with the collection of the sample from the crime scene dry swabbing or wet swabbing or cut method is the most familiar methods that used in collection of Touch DNA. Swabbing is mostly used for non porous surface like glass or metal surface which is a method of rubbing the surface using cotton swab to collect the cells. In case of small cloth or paper cutting method is followed, The collected sample is further involved for extraction process QIAsymphony® DNA Investigator® Kit, and DNA IQ™ are used as they results in a high success rate for DNA extraction which is followed by amplification of DNA which helps in increased amount of sample and helps in STR analysis and helps in identification which is a unique identity.

ADVANTAGES 

     Helps in connecting the suspect with crime scene even the sample amount is lesser than 1ng especially in the presence of some properties, It have applications in solving some cold cases too, for example: Touch DNA to Solve Decades-Old Murder Of Las Vegas Teen

     This case happened in 1989, 14 year old Stephanie Isaacson was brutally attacked and murdered by some unknown, the least of only 15 cells was found on the shirt of Isaacson which contains less than 1ng of DNA only (0.21ng) usually minimum of 10-100ng is required, Othram corporation a laboratory designed the gene with the available DNA after 32 years of incident which leads to pointing at the culprit’s cousin and revealed that the culprit is Marchand who died by suicide in 1995

DISADVANTAGES

     In most of the cases the sample won’t be able to find as there are more chances for destruction of sample. Even the sample is available it won’t be sufficient in most cases and not all samples are suitable for the extraction.

CONCLUSION

     The technology is still to develop to extraction of DNA from different samples and also the collection methods to be developed which can help in several cases, Touch DNA is one of the developing application which helps in gene sequencing, reverse DNA tracking method which provides details about the family related to the suspect helps in cases where suspect list is absent.

REFERENCES

• Touch DNA: Forensic Collection and Application to Investigations Article Angela L. Williamson, PhD Bode Technology, Lorton, Virginia, US
• Improved strategies for sampling and mixture separation of trace biological materials Timothy James Verdon B.Sc. Hons (Forensic Genetics) La Trobe University B.Sc. (Biomedical Science in Forensic Biology) University of Technology, Sydney
• The Affecting Factors of Touch DNA Salem K. Alketbi* General Department of Forensic Science and Criminology in Dubai Police, UAE *Corresponding author: Salem K. Alketbi, General Department of Forensic Science and Criminology in Dubai Police, UAE, Tel: 00447774141205; E-mail: alkitbe. 11@hotmail.com Received date: July 09, 2018; Accepted date: July 30, 2018; Published date: August 03, 2018.