Role of biotechnology in forensic science

ROLE OF BIOTECHNOLOGIST IN FORENSIC REPORTS

1. R ole of BIOTECHNOLOGist IN FORENSIC SCIENCE KAMALESH GUPTA .B BY

2. BIOTECHNOLOGY Any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use

3. FORENSIC SCIENCE Forensic sciences involve the scientific analysis and documentation of evidence suitable for legal proceedings

4. BIOTECHNOLOGIST To collect or process trace evidence such as hair, skin, blood or semen samples, which is found at crime scenes Analyzing or creating DNA profiling or genetic fingerprinting . Using the Sources of DNA include blood, hair, semen, saliva, bone and tissue.

5. PRINCIPLE OF DNA PROFILING The only difference between people (or any animal) is the order of the base pairs . There are so many millions of base pairs in each person’s DNA that every person has a different sequence

6. DNA PROFILING Every person has a unique DNA profile. The only exception to this is monozygotic twins. The chemical structure of everyone’s DNA is the same. But the order of sequence vary for each one To identify individuals, forensic scientists scan 13 DNA regions, or loci, that vary from person to person and use the data to create a DNA profile of that individual (called a DNA fingerprint).

7. DNA PROFILING There is an extremely small chance that another person has the same DNA profile for a particular set of 13 regions . The technique of DNA fingerprinting is based on the analysis of two types of highly variable sequences present in human genome : VNTR ( Variable Number Tandem Repeats) and STR (Short Tandem Repeats ). By combining the information obtained from the analysis of more VNTR or STR regions it is possible to obtain the distinctive profile of a person.

8. TOOLS OF FORENSIC SCIENCE  Restriction Fragment Length Polymorphism Polymerase Chain Reaction Random Amplified Polymorphic DNA Inter Simple Sequence Repeats analysis Mitochondrial DNA analysis Y chromosome markers analysis Alu repeats analysis

9. RESTRICTION FRAGMENT LENGTH POLYMORPHISM Restriction Fragment Length Polymorphism (RFLP) is a technique in which organisms may be differentiated by analysis of patterns derived from cleavage of their DNA

10. 1.WHOLE BLOOD OR STAINS 2.ISOLATE NUCLEI 3.RECOVER DNA 4.CUT DNA INTO FRAGMENTS 5.SEPARATE FRAGMENTS BY SIZE 6.TRANSFER DNA TO MEMBRANE 7.ADD LABELED DNA PROBE 9.WASHED MEMBRANE 10.DEVELOP X-RAY FILM 11.ANALYZE DNA PROFILE Restriction Fragment Length Polymorphism [RFLP] 8

11. ADVANTAGE Highly robust methodology with good transferability between laboratories. No sequence information required. DISADVANTAGE Large amounts of DNA required.

12. POLYMERASE CHAIN REACTION PCR is a technique that takes specific sequence of DNA of small amount and amplifies it to be used for further testing In vitro technique It amplify a lot of double-stranded DNA molecules (fragments) with same (identical) size and sequence by enzymatic method and cycling condition.

13. ADVANTAGE Small amount of DNA is required per test Result obtained more quickly - usually within 1 day for PCR Usually not necessary to use radioactive material (32P) for PCR

14. RANDOM AMPILIFIED POLYMORPHIC DNA RAPD analysis is a PCR based molecular marker technique. Single short oligonucleotide primer is arbitrarily selected to amplify a set of DNA segments distributed randomly throughout the genome.

15. 1.BLOOD SAMPLE 2.ISOLATION OF DNA 3.CUT DNA INTO FRAGMENTS 4.SELECTION OF RANDOM PRIMERS 5.DNA IS AMPLIFIED THROUGH PCR 6.A MULTIPLE NUMBER OF DNA IS DEVELOPED APPLICATION Use of non-specific primers to amplify many regions of a sample DNA Can amplify upto 100 or more loci in one sample Special importance in the entomological investigations of corpses

16. INTER SIMPLE SEQUENCE REPEATS Based on microsatellite primers No prior genomic information required Highly sensitive and informative   It is PCR based analysis

17. MITOCHONDRIAL DNA ANALYSIS  Preferred due to • High copy number • Lack of recombination • Only maternal lineage identification

18. ROLE OF MT DNA IN FORENSIC mt DNA will be used when "biological evidence may be degraded [i.e. charred remains] or in small quantity“ Cases in which evidence consists only of: HAIR BONE TEETH Missing Persons Cases (use of skeletal remains) Establishing Individuals as suspects (hair evidence) 

19. Y CHROMOSOME ANALYSIS  For gender discrimination Identity fixation in rape cases For paternal lineage analysis 

20. Alu repeats analysis Transposable elements Site for Arthrobacter luteus ( Alu ) restriction endonuclease Can be present/absent on same chromosome among different families Identification of population ancestral lineage

21. APPLICATION Sample analysis Lineage analysis Suspect identification Anthropological studies Population genetics studies