ABSTRACTForensic Science: A Very Short Introduction introduces the concept of forensic science and explains how it is used in the investigation of crime, and history of forensic science. In forensic science, a criminal case can often hinge on a piece of evidence such as a hair, a blood trace, half a footprint, or a tyre mark. High profile cases have attracted enormous media attention and enhanced this interest in recent years. However, the public understanding of forensic science is poor, and largely based on TV shows.
This article explains the principles of crime scene management, explores how forensic scientists work, and considers the techniques they use. At last you will also came to know what is DNA fingerprinting? And how DNA fingerprinting is used in solving complicated scenes .Keywords: crime, evidence, examination, forensic, forensic science, identity, information, justice, DNA, DNA fingerprinting, DNA sequencing, crime lab, PCR, Restriction Fragment Length Polymorphisms. FORENSIC SCIENCEINTRODUCTION DEFINITION Forensic is scientific tests or techniques used in connection with the detection of crime OR relating to or applying the application of scientific methods and techniques to the investigation of crimes and the word ‘forensic’ was derived from the Latin word ‘forensis’, meaning ‘before the forum’.
FORENSIC SCIENCE is the application of science to criminal and civil laws, mainly on the criminal side during criminal investigation, as governed by the legal values of allowable evidence and criminal procedure. In other words, Forensic science is the application of science to those criminal and civil laws that are enforce by police agencies in a criminal justice system. Forensic science is to collect, preserve, and analyze scientific evidence during the course of an investigation. In order to solve the criminal cases forensic scientists sometimes travel to the scene of the crime to collect the evidence by themselves, others occupy a laboratory role, performing analysis on objects brought to them by other peoples from the crime scene. The evidence may ranges from fingerprints to blood samples or from a memory card to a hard disk. Forensic science is the interaction of law and science. It can be used to condemn the guilty or exonerate the innocent. Many court cases hinge on scientific evidence provided by forensics. Throughout the years scientists have developed technologies to uncover facts in criminal investigations, and the law has been quick to embrace these new technologies as they became available. Figure 1 CRIME SCENESCOPE OF FORENSIC SCIENCE Forensic science in its broadest definition is the application of science to law. As our society has grown more complex, it has become more dependent on rules of law to regulate the activities of its members. Forensic science offers the knowledge and technology of science for the definition and enforcement of such laws. Each year, as government finds its increasingly necessary to regulate those activities that most intimately influence our daily lives, science merges more closely with civil and criminal law. In the arena of criminal justice, laws are continually being broadened and revised to counter the alarming increase in criminal rates. In response to public concerns, law enforcement agencies have expanded their patrol and investigative functions, hoping to stem the rising tide of crime. At the same timing they are looking more and more to the scientific community for advice and technical support of their efforts. Can the technology that put man on the moon, split the atom, and eradicated man’s most dreaded diseases be enlisted in this critical battle? Unfortunately, science cannot offer final and authoritative solutions to problems that stem from a maze of social and psychological factors. However, science does occupy an important and unique role in the criminal justice system—a role that relates to the scientist’s ability to supply accurate and objective information that reflects the events that have occurred at a crime. Its due to the advancement in the forensic sciences that nowadays we can easily solve complicated cases (criminal) with ease. FORENSIC SCIENCE HISTORY The ancient world lacked standardized forensic practices, which aided criminals in escaping punishment. Criminal investigations and trials heavily relied on forced confessions and witness testimony. The 18th and 19th centuries saw a great deal of progress in the field of forensic science in Europe. One of the first recorded instances of its application in solving a legal case came in 1784, in England, when a torn piece of paper recovered from the bullet wound in the victim’s head matched the other piece of paper from John Tom’s pocket and led to his sentence.Today, many believe that SIR ARTHUR CONAN DOYLE had a considerable influence on popularizing scientific crime-detection methods through his fictional character SHERLOCK HOLMES. It was Holmes who first applied the newly developing principles of serology, fingerprinting, firearm identification, and questioned-document examination long before their value was first recognized and accepted by real-life criminal investigators. Figure 2 SHERLOCK HOLMES (an imaginary character) A lot of scientists make their own contributions to the forensic sciences; out of them some are ALPHONSE BERTILLION (1853-1914), FRANCIS GALTON (1822-1911), LEONE LATTES (1887-1954), CALVIN GODARD (1891-1955). Another important milestone marking the development of forensic science was the creation of CENTRAL RESEARCH ESTABLISMENT in AlDERMASTON , ENGLAND in 1966. This laboratory was the first of its kind in the world to be solely dedicated to performing basic research in forensic science. THE ORGANIZATION OF A CRIME LABORATORYThe organization of a crime laboratory is the first and utmost step in solving a crime scene. As increasing in crime rates so there is a need to increase the crime laboratories in order to solve crime scenes with ease. The crime laboratory is simply known as crime lab. Figure 3 CRIME LABORATORY. The typical crime labs have two sets of personnel: (a): Field analysts’ (b): Laboratory analysts Field analysts or investigators that go to crime scenes, collect evidence, and process the scene. Job titles include: Forensic evidence technician Crime scene investigator Scenes of crime officer Laboratory analysts or scientists or other personnel who run tests on the evidence once it is brought to the lab ( DNA tests, or bullet striations). Job titles include: Forensic Technician (performs support functions such as making reagents) Forensic Scientist/Criminalist (performs scientific analyses on evidence) Fingerprint Analyst Forensic Photographer Forensic Document Examiner Forensic EntomologistWHAT IS A DNA FINGERPRINT? We know that every human carries a unique set of genes different from other individuals. The chemical structure of DNA is always same but the order of the base pairs in chromosomes differs in individuals. The novel assemblage of the 3 billion nucleotides formed into 23 pairs of chromosomes gives each us a unique genetic identity. DNA fingerprinting is a method used to identify an individual from a sample of DNA by looking at unique patterns in their DNA. Almost every cell in our body contains our DNA. On average, about 99.9 percent of the DNA between two humans is the same. The remaining percentage is what makes us unique (unless you are an identical twin!). Although this might sound like a small amount, it means that there are around three million base pairs that are different between two people. These differences can be compared and used to help distinguish you from someone else. DNA fingerprinting was invented in 1984 by Professor Sir Alec Jeffreys after he realized you could detect variations in human DNA, in the form of these minisatellites.( Minisatellites are short sequences (10-60 base pairs long) of repetitive DNA that show greater variation from one person to the next than other parts of the genome. This variation is exhibited in the number of repeated units or stutters’ in the minisatellite sequence). DNA fingerprinting is a technique that simultaneously detects lots of minisatellites in the genome to produce a pattern unique to an individual. This is a DNA fingerprint. Figure 4 FINGERPRINTHow was the first DNA fingerprint produced? The first step of DNA fingerprinting was to extract DNA from a sample of human material, usually blood. Molecular scissors’, called restriction enzymes were used to cut the DNA. This resulted in thousands of pieces of DNA with a variety of different lengths. These pieces of DNA were then separated according to size by a process called gel electrophoresis. The DNA was loaded into wells at one end of a porous gel, which acted a bit like a sieve. An electric current was applied which pulled the negatively charged DNA through the gel. The shorter pieces of DNA moved through the gel easiest and therefore fastest. It is more difficult for the longer pieces of DNA to move through the gel so they travelled slower. As a result, by the time the electric current was switched off, the DNA pieces had been separated in order of size. The smallest DNA molecules were furthest away from where the original sample was loaded on to the gel. Once the DNA had been sorted, the pieces of DNA were transferred or blotted’ out of the fragile gel on to a robust piece of nylon membrane and then unzipped’ to produce single strands of DNA. Next the nylon membrane was incubated with radioactive probes. Probes are small fragments of minisatellite DNA tagged with radioactive phosphorous. The probes only attach to the pieces of DNA that they are complementary to ” in this case they attach to the minisatellites in the genome. The minisatellites that the probes have attached to were then visualised by exposing the nylon membrane to X-ray film. When exposed to radioactivity a pattern of more than 30 dark bands appeared on the film where the labelled DNA was. This pattern was the DNA fingerprint. To compare two or more different DNA fingerprints the different DNA samples were run side-by-side on the same electrophoresis gel. Figure 5 STEPS IN DNA FINGERPRINTINGDNA profiles are very useful in forensics because only a tiny sample of human material left behind after a crime may be sufficient to identify someone. A match made between a crime scene profile and an individual profile identifies a possible suspect. The police may use this DNA evidence to support other evidence to help prosecute someone for a crime. Complete DNA profiles give very reliable matches and may provide strong evidence that a suspect is guilty or innocent of a crime. Figure 6 Illustration showing a comparison of a DNA fingerprint from a crime scene and DNA fingerprints from two suspects. The DNA fingerprint from suspect 2 matches that taken from the crime sceneTHE FUTURE OF DNA ANALYSIS The forensic community, as it always has, is facing the question in which direction the DNA Fingerprint technology will be developed. A growing number of colleagues are convinced that DNA sequencing will soon replace methods based on fragment length analysis and there are good arguments for this position. With the emergence of current Next Generation Sequencing (NGS) technologies, the body of forensically useful data can potentially be expanded and analyzed quickly and cost-efficiently. Currently, the rather high error rates are preventing NGS technologies from being used in forensic routine, but it is foreseeable that the technology will be improved in terms of accuracy and reliability. At present the forensic DNA technology directly affects the lives of millions people worldwide. The general acceptance of this technique is still high, reports on the DNA identification of victims of the 9/11 terrorist attacks, of natural disasters as the Hurricane Katrina, and of recent wars (for example, in former Yugoslavia) and dictatorship (for example, in Argentina impress the public in the same way as police investigators in white suits securing DNA evidence at a broken door.GENOMICS-THE FUTURE: Genomics is the scientific study of the molecular instructions encoded in our cells. It maps our entire genetic structure. Till now, forensic science has focused on only identifying our cell’s nuclei signature ” our inner DNA (deoxyribonucleic acid) and, to a degree, our outer miDNA (mitochondrial DNA) ” not our genes. The old method of forensically profiling your biological fingerprint by DNA analysis is being replaced by a computerized 3D genome recreation of your entire being.Genomics is a concept first developed in the 1970’s. It led to the Human Genome Project (HGP) being completed in 2003. The HGP was a massive international research venture that sequenced and mapped all of the human cell genes ” together known as the genome. The HGP gave us the ability to read nature’s complete genetic blueprint for building a human being.So what’s a genome?A genome is the whole ensemble of our genetic material. It’s the molecular guide of our DNA, our chromosomes, and our genes that describes how to make our cells. It’s the instruction manual for our body. That book is our genome and the study of that book is termed genomics. It’s pretty much a math exercise. And it’s deadly stuff for identifying criminals with.ADVANTAGES OF DNA FINGERPRI NTING It helps people know more about their family background. It helps solve crimes. It can help determine and even prevent illnesses.DISADVANTAGES OF DNA FINGERPRINTING It can violate people’s privacy. It can point the finger at the wrong person. It’s complex and prone to errors.DNA fingerprinting has several advantages and can help both the authorities and ordinary people. However, it does have its own drawbacks, so it’s up to the experts to make sure that the DNA fingerprinting process is used properly and wisely.REFRENCES: