HOW TO DETECT CRIMINALS THROUGH DNA TEST

Whole human body is made up of DNA (Deoxyribose nucleic acid).Each person has different DNA from other individuals. But structure of DNA is same in twins. Nowdays DNA became very useful for law during investigations. There number of sources to extract DNA. These are:

1.          Hair
2.          Bones
3.          Teeth
4.          Saliva
5.          Blood

DNA can be  easily contaminated. So handle it carefully by wearing gloves, avoid cough and using paper bags to collect the samples. These samples can be collected from tooth-brush, razor.

This technique is used by law to identify the person based on their DNA. This term is known as DNA profiling. Federal Bureau of investigation launched a national DNA database which is known as Combined DNA Index System (CODIS). Further large number of DNA sample go into the CODIS. It is a software of computer technology which can store the DNA profile at local and national level. It is used to compare the DNA profiles which are obtained from the crime scene with the convicted offenders and arrestees. According to FBI reports more than 9 billion offender DNA profile store in the CODIS.

                                            

        In 1980, DNA test is begun and sample is collected from  offenders during sexual and other violent crimes. Then samples were analyze and their profiles entered into state databases. According to Dr. Alec Jeffreys that certain areas of the DNA strand contain patterns that repeat many times. These repetitions are not similar in different individuals. Therefore a test was developed by Dr. Jeffreys to measure the variation in length of these repetitions. By this test, Dr. Jeffreys identify individuals and then compare the sample of DNA with other individual. This test is known as restriction fragment length polymorphism (RFLP).

 But large amount of DNA sample is required for RELP test. Nowdays this test is carried out by polymerase chain reaction (PCR) method, in which very small amount of DNA sample is required.

       Investigators collect DNA evidence from a number of different sources. But every sample does not contain sufficient amounts of DNA to enable DNA profiling. After that Forensic investigators will analyze the biological samples and find out the DNA profiling of the individual.

      If suspect is known then the sample is collected by the investigators and then compare the sample to the evidence which are collected at the scene.DNA evidence is extremely accurate. On the other hand fingerprinting and eyewitness testimony are inaccurate. Therefore DNA evidence is a highly effective way to match a suspect to biological samples collected during a criminal investigation.

Article Written By:

Dr. Navneet Kaur Brar [B.sc Medical, M.sc Biotechnolgy]

Special Thanks to mam Navneet Kaur from our world of modern technology team for this wonderful and highly informative article for our viewers.we are looking forward to hear from you soon, some  more articles like this article.

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Er. Jagmeet Singh brar.