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1.Prospects for DNA profiling (Indian Express)

2.Plastic waste can be used for decontamination of water (Down to Earth)

1.Prospects for DNA profiling (Indian Express)

Synoptic line: It throws light on how DNA profiling can be a useful tool for state investigation. (GS paper II)


  • As the scientific community mourns the loss of Lalji Singh, the ‘father’ of DNA fingerprinting in India, a look at how this technology has become so crucial in establishing both culpability and innocence.

Evolution of DNA Fingerprinting

  • DNA fingerprinting was first developed in 1984 by Alec Jeffreys in the UK, after Jeffreys discovered that no two people could have the same DNA sequence. Within three years of the discovery, the UK achieved the world’s first conviction based on DNA evidence in a case of rape and murder. Crucially, the evidence also saved the life of an innocent man who had earlier been charged with the crime.
  • Lynda Mann, a 15-year-old girl, had been found raped and murdered in Narbourough, England. This was followed by a similar rape and murder case three years later in the same area. The police arrested one Richard Buckland, who confessed to both crimes. However, with the advent of DNA fingerprinting, his samples were checked against those found on the dead bodies — they didn’t match. Buckland was cleared and another man, Colin Pitchfork, was then arrested and convicted of the murders.
  • By 1988, Lalji Singh, who had been in the UK from 1974 to 1987 on a Commonwealth Fellowship, developed DNA fingerprinting for crime investigations at the Centre for Cellular and Molecular Biology (CCMB) in Hyderabad, which he joined after returning to India. In 1989, DNA fingerprinting was first used in a case by the Kerala Police. By the early 1990s, the technology had begun to be used for establishing paternity, and to link criminals and identify victims in sensational crimes. From the 2000s onwards, the technology became a staple in rape cases where vaginal swab samples were matched with semen samples from suspects.

Convictions via DNA based evidence: Achievements

  • From 1995’s Naina Sahni murder case to modern-day incidents of terrorism such as the 2013 Hyderabad blasts, DNA fingerprinting has not only come of age, but is also being increasingly used for crime investigations and prosecutions.
  • In March 2011, Bollywood actor Shiney Ahuja was convicted and sentenced to seven years of rigorous imprisonment for raping his maid even though the victim had told the court that she was never raped. But the Sewri fast-track court, which delivered the verdict, relied heavily on DNA evidence, in which semen samples from the vaginal swab of the victim matched with the samples obtained from the accused.
  • It was DNA evidence that established the identity of Thenmozhi Rajaratnam, also known as Dhanu, the suicide bomber who killed Rajiv Gandhi on May 21, 1991. And until the blueprint another word for DNA of some charred bones were discovered in a forest in Raigad, Maharashtra, in August 2015, and matched with the DNA of media entrepreneur Indrani Mukherjea, she had maintained that her daughter Sheena Bora was away in the USA.

Uniqueness of DNA profiling

  • The uniqueness of DNA fingerprinting as a tool of investigation is not just limited to its accuracy but extends to the way it can sift through crime scene evidence. Advanced DNA fingerprinting can make separate prints of various individuals even from a sample mixture found at the crime scene for example, in a gangrape case, DNA fingerprinting can identify each of the individuals involved in the act through one sample. In such cases, it becomes the clinching evidence against the accused, and also helps exonerate those whose samples do not match.
  • DNA can typically be extracted from blood and semen stains on clothes or on the body, from hair and teeth (with roots), and even from bones and flesh if they are not completely charred. Under the Indian criminal justice system, there are broad guidelines on how DNA samples are to be collected from a crime scene. It is vital to ensure that the DNA of the investigators does not get mixed with that of the victims or the suspects. Thus, picking up samples from a crime scene with sterile tools and storing samples in a proper manner are crucial for the evidence to stand a judicial test.
  • And this is where India’s police forces have a lot of catching up to do with counterparts overseas. While central agencies such as the Central Bureau of Investigation (CBI) and the National Investigation Agency (NIA) have found DNA fingerprinting to be very effective, thus ensuring that crime scenes are protected and samples collected by forensic teams, state police forces are yet to be trained in conducting such scientific investigations.
  • “The Aarushi Talwar murder case of 2008 is a prime example. Because the crime scene was not made out of bounds, both police and media trampled all over it. Now the case has no evidence to conclusively establish who killed the 14-year-old girl.
  • Contrast the NIA’s investigation in 2013’s Bodh Gaya blasts, where a Buddhist robe was found abandoned at the crime scene. The agency got a forensic team to pick up strands of hair from the robe these matched with strands from the suspected bomber, Haider Ali, when he was arrested the following year. This has now become the most crucial piece of evidence against him, the case having gone to trial recently.

Way ahead

  • There is a serious paucity of capacity for DNA fingerprinting in the country. While several states have their own forensic labs, DNA fingerprinting is available only at a few places — Maharashtra, West Bengal, Delhi, Hyderabad and Chandigarh. Advanced practices in the technology are limited to the Centre for DNA Fingerprinting and Diagnostics (CDFD) in Hyderabad. There are also several private labs that offer DNA testing, but all work under an unregulated environment, as a law to regulate such institutions has lain in a limbo since 2003.

Question What type of interventions are needed at the part of government to use the tool of DNA profiling in enhancing the capacity of state but without breaching the right to privacy?

2.Plastic waste can be used for decontamination of water (Down to Earth)

Synoptic line: It throws light on the newly developed low-cost magnetic nanomaterial that has the adsorptive potential for cephalexin from the water. (GS paper III)


  • Recycling is the only option to handle plastic waste at present. Now Indian scientists have found a new use for plastic waste – for decontamination of water.

The technology

  • Indian Institute of Toxicology Research, Lucknow have used plastic waste to develop  a low-cost magnetically responsive adsorbent material which can be used to remove an antibiotic cephalexin from water.
  • The indiscriminate burning of plastic results in emission of deadly gases and carcinogens into the environment. Dumping them in landfills results in leaching of toxins into ground and surface water resources. Now scientists have formulated an effective strategy of upcycling polyethylene terephthalate (PET) waste into a functional material to mitigate another critical environmental problem the emerging levels of antibiotics in water.
  • We collected PET refuse from the surroundings and converted the same  into a magnetically responsive carbon nano-material by carbonization and activation of the PET char under controlled conditions and magnetic modification by a simple chemical precipitation route.

Potential solution to problems

  • Extensive use and disposal of pharmaceuticals in the environment is leading to its contamination and increasing antibiotic resistance. Widely used antibiotic, Cephalexin, is detected as micropollutant in the environment.
  • This newly developed low-cost magnetic nanomaterial has the adsorptive potential for cephalexin from the water. The minimal adsorbent dose of 0.4 gram per liter could remove greater than half of the initial cephalexin concentration under laboratory conditions.
  • This technique of magnetic separation for spent adsorbent decreases the secondary pollution problems associated with the non-magneto active adsorbent.

Way ahead

  • The newly developed adsorbents have considerable desorption potential and can be reused. These advantages make it an efficient adsorbent for removal of emerging micropollutants. These findings will prompt to develop more innovative strategies for non-biodegradable waste management.

Question–  What are the innovative methods that can be used to treat the water contamination with sustainable results?