Question

how has the advancements made since 1983 in DNA Testing been used to both convict the guilty and release the innocent?

PS. this is a Forensic Science Question.

Answer 1

DNA testing or DNA fingerprinting as it is commonly known around the world was first introduced by a British Geneticist, Alec Jeffreys. This can be done with any biological sample viz. blood, hair samples with root intact, semen, sweat, body tissue/cells.

There are many types of DNA testing like RFLP, DQ alpha, STR, mitochondrial DNA, etc.

It was mainly used in paternity testing i.e. to resolve issues regarding who is the child's biological parent. This was then further extended to be used in solving other crimes like robbery, theft, etc.

DNA testing helped in following scenarios -

1. whether the person in question was present at the scene of the crime e.g. in case of robbery, murder, whether the convict's biological sample might be present while committing the crime.

2. whether the person in question really committed the crime e.g. assault etc.

3. whether it was committed by a single person or a gang.

DNA testing as previously said also helps in identifying the biological parent in case of a dispute.

Many cases have come forward where the convicts' sample was not present at the crime scene and due to lack of evidence, the person was proved innocence. All thanks to DNA testing.

Many times, when the perpetrator's identity was not available, DNA testing was used to identify the guilty and provide evidence for the courts to decide judgement. This is possible due to the maintenance of an online database system, the CODIS (Combined DNA index system) which helps in identifying the guilty.