Question

How is DNA used to help solve crimes?

Answer 1

DNA is an investigative tool in the field of forensic science or DNA forensic and it is used in a criminal investigation as it is one of the important factors in solving the criminal case, parentage testing, medical research, etc.

Complete answer:
DNA which stands for Deoxyribonucleic acid is an essential building block of the body’s cells. Each individual is having a unique DNA. DNA is composed of four chemical bases which are adenine (A), guanine (G), cytosine (C), and thymine (T). DNA bases are organized and sequenced in an organism’s genome, which is a kind of genetic blueprint that provides cells with the information needed to build an organism. Each cell in the body contains a nucleus that holds chromosomes and DNA molecules make up these chromosomes.

DNA profiling or DNA fingerprinting is a process used to determine the nucleotide sequence at a particular part of the DNA that is based on their unique genetic makeup in all human beings. This means this process can be used in solving crimes. Forensic scientists or experts can compare the DNA found at a crime scene (i.e. from blood or hair, semen, saliva, etc.) to DNA samples taken from the suspects. DNA molecules collected from the evidence sample can be compared with the VNTR (variable number of tandem repeats) prototype any piece of DNA sample found at the crime scene can be analyzed for the level of polymorphism in the non-coding repetitive sequences, as every individual contains a distinct number of VNTR which is the basic principle of this DNA fingerprinting technique.

Note: The process of DNA fingerprinting was discovered by Sir Alec Jeffrey, and in this technique, he used satellite DNAs also known as VNTRs as a probe because it showed a high level of polymorphism.