Question

Name and describe the steps involved in the technique widely used in forensics that serves as the basis of paternity testing in case of disputes.

Answer 1

DNA fingerprinting is a technology used to do a paternity test to determine the true parents of a newborn infant. This approach is also known as "DNA profiling" since the DNA sequences of both parents and child are matched. To perform the paternity test, the following steps are involved:

1. DNA sample: A DNA sample to be analysed is first collected.
2. Extraction of DNA: DNA is then extracted from the sample by lysis method.
3. Digestion by restriction endonucleases: Using a specific restriction enzyme, a DNA fragment is cut at a specific site. This is done to obtain RFLP (Restricted Fragment Length Polymorphism).
4. Electrophoresis: Using gel electrophoresis, DNA fragments of various sizes are obtained.
5. Denaturing DNA fragments: The gel containing DNA fragments is then immersed in NaOH solution. This will denature DNA into single-stranded DNA.
6. Southern blotting technique: This is performed to transfer single-stranded DNA from the gel onto the nitrocellulose membrane.
7. Hybridization: This DNA fragment is subjected to hybridization with a suitable DNA probe tagged with a radioactive substance.
8. Comparing the sample: Using X-ray films, the DNA samples showing radioactivity are compared. This is the most reliable technique to find the parents of the newborn baby.