DNA Fingerprinting - Definition, Steps, Examples, Applications & Facts

DNA Fingerprinting - Definition, Principle, Steps, Applications & Diagram

Edited By Irshad Anwar | Updated on Jul 02, 2025 05:52 PM IST

“DNA fingerprinting is a technique that shows the genetic makeup of living things. It is a method of finding the difference between the satellite DNA regions in the genome.” DNA fingerprinting is a technique used to identify individuals based on their unique genetic makeup. It involves analyzing specific regions of the DNA that vary between individuals, making it possible to distinguish one person from another. Being part Biotechnology chapter class 12th Biology it becomes important from an examination perspective.

This Story also Contains

What is DNA Fingerprinting?
Principles of DNA Fingerprinting
DNA Fingerprinting Steps
Methods of DNA Fingerprinting
DNA Fingerprinting Applications
Recommended Video for DNA Fingerprinting

DNA Fingerprinting - Definition, Principle, Steps, Applications & Diagram

What is DNA Fingerprinting?

DNA Fingerprinting, also known as DNA Profiling, is a procedure that reveals the genetic makeup of any living organism. Differentiation of one person from another is made through variations in their satellite DNA regions. This has brought a revolutionary change in the field of modern science, particularly in forensic and genetic studies.

DNA fingerprinting was first discovered in the 1980s. In 1984, the British geneticist Dr Alec Jeffreys discovered a novel breakthrough technique; eventually, it created a powerful tool for genetic identification and analysis.

DNA fingerprinting is vital in many applications and areas, including forensic science and paternity testing. It is highly applied in the disclosure of crime scenes, diagnosis of genetic diseases, and understanding of biological evolution.

Also Read:

Principles of DNA Fingerprinting

Genetic Uniqueness

NEET Highest Scoring Chapters & Topics

Know Most Scoring Concepts in NEET 2024 Based on Previous Year Analysis.

Know More

DNA fingerprinting is based on the fact that every person, except for identical twins, will have a unique DNA sequence.

Polymorphic Regions in DNA

DNA has very polymorphic regions, for instance, Short Tandem Repeats (STRs) and Variable Number Tandem Repeats (VNTRs), that exhibit great differences among individuals and are, therefore, hyper-informative for genetic identification.

Structure of STRs and VNTRs

Structure of STRs and VNTRs

DNA Fingerprinting Steps

Sample Collection

DNA could be extracted from blood, hair, saliva, and skin cells, amongst others. Care should always be taken to ensure the cleanliness and purity of the sample for the best results.

Isolation of DNA

DNA extraction from preserved samples did not distort or contaminate the sample in any way.

DNA Extraction Process

DNA Extraction Process

Digestion of DNA by Restriction Endonucleases

Restriction enzymes work on cutting DNA at precise recognition sites, thereby creating a specific pattern of DNA fragments. The DNA fingerprint is then composed of these fragments.

The action of Restriction Endonucleases on DNA

Action of Restriction Endonucleases on DNA

Separation of DNA Fragments by Electrophoresis

DNA fragments are sorted by size using agarose gel electrophoresis and an electric field. This step images the DNA bands.

Gel Electrophoresis Setup

Gel Electrophoresis Setup

Transferring (Blotting) Separated DNA Fragments to Synthetic Membranes

The DNA fragments are transferred from the gel onto a nylon or nitrocellulose membrane in preparation for hybridisation.

Blotting Process

Blotting Process

Hybridisation Using Labelled VNTR Probe

The transferred membrane strands of DNA are exposed to labelled DNA probes, which are complementary to the known DNA sequences to be measured. The unique DNA patterns are thus highlighted.

Hybridization Process

Hybridization Process

Detection of Hybridised DNA Fragments by Autoradiography

Autoradiography exposes the radiolabeled DNA probes to the separated fragments of DNA on the membrane, revealing unique DNA band patterns for different individuals.

Autoradiography Process

Autoradiography Process

Methods of DNA Fingerprinting

The methods of DNA fingerprinting are described below:

Restriction Fragment Length Polymorphism (RFLP)

RFLP studies the variability in the lengths of DNA fragments digested by restriction enzymes. This technique, although not in use so frequently at present, was one of the earliest methods of DNA profiling.

Steps in RFLP Analysis

Steps in RFLP Analysis

Polymerase Chain Reaction (PCR)

PCR helps to amplify desired DNA fragments, making it possible to look for analysis in very small amounts of DNA. PCR is a popular technique, as it is fast and very sensitive.

Diagram: PCR Process

PCR Process

Short Tandem Repeats (STR) Analysis

STR analysis is the most commonly used technique at present for DNA fingerprinting. It studies only specific areas of DNA that show hypervariability between individuals.

Diagram: STR Profiling

STR Profiling

Mitochondrial DNA Analysis

Mitochondrial DNA analysis is used for studying ancient DNA and tracing the maternal lineage. It can often be the only source of DNA in forensic applications due to the lack of nuclear DNA.

Diagram: Mitochondrial DNA Structure

1723440986572

DNA Fingerprinting Applications

Forensic Science

It is an essential technique in forensic science for use in crime scene investigations and paternity testing.

Diagram: Use of DNA Fingerprinting in Crime Scenes

DNA Fingerprinting in Crime Scenes

Medical Applications

It is involved in the clinical diagnosis of genetic diseases and matching tissues for transplants to develop a personalized medicine system.

Biological Research

In evolutionary biology and population genetics, DNA fingerprinting studies genetic variability and the evolutionary relationship among species.

Advantages and Limitations of DNA Fingerprinting

High Accuracy and Reliability - DNA fingerprinting has the highest precision and reliability and is therefore useful in almost every field.
Non-invasive and Rapid- The technique can be done with high speed and noninvasively, only with a small sample.

Also Read:

Recombinant DNA Technology	Biopiracy
Biotechnology Application in Medicine	Biotechnology in Agriculture
Bioremediation	Biosafety Issues

Recommended Video for DNA Fingerprinting

Frequently Asked Questions (FAQs)

1. What is DNA fingerprinting?

DNA fingerprinting is the process of identifying the individual by looking at the unique DNA sequence.

2. What is DNA fingerprinting?

DNA fingerprinting is a technique used to identify and compare individuals based on their unique DNA patterns. It analyzes specific regions of DNA that vary between individuals, creating a "genetic fingerprint" that is highly specific to each person.

3. How is DNA fingerprinting used in forensic science?

The technique is used to match DNA samples found at crime scenes to suspects, thereby assisting criminal investigations.

4. What are the key methods of DNA fingerprinting?

Key methods to be used comprise RFLP, PCR, STR analysis, and mitochondrial DNA analysis.

5. What are the advantages of DNA fingerprinting?

The advantages are high accuracy, reliability, and the ability to analyze small samples.

6. What ethical issues are associated with DNA fingerprinting?

Ethical issues stem from privacy concerns and possibly misusing genetic information.

7. Can DNA fingerprinting be used to determine familial relationships?

Yes, DNA fingerprinting can determine familial relationships. Since children inherit DNA from both parents, their genetic profiles will show similarities to their biological parents and siblings, allowing for paternity testing and family relationship verification.

8. What are the main applications of DNA fingerprinting in forensic science?

In forensic science, DNA fingerprinting is used to identify suspects, link criminals to crime scenes, exonerate wrongly accused individuals, identify human remains, and solve cold cases by analyzing old evidence with new technology.

9. How is DNA fingerprinting used in wildlife conservation?

In wildlife conservation, DNA fingerprinting helps track endangered species, identify illegal wildlife products, study population genetics, and even trace the origin of poached animals, aiding in the protection and management of wildlife.

10. What ethical concerns are associated with DNA fingerprinting?

Ethical concerns include privacy issues, potential misuse of genetic information, the reliability of DNA evidence in court, and the creation of DNA databases. There are also concerns about genetic discrimination and the potential for false incrimination.

11. How accurate is DNA fingerprinting?

DNA fingerprinting is highly accurate, with a probability of a random match typically less than one in several billion. However, the accuracy can depend on the number of DNA markers analyzed and the quality of the sample.

12. What are the main steps involved in DNA fingerprinting?

The main steps in DNA fingerprinting are: 1) DNA extraction from a biological sample, 2) DNA amplification using PCR, 3) Cutting DNA into fragments using restriction enzymes, 4) Separating DNA fragments by size using gel electrophoresis, 5) Transferring DNA to a membrane (Southern blotting), 6) Probing for specific DNA sequences, and 7) Visualizing and analyzing the results.

13. How long does it take to perform DNA fingerprinting?

The time required for DNA fingerprinting can vary depending on the method used and the complexity of the sample. With modern techniques, results can be obtained in as little as 24-48 hours, but more complex cases may take several days to weeks.

14. How has DNA fingerprinting technology evolved since its discovery?

DNA fingerprinting has evolved from using RFLP analysis, which required large amounts of DNA, to PCR-based methods that can work with minute samples. Modern techniques use automated sequencing and can analyze multiple DNA markers simultaneously, increasing speed and accuracy.

15. Can DNA fingerprinting be performed on degraded or old samples?

Yes, DNA fingerprinting can often be performed on degraded or old samples, thanks to PCR technology which can amplify even small amounts of DNA. However, the quality of results may be affected, and special techniques might be needed for highly degraded samples.

16. What is the role of DNA databases in fingerprinting?

DNA databases store genetic profiles from various sources, including convicted criminals, crime scene evidence, and sometimes voluntary contributors. They allow for rapid comparison of DNA profiles, helping to solve crimes and identify individuals.

17. What types of biological samples can be used for DNA fingerprinting?

DNA fingerprinting can be performed using various biological samples, including blood, saliva, hair follicles, skin cells, and even bone or tooth samples. Only a small amount of DNA is needed for analysis.

18. What is PCR, and why is it important in DNA fingerprinting?

PCR (Polymerase Chain Reaction) is a technique used to amplify small amounts of DNA. It's crucial in DNA fingerprinting because it allows scientists to create millions of copies of specific DNA regions, making analysis possible even with tiny or degraded samples.

19. What is gel electrophoresis, and how does it contribute to DNA fingerprinting?

Gel electrophoresis is a technique used to separate DNA fragments based on their size. In DNA fingerprinting, it helps create a visual pattern of DNA bands that can be compared between samples, contributing to the unique "fingerprint" for each individual.

20. How does restriction fragment length polymorphism (RFLP) analysis work in DNA fingerprinting?

RFLP analysis involves cutting DNA at specific sites using restriction enzymes. The resulting fragments vary in length between individuals due to genetic variations. These fragments are then separated and analyzed, creating a unique pattern that forms the basis of the DNA fingerprint.

21. What are Short Tandem Repeats (STRs), and why are they important in DNA fingerprinting?

STRs are repeated sequences of 2-6 base pairs in DNA. They're important in DNA fingerprinting because the number of repeats varies greatly between individuals, making them highly useful for creating unique genetic profiles.

22. What is the basic principle behind DNA fingerprinting?

The principle behind DNA fingerprinting is that certain regions of DNA (called Variable Number Tandem Repeats or VNTRs) vary in length between individuals. By analyzing these regions, scientists can create a unique genetic profile for each person.

23. How does DNA fingerprinting differ from traditional fingerprinting?

Unlike traditional fingerprinting that relies on physical patterns on fingertips, DNA fingerprinting examines genetic material. It's more accurate, can be performed with minimal biological samples, and can identify individuals even when traditional fingerprints are unavailable.

24. What is the difference between nuclear DNA and mitochondrial DNA fingerprinting?

Nuclear DNA fingerprinting analyzes DNA from the cell nucleus, which is inherited from both parents. Mitochondrial DNA fingerprinting examines DNA from mitochondria, which is inherited only from the mother. Mitochondrial DNA is often used when nuclear DNA is degraded or unavailable.

25. Can DNA fingerprinting be used to predict a person's physical characteristics?

While traditional DNA fingerprinting doesn't predict physical traits, advanced genetic analysis techniques can provide some information about physical characteristics like eye color, hair color, and ancestry. This field, known as forensic phenotyping, is still developing and has limitations.

26. How does DNA fingerprinting contribute to paternity testing?

In paternity testing, DNA fingerprints of the child, mother, and alleged father are compared. Since a child inherits half of their DNA from each parent, the child's DNA fingerprint should show a 50% match with each biological parent, allowing for determination of paternity.

27. What is the difference between DNA fingerprinting and DNA profiling?

The terms are often used interchangeably, but DNA profiling typically refers to the broader process of analyzing genetic markers for identification purposes. DNA fingerprinting specifically refers to the technique of creating a visual representation of an individual's DNA pattern.

28. Can identical twins be distinguished by DNA fingerprinting?

Traditional DNA fingerprinting cannot distinguish between identical twins as they share the same DNA. However, advanced techniques that look at epigenetic modifications or rare mutations that occur after fertilization can potentially differentiate between identical twins.

29. What are the limitations of DNA fingerprinting?

Limitations include the need for a sufficient quantity and quality of DNA, the possibility of contamination, the potential for human error in analysis, and the fact that it can't determine when DNA was deposited at a crime scene. It also can't distinguish between identical twins using standard methods.

30. How does DNA fingerprinting contribute to personalized medicine?

While DNA fingerprinting itself isn't used in personalized medicine, the underlying principles and technologies contribute to genetic testing that can identify disease risks, predict drug responses, and tailor treatments to an individual's genetic profile.

31. What is the importance of chain of custody in DNA fingerprinting for legal cases?

Chain of custody refers to the documentation of the movement and handling of evidence from collection to analysis. It's crucial in legal cases to ensure the integrity of DNA evidence, preventing contamination or tampering that could invalidate the results in court.

32. How does DNA fingerprinting contribute to anthropological studies?

In anthropology, DNA fingerprinting helps study human migration patterns, trace ancestral lineages, and understand genetic diversity among populations. It can provide insights into historical human movements and relationships between different ethnic groups.

33. How does DNA fingerprinting help in identifying victims of mass disasters?

In mass disasters, DNA fingerprinting can help identify victims when other methods (like visual identification) are impossible. By comparing DNA from recovered remains to DNA from family members or personal effects, authorities can make identifications even with fragmented remains.

34. What is the role of bioinformatics in DNA fingerprinting?

Bioinformatics plays a crucial role in DNA fingerprinting by providing tools for analyzing and interpreting complex genetic data. It helps in managing large DNA databases, developing algorithms for pattern matching, and improving the accuracy of DNA profile comparisons.

35. What is the difference between autosomal and Y-chromosome DNA fingerprinting?

Autosomal DNA fingerprinting analyzes DNA from non-sex chromosomes and can be used for any individual. Y-chromosome DNA fingerprinting specifically examines the Y chromosome, which is passed from father to son, and is useful for tracing paternal lineages or in cases where only male DNA is relevant.

36. How does DNA fingerprinting contribute to plant and animal breeding programs?

In breeding programs, DNA fingerprinting helps identify and select individuals with desirable genetic traits, verify the purity of breeding lines, and track the inheritance of specific genes. This accelerates the development of improved crop varieties and animal breeds.

37. What is the role of DNA fingerprinting in detecting genetically modified organisms (GMOs)?

DNA fingerprinting techniques can be used to detect and identify GMOs by looking for specific genetic sequences that have been introduced. This is important for regulatory compliance, food labeling, and monitoring the spread of genetically modified crops.

38. How does DNA methylation affect DNA fingerprinting results?

DNA methylation, an epigenetic modification, doesn't typically affect standard DNA fingerprinting results as it doesn't change the DNA sequence. However, methylation patterns can be analyzed separately to provide additional information, such as determining the age of a sample or distinguishing between identical twins.

39. What is the significance of allele frequency in DNA fingerprinting?

Allele frequency refers to how common certain genetic variants are in a population. Understanding allele frequencies is crucial for calculating the probability of a DNA match occurring by chance, which is important when presenting DNA evidence in court.

40. How does DNA fingerprinting contribute to the study of evolutionary biology?

DNA fingerprinting techniques allow scientists to compare genetic similarities between species, track genetic changes over time, and reconstruct evolutionary relationships. This helps in understanding speciation, adaptation, and the genetic basis of evolution.

41. What is the role of DNA fingerprinting in agriculture and food safety?

In agriculture and food safety, DNA fingerprinting is used to verify the authenticity of food products, detect food fraud, trace the origin of contaminated foods during outbreaks, and ensure the genetic purity of seeds and livestock.

42. How does DNA fingerprinting contribute to conservation genetics?

In conservation genetics, DNA fingerprinting helps assess genetic diversity within endangered populations, identify distinct subspecies or populations for protection, detect inbreeding, and guide breeding programs to maintain genetic health in small populations.

43. What is the difference between STR and SNP-based DNA fingerprinting?

STR (Short Tandem Repeat) fingerprinting looks at the number of repeats in specific DNA regions, while SNP (Single Nucleotide Polymorphism) fingerprinting examines single base pair variations. SNP analysis can provide more detailed genetic information but requires more advanced technology.

44. How does DNA fingerprinting contribute to the study of human migration and population genetics?

DNA fingerprinting techniques allow researchers to trace human migration patterns by comparing genetic markers across populations. This helps reconstruct historical movements, understand genetic diversity, and study how populations have mixed over time.

45. What is the role of DNA fingerprinting in intellectual property protection for biotechnology?

In biotechnology, DNA fingerprinting can be used to protect intellectual property by uniquely identifying genetically modified organisms, cell lines, or other biological inventions. This helps in patent applications and in detecting unauthorized use of proprietary genetic material.

46. How does contamination affect DNA fingerprinting results, and how is it prevented?

Contamination with foreign DNA can lead to false or inconclusive results. It's prevented through strict laboratory protocols, use of protective equipment, regular cleaning, and negative controls. Advanced techniques can also sometimes distinguish between sample DNA and contaminants.

47. What is the importance of population databases in DNA fingerprinting?

Population databases contain DNA profiles from various populations. They're crucial for calculating the statistical significance of a DNA match, understanding the distribution of genetic markers in different groups, and ensuring the accuracy of DNA evidence in diverse populations.

48. How does DNA fingerprinting contribute to the field of pharmacogenomics?

While not directly used in pharmacogenomics, DNA fingerprinting technologies contribute to identifying genetic variations that influence drug responses. This helps in developing personalized medication strategies based on an individual's genetic profile.

49. What is the role of DNA fingerprinting in studying the human microbiome?

DNA fingerprinting techniques are used to identify and characterize the diverse microorganisms in the human microbiome. This helps in understanding the composition of microbial communities, their impact on health, and how they vary between individuals or populations.

50. How does DNA fingerprinting contribute to the study of ancient DNA and paleogenetics?

In paleogenetics, DNA fingerprinting techniques are adapted to analyze highly degraded DNA from ancient specimens. This allows scientists to study the genetics of extinct species, trace human evolution, and understand historical population dynamics.

51. What is the significance of mitochondrial DNA in forensic DNA fingerprinting?

Mitochondrial DNA is useful in forensics because it's abundant in cells and can often be recovered from degraded samples. It's inherited maternally, making it valuable for tracing maternal lineages and identifying remains when nuclear DNA is unavailable.

52. How does DNA fingerprinting contribute to the field of nutrigenomics?

While not directly used in nutrigenomics, DNA fingerprinting technologies contribute to identifying genetic variations that influence nutrient metabolism and dietary responses. This helps in developing personalized nutrition strategies based on an individual's genetic profile.

53. What is the role of DNA fingerprinting in studying the genetics of behavior?

DNA fingerprinting techniques are used to identify genetic markers associated with behavioral traits. While behavior is complex and influenced by many factors, these studies help understand the genetic components of personality, mental health conditions, and cognitive abilities.

54. How does DNA fingerprinting contribute to the study of epigenetics?

While traditional DNA fingerprinting doesn't directly study epigenetics, related techniques can analyze epigenetic modifications like DNA methylation. This helps in understanding how environmental factors affect gene expression without changing the DNA sequence.

55. What is the future of DNA fingerprinting technology?

The future of DNA fingerprinting likely involves faster, more portable technologies for rapid on-site analysis, increased integration with other biometric data, more comprehensive genetic analysis beyond just identification, and the ability to extract more information from smaller or more degraded samples. Ethical considerations and privacy protections will continue to be important as the technology advances.