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DNA fingerprinting, or DNA profiling, is a powerful tool for identifying individuals based on their genetic makeup.  

The method involves analyzing specific regions of the DNA that differ greatly among individuals. 

The specific regions of the DNA are highly polymorphic, relating to different forms. This difference makes them ideal for distinguishing one person’s DNA from another’s.    

The process of DNA fingerprinting involves various stages, and we shall discuss them in this blog. Keep reading.  

What Is DNA Fingerprinting 

The technique of DNA fingerprinting, or DNA profiling, is useful in identifying individuals based on their unique genetic makeup. It is also known as genetic fingerprinting.  

The method involves examining specific regions of the DNA that vary significantly among individuals.  

The specific regions of DNA are different in the case of every individual. These regions are highly polymorphic and vary from one individual to another.  

The polymorphic nature of these specific regions makes them ideal for distinguishing among individuals. These regions have a high degree of variability, making distinction easy.  

Various Stages of DNA Fingerprinting  

The process of DNA fingerprinting involves various stages. They facilitate the identification and analysis of genetic makeup for distinction.  

DNA fingerprinting steps are as follows: 

  • Sample Collection – The DNA fingerprinting process involves sample collection for obtaining biological material from a person. The sample can be blood, saliva, hair follicles, or skin cells. The collected sample must contain cells with intact DNA. The collection of blood samples is done using a sterile needle. For the saliva samples, rubbing the insides of the cheek using buccal swabs will obtain the sample. To avoid contamination, it is necessary to use sterile techniques. It is also crucial to store the samples properly, which will preserve the DNA integrity after extraction.   
  • DNA Extraction – The process of DNA extraction for DNA fingerprinting involves DNA isolation from the collected sample. For extracting the DNA, some chemicals are used, which conduct cell lysis for releasing the DNA. For dissolving the cell contents and proteins, several enzymes are added to the mixture. Some salt solution is also added to the mixture to isolate the DNA and separate the cellular debris from it. In the next step, to form precipitation of the DNA, the mixture is treated with alcohol, usually ethanol or isopropanol. The mixing of alcohol leads to the formation of a visible pellet. The pellet is washed and rehydrated in a buffer solution. Rehydration obtains purified DNA. The extraction of pure DNA makes it ready for further analysis.    
  • DNA amplification is done with Polymerase Chain Reaction (PCR). PCR is to target specific DNA regions to produce millions of identical copies of such sequences. DNA amplification involves three main steps, including denaturation, annealing, and extension (using DNA polymerase to synthesize new DNA strands from the primers). Denaturation involves heating the DNA to isolate the strands. In annealing, the DNA cools down, allowing primers to attach to the target sequences. And in the third step, new DNA strands are produced from the primers using DNA polymerase. The steps repeat cyclically several times to amplify the focused DNA regions. Repetitions make them easier to analyze and compare. 
  • DNA Fragmentation – This stage involves cutting the amplified DNA into smaller fragments using restriction enzymes. Restriction enzymes are the molecular scissors that cut DNA into pieces. The enzymes identify specific DNA sequences and bind to them. The location where they bind is known as a restriction site. They make precise cuts at or near these sites. The size and lengths of the fragments vary from one another after cutting, depending on the restriction sites within the DNA.  The process of DNA fragmentation leads to the creation of a unique pattern of DNA sequence in every individual. Due to the uniqueness of the DNA pattern, the identity of an individual is identifiable in forensic and paternity cases.   
  • Gel Electrophoresis – This process enables the separation of DNA fragments according to their size with the help of gel electrophoresis. It involves the application of an electric current, which makes the smaller fragments of DNA move rapidly.The fragments move throughout the gel, forming a distinct pattern of bands.  
  • Analysis – This is the final step which involves the visualization and comparison of band patterns with other DNA samples. The DNA fingerprint analysis will reveal the genetic coding of an individual, which is unique to them. It will be unique even in the case of identical twins.    

Application Of DNA Fingerprinting 

DNA fingerprinting technology is useful in a wide range of applications, which are as follows: 

  • Forensic Science – DNA fingerprinting is a useful tool in forensic science. The technology enables the identification of suspects and victims in criminal investigations.In such cases, the biological sample or evidence is collected from the crime scene, to be matched to the suspect’s DNA. Technology can help resolve criminal cases.  
  • Medicine – The technology can help design personalized medicines to tailor treatments and develop new treatment strategies. It plays a crucial role in diagnosing genetic disorders and identifying carriers of genetic diseases.   
  • Paternity Testing – The technology facilitates the comparison of the DNA profiles of a child and the alleged parent. It can determine biological relationships.  
  • Wildlife Conservation – Wildlife researchers can use this tool to assess genetic diversity within endangered species. It also supports animal breeding.  

DNA Fingerprinting Diagram  

A DNA fingerprinting diagram depicts the unique patterns of DNA sequences after gel electrophoresis.  

The restriction enzymes cut the DNA samples to separate them depending on their size. The process of DNA purification follows.   

The resulting bands are visualized, which creates a distinct pattern for each individual. The pattern can be used further for the identification and comparison in forensic analysis.   

DNA Fingerprinting and Genetic Testing  

Both DNA fingerprinting and genetic testing can help analyze DNA for the identification of genetic differences.  

DNA fingerprinting facilitates individual identification by creating unique DNA patterns. Whereas genetic testing enables the identification of specific genes or markers to diagnose diseases, assess risks, and determine genetic relationships.  

Both these techniques involve DNA analysis to obtain precise and individualized information.   

Conclusion   

The technique of DNA fingerprinting involves a series of various steps, from sample collection to analysis. It enables the creation of a unique genetic profile for everyone.  

The technique is applicable in various fields, including forensic science, paternity testing, and the domain of biological research. It serves as a reliable method for DNA identification and comparison. 

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