DNA fingerprinting is a technique that can identify individuals based on their unique genetic code. In this blog, I will explain what DNA fingerprinting is, how it works, and what are some of its applications and limitations. DNA fingerprinting can be used for various purposes, such as solving crimes, identifying relatives, tracing ancestry, and diagnosing diseases. However, it also raises some ethical and social issues, such as privacy, consent, and discrimination. By reading this blog, you will learn more about this fascinating and controversial topic.

DNA FINGERPRINTING


DNA fingerprinting is a technique that identifies individuals based on their unique genetic code. It is also known as DNA profiling, DNA typing, or genetic fingerprinting. DNA fingerprinting can be used for various purposes, such as solving crimes, establishing paternity, identifying victims of disasters, tracing ancestry, and detecting genetic diseases. 

DNA fingerprinting works by analysing specific regions of DNA that vary among individuals. These regions are called DNA markers or loci. There are different types of DNA markers, such as short tandem repeats (STRs), single nucleotide polymorphisms (SNPs), and variable number tandem repeats (VNTRs). Each individual has a specific pattern of DNA markers that can be compared to other individuals or to a database of known profiles.

To perform DNA fingerprinting, a sample of biological material, such as blood, saliva, hair, or skin, is collected from the individual or the scene of interest. The DNA is extracted from the sample and amplified using a technique called polymerase chain reaction (PCR). The amplified DNA is then separated by size using a technique called gel electrophoresis. The resulting pattern of bands on the gel is called a DNA fingerprint or profile. The DNA fingerprint can be visualized using various methods, such as staining, labeling, or hybridization.

DNA fingerprinting is a powerful tool that can provide conclusive evidence in many cases. However, it also has some limitations and challenges, such as contamination, degradation, interpretation, and ethical issues. Therefore, DNA fingerprinting should be performed with caution and accuracy, and the results should be interpreted with care and context.

PROCESS OF DNA FINGERPRINTING:


DNA fingerprinting is a technique that identifies the unique genetic profile of an individual. It is based on the fact that every person inherits a set of DNA sequences from their parents, and these sequences vary among individuals. DNA fingerprinting can be used for various purposes, such as paternity testing, forensic analysis, genetic counseling, and medical diagnosis.

The process of DNA fingerprinting involves several steps:

- First, a sample of DNA is obtained from the person, such as blood, saliva, hair, or skin cells.
- Second, the DNA is extracted and purified from the sample using chemical and enzymatic methods.
- Third, the DNA is cut into smaller fragments using special enzymes called restriction endonucleases. These enzymes recognize specific sequences of DNA and cut them at those sites. The resulting fragments are called restriction fragments.
- Fourth, the restriction fragments are separated by size using a technique called gel electrophoresis. This technique involves applying an electric current to a gel matrix that contains the DNA fragments. The smaller fragments move faster than the larger ones, creating a pattern of bands on the gel.
- Fifth, the pattern of bands on the gel is transferred to a membrane using a technique called Southern blotting. This technique involves soaking the gel in a solution that denatures the DNA, making it single-stranded. Then, the membrane is placed on top of the gel and heated, allowing the DNA to bind to the membrane.
- Sixth, the membrane is exposed to a radioactive or fluorescent probe that binds to a specific sequence of DNA. The probe is usually designed to target a region of DNA that is highly variable among individuals, such as a microsatellite or a minisatellite. These regions are also called variable number tandem repeats (VNTRs), because they consist of repeated units of DNA that vary in number and length among individuals.
- Seventh, the membrane is placed on a film or a scanner that detects the signal from the probe. The signal reveals the presence and location of the probe-bound DNA fragments on the membrane. The resulting image is called a DNA fingerprint or a DNA profile. It shows a series of bands that correspond to the size and number of VNTRs in the person's DNA.
- Finally, the DNA fingerprint can be compared with other fingerprints to determine the degree of similarity or difference among individuals. For example, if two fingerprints have identical bands at every position, they belong to the same person or to identical twins. If two fingerprints have some bands in common and some bands different, they belong to related individuals who share some common ancestors. If two fingerprints have no bands in common, they belong to unrelated individuals who have no genetic relationship.

USES OF DNA FINGERPRINTING:


DNA fingerprinting is a technique that identifies the unique genetic profile of an individual. It can be used for various purposes, such as:

- Forensic science: DNA fingerprinting can help solve crimes by matching the DNA found at a crime scene to a suspect or a victim. It can also help exonerate innocent people who have been wrongly convicted.
- Paternity testing: DNA fingerprinting can determine the biological father of a child by comparing the DNA of the child and the potential father. It can also help establish family relationships for immigration or inheritance purposes.
- Medical diagnosis: DNA fingerprinting can help diagnose genetic diseases or disorders by detecting mutations or variations in the DNA of a patient. It can also help identify the risk of developing certain diseases or passing them on to offspring.
- Conservation biology: DNA fingerprinting can help protect endangered species by monitoring their population size, genetic diversity and mating patterns. It can also help identify poachers or illegal traders of wildlife products by tracing the origin of the DNA samples.

DNA FINGERPRINTING EXAMPLES:

DNA fingerprinting is a technique that uses the unique patterns of DNA sequences in an individual's genome to identify them. DNA fingerprinting can be used for various purposes, such as:

- Forensic science: DNA fingerprinting can help solve crimes by matching DNA samples from crime scenes to suspects or victims. For example, DNA fingerprinting was used to identify the remains of the Romanov family, the last imperial dynasty of Russia, who were executed in 1918.
- Paternity testing: DNA fingerprinting can determine the biological father of a child by comparing the child's DNA to the potential father's DNA. For example, DNA fingerprinting was used to confirm that Prince Harry is the son of Prince Charles and Princess Diana, and not James Hewitt, a former lover of Diana.
- Medical diagnosis: DNA fingerprinting can diagnose genetic diseases or predispositions by detecting mutations or variations in certain genes. For example, DNA fingerprinting can identify carriers of cystic fibrosis, a hereditary disorder that affects the lungs and digestive system.
- Biodiversity conservation: DNA fingerprinting can help protect endangered species by assessing their genetic diversity and population structure. For example, DNA fingerprinting can monitor the genetic health of pandas, which are threatened by habitat loss and poaching.

DNA fingerprinting is a technique that can identify individuals based on their unique genetic code. DNA fingerprinting can be used for various purposes, such as paternity testing, forensic analysis, medical diagnosis, and biodiversity studies. Some examples of DNA fingerprinting are:

- In 1987, DNA fingerprinting was used for the first time in a criminal case in the UK, where it helped to convict a rapist and murderer who had left his semen on the victims.
- In 1993, DNA fingerprinting was used to confirm the identity of the remains of the last Russian tsar, Nicholas II, and his family, who were executed by the Bolsheviks in 1918.
- In 2003, DNA fingerprinting was used to identify the SARS-CoV virus, which caused a global outbreak of severe acute respiratory syndrome (SARS).
- In 2010, DNA fingerprinting was used to determine the ancestry of Barack Obama, the former US president, who was found to have African, European, and Native American roots.
- In 2019, DNA fingerprinting was used to create a facial reconstruction of a Neanderthal woman, who lived about 50,000 years ago in Croatia.

DNA PROFILING:


DNA profiling is a technique that analyses the genetic material of an individual to identify them or determine their biological relationships. DNA profiling can be used for various purposes, such as forensic investigations, paternity testing, medical diagnosis, genealogy, and ancestry tracing. DNA profiling is based on the fact that each person inherits a unique combination of DNA segments from their parents, and that these segments vary among different populations and individuals. DNA profiling involves extracting DNA from a biological sample, such as blood, saliva, hair, or bone, and then amplifying specific regions of the DNA using a method called polymerase chain reaction (PCR). The amplified DNA regions are then compared to a reference database or another sample to find matches or differences. DNA profiling can provide reliable and accurate evidence in criminal cases, as well as reveal important information about a person's health and heritage.

DNA IDENTIFICATION:


DNA identification is a process of determining the genetic identity of an individual or a species based on their DNA sequence. DNA identification can be used for various purposes, such as forensic investigation, paternity testing, ancestry tracing, wildlife conservation, and genetic diagnosis. DNA identification relies on the fact that each individual or species has a unique DNA sequence that can be distinguished from others by using molecular techniques. Some of the common methods of DNA identification are:

- Polymerase chain reaction (PCR): This method amplifies a specific region of DNA from a small sample, such as blood, hair, or saliva. The amplified DNA can then be analysed by using gel electrophoresis, sequencing, or hybridization.
- Restriction fragment length polymorphism (RFLP): This method cuts the DNA into fragments using enzymes called restriction endonucleases. The fragments are then separated by size using gel electrophoresis and compared with a reference sample.
- Short tandem repeat (STR): This method focuses on regions of DNA that contain repeated sequences of two to six nucleotides. The number of repeats varies among individuals and can be used to generate a DNA profile.
- Single nucleotide polymorphism (SNP): This method detects variations in single nucleotides in the DNA sequence. SNPs can be used to identify genetic markers associated with certain traits or diseases.


GEL ELECTROPHORESIS DNA FINGERPRINTING:

Gel electrophoresis is a technique that separates molecules based on their size and charge. DNA fingerprinting is a method that uses gel electrophoresis to identify individuals based on their unique DNA sequences. In this article, we will explain how gel electrophoresis and DNA fingerprinting work, and how they can be used for various applications.

Gel electrophoresis involves applying an electric current to a gel matrix that contains the molecules of interest. The gel matrix is usually made of agarose, a polysaccharide derived from seaweed, or polyacrylamide, a synthetic polymer. The gel matrix acts as a sieve that allows smaller and more negatively charged molecules to move faster and farther than larger and less negatively charged molecules. The molecules are stained with a dye that makes them visible under ultraviolet light.

DNA fingerprinting uses gel electrophoresis to compare the DNA samples of different individuals. DNA is a long molecule that consists of four types of nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G). The sequence of nucleotides determines the genetic information of an organism. However, not all regions of DNA are equally informative. Some regions are highly variable among individuals, while others are highly conserved. These variable regions are called polymorphic regions, and they can be used as markers to distinguish individuals.

One type of polymorphic region is called a short tandem repeat (STR). An STR is a sequence of 2 to 6 nucleotides that is repeated several times in a row. For example, an STR could be AGATAGATAGAT. The number of repeats varies among individuals, and can be used as a fingerprint. To perform DNA fingerprinting using STRs, the DNA samples are first extracted from cells, such as blood, saliva, or hair. Then, the DNA samples are amplified using a technique called polymerase chain reaction (PCR), which makes many copies of specific regions of DNA. Next, the amplified DNA samples are cut with restriction enzymes, which are proteins that recognize and cut specific sequences of DNA. This results in fragments of different sizes that correspond to different STRs. Finally, the fragments are separated by gel electrophoresis and compared by their size and pattern.

Gel electrophoresis and DNA fingerprinting have many applications in fields such as forensic science, paternity testing, medical diagnosis, genetic engineering, and evolutionary biology. They can help identify suspects or victims of crimes, determine biological relationships, diagnose genetic diseases, create transgenic organisms, and trace evolutionary relationships.