DNA Polymorphism

Today DNA Fingerprinting is a necessary tool for varied purposes which uses the DNA uniqueness due to DNA Polymorphism.

What is DNA Fingerprinting?

DNA fingerprinting is a scientific technique used to identify individuals based on their unique genetic profiles.
DNA fingerprinting is a process of identifying individuals based on specific DNA sequences called short tandem repeats (STRs).
It is used for establishing genetic relationships, criminal investigations, and forensic identification.
DNA fingerprints can be obtained from various biological samples such as blood, saliva, sweat, semen, skin cells, bones, and teeth.
DNA fingerprinting is highly reliable, as every person (except identical twins) has a unique DNA profile.

DNA polymorphisms are small variations in DNA sequences that differentiate individuals.
These variations occur due to differences in inherited DNA from both parents.
They are essential for tracing ancestry, identifying individuals, and understanding genetic diversity.

Arises from mutations like SNPs (Single Nucleotide Polymorphisms) and VNTRs (Variable Number Tandem Repeats).
Involves genetic variations in non-coding and coding regions of DNA.
Affects gene expression, protein function, and phenotype variability.
Can result from genetic recombination, replication errors, or environmental factors.

Enhances genetic diversity, enabling species to adapt to changing environments.
Plays a crucial role in natural selection and evolutionary fitness.
Helps trace ancestry and evolutionary relationships among populations.
Aids in understanding disease susceptibility and resistance in different genetic groups.

STRs are repetitive DNA sequences that vary in length between individuals.
Each STR consists of short repeating units of DNA bases (A, T, G, C).
These variations in repeat numbers at specific locations form the basis of DNA fingerprinting.
STR analysis is commonly used in criminal investigations and genetic identification.

Aspect	DNA Copying (PCR Process)	DNA Fingerprinting
Definition	A technique used to amplify (make multiple copies of) a specific DNA sequence.	A technique used to identify individuals based on unique DNA patterns.
Purpose	To generate multiple copies of DNA for research, diagnosis, and forensic analysis.	To establish identity, verify biological relationships, and solve forensic cases.
Key Process	Polymerase Chain Reaction (PCR).	STR analysis and Capillary Electrophoresis.
Steps Involved	Denaturation (95°C): DNA strands separate. Annealing (60°C): DNA primers bind. Extension (72°C): DNA polymerase synthesizes new strands.	DNA extraction from samples (blood, saliva, etc.) STR amplification via PCR Separation of DNA fragments via Capillary Electrophoresis Creation of a unique DNA profile.
End Product	Millions of identical copies of a specific DNA segment.	A unique DNA pattern (fingerprint) for an individual.
Use in Forensics	Used to amplify DNA from crime scene samples before analysis.	Used to compare DNA from a crime scene to a suspect’s DNA.
Use in Medicine	Helps in disease diagnosis and genetic research.	Helps in organ transplant compatibility and hereditary disease identification.
Data Output	Large amounts of identical DNA for further study.	A unique STR profile that distinguishes individuals.

Forensic Science: Identifies criminals using DNA evidence from crime scenes.
Paternity Testing: Establishes biological relationships.
Disaster Victim Identification: Helps identify mortal remains.
Medical Applications: Assists in organ transplantation compatibility.
Exoneration of Wrongly Accused Individuals: Used in retrials and cold case investigations.

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