1. VNTRs (Variable Number Tandem Repeats):
VNTRs, also known as minisatellites, are regions of DNA where short nucleotide sequences (typically 10 to 100 base pairs in length) repeat in tandem. What sets VNTRs apart is their variability in the number of repeated units among individuals, making them excellent candidates for DNA fingerprinting and forensic identification. The high mutation rate in VNTRs contributes to their diversity, allowing for unique patterns in each individual's DNA.
Researchers use polymerase chain reaction (PCR) to amplify VNTR regions, enabling the detection of varying lengths of repeats in different individuals. This information aids in establishing genetic profiles for forensic analysis, paternity testing, and population studies.
2. STRs (Short Tandem Repeats):
STRs, also called microsatellites, are another type of repetitive DNA sequence composed of short repeating units (usually 2 to 6 base pairs long). Similar to VNTRs, STRs are highly polymorphic, meaning the number of repeats can differ significantly among individuals. STR analysis has become a standard tool in forensic science due to its accuracy and reliability in identifying individuals and establishing familial relationships.
Forensic experts use PCR to amplify specific STR loci and determine the lengths of repeated units, creating a unique genetic profile. This method has proven invaluable in criminal investigations, disaster victim identification, and ancestry testing
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