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Uncovering the Mystery of DNA Fingerprinting: How Powerful Is This Technology?
The emergence of DNA fingerprinting technology has brought revolutionary changes to criminal investigation and biological research. This technology can not only help the police quickly identify suspects, but also be used in paternity testing, immigration eligibility assessment, and genetic medicine research. play a role in. As technology advances, this technology is becoming more and more powerful, but just how powerful is it?
Historical Background of DNA FingerprintingSince the mid-1970s, advances in science and technology have made DNA a substance that can be used to identify individuals. In 1983, the first patent for the use of DNA mutations for forensic identification appeared, filed by Jeffrey Glassberg of Rockefeller University in the United States. In 1984, British geneticist Alec Jeffreys independently developed DNA fingerprinting technology at the University of Leicester. The birth of this technology has injected new impetus into solving criminal cases. In 1988, this technology was used for the first time in solving the rape and murder of two teenagers in London, directly leading to the release of the innocent and the conviction of the real murderer.
DNA profiling procedures DNA ExtractionExtracting DNA from samples such as blood and saliva is the first step in DNA analysis. This process requires the destruction of cell and nuclear membranes, allowing the DNA to freely dissolve and separate from the rest of the cell. Common extraction methods include organic extraction, Chelex extraction and solid phase extraction. The choice of these methods generally takes into account cost, time and DNA quality.
Restriction fragment length polymorphism (RFLP) analysis
RFLP is a method that uses restriction enzymes to cut DNA for analysis. The method requires extraction, enzymatic digestion, and Southern blotting, which can take several days to a week, depending on the complexity of the sample.
Polymerase chain reaction (PCR) analysis
Polymerase chain reaction, or PCR for short, is an important technology used to amplify specific DNA sequences. The process consists of three main steps: dethrombination, annealing and amplification, which allows even trace amounts of DNA samples to be amplified to amounts that can be analyzed.
Short tandem repeat (STR) analysis
Today's DNA analysis systems are mainly based on PCR and use simple sequence features. The common STR system used in the United States has extremely high statistical recognition capabilities. Its calculations show that the overlap rate of a single DNA sample with other samples in the overall database is extremely small, reaching a probability of one in a thousand.
Y chromosome and mitochondrial analysis
Y chromosome analysis can trace paternal inheritance, while mitochondrial DNA (mtDNA) analysis can be extracted from samples such as hair and ancient bones. These techniques help understand genetic ancestry and its application in criminal investigations.
Challenges of Forensic DNA Samples
For many researchers, analyzing DNA samples is not as simple as it seems in the TV series. In reality, many DNA samples obtained from crime scenes may have degraded. When dealing with degraded samples, condensed DNA can be very fragile, making analysis difficult.
Modern PCR technology has made it possible to analyze degraded samples, an advance that has changed the way evidence is obtained in conflict cases.
The Development of DNA Databases
With the establishment of a DNA database, more solid evidence against suspects can be found. The database contains a large amount of DNA information, which plays a vital role in criminal investigations. Such a database not only helps in finding suspects, but also serves as a warning to increase the risk of innocent people being wrongly convicted.
ConclusionToday's DNA fingerprinting technology is undoubtedly extremely powerful. Whether it is used in criminal investigation, paternity testing or genealogy research, it plays an indispensable role. As technology continues to advance, how will future criminal investigations be shaped by this technology?
