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The Miracle of DNA Fingerprinting: Why has VNTR become a key tool in criminal investigation?
In today's era of science and technology, DNA fingerprinting can be said to be one of the most revolutionary discoveries. VNTR, or variant number tandem repeat, is an important location in the genome characterized by the short nucleotide sequences it contains, organized in tandem repeats. The length of these repeats can vary between individuals, making VNTRs an effective tool for personal and parent identification.
These mutations not only help scientists with genetic analysis, but also play a key role in forensic science.
Structure and allelic variation of VNTR
The peculiarity of VNTR is that each of its repeated DNA sequences are in the same direction and closely aligned with each other. When the repeating units of a VNTR are removed or added through the process of recombination or copying errors, it results in different numbers of repeats forming different alleles. These VNTR blocks are extracted using restriction enzymes, analyzed by RFLP (restriction fragment length diversity), or enhanced in quantity using polymerase chain reaction (PCR) technology, and finally determined by gel electrophoresis.
Application of VNTR in genetic analysis
With the further advancement of genome sequencing, VNTR has become one of the crucial tools in forensic crime investigation. Through DNA fingerprinting technology, VNTR is able to produce a unique banding pattern for each individual. When tested against a set of independent VNTR markers, the likelihood that two unrelated individuals share the same allele is extremely low, significantly improving identification accuracy in criminal investigations.
In this way, police can quickly and accurately compare DNA samples from the scene to the suspect's database.
VNTR inheritance method
Two key genetic principles are particularly important when analyzing VNTR data. The first is identity matching: the two VNTR alleles from a specific location must match to ensure the sample is from the same individual. Second is inheritance matching: VNTR alleles must follow the rules of inheritance. When confirming the relationship of an individual to his or her parents or children, each sample must obtain the corresponding allele from the parent.
Relationship with other types of repetitive DNA
Repetitive DNA accounts for more than 40% of the human genome, and these repeated structures can present various complex patterns. VNTR belongs to the smaller mini-satellite category, and the length of its repeat sequences is generally between ten and one hundred bases. Compared with microsatellites (usually only 1 to 6 base repeat sequences), VNTR The repeat sequence is much longer.
Types and distribution of VNTR
VNTRs can be divided according to the length of their repeat sequences, with minisatellite repeats ranging from ten to one hundred bases, while microsatellites are shorter. For some types of VHAT mini-satellites, the number of repeats is consistent in all individuals that contain the repeat sequence, which is in clear contrast to the variation characteristics of VNTR.
VNTR analysis is not limited to forensic science, but can also contribute to the study of animal genetic diversity and breeding patterns.
Future Outlook
As DNA fingerprinting technology continues to advance and its application scope expands, VNTR will continue to play an important role in forensic medicine and genetics. Scientists are constantly exploring how to further optimize and expand the application of this technology to deal with increasingly complex cases and challenges. In the future, through more precise genetic analysis methods, such as multi-locus VNTR analysis (MLVA), we have reason to believe that the applications of VNTR will be more diversified and popular.
With the advancement of science and technology and the innovation of experimental techniques, can we further uncover the mysteries of human genes and chart a clearer direction for our future?
