Forensics is a very interesting science. It is used to arrest the criminals and is useful in a positive way that it gives information about the paternity of the child whether the child is missing or there is a case of child custody. The science of forensics also plays with DNA to acquire the purpose. There are many technologies of DNA which are used in this field or we can say that the science of forensics is incomplete without DNA.
Polymerase Chain Reaction is a technique of biotechnology which is used to produce several DNA molecules from a single strand of DNA. In this process, restriction enzymes are used to cut the DNA molecule from specific locations and this technique uses the same process of replication for DNA as the process of replication occurs in the cell naturally. DNA taken from the skin cells can also be replicated and observed. PCR allows the identification of DNA molecule with the criminal's DNA molecule.
Mitochondrial DNA Analysis:-
Mitochondria are cell organelle and stores energy for the cell in it. In other words, mitochondria are the energy houses of the cell. Mitochondrial DNA is present inside the mitochondria and even if the sample of evidence degraded, its mitochondrial DNA remains still functional and the sample can still successfully be analyzes and observed by the scientists.
Mitochondrial DNA analysis is performed when,
1) The cases which remained unsolved for many years, mitochondrial DNA technique made it possible to solve them, because the nuclear DNA becomes degraded if they are kept for so long then cases can be solved by observing the mitochondrial DNA. The cases which cannot be solved with RFLP and STR, they can be solved with mtDNA.
2) There are some samples of hair found from the crime scene which do not have roots, those hair cannot be analyzed by STR, that I why mtDNA is used to analyze them.
3) If the samples are the result of some environmental effects like extreme heating, burning or humidity, they can also be analyzed with this technique.
Short Tandem Repeats Analysis:-
Nuclear DNA contains specific regions which are evaluated through Short Tandem repeat technology. This technique is used to identify the required DNA and to differentiate from the other DNA molecules present. FBI with the help of a software CODIS, uses a set of 13 loci of DNA and matches these loci with the criminal's DNA. There is very rare possibility that one person's 13 loci will match with the other person.
Restriction Fragment Length Polymorphism:-
RFLP is a technique of forensics which uses restriction enzymes to cut the DNA molecule from specific locations. It separates these cut DNAs through agarose gel and electrophoresis by determining how many number of fragments are present in the gel. This technique is also useful for tracing the ancestry of the individuals.
It is a fact that father can pass his Y chromosome only to son, that is why if the relationships are to be traced then genetic markers on the Y chromosome are analyzed by the scientists.
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