Introduction
In today's age, hundreds of foreign secretaries in both public and private sectors, alongside paternity as well as maternity testing laboratories, utilize 10000 DNA (deoxyribonucleic acid) test computer databases with DNA profiles compiled from all sorts of profiles available.
Other than just punishing the guilty, forensic DNA testing has a bigger scope. A piece of DNA has also been helpful in saving the innocent from the blame for crimes they have not committed. They were reports where the innocent were wrongfully convicted due to fake evidence before forensic DNA testing was implemented. In the early 1980s, genetic fingerprinting for the identification of humans began. As the efficiency and reliability of the scientific method of DNA printing increased, police work in identifying the majority of criminal cases became easy. DNA is a powerful human identification tool, and hence methods for testing and evaluating along with characterizing a person's DNA or DNA from a sample are essential in forensic sciences.
What Is Forensic Science?
Using scientific methods for digging the truth behind major crimes or examining the evidence and proofs which are presented in the court comes under the study of forensic science. Fingerprint analysis, along with DNA analysis, irrespective of human or wildlife, is included in forensic science.
Irrespective of the crime or evidence, forensic scientists face a common set of challenges listed below:
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Reliability of the results.
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Keeping up with the new technology.
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Communicating the results to a jury in an accurate way.
What Is DNA Testing and Why Is It Done?
DNA testing is conducted in a laboratory with all the facilities and equipment that are required. Publicly funded DNA crime laboratories or municipal law enforcement agencies are the DNA testing centers. Before performing DNA analysis at the laboratory, initial testing is conducted at the crime scene to determine the type of biological material in question screening for the presence of biological materials may also be conducted in the laboratory to determine if a specific biological fluid may be present. Most biological screening tests are presumptive and do not specifically identify a bodily fluid.
To determine who deposited biological material at a crime scene, unknown samples are collected that are compared to known samples, which are taken directly from a suspect or the victims.
How Is DNA Testing Done in Forensic Science?
Most of the DNA samples submitted to a laboratory undergo the following process:
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Extraction: It is the process of releasing the DNA from the cell.
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Quantitation: It is a process of determining the amount of DNA.
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Amplification: It is the process of producing multiple copies of DNA to characterize it.
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Analysis and Interpretation: It is the process of quantitatively and qualitatively comparing DNA evidence samples to known DNA profiles.
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Quality Assurance: The process of reviewing analyst reports for technical accuracy.
How Are DNA Testing Results Interpreted?
The process of DNA analysis is provided with a chart known as an electropherogram. This chart displays the tested locus with genetic material present at each locus. The analyst uses this chat as a complete profile of the person whose genetic locus is visualized. If only one is displayed at each loci, it is said that the individual has acquired the same marker from both mother and father at that position. The evidence or proof presented in the court of law often contains a combined mixture of DNA from more than one individual, and such evidence is very challenging to analyze and interpret. If any locus is missing in an allele, this is considered a partial profile which can happen for a variety of reasons. This can also happen when the sample is degraded.
How Is a DNA Sample Collected and Cross Checked With All the Profiles?
The profile is compared against a central database which includes culprits of a region.
The national database of a country is a part of the combined DNA index system CODIS which enables law enforcement agencies throughout the nation to share and compare DNA profiles that help investigate cases.
More than 10 million DNA profiles are installed in the system, and this concept has helped in finding out many DNAs.
It elaborately enters a case into the system. A weekly search of the DNA profiles is conducted, and resulting matches are automatically returned to the laboratory that originally submitted the DNA profile.
CODIS has 3 levels of operation:
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Local DNA index system.
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State DNA index system.
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National DNA index system.
The database has profiles from convicted offenders, forensic unknowns, missing persons, biological relatives of missing persons, and unidentified humans.
What Is the Meaning of DNA Match?
When DNA profiles from known samples are obtained, upon performing genetic tests, the following possible outcomes can be stated in a report.
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Inclusion.
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Exclusion.
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Inconclusive.
Inclusion or a match indicates that the technical difference between the samples from different profiles can be explained.
Exclusion or a nonmatch states that there are differing genotypes within the profiles that represent the origination of the samples from different sources.
Inconclusive indicates that the information is not sufficient to form a final conclusion and also states that two DNA analyses are in disagreement during the technical review process.
A match can indicate the samples obtained are similar or match with the evidence, and it has to be noted that there are chances of false positive results produced by the laboratory process or the suspect did not deposit the sample but happened to have the sample. However, when one locus does not match when two genotypes of samples are compared, the question and the non-samples are reported as a nonmatch.
Conclusion
DNA testing plays an important role in forensic science. From finding out the culprits to helping the victims and helping the child know their parents, many issues are dealt with and solved using DNA testing. When a person leaves a place, his body might not be in the place, but certain things which contain the DNA are present. Such samples are collected and tested for DNA, comparing the results with records present in the database of the state or nation.
