DNA reports are believed to be very reliable as they give vital information in forensic science, paternity testing, and medical diagnosis. These may include sample contamination, mistakes done during sampling, or incorrect interpretation made on test outcomes.

More so, the reliability of a DNA report is aided by the integrity of the sample taken in that poor quality samples lead to unreliable evidences. Improved DNA tests due to advancements in technology bring one point of caution-the need to have a very strict protocol or process when interpreting test results because there is possible error when dealing with living things.

Limitations of DNA Report

DNA report may become unreliable due to the following reasons:

• Sample Contamination: The DNA collected may be unreliable in case of contamination of the sample. This contamination may happen where they are collected, handled, or processed with other agents' DNA that might be misleading in interpreting these findings.
   
• Mixing of Samples: Sample mix-up occurs when samples from various individuals are processed jointly. They are likely to give wrong results, mostly in a situation when you need to distinguish DNA profiles of different people.
   
• Degradation of DNA: DNA testing may not be reliable if a sample has degraded or damaged DNA. Exposure to environmental factors like heat, light, or dryness may lead to degradation and inaccuracy.
   
• Low DNA Quantity: DNA testing may have low reliability when there is little or poor-quality DNA sample presented in the said case. Forensic and degraded samples often have low DNA concentration that may challenge the accuracy of the profile generated.
   
• Chain of Custody Issues: For the DNA evidence to be reliable, it is essential to keep a proper chain of custody. Inconsistencies or lapses in preserving and documenting the sample's custody chain might lead to doubts about the outcome's soundness.
   
• Laboratory Errors: One of the factors affecting the accuracy of DNA analysis is the faults appearing inside the laboratory in the shape of an equipment failure, errors regarding procedure or human error. Thus, stringent quality control is necessary so as to reduce associated laboratory faults.
   
• Interpretation Challenges: Interpretation of high-complex DNA profiles is very difficult – particularly where they relate to mixed samples or degraded DNA. The results may become unreliable by allowing subjectivity into the interpretational process, especially when it comes to making conclusions based on their accuracy.
   
• Population Database Limitations: Availability, and more significantly, accuracy of reference database affect on DNA testing reliability. However, if the databases do not capture diversity or represent the population, then it could become harder to distinguish among some persons thus compromising reliability.
   
• Twinship: Although these new modern DNA testing methods can usually tell identical twins apart, there always remains a possibility for error. In some instances, such as the similar DNA samples with identical twins, it could bring difficulties hence reducing the level of precision.
   
• Complex Family Relationships: In instances with complicated families or relatedness, DNA may not be as accurate. Interpretation becomes difficult leading to errors especially in establishing relationship within the extended family structure.
   
• Adulteration of Samples: Adulteration of intentional DNA sample is possible at most, particularly under legal or forensic settings. When someone manipulates or adulterates a sample, it results in misleading outcomes, which compromises testing accuracy.
   
• Biological Factors: The reliability of a test result may be affected by biological factors like the presence of substances impeding with DNA analysis. Some inhibitors may prevent proper DNA extraction and amplification of specific profiles.
   
• Inadequate Sampling: The type of sample that has been taken correctly for a person who will be tested will determine if an accurate picture on the same will be established through a DNA profile.
   
• Cross-Contamination: If these precautions are not taken into consideration, cross contamination may be encountered when handling samples. Such an event might result in contamination of one sample's DNA to another sample leading to flawed outcomes.
   
• Technical Limitations: Notwithstanding the development of improved methods for DNA analysis there are still technological constraints. Some DNA segments might prove challenging to evaluate while genome profiling can at times be complicated due to complex structural variations such as telomeric heterogeneity.
   
• Biases in Testing Methods: DNA tests themselves are not without bias. Such biases might distort presentation of different genetic markers and could seriously affect the reliability of research especially in indigenous communities.
   
• Inconsistent Protocols: Variations may occur in results if different laboratories use inconsistent and insufficiently standardized protocol. Therefore, it is crucial that testing protocols are harmonized to guarantee that DNA test results are reliable and comparable.
   
• Statistical Interpretation Issues: Statistical interpretations of DNA are sometimes unreliable as they may not be sensitive enough when processing complex mixed samples. The reliability of the conclusions from the results largely depends on statistical uncertainties.
   
• Evolutionary Changes in DNA Markers: In due course, our comprehension about DNA markers and their changes can change. The accuracy and reliability depend on the changes made in the reference databases and markers compared.
   
• Ethical Considerations: The perception of the reliability of DNA testing is influenced by ethical considerations such as the question of privacy and the right use of genetic data. Concerns related to informed consent, data security, as well as misuse of genetic information will in all likelihood create challenges with regard to the integrity of the entire test itself.

Conclusion
DNA is neutral and objective by nature as a scientific instrument. However, its reliability is determined by the morality and sincerity of its operators. Recent cases have exposed the dark side of forensic analysis where several forensic analysts have been involved in malpractices such as deception, practicing with no integrity and tempering with official records. Consequently, courts were given false DNA reports which had been created for court purposes only.

Although DNA has always remained a firm scientific procedure in this context, ethical standards must be maintained in order to preserve the credibility of evidence used in legal contexts. In such scenarios, it is not science that should be blamed but people who make mistakes in proper DNA analysis or use it wrongly thereby necessitating strict supervision and adherence to ethics while working in forensic sets.

Written By: Md.Imran Wahab, IPS, IGP, Provisioning, West Bengal
Email: [email protected], Ph no: 9836576565