Deoxyribonucleic acid (“DNA”) testing, also commonly known as genetic testing, is a type of test that is often used in criminal and civil court matters to identify changes in the genes, chromosomes, or proteins in an individual’s body. DNA testing specifically involves obtaining DNA from a sample of cells in an individual’s body to identify specific genes, chromosomes, or proteins, including genes that are faulty.
Although 99.9% of human DNA sequences are the same in every person in the world, there are still enough differences in the DNA to allow every single person to be distinguishable from another. Using the scientific method of DNA testing and DNA profiling, scientists are able to analyze a long chain of DNA to identify specific “loci.”
Importantly, loci are very similar when comparing the loci of two closely related people, but among people who are completely unrelated, the differences between the loci are much greater.
As mentioned above, DNA testing is utilized in both civil and criminal proceedings. In criminal proceedings, DNA evidence is often used to link a person to the scene of the crime and even to support the charge that they committed the crime. However, DNA evidence can also be used by the defendant in order to prove their innocence.
In fact, the “Innocence Project” is a non-profit organization that promoted reforming the criminal justice system by utilizing DNA testing to exonerate people who have been wrongly convicted of a criminal act. The Innocence Project has documented 375 criminal cases in which DNA analysis has resulted in the exoneration of a person who had been wrongly convicted of a crime. In other words, had DNA testing been available and properly utilized at the time of their original sentencing, they would not have been convicted of the crime that most of them have already served multiple years of imprisonment for.
In addition to criminal proceedings, DNA testing is also widely utilized in civil proceedings where DNA testing is needed to prove or disprove paternity. In connection with testing for paternity, DNA profiling allows for the direct examination of a child’s genetic material. Then the genetic characteristics of the child are compared to their mother.
The characteristics that are compared that are not found in the mother are determined to have been inherited from the father. Next, the suspected father is tested. If the suspected father does have the characteristics inherited by the child, then the probability that he is the biological father will be calculated and presented as evidence to the court.
In some cases, mandatory DNA sampling will be ordered by the Court in order to determine paternity in a family law case. Then, the results of the DNA testing will be substantial evidence in determining paternity.
How Reliable Is DNA Evidence in Court?
As far as the DNA evidence reliability utilized in civil court, DNA tests can currently determine paternity with 99.9% accuracy and can rule out paternity with 100% accuracy. As such, DNA tests have become the primary admissible method of establishing paternity in court.
Criminal courts have also generally accepted the accuracy and value of DNA testing that is performed to professional standards. For example, courts have allowed prosecutors to search for suspects and interview people in the DNA database whose DNA was found to be merely similar to a DNA sample found at the crime scene.
However, as far as the reliability of DNA evidence in criminal court, there are many complications that may arise that could affect the reliability of DNA evidence. For example, the manner in which law enforcement collects, handles, and tests a DNA sample affects its reliability. In other words, human error can occasionally affect DNA results.
A DNA sample is only as reliable as the procedures that are utilized to preserve and test it. As such, if the procedures are not careful and precise, or if they prioritize results over accuracy, then the DNA evidence that results may not be trustworthy and perhaps should not be relied on to convict a defendant of a crime. Generally, DNA evidence alone is not enough to convict an individual of a crime.
For example, if an individual has been charged with criminal assault, and a DNA sample is found and collected at the scene, including blood stains and hair, that sample can be damaged by exposure to heat or cold or other features of the environment in which it is kept. There can also be a question as to the person whose sample it is. In other words, does the sample belong to the suspect, or did it simply belong to someone that was in the area.
Many scientists have concluded that ideally a complete DNA sample is needed in order to create a comprehensive DNA profile of an individual. A complete DNA sample would have at least 16 different markers for a comprehensive profile, whereas a damaged DNA sample, such as one exposed to moisture or extreme temperatures, will often result in a partial profile. A partial profile might only describe one trait of a person’s DNA profile, such as their hair color.
Importantly, every state and the FBI maintain DNA databases. Further, all states permit the collection of a DNA sample from a person who is convicted of a crime for inclusion in DNA databases. Many states require defendants convicted of any felony to provide a DNA sample to the state, while other states, allow DNA collection only from defendants who were convicted of certain violent crimes, such as murder, rape, or other sexual crimes.
Additionally, many states also allow state law enforcement agencies to collect a DNA sample from any individual who has been arrested or charged with a crime. Once again, the goal behind collecting DNA samples is to build the state’s DNA database for purposes of being able to identify individuals through a DNA sample.
The national DNA database in the United States is the National DNA Index System (“NDIS”). The NDIS contains DNA profiles that are submitted by participating federal, state, and local forensic laboratories. There is also the Combined DNA Index System (“CODIS”), which is a program used by the FBI to analyze DNA data.
As far as the storage of DNA samples, the DNA samples are stored in databases that are operated by either:
- Private testing laboratories;
- Government agencies that are tied to law enforcement, such as the Department of Justice (“DOJ”) and Department of Public Safety (“DPS”); or
- Government agencies that are not tied to law enforcement, such as the Department of Health (“DOH”).
Many states automatically submit every DNA profile for entry in the NDIS. Laboratories that submit DNA data to NDIS must be accredited and submit to audits to show their compliance with FBI standards. Importantly, private laboratories do not qualify to submit DNA data to NDIS, because they lack these assurances of the quality of their work.
All in all, every effort in connection with assuring quality in DNA sampling and testing and building of databases comes from the fact that DNA testing has proven to be an invaluable tool in both criminal investigation and prosecution. However, DNA evidence can still be challenged due to factors such as the DNA sample quality, contamination, and human interpretation.
When challenging the reliability of DNA evidence, the defendant who wishes to contest a DNA match will often need the services of an expert witness that will be able to provide expert testimony necessary to mount a meaningful challenge to DNA evidence of their guilt.
Do I Need a Lawyer to Challenge the Reliability of a DNA Test?
As can be seen, forensic DNA testing can often become a very complicated matter, and the use of DNA testing can have a tremendous impact on an individual’s court case. As such, before submitting to a DNA test, it may be in your best interests to consult with an experienced criminal defense attorney.
If you have been charged with a crime, and you wish to submit to or otherwise utilize DNA testing as a defense in your case, an attorney will be able to assist you in building a defense to the charges you are facing. An experienced attorney can guide you through the DNA testing process, and help you understand your legal options and your best course of legal action.
Further, an attorney can also help you challenge DNA test results, if applicable in your case. Finally, an attorney can also represent you at any in person criminal or civil proceedings where DNA testing is serving as evidence in your specific case.
