The technologies of DNA science have revolutionized modern criminal law in every respect, from crime scene processing and case investigation to prosecutorial strategy and post-conviction appeals. The lightning speed of progress in the DNA sciences represents a public policy challenge to optimize its evidentiary value without violating established principles of constitutional protections, criminal procedure and statutory rules of evidence. Ultimately, projected developments in DNA science and technology will affect ordinary life far beyond the realm of the criminal justice system by eliminating genetic diseases and providing a cure (or preventative) for all forms of cancer as well.
Background and History:
Throughout the eighteenth century, medical science was still entirely ignorant of the reason that human blood transfusions succeeded sometimes, but failed other times, with deadly consequences. By the turn of the twentieth century, scientists realized that human blood could be differentiated by four types, by analyzing the coagulation or "clumping" that resulted when some blood samples were mixed together in the laboratory. Continued research into the antigens responsible for different hemoglobin characteristics lead to the standardized blood group designations that are still employed today, and upon which all subsequent medical and surgical progress and techniques requiring transfusions or organ transplants depend.(1)
It was realized almost immediately, that blood typing had potential value for criminal identification investigations, paternity confirmation and exclusion, and other evidentiary purposes, because they were dictated by Mendel's Laws of Inheritance.
By the 1960s', researchers had identified many other more subtle factors than surface antigens, enabling them to differentiate blood samples by virtue of specific enzymes and serum proteins that conferred much greater accuracy to the determinations (or exclusions) of identity revealed through blood studies.
Initially, evidence relating to identity and paternity primarily sought to exclude potential candidates from further consideration or exonerate criminal suspects, rather than to include candidates or inculpate suspects, owing to the factor of mathematical error inherent in blood testing principles relying on the parameters capable of analysis. Similarly, when first admitted into evidence in courts of law, identification by blood evidence was first accepted in civil matters, where the standard of proof is preponderance, and much more rarely in criminal matters, where stricter thresholds of proof precluded its use, in principle. (2)
In 1953, decades of research by many scientists in the United States and Europe culminated in the monumental discovery and publication of the actual structure of the DNA molecular helix by Watson and Crick, for which they received the Nobel Prize in 1962. Continued research over the next two decades yielded a much deeper scientific understanding of the role of DNA and produced incredibly precise technologies based on more sophisticated principles governing recombinant
1985 marks a watershed in the history of forensic science, when so-called variable-length DNA segments were used in England to exonerate an innocent man of rape charges and to conclusively establish the guilt of the actual perpetrator.(3)
Since that time, the reliability and demonstrable accuracy of DNA evidence has been established and confirmed conclusively, and is not contested, in principle, in court.
On the other hand, the technological sophistication of modern DNA sequencing techniques have given rise to a plethora of public policy debates about the privacy of medical records, precisely because of the wealth of diagnostic and particularly, prognostic information contained therein. Constitutional issues arise in connection with 4th Amendment search and seizure of biological criminal evidence, requiring a legal definition of the "privacy" expectations of medical information and establishing "ownership" of biological samples and patent applications for genetically engineered organisms.(4)
Modern Law Enforcement Applications:
When fingerprinting was first used for identification purposes in 1892, it revolutionized criminal investigations, forming the cornerstone of countless successful investigations, prosecutions and convictions in every imaginable area of law enforcement. Suddenly, criminals could be tied directly to their crimes and authorities simultaneously acquired an invaluable tool for reliably cataloging and cross-referencing career criminals. The explosive evolution of DNA science since
1985 advanced criminal investigations and forensic science by a much greater magnitude than even the finger print revolution of one hundred years ago.
DNA-based techniques reveal evidentiary clues in such a wide variety, that a clean" crime scene is quite rare. Positive identification beyond the shadow of doubt can be gleaned from a single human hair, a drop of blood or perspiration, a saliva stains on cigarette butts and postage stamps, or a microscopic particle of skin or dandruff. It has enabled law enforcement to establish "CODIS" (for Combined DNA
Index System), a nationwide DNA data bank and identification system modeled in principle, after the AFIS automatic fingerprint identification system. (5)
Prosecutors in some states have filed so-called "John Doe" warrants against individuals at large and as yet, unknown by name, but identified in court papers by genetic markers matching DNA evidence left at the crime scene. (6)
In some states, prosecutors have managed successful challenges to statutes of limitations in particular cases of sexual assault where DNA evidence links a suspect to the crime (7); in other states, statutes of limitations have been completely repealed by the legislature in DNA-based cases.(8)
While the ability to analyze DNA evidence represents a powerful set of forensic tools, it also imposes certain requirements in the field. Detectives must coordinate their crime scene processing and evidence collection with crime scene
DNA specialists, and training of first responding patrol officers must include the preliminary identification of potential sources of DNA evidence in order to preserve the most crucial elements of crime scenes and to collect and transport it without contaminating it or breaking the chain of custody necessary to preserve its evidentiary value. Finally, because some sources of DNA are also potential vehicles for transmission of deadly pathogens such as HIV and Hepatitis B, first responding law enforcement officers require training and protective equipment to minimize risks to themselves inherent in recovering and handling biological evidence specimens. (9)
DNA evidence gives rise to a new class of challenges to the admissibility of evidence under 4th Amendment principles issues defining whether or not one has a reasonable expectation of privacy concerning one's bodily fluids and under what circumstances samples provided by compliant subjects are truly "voluntary."
Equal Protection challenges arise where authorities routinely collect DNA samples from arrestees for inclusion into DNA databanks, where the resulting data bank is racially skewed owing to the demographics of arrestees.(10) Likewise, law enforcement efforts to identify suspects by collecting samples in a "dragnet" of DNA specimens from subjects in the surrounding neighborhood.(11)
Generally speaking, sophisticated DNA evidence is relied upon more often to establish the elements of State's case than by the defense, but it has also proved invaluable in post-conviction appeals where it excluded defendants wrongly convicted beyond doubt. Finally, the definitive accuracy of DNA sequencing has revealed the occasional phenomenon of voluntary false confessions, where defendants already serving time are absolutely excluded by evidence adduced only much later.
Privacy and Public Policy Issues:
Privacy advocates have lobbied aggressively to constrain any alternate or adjunct uses of DNA information collected in connection with medical and other non-law enforcement data banks. Even where specimens are collected by law enforcement agencies, its subsequent use has been challenged: sometimes DNA samples are properly collected pursuant to duly issued warrants, but their subsequent inclusion in the CODIS data bank becomes the subject of additional litigation after the subject is exonerated. Other times, defendants have asserted privacy rights to the saliva residue on cigarette butts obtained through alleged "trickery" of law enforcement, where no probable cause sufficient for a warrant existed and police obtained samples by impersonating restaurant service personnel.(12)
One of the most profound concerns relates to the dissemination of medical records containing genetic information, owing to insurance policy implications. If health insurance companies obtained access to such information, they might deny coverage to people genetically predisposed to diseases requiring costly treatments.
In 1979, the U.S. Supreme Court first allowed the patenting of a living organism, the Pseudomonas Bacterium, developed through genetic engineering and intended to consume oil slicks resulting from accidents at sea. Since then, genetic research has been transformed from a field formerly limited to academic interest, to a highly competitive commercial enterprise, essentially dominated by private industry.
Leading market analysts immediately recognized the interest of private corporate investors and investment brokers as reliable indicators of the commercial growth potential of the private genetic engineering industry that has since blossomed into a multi-billion dollar industry. The obvious implications of any juxtaposition of existing genetic tissue engineering techniques with the mapping of the complete human genome require appropriate legislation in accordance with delicate concepts of medical ethics and research guidelines.
When the Human Genome Project was first designed in 1990 to identify all of the 100,000 individual genes thought to distinguish human intelligence from other animals, it was scheduled for completion between 2005 and 2010. By February of 2001, the project was several years ahead of schedule (and under budget), and scientists announced that the human genome contains only about…