Another genetic marker called MAOA deficiency has been linked to violent behavior. A 2002 study published in Science by Avshalom Caspi and his colleagues looked at the DNA of 1,037 children who had participated in a 23-year survey of health and development conducted in New Zealand. Caspi and colleagues observed that a particular polymorphism—a gene on the X chromosome that regulates the production of the enzyme monoamine oxidase A (MAOA)—tended to moderate the effect of childhood maltreatment. That is, children with a version of the gene that caused greater production of MAOA were less likely to respond to maltreatment by lashing out and developing antisocial tendencies, while children with the low-MAOA-producing version of the gene had a higher rate of violent behavior. The MAOA gene oxidizes a chemical tryptophan into serotonin, one of several neurotransmitters (with dopamine and norepinephrine) that it uses to send signals. Mutations in MAOA can alter the amount of serotonin produced in the brain and biochemically affect emotion and behavior. Caspi and colleagues’ study makes no broad claims about genetic determinism but rather asserts that genetics may lend a partial explanation for differing behavioral responses to childhood maltreatment and concludes with the conjecture that “these findings could inform the development of future pharmacological treatments.”29
The MAOA gene could play several roles in criminal justice. Defense law-yers may seek to use MAOA testing results to support their client’s claim of mitigating circumstances in a violent crime (i.e., genetic defense against culpability). Alternatively, detection of an MAOA mutation in a crime-scene sample can lead police on a search for individuals with the defect, culling medical information for the match or using the result to profile individuals who may have a history of aggressive behavior. MAOA screening could become a factor in sentencing determinations or a requirement for consideration for early parole. Correctional facilities might prescribe routine MAOA testing for prisoners and forcibly administer medication to those presumed to be prone to violence on the basis of that testing. A 2002 Consensus Report by the Council of State Governments found that “staff at many correctional facilities have overrelied on the use of psychotropic medications and, in many cases, sedative-hypnotic medications, simply to pacify and to control inmates with mental illness and others believed to be disruptive.”30 Medication is often administered without adequate psychiatric evaluation and follow-up counseling and is often the sole treatment for mental illness and even nonclinical behavioral problems.31
The potential applications of behavioral genetic research to the criminal justice system raise profound questions for individual liberty and social justice. Past attempts to apply behavioral research to social policy—as evidenced most poignantly by the eugenics policies of the early to middle parts of the twentieth century—have been dismissive of the rights of individuals and vulnerable groups. Despite the increasing precision of molecular biology and repeated calls for caution about making social claims based on such research, there is a recurrent tendency to “biologize” crime and antisocial behavior and to use behavioral science as a justification for inequality and the promotion of new measures of social control. Therefore, we should be wary of any applications of behavioral genetics to the criminal justice system, whether for the narrow purpose of testing crime-scene samples on a case-by-case basis to predict behavioral traits of individual suspects or for the far broader purpose of characterizing the future dangerousness of the prison population or the general citizenry.
Medical Phenotyping
Medical geneticists seek to identify genes or multiple genetic loci (genetic markers) that correlate with individual disease states, predisposition to disease, or drug sensitivity. According to Wojciech and colleagues, “Studies developing genotype to phenotype correlations have advanced rapidly in medicine.”32 According to the National Institutes of Health, genetic tests are currently available for more than 1,700 diseases.33 In 2004 Hui Huang and colleagues utilized nearly 1,200 human disease sequences in a study.34 Some of these genetic mutations are asymptomatic, such as the Tay-Sachs trait, where only one copy of the mutation will not trigger disease manifestations. Others, such as Duchenne muscular dystrophy, which afflicts boys whose mothers are carriers, are severely disabling and prevent a person from living an independent life. Between these extremes are many cases where the genetic mutations may be connected to a disease of late adult onset where there are different intensities of disease expression. If DNA at a crime scene were analyzed for some or all known disease-related genetic mutations and there were a positive result for one that required medical treatment, police could track down potential suspects from hospital or pharmacy records of individuals treated for the relatively rare condition.
Consider the following scenario:
A series of burglaries take place in a small town in Virginia. DNA evidence in the form of a blood sample is collected from a window ledge of one of the homes. The Virginia authorities run the DNA against the state database; no match is found. They then send the sample to an outside laboratory for further testing. The lab runs a series of genetic screens on the sample and finds that the sample contains all four of the mutations that are among those most commonly associated with Gaucher’s disease. Upon receiving this analysis, Virginia authorities contact the National Gaucher Foundation and learn that most people living with Gaucher’s disease receive biweekly enzyme-replacement treatments. Furthermore, these treatments are administered at only two locations in Virginia, the Children’s Hospital and the University of Virginia. They contact the treatment centers and request a list of all individuals who have been treated for Gaucher’s disease over the last five years. The Children’s Hospital complies and turns over the records, but the University of Virginia refuses, claiming that this is private medical information that cannot be released.
To our knowledge, this scenario has not occurred. However, the facts about Gaucher’s disease and the locations of the treatment centers are accurate. In their pursuit of a felon, can and should the police be permitted to explore medical information from the genome of crime-scene evidence? Currently there is nothing to stop law enforcement from using whatever means it chooses to identify and analyze evidence obtained from the scene of a crime, including blood, tissue, hairs, and semen—that is, any biological materials. Crime-scene evidence does not possess any rights or privacy. The person who left that evidence at the scene or who is the source of the biological materials found at the scene has legal rights and privacy rights under the Fourth Amendment, but those rights do not include a protection against police acquiring information from the shed DNA. Therefore, criminal investigators can use whatever techniques they choose to find suspects from the evidence left at the crime scene. Some law-enforcement agencies have even resorted to hiring psychics who claim to have extrasensory powers that can provide information from objects found at the crime scene.35
If investigators are allowed to obtain scientific evidence in the form of mutations that are strongly correlated with Gaucher’s disease from discarded DNA at a crime scene, they then have a phenotypic clue to narrow the field of possible suspects. Can police gain access to medical records from hospitals, physicians, or medical centers for an undesignated and unspecified number of individuals who meet a specific medical criterion? Should this be considered a normal part of police investigation, or is this an intrusion on medical privacy that must be accompanied by a court warrant? Is this a type of “medical dragnet” without informed consent?
When police suspect that a fleeing suspect has been shot, they contact hospitals and seek information on whether someone was recently treated for gunshot wounds. Why would contacting local hospitals for information about people who are treated for Gaucher’s disease be any different? One answer is that when a person has a gunshot wound, he cannot be expected to have an expectation of privacy because he has entered the hospital in full view of everyone in his direct sight and is expecting emergency attention, perhaps to save his life from loss of blood or from damage to an organ. The situation is diff
erent for his medical information that may reside in hospital records.
Federal law does protect individual privacy in regard to personal medical records, but those protections are not absolute. If there is probable cause that an individual may have committed a crime, police can usually obtain a court warrant to gain access to medical records of an individual suspect. Confidentiality of medical records is established under the Health Insurance Portability and Accountability Act (HIPAA, passed on August 21, 1996). Applied to public health information, confidentiality means that information or data are not made available or disclosed to unauthorized persons and without proper cause. However, HIPAA contains a broad exception that allows disclosure of protected health information to law-enforcement officials, not only in compliance with a court order or grand-jury subpoena but also in response to an administrative subpoena, summons, or civil investigative demand—all legal instruments issued without judicial review.36 Broad administrative discretion is given to those with stewardship over health information at the hospitals in determining how to respond to written requests from law enforcement for patient records. HIPAA also allows health-care providers to disclose to law enforcement, on request, a broad array of identification information, including name, address, Social Security number, blood type, date of treatment, and a physical description.
When there is individualized suspicion and probable cause, police generally have no problem obtaining a court warrant for a suspect’s medical records. But in the case outlined, there is no individualized suspicion and therefore no probable cause against any single Gaucher’s patient. Should law enforcement be able to acquire information about all people of a certain geographical region who are treated for Gaucher’s disease because the crime-scene DNA has been medically screened and shown to have the alleles for the disease?
Judges do not typically give police investigators warrants when they are on a fishing expedition without probable cause that an individual or some small number of individuals is suspect. So our investigators may not be successful in getting a “wide-net” warrant from the courts to obtain the medical records of all Gaucher’s patients in an area. Should police be legally permitted to access medical records at Children’s Hospital and the University of Virginia without court warrants on the basis of the finding that DNA at the crime scene (which may or may not be the perpetrator’s) has the Gaucher mutation? Will the privacy of medical records keep the police from obtaining the information about males treated for Gaucher’s disease without a warrant? Will health centers turn over the information under current federal medical privacy statutes?
In our scenario the police are undertaking a kind of medical dragnet. Is a medical dragnet without informed consent ethically and/or legally justifiable? Should the same informed-consent principles hold for a medical dragnet that we expect to be in place for a DNA dragnet? Suppose that Children’s Hospital turns over to the police the names of the male patients who have been treated there for Gaucher’s disease over a period of 10 years. If police then narrow their suspects to three males on the basis of treatment for Gaucher’s disease and a suspected age range, is that reasonable suspicion to get a warrant for their DNA? These questions remain to be answered by the courts.
Predicting Sex, Hair Color, Eye Color, and Skin Color from DNA
Companies like DNAPrint Genomics that began providing products and services to the criminal justice sector for correlating phenotype with segments of DNA focused on a few genes and chromosomes where there had already been published studies that linked DNA alleles to physical characteristics. The most definitive trait prediction from DNA is sex. This can be done by chromosome analysis because the male has an X and a Y chromosome, while the female has two X chromosomes. The sex of a DNA donor can also be determined by a gene called the amelogenin sequence, which is present on both the X and Y chromosomes. But the genes on these chromosomes have different sizes, and those sizes can be read off a DNA analyzer.37 There are also male-specific genes (e.g., SRY) and female-specific genes (AR), which can be analyzed by PCR techniques.38 The amelogenin genetic analysis has been used in forensics and prenatal diagnosis.
According to Elkins, “Genetically-derived trait information may be superior to human-derived trait information because, unlike humans, machines cannot be fooled by changes in physical appearance.”39 This may be true, but the practical value of predicting appearance is less clear. For example, let us suppose that a witness described a possible suspect in a crime as having blond hair. Let us also imagine that the perpetrator of the crime left DNA at the crime scene, and a DNA test revealed that the suspect in fact had brown hair. Indeed, such a test might have greater reliability for natural hair color than an eyewitness report. But how helpful would this information be in tracking down the suspect if in fact the individual had dyed his hair?
In terms of inferring human nondisease physical characteristics from DNA left at a crime scene, we probably cannot do much better than the phenotype red hair/light skin. Red hair has been linked to variants of a single gene called MC1R, which encodes the melanocortin-1 receptor. Receptors reside at the surface or in the nucleus of cells and are acted on by specific proteins (such as hormones) to produce other proteins through the mechanism of DNA transcription. The action of a stimulating hormone called alphamelanocyte (aMSH) on the receptor MC1R controls the switch between a red/yellow substance (phaeomelanin) and the black/brown substance (eumelanin). People with red hair produce more phaeomelanin than brown- or black-haired people. One study found 12 variants of MC1R. Of those, 8 were associated with red hair. The authors found that for 96 percent of individuals they studied, those with 2 of the 8 red-hair-causing mutations had red hair. Two of their subjects who had the mutations but were not red haired (either blond or light brown) described themselves as having had red hair in their youth.40
Writing in the Journal of Forensic Sciences, Branicki Wojciech and colleagues noted that “determination of one of the [relevant] MC1R variants in the homozygous state or heterozygous combination can be considered a strong indicator that the sample donor has red or strawberry-blond hair and fair skin.”41 The relationship between certain genetic variants in MC1R has been reproduced and validated.42 From a forensic viewpoint, if a DNA sample shows two MC1R sequence mutations, it is a good bet that the donor of the sample has or had red hair. If the DNA shows that the individual is homozygous (has two copies) of the allele that is not associated with red hair, then it is a good bet that the donor of the DNA does not have red hair. The presence of one mutation would be inconclusive.43
Iris color is largely a genetic rather than an environmental trait. Studies of twins show high correlations (about 85 percent) of iris color between homozygote twins. How much pigment a person expresses in his or her iris is linked to three SNPs, also known as single-letter variations, in a DNA sequence near a gene known as OCA2. According to a 2007 study in the journal Human Genetics, OCA2 is the major human iris-color gene, and SNPs within this gene can accurately predict melanin content from DNA.44 Among the individuals carrying the same SNP sequence in all three locations on both copies of the gene, 62 percent were blue eyed.45 Because iris color does not change with age or sunlight, it is viewed as a stable and predictable trait that could be useful for crime-scene DNA profiling. However, with only slightly more than 50 percent genotype-to-phenotype predictability, phenotyping for iris color has limited reliability.
Skin color is considered a polygenic trait. This means that many genes in different loci of the human genome are responsible for pigmentation of the individual. There may be 30 to 40 genes responsible, which may act both additively and nonadditively in producing a spectrum of pigmentation colors that are found within the human family. Others have speculated that there are more than 120 genes that play some role in skin pigmentation. Variations of the color of human hair and skin are determined by the amount, density, and distribution of the two components making up the pigment melanin, which is produced in specialized cells known as melanocytes. Th
e synthesis of two organic polymers, namely, eumelanin (dark brown/purple/black pigment) and phaeomelanin (yellow to reddish brown pigment), determines the amount of melanin in the skin. The exact role of the genes responsible for producing the ratio of these pigments (eumelanin and phaeomelanin) is not fully understood. Much of what is known about human pigmentation has been learned from mouse studies.46 Not only are the genetics and chemical pathways of melanin synthesis complex, but environmental factors in skin pigmentation also play a role.47
In his book Molecular Photofitting Tony Frudakis reports that an individual with each of nine major variants of a gene MC1R will more likely than not express a fair or pale skin phenotype relative to the average European. But he adds that “we need to be able to measure more than just the MC1R genotypes to make inferences and because skin color varies so much with biogeographical ancestry (on a continental level), the approach that could be useful is the admixture mapping approach.”48 Admixture mapping is a tool for uncovering genes that contribute to complex traits. It involves examining the gene frequencies of two or more genetically diverse intermating populations (admixture populations).
Given the complexity of the genetics and the gaps in our knowledge of human skin pigmentation, we cannot yet go directly from DNA to skin color. The indirect route to specifying skin color from genotype is through ancestry analysis, as previously discussed. However, ancestry analysis will yield mixtures of a person’s biogeographical heritage; skin pigmentation cannot be predicted determinatively from that knowledge.
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