|
The primary use of genetics in criminal law
is for identification of defendants, such as in a rape case,
and as a defense to exculpate or provide mitigating reasons for
a crime.
All crimes have several basic elements. First,
the defendant must have committed a voluntary act (“actus
reus”). This reflects the primary concern of criminal
law with intentional conduct, rather than a person’s thoughts
or involuntary acts. A guilty thought is not punishable
but a guilty act is. Secondly, a defendant must have a
culpable intent (“mens rea”). Mens rea represents
the requirement that a person possess a “culpable state
of mind” to be punished for a crime. This means that
a person must have acted purposely or knowingly in committing
the act. The culpability requirement is related to the
punitive nature of criminal law. Criminal liability is
rarely imposed without a criminal state of mind. An underlying
principle of the criminal system is that the threat of punishment
will deter crime. An individual who acts without knowledge
or intent is plainly beyond the deterrent force of the law. A
person who is punished must be blameworthy for the criminal act.
What happens when a criminal defendant has
made a mistake of fact or law? Under the Model Penal Code,
ignorance or mistake as to a matter of fact or law is a defense
only when it negates the mens rea required to establish a crime.
Negligent or reckless behavior can be sufficient
to infer mens rea. When a criminal defendant consciously
disregards a substantial and unjustifiable risk, his behavior
may establish a culpable state of mind. When a person,
who is intoxicated with alcohol or another drug which impairs
mental and physical abilities, gets behind the wheel of a car,
strikes and kills a person, he can be found guilty of manslaughter,
even if he did not intend to commit that act. This supposes
an awareness of the creation of a substantial homicidal risk
that has been ignored by the actor.
Is a person culpable for his conduct when
he has a genetic disease that is responsible for his criminal
behavior? Consider the following case. John Wilson had
been in trouble with the law since a teenager. He had served
prison time on several different occasions for assault, burglary,
and disorderly conduct. One night, Wilson had been out
drinking at a bar when he stopped off at all night convenience
store. Wilson took a bottle of soda to the cash register,
but before paying for it, he pulled out a gun from his jacket,
and pointed it at the store clerk, ordering him to empty the
money in the cash register into a brown paper bag. The
clerk followed Wilson’s directions, filling the bag with
the contents of the register. Wilson was sure that there
was another money stash, having seen clerks reach below the register
in previous visits to the store. When the clerk denied
any knowledge of it, Wilson become very angry, believing that
he was being lied to and disrespected. He walked the clerk
to the back of the store. Forcing the clerk to kneel on
the ground, Wilson placed his gun behind the base of the clerk’s
skull, and fired the gun. The clerk was killed instantly. Wilson
fled. Two days later, Wilson was arrested when he was pulled
over for speeding and the police found the murder weapon on the
car floor.
At the murder trial, Wilson’s attorney
claimed that Wilson did not have a culpable state of mind. Instead,
he called a medical geneticist to the stand who testified that
Wilson had a genetic X-linked condition characterized by mild
mental retardation and aggressive, sometimes violent, behavior. Four
generations of males in Wilson’s had manifested this genetic
disorder. Two of Wilson’s uncles were in prison at
the time of his act and his grandfather had received the death
penalty in a capital murder case. The geneticist argued
that Wilson had not acted voluntarily in committing the act. Rather,
his genetic disorder had compelled him to commit violent acts. Alcohol,
he said, induced violent behavior in Wilson, as it did all afflicted
family members.
The issue raised by the hypothetical Wilson
case is intriguing in view of recent scientific research which
has identified numerous links between gene and behaviors. Various
gene alleles have been identified which are associated with pathological
behaviors. A genetic basis has been established for a variety
of human behaviors, including aggression, anxiety, and depression. If
it is true that one’s genes shape, or even control, one’s
behavior, how should such facts square with the criminal system? The
purpose of criminal law is to punish a person for a voluntary,
culpable act. Suppose it is proved beyond doubt that a
particular gene is responsible for a defendant’s aggressive
behavior. Is it fair to hold that person accountable for
his act? One of the central issues is to distinguish between
propensity and causality. Mr. Wilson’s genetic disorder
may have made it more likely that he would commit a violent act,
but did it directly produce the criminal conduct. What
if an aggressive behavior was a response to an emotional stress
or environmental cue? In Wilson’s case, the medical
expert testified that alcohol incited Wilson to violence. Is
he culpable for his crime because he voluntarily and recklessly
took an alcoholic drink and knew, or should have known, that
it would arouse violent behavior?
One of the functions of the criminal system
is to punish a person for criminal acts. Traditionally,
several explanations have been offered for the punishment requirement:
(1) deterrence; (2) incapacitation or isolation of the guilty
person from society; (3) rehabilitation; and (4) retribution. Should
the terms of punishment take into account the causality between
the crime and an individual’s biological status? In
the Wilson case, the defense team argued that Wilson was not
responsible for his conduct because he had a genetic disorder
that caused him to commit violent acts. One of the difficulties
of Wilson’s argument is establishing direct causality between
the act and the genetic defect. A more reasonable formulation
may ask what the probability is that an individual with a particular
genotype will lead to criminal conduct. If it is 100%,
do we let him off on the grounds that either the act was not
voluntary or he could not have possessed mens rea because of
the genetic defect? If the defect only establishes a propensity
to criminal activity, say 20%, then should his punishment be
adjusted accordingly.
These issues are not new to the criminal
system. According to Section 4.01(1) of the Modern Penal Code: “A
person is not responsible for criminal conduct if at the time
of such conduct as a result of mental disease or defect he lacks
substantial capacity either to appreciate the criminality [wrongfulness]
of his conduct or to conform his conduct to the requirements
of law.” The rationale is that punishing a person
who, as a result of mental disease or defect, is incapable of
understanding that their conduct is of such nature to merit punishment,
or is substantially incapable of refraining from criminal conduct,
does not further the objective of the criminal system to deter
potential offenders from the commission of a crime. The
purpose of 4.01(1) is to identify those individuals whose behavior
would not be intimidated by the threat of punishment, and whose
punishment would not deter others. Does this legal test
distinguish the nondeterrables from those who are merely mentally-disordered,
but understand the nature of their conduct? Now that genetic
bases for mental disease have been identified would it be better
to use a genetic test?
The People of The State of New York, Plaintiff, v. Charles Yukl,
Defendant, 83 Misc 2d 364; 372 N.Y.S.2d 313 (1975, Supreme Court
of NY, NY County)
Stephen A. Mobley v. The State, 265 Ga. 292; 455 S.E.2d 61 (Supreme
Court of Georgia, 1995)
(1) A genetic map of the human genome is a map of the chromosomes
having polymorphic DNA markers at determined intervals. A
polymorphism means that different sequences of DNA are found
in the population at the same locus. The utility of such
a map is to facilitate the localization of disease and behavior
genes by family-linkage and population studies. Hoffman,
Am J Hum Gen, 54:129 (1994); Marshall, Science, 274:488 (1996);
Lander, Science, 274:536, 1996.
(2) The report referred to in Mobley was a study of Dutch family
in the Netherlands. The author of the report, Dr. Han G.
Brunner, a medical geneticist, had been contacted by a woman
who sought help for a problem in her family. For generations,
many of the men in her family had been prone to violent and unprovoked
aggressive attacks. The problem had been so severe that
an unaffected maternal grandmother had collected detailed information
about nine men in the family who displayed the aberrant, apparently
inherited, behavior. One affected male had been convicted
of the rape of his sister. Another affected male had attempted
to run his boss over with a car. A third affected male
would enter his sisters’ bedrooms at night, armed with
a knife, and force them to undress. Two of the family members
were convicted arsonists. Brunner and his colleagues performed
DNA analysis of tissue samples of 24 members of the family. A
DNA marker was identified on the X-chromosome which was present
in affected males but not in unaffected males. The DNA
marker was located at the locus of the structural gene for monoamine
oxidase a (“MAOA), an enzyme involved in the metabolism
of the monoamine neurotransmitters dopamine, serotonin, epinephrine,
and norepinephrine. Affected males also displayed a marked disturbance
in monoamine metabolism, suggesting that MAOA was defective. Brunner
et al., A. J. Hum. Genet., 52:1032-1039, 1993; Morell, Science,
260:1722-1723, 1993.
(3) Turpin v. Mobley, 269 Ga. 635; 502 S.E.2d 458 (Supreme
Court of Georgia, 1998). Mobley appealed the death sentence
on the grounds that his trial counsel Summer had been ineffective
in the preparation for and conduct of the sentencing phase. While
preparing Mobley’s defense, Summer had read an article
describing Brunner’s research establishing a connection
between antisocial and violent behavior with a genetic defect
in the MAOA gene.
“Summer investigated the use of this genetic link to
violence as a possible mitigation defense. He contacted a professor
of genetics at Harvard Medical School and reviewed the case with
her. She informed Summer that he needed to conduct a Mobley family
history to determine if there was a prevalence of violent behavior
that might suggest a genetic predisposition. Summer then spoke
with Joyce Ann Elders, Mobley’s father's cousin, who was
considered the family historian. She revealed to Summer that
a number of people in the last three generations of the Mobley
family had exhibited aggressive and antisocial behavior. These
people included a murderer, a rapist, an armed robber, several
substance abusers, and several spouse abusers.
Summer then contacted the National
Psycho Pharmacology Lab and a doctor at the Emory Nuclear Medicine
Laboratory about the cost of preliminary testing to determine
if Mobley had the same gene mutation as the people in the Netherlands
study. Summer
filed a “Motion for Continuance and Motion to Provide Funds
for Expert Witness Assistance to Conduct Preliminary Analysis
for MAOA Deficiency and other Genetic Analysis as Information
Becomes Available” and supported the motion with his research,
affidavits from doctors, and testimony from the family historian.
After a hearing, the trial court denied Mobley funds to hire
a geneticist and funds to conduct the genetic testing because
the Netherlands family had a prevalence of mental retardation
and Mobley’s family did not. Mobley’s father offered
to pay for the genetic testing himself, but Summer declined.
The habeas court has ruled that trial counsel was ineffective
for failing to accept Mobley’s father’s offer to
pay for the genetic test.
“The evidence shows that trial counsel decided against
going forward with the genetic test because (1) they believed
that there was only a slim chance that the genetic test would
reveal that Mobley had the same genetic defect as the people
in the Netherlands study, (2) they intended to present a genetic
defense without the geneticist, by using the family historian,
and (3) they believed that the trial court's denial of funds
might constitute reversible error and they wanted to preserve
the issue for appeal. The first two reasons for declining the
father's offer were reasonable conclusions. Trial counsel’s
desire to “preserve” the issue for appeal, however,
was not a reasonable basis for the decision. We do not condone
trial counsel foregoing a vigorous defense in the hope that a
ruling might constitute error on appeal. If Mobley had prevailed
on this issue on appeal, the reversal of the trial court would
only result in a new trial in which counsel would have the assistance
of a genetics expert, which is the same relief Mobley’s
father offered in the beginning.
“Nevertheless, we conclude that
the decision regarding the genetic test was a reasonable strategic
decision and therefore did not constitute ineffectiveness by
trial counsel. The presence of one flawed reason does not render
counsel's otherwise reasonable strategic decision deficient
performance. Additionally, Mobley was able to present the genetics
theory and there has been no showing that a geneticist would
have offered additional significant evidence. Therefore, even
if the decision constituted deficient performance, Mobley has
not demonstrated prejudice.
“D. The mitigation defense.
“The habeas court ruled that trial counsel presented an
inadequate mitigation defense. Specifically, the habeas court
found that, after being denied the funds for a geneticist, Mobley’s
counsel nonetheless persisted with presenting an unconventional
genetic theory for Mobley’s behavior, without the assistance
of an expert witness. We disagree because this ruling fails to
take into account the fact that the genetic defense was only
one part of trial counsel's overall mitigation strategy.
“Mobley’s counsel's strategy in the penalty phase
centered around the following theme: Mobley has a personality
disorder that has affected his behavior since he was a child,
this behavior may be the result of a genetic problem that he
cannot control, the jury should show him mercy because people
with personality disorders tend to “mellow out” as
they age, and Mobley has accepted responsibility for his crimes
by cooperating with the police and offering to plead guilty.
Trial counsel adequately prepared the witnesses for their testimony
and called Mobley?s father as the first mitigation witness. He
testified about Mobley's childhood problems and all the schools
and juvenile institutions that Mobley had attended. He stated
that a doctor had told him that his son would “mellow out” by
age 40, and he also pleaded with the jury to spare his son's
life. The next witness was Dr. J. Steven Ziegler, who had evaluated
Mobley when he was almost seventeen years old. Dr. Ziegler testified
that Mobley had a conduct disorder that would develop into a
personality disorder and that a person who has this disorder
displays antisocial personality characteristics. Dr. Ziegler
further testified that people with conduct or personality disorders
tend to display fewer problems as they age, and that there were
some experimental drugs that had shown promise in treating people
like Mobley. Next, Summer himself testified that Mobley had been
willing to accept responsibility for his actions by pleading
guilty and accepting the maximum years for each crime. The
following witness was another lawyer, who testified that it would
have been unprofessional for Summer to plead Mobley guilty without
some type of assurance that death would not be imposed. Lastly,
Joyce Ann Childers testified about the prevalence of people with
criminal or behavioral problems in the last three Mobley family
generations. She also testified that these people had tended
to exhibit fewer aggressive tendencies (“mellow out”)
as they reached middle age. In his closing argument, Summer argued
that Mobley's personality disorder had a genetic basis, that
the jury should not sentence him to death for a disorder that
may lessen with age, and that medical technology may be able
to treat in the future.”
(4) Neurons. The basic unit of structure and function
in the nervous system and brain is the neuron, a specialized,
excitable, cell capable of conducting electrical signals. A
neuron has three basic parts: (1) cell body or soma; (2) dendrite;
and (3) axon. The dendrites and axons are long processes
that extend from the cell body which, like electrical cables,
conduct electrical impulses towards and away, respectively, from
the cell body.
The nervous system communicates by electrical signals. Its
functionality and operation relies on the flow of these electrical
signals through a chain of neurons distributed throughout the
body, connecting the brain to the motor and sensory organs. The
neurons which comprise the chain are not in physical contact
with each other, but are separated by a minute space called a “synapse.” Typically,
an axon from one neuron will form a synapse with the dendrite
or cell body of a neighboring neuron. An electrical
signal is propagated through the synaptic space. A signal
moves along the dendrite, through the cell body, and then out
along the axon. When the signal arrives at the tip of the
axon, it causes the release of specific chemical molecules called “neurotransmitters.” There
are more than a dozen different neurotransmitters; cells normally
produce only one or two kinds. The neurotransmitter, when
released from the axon, diffuses across the short, synaptic cleft. At
the other side, is the dendrite or cell body of another neuron
containing special proteins, called “neurotransmitter receptors,” which
receive the neurotransmitter like a key fitting into a lock. Attachment
or “binding” of a neurotransmitter to its cognate
receptor initiates an electrical signal which, in turn, travels
down the dendrite, into the soma, and out the axon. This
successive chain of events underlies almost all sensory and motor
functions.
Neurotransmitters and their receptors are important targets
in the treatment of mental conditions and diseases. Schizophrenia
is believed to be a defect in the dopaminergic system. Many
anti-schizophrenic drugs operate by blocking the action of dopamine
at the dopamine receptor. Such blocking drugs are referred
to as dopamine antagonists because they bind to the dopamine
receptor without stimulating it. Another target for mental
disease are enzymes involved in neurotransmitter synthesis. Monoamine
oxidase (“MAO”) is an enzyme in the synthetic pathway
for the neurotransmitters, epinephrine and serotonin. Nardil,
is a MAO inhibitor used to treat depression and anxiety. By
inhibiting MAO, synthesis of the neurotransmitter is decreased,
presumably depressing neuronal activity. There are many
strategies for pharmacologically modulating synapses. Fluoxetine,
sold under the tradename “Prozac,” blocks the re-absorption
of serotonin from the synapse, apparently prolonging the stimulatory
effect of serotonin. Prozac is commonly prescribed for
depression.
(5) The XYY myth. In the 1960’s, several studies identified
an increased frequency of men with the XYY genotype in prison
populations. These observations led to the hypothesis that
the extra Y chromosome caused aggressive and violent behavior. See,
e.g., Jacobs, 1965; Hook, 1973. The association between
the XYY genotype and antisocial behavior has been hotly debated. A
comprehensive study in 1976 of males born between 1944 and 1947
in Denmark found no support for the hypothesis. Witkins
et al., Science, 193: 547-555, 1976. Instead, they found
that in the general population XYY men did not differ from genotypically
normal XY men in violent or criminal behavior. However,
they were more likely to be taller than their normal counterparts.
These, and other studies, have also shown that XYY men scored
significantly and substantially lower on intelligence tests than
normal XY men. Schiavi et al., Arch. Gen. Psychiatry, 41:93?99,
1984.
(6) The legislature of the State of New Biology passes a statute
requiring genetic testing of 4-6 week old fetuses for a list
of 100 disease genes, including cystic fibrosis, Duchenne’s
Muscular Dystrophy, and Down’s syndrome, 20 genes involved
in the predisposition to cancer, and 25 genes involved in increasing
propensity to schizophrenia, aggression, anxiety, and neurosis. Abortion
is required if one or more such identified genes are found present
in the fetus. According to the legislative history, the
purpose of the statute is to protect the community as a whole
from disease, and to conserve economic resources by eliminating
the high costs associated with chronic disease. Is this
a valid exercise of the state’s police power?
|
