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The Genetics Of Violence Essay, Research Paper

The Genetics of Violence

Introduction

We, in the 1990?s, are slowly and inevitably being faced with the

sociological and biological implications of impending genetic power. This power

is analytical, in such cases as the Human Genome Project, which will hopefully

succeed in mapping out the genetic code for the entire human genetic composition.

Moreover, this power is preventative and participatory in that it can be, and is

being, used to control the behavior of humans and other animals. This new power,

in the eyes of many, is as risky and potentially hazardous as atomic energy: it

must be treated carefully, used under close supervision, performed under

professional consent and observation, otherwise, people will begin to see this

new genetic power as a dangerous drawback, rather than an advancement of human

culture.

One of the most highly contested and objectionable topics of genetic

power is the analysis of crime, violence, and impulsivity. Doubtless, most will

agree that children are not born with a natural affinity for violence and crime;

yet, new genetic studies are beginning down a long road of finding the

hereditary basis for impulsivity. While these studies continue to search for the

genetic source of aggression, child testing programs, drug manufacturers, civil

rights activists, lawyers, and anxious citizens await the resulting testimony of

the scientists. The social implications of the genetic search for aggressive

tendency is seen by some as a great step forward, by others as a dangerous power

with the ability to give birth to another Holocaust, and by still others as

racist.

At one time, it was believed that one?s character could be determined

from the bumps in one?s skull. Much later, in the 1960?s, as science marched on

in its regular pace, it was theorized that carriers of an extra Y (male)

chromosome were predisposed to criminality. Today, we are faced with the power

to determine and alter one?s character through genetics. We must collectively

decide whether the ultimate price, not of money but of natural evolution, is

worth the ultimate result.

Behavioral Genetics and Aggression

One day in 1978 a woman entered the University Hospital of Nijmegen, the

Netherlands, with complaints regarding the men in her family. Many of the men

seemed to have some sort of mental debility, including her brothers and her son.

In time, a pattern of strange behavior of the men emerged: one had raped his

sister, and, upon being institutionalized, stabbed a warden in the chest with a

pitchfork; another tried to run over his boss in an automobile after he had

criticized the man?s work; a third had a regular habit of making his sisters

undress at knife point, and two more were convicted arsonists. Additionally, the

known IQ?s of the men were typically around 85. The history of this sort of

behavior was found to be typical, as nine other males in the family, tracing

back to 1870, had the same type of disorder. It became evident that there was

something wrong in the lineage of the family. Hans Brunner, a geneticist at the

University Hospital, has been studying the family since 1988.

It was discovered that the men had a defect on the X chromosome that

helps regulate aggressive behavior. Brunner was cued to the fact that the defect

was on the X chromosome because the trait was passed on from mother to son, and

none of the women, with two X chromosomes, were afflicted. The gene normally

codes for the production of the enzyme monoamine oxidase A (MAOA), which breaks

down three important neurotransmitters that trigger or inhibit the transmission

of nerve impulses. One of these neurotransmitters is norepinephrine, which

raises blood pressure and increases alertness as part of the body?s “fight or

flight” mechanism. Brunner believes that the lack of this neurotransmitter

could cause an excess of chemical messages to the brain, in times of stress,

causing the victim?s fury. The men?s urine found extremely low levels of the

breakdown products of the three neurotransmitters, which are the breakdown

products after MAOA has done its work.

Another of the chemicals is serotonin, which inhibits the effects of

spontaneous neuronal firing, and consequently exerts a calming effect. The lack

of this inhibitor is held responsible for the “Jekyll and Hyde” personalities of

the afflicted men, and may be responsible for their low IQ?s.

Over the course of four years, Brunner was the first to ever link and

pinpoint a single gene to aggression. Also, he analyzed the X chromosomes of 28

members of the family, compiling sufficient evidence to prove his discovery.

However, Brunner never studied the influence of a shared environment on the men.

Many other factors of genetic and biochemical signals have been shown to

greatly influence behavior. In humans, impulsive aggression has been linked to

low concentrations of a chemical known as 5-HIAA in the cerebrospinal fluid.

Scientists have found a human gene which lies on chromosome 6 that creates a 25

percent higher susceptibility to schizophrenia. Also, MAOA has been found

responsible for REM sleep deprivation in rats, which increases the incidence of

fighting among the animals. Testosterone levels in repeated sex offenders is,

almost without exception, extremely high. The

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