Dana Wensley: Gene-typing divides society

The last century has been called the century of the gene. It began with the rediscovery of the Augustinian monk Gregor Mendel's laws of genetic inheritance, and culminated with the partial sequencing of the human genome in 2001.

In 100 years the gene emerged from being a mere hypothesis, to being a material object, known to be on chromosomes in every cell of the human body.

Everything today seems to have a genetic explanation. If we believe what we read and hear in the media, we would think that there was a gene for being left-handed, a gene for believing in God, and a gene for risk taking, a gene for homosexuality ... the list goes on.

While genes may play a role in a number of these characteristics and behaviours, it is misleading to think that "having a gene" for these things means a person is destined to act in a particular way. For most conditions we also need an environment that triggers these genes to act in a way that displays the specific behaviour.

New Zealand researchers have recently ventured into the controversial area of genetics and behaviour with their latest research on New Zealand Maori.

At the 11th International Congress on Human Genetics in Australia this week, Rod Lea, a researcher based at ESR in Wellington, investigated what has been dubbed the "warrior gene".

Lea and his team discovered a repeat sequence on the X chromosome (previously linked to risk taking and aggressive behaviour) is found in greater numbers in the Maori male population compared to Caucasian males. Is this significant medically, socially, or politically, or is it merely a great "sound-bite"? What sense can the general public make of this discovery, reported as the "warrior gene"?

One of the reported implications is that risk taking and aggressiveness leads to higher rates of gambling, criminality and other antisocial behaviours.

First we need to put this in context. Even if we should discover a genetic fingerprint that suggests some people will be more prone to exhibit antisocial behaviours, this does not mean they are destined to do so.

The "warrior gene" is actually a sequence in the repeating letters of our DNA that, with the right environmental triggers, may result in some unwanted behaviours. It is by no means a foregone conclusion.

To simplify it more, consider basic chemistry at school, where we learned water is made up of the building blocks of two hydrogen molecules and one oxygen molecule.

If we put this molecule in low temperatures we get ice, if we put if in high temperatures we get gas or steam. This tells us that the same molecular structure can be either water or a gas or a solid. Unless we know something about the environment in which the molecule is placed, we do not know if we should put on our ice-skates or a swimsuit.

Genes are a little like this. According to latest Ministry of Health statistics 1.2 per cent of the population are estimated to be problem gamblers, with Maori and Pacific people disproportionately affected.

Before we jump to accept a genetic causation consider the other important factor - almost two thirds of problem gamblers live in New Zealand's 40 per cent most socio-economically deprived areas.

Problem gambling is linked to lower socio-economic status.

Misinformation about genes and what they mean leads to discrimination. This is something New Zealand Maori and all New Zealanders have an interest in minimising, and it is no wonder that Maori leaders have reacted harshly to Lea's latest research.

In June, a joint study by the Ministry of Health, Massey University and University College London, published its findings on the impact of racial discrimination on the health of New Zealanders.

The research showed Maori, Asian and Pacific people were more likely to experience racial discrimination than New Zealand Europeans. Those who reported discrimination were more likely to report poorer health, lower physical and mental health, more cardiovascular disease, and higher rates of smoking than others. This was true even after correcting for socio-economic status.

In relation to the high rates of criminal prosecutions among New Zealand Maori, last year the Ministry of Justice described this as being a "significant" cause of concern.

This does not mean there is a gene for criminal behaviour. What it suggests is something is going on that makes New Zealand Maori more likely to commit, and be charged with criminal offences.

According to a report also released this week by the Ministry of Social Development, the gap between New Zealand Maori and Pakeha has widened further. While Maori have made some gains in the last 20 years in employment and income level, Pakeha have made larger gains.

According to recent World Health Organisation statistics, one common uniting factor of the world's 300 million indigenous people is the fact that their health is generally worse than others. They have higher infant mortality rates, a lower life expectancy, greater morbidity rates, and more chronic illness.

We need to address social problems with changes in social policy.

Unfortunately genetics tends to confirm social prejudices, and make it less likely we will work together as a society.

Genetics tells us there are more genetic differences within racial or ethnically defined groups than between them.

If we start looking for genetic differences we will find them. But, before we do, we should know what to do with them and make sure genetic (mis)information does not dictate social policy.

* Dana Wensley is a research fellow at the Human Genome Research Project based at the University of Otago.