New Zealand Maori carry a warrior gene which makes them more prone to violence, criminal acts and risky behavior

Tamara McLean:

New Zealand researcher Dr Rod Lea and his colleagues have told an Australian genetics conference that Maori men have a "striking over-representation" of monoamine oxidase – dubbed the warrior gene – which they say is strongly associated with aggressive behaviour.

The unpublished studies proved that Maori had the highest prevalence of this strength gene, first discovered by American researchers but never linked to an ethnic group, he said.

This explained how Maori managed to migrate across the Pacific and survive as they had, said Dr Lea, a genetic epidemiologist at the New Zealand Institute of Environmental Science and Research.

"Maori, being very adventurous individuals as they crossed the Pacific, have carried this gene forward and it was partly responsible for them arriving in New Zealand and surviving," he told AAP.

But he said the presence of the gene also "goes a long way to explaining some of the problems Maori have".

"Obviously, this means they are going to be more aggressive and violent and more likely to get involved in risk-taking behaviour like gambling," Dr Lea said ahead of his presentation to the International Congress of Human Genetics in Brisbane.

"It is controversial because it has implications suggesting links with criminality among Maori people," he said.

"I think there is a link, it definitely predisposes people to be more likely to be criminals and engage in that type of behaviour as they grow older."

Dr Lea said he believed other, non-genetic factors might be at play as well.

"There are lots of lifestyle, upbringing-related exposures that could be relevant here so, obviously, the gene won't automatically make you a criminal."

He said the same gene was linked to high rates of alcoholism and smoking among Maori.

"In terms of alcohol metabolising genes we've found that Maori have a very unique genetic signature," he said.

"That influences their drinking behaviour so they're much more likely to binge drink than other groups which are more likely to moderate their drinking."

The scientists also studied another gene linked to obesity with a high prevalence among Maori.

Dubbed the thrifty gene, it is believed to be related to energy conservation and responsible for Maori making it to New Zealand shores in the first place.

"They specifically conserved their energy for long voyages and because of this survived, bringing their genes with them," Dr Lea said.

He said Maori were more prone to obesity than white New Zealanders, and while the researchers do not yet know the degree of lifestyle factors' role, they believe ancestral genetics play a vital role.

The group was now collecting thousands of DNA samples from Maori to investigate these traits.

They can then work out exactly what role each gene plays and use this to explore these trends in the mainstream populations.

"With Maori it's easier to find the genes than it is in the broader Caucasian population so it's a great case study," he said.

'Warrior' gene claim slammed by Maori