UC Berkeley researcher probes evolution of alcohol use

BERKELEY, Calif. (KGO) -- A researcher at the University of California is following a trail that could someday explain why many humans have a taste for alcohol. But this trail doesn't lead to a bottle or even a bar stool, but the jungles of Africa and Central America.

"We know what humans are up to, but do monkeys get into the bottle given the opportunity? And, the answer is yes, but the question is how much alcohol is out there in the natural world," says Robert Dudley, Ph.D.

Dudley is a professor of integrative biology at UC Berkeley. In his new book, , he explores how diet and evolution may have favored animals who could detect and process the alcohol contained in wild foods. To document how much alcohol might be available in the wild, Dudley and his team collected samples and analyzed them in portable spectrometers, including fermenting fruit, found on tropical trees.

"Depending how many of these fruits you eat, you can get concentrations in pulp all the way from .5 percent up to 8 percent," he says.

Rather than just catching a buzz, he believes an alcohol attraction might help monkeys and chimps locate fruit that's hidden in thick foliage or buried in the ground-cover. If true, the behavior may stretch back more than 18 million years.

But if monkeys, and perhaps our own evolutionary ancestors, had a genetic attraction to alcohol, what does it mean for modern humans who often enjoy, and sometimes abuse, alcohol?

Dudley points out that animals typically stop eating when they're full, limiting the amount of alcohol they ingest. And drunkenness could also make them vulnerable to predators. With modern humans the trouble may have started when we learned to distill alcohol from plants, in concentrations much higher than those found in nature.

"So one approach would be to look at the enzymes that metabolize alcohol and compare those in humans, with those of our closest relatives -- so the great apes, chimps, orangutans, gorillas -- and see if there have been any changes in recent evolutionary times," Dudley says.

He believes the breakthrough would be identifying specific genes that allow some humans to drink moderately, while other become vulnerable to alcohol abuse. It is a potentially life-saving difference, hidden by millions of years of evolution.

[b][i]Written and produced by Tim Didion[/i][/b]