Alcohol gene first appeared in vertebrates some 450 million years ago

It was previously thought that the gene for alcohol dehydrogenase (ADH) - a protein that breaks down ethanolevolved in humans.

But then the enzyme was revealed in animals, leading one to believe that they evolved a version of ADH to break down ethanol in the fermenting fruit of flowering plants, which appeared on Earth around 140 million years ago.

And now, Hector Riveros-Rosas at the National Autonomous University of Mexico in Mexico City has overturned these stories.

He analysed the available ADH gene sequences from animals, and says they suggest that ADH first appeared in vertebrates some 450 million years ago - long before flowering plants evolved, and even before the conifers that appeared around 315 million years ago began producing sweet berries that can ferment to generate small quantities of alcohol, reports New Scientist.

Riveros-Rosas believes ADH was initially used to metabolize natural hormones, and was later seized for our drunken pleasures.

He points out that studies have found evidence that ADH breaks down naturally produced hormones such as dopamine much faster than ethanol.

source: DNA