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ptaylor@globeandmail.com

Don't be insulted if someone says you have a lot in common with a cow. It turns out we do, indeed, share certain genetic characteristics with our bovine friends - and more than you might have imagined.

After six years of work, 300 scientists from 25 countries including Canada have just finished sequencing - or mapping - the genetic code of cattle.

Their findings, published today in Science and the online journal BioMed Central, will likely lead to agricultural advances that help beef up dairy and meat production.

But some researchers believe the cow genome can also teach us a few things about our own genetics.

"Mice have been used as a model for many medical studies, and now we have convincing evidence that cattle genes are actually more similar to human genes than mice," said Fiona Brinkman of Simon Fraser University in Vancouver.

"There are over 300 types of genes that are shared between humans and cattle that are not found in mice," said Dr. Brinkman, one of the scientists involved in the Bovine Genome Sequencing Project. "It is a huge benefit having [decoded] this genome."

Although it's been several years since scientists completed a map of the 20,000 to 25,000 genes that make up the human genome, they still don't know the functions of a lot of this genetic material. By comparing the human genome with that of other species, researchers hope to gain a better understanding of how our biological blueprint has evolved.

Dr. Brinkman and colleagues in Canada and Ireland have focused their attention on genes that regulate the bovine immune system.

The team has already discovered some of these genes are going through "unusual rates of evolution," Dr. Brinkman said. "It seems their immune systems have undergone accelerated change to help them survive in an environment of domestication."

She noted that cattle are potentially exposed to lots of infectious diseases because they are kept in close quarters with each other. Over the generations, only those with the fittest, and most robust, immune systems have tended to survive.

In a similar vein, the human immune system appears to be undergoing relatively rapid changes. And those changes are likely linked to the fact that large numbers of people live in close proximity - just like cows.

"From an evolutionary standpoint, the similarities are fascinating," she said.

ALCOHOL CANCER RISK

If you are of East Asian descent and even a tiny bit of alcohol makes you red in the face, you could be at an elevated risk of developing esophageal cancer.

About one-third of East Asians - Japanese, Chinese and Koreans - develop a flushed faced when they drink booze. The flushing is caused by an inherited deficiency in an enzyme called ALDH2 that helps metabolize alcohol.

Without sufficient levels of the enzyme, the body has a hard time breaking down alcohol into a non-toxic form. Those with an extreme deficiency can't tolerate any alcohol. They suffer nausea and a rapid heart beat as well as a red face.

Yet, ironically, it's the milder form of the deficiency that is potentially most hazardous. That's because the afflicted might keep drinking despite the flushing, and make themselves vulnerable to cancer of the esophagus. Essentially, the long tube that connects the throat to the stomach is exposed to the toxic effects of alcohol without the neutralizing effects of the enzyme.

In a recent issue of the on-line journal PLoS Medicine, Japanese and U.S. researchers wrote an article to alert physicians and the public about the potential danger.

Akira Yokoyama of Japan's Kurihama Alcohol Centre, a co-author of the article, noted that esophageal cancer is a relatively rare disease. But moderate to heavy alcohol consumption can raise the risk substantially in this vulnerable population.

For instance, just three out of every 100,000 non-drinking Japanese men would be diagnosed with the cancer annually. Among moderate to heavy drinkers, that number jumps to 260 men per 100,000 men between the ages of 40 and 79.

Dr. Yokoyama doesn't feel that those with the enzyme deficiency need to give up alcohol completely. "But we

can educate them about the cancer risk and advise to reduce alcohol consumption to the light drinking category,"

he said in an e-mail. Regular esophageal-cancer screening tests would also be a good idea, he added.

FASHION RISK

In fashion-conscious France, being thin is still in. A new study shows that France has the highest proportion of clinically underweight women in Europe, yet only half of them think of themselves as being too thin.

"This shows that what people consider an ideal weight in France is lower than in other countries," the study's author, Thibault de Saint Pol of France's National Institute for Demographic Studies, told Agence France-Presse.

"When women are underweight, they do not devalue that at all. But as soon as they cross the line into overweight, they find that unacceptable," the researcher added.

Medical experts are concerned about the obesity epidemic that is sweeping through many countries. But being severally underweight carries health risks, too, especially if it results from eating disorders.

In the study, France was the only country in which more than 5 per cent of women were deemed to be medically underweight.