SCIENCE NEWS This Week Genetic Lynx North American lynx make one huge family A new study of lynx in North America suggests the animals interbreed widely, sometimes with populations thousands of kilometers away. This genetic finding could be a boon for conservationists hoping to secure the cats’ future.

The Canada lynx has recently been offi- cially designated as athreatened species in the United States, spurring studies of the animals’distribu- tion and behavior. Researchers have been squabbling over one thorny issue for

ulations live in iso- lated pockets or travel long distances to mix with other groups? Lots of long-distance interaction might point toward policies that maintain con- nections between known lynx habitats.

Researchers have long known that the Canada lynx popula- tion in any given area

decades: Do lynx POP-

New genetic data may help solve this riddle. Michael K. Schwartz at the United States Forestry Service (USFS) Rocky Mountain Research Station in Missoula, Mont., led ateam of federal biologists in an examination of lynx DNA derived from 17 populations throughout North Ameria

Using mathematical models, the researchers compared the DNA samples and found that lynx from Alaska to Wyoming share strikingly similar genetic profles. The findings suggest that the ani- mals commonly travel far and wide, inter- breeding with the populations encountered along the way.

‘We found evidence of high gene flow.. . which offers a lot of support for the dis- persal hypothesis,” says Schwartz. His team describes its findings in the Jan. 31 Nature.

Despite evidence for epic lynx journeys, it’s been difficult to establish whether this behavior is typical and far-flung animals are closely related, says Keith Aubry of the USFS Pacific Northwest Research Station. The fact that lynx from Alaska to the Rocky Mountains are physically similar enough to be classed as a single subspecies ‘‘suggested that kind of connectivity,” he notes. But the new genetic study confirms it, he says.

The cause of the domino effect during boom times in lynx populations has been difficult to determine by radio tagging and mapping, adds Lisette Waits of the University of Idaho in Moscow. Huge amounts of data from many years of obser- vation are required. However, by using DNA, she says, it’s possible to rapidly answer many ques- tions regardingbehav- i o d strategies.

The new finding may have far-reach- ing implications for - -

undergoes- several- FACING THE FUTURE New data lynx conservation pol- year cycles of boom icy and practice. To and bust. Booms fol- ensure afutureforthe low continentwide lynx, “we must focus

indicating how lynx populations fit together may guide conservation efforts.

patterns, with population explosions start- ing far inland and fanning toward coast- lines like a trail of falling dominoes.

A major question for conservation pol- icy is, What lies behind this surge? Some sci- entists contend that lynx communities are isolated and that the wavelike pattern arises from extrinsic factors such as weather con- ditions. Others explain the patterns by way of a dispersal mechanism, that is, under crowded conditions, lynx migrate to less populous areas.

efforts on maintaining connectivity between lynx populations,” proposes Schwartz.

He notes that the genetic materials used in this study are distinct from the lynx samples in a separate project that were recently the target of fraud allegations. Seven state and federal scientists stand accused of misrepresenting the origin of fur samples submitted for identification to the lab of L. Scott Mills, one of Schwartz’ collaborators. Officials now are investi- gating the case. -J. PICKRELL

Drink and Thrive Moderate alcohol use reduces dementia risk Alcohol doesn‘t often get billed as a brain food, but new research suggests that booze offers at least one cerebral benefit. It may reduce aging drinkers’ risk of developing Alzheimer’s disease and other forms of dementia.

Although extreme alcohol consumption kills brain cells, there’s contradictory evi- dence about whether long-tern drinking has permanent effects on cognitive abilities such asreasoningandmemoT. Prolonged, exces- sive drinking can lead to the liver disease cir- rhosis and may contribute to breast cancer risk, however. Drinking is also responsible for many accidental injuries and deaths.

Nevertheless, alcohol in moderation pro- motes cardiovascular health by boosting concentrations of good cholesterol and inhibiting the formation of dangerous blood dots (W: 2/28/98,p. 142). Additional com- poundsinredwineseemtoben&theheart

ing also appears to guard against macular degeneration, an incurable eye disease.

Now, the brain joins the list of organs that seem to benefit from alcohol.

From 1990 to 1999, Monique M.B. Breteler and her colleagues at the Erasmus Medical Centre in Rotterdam, the Nether- lands, observed 5,395 individuals age 55 and older who didn’t initially show signs of dementia. Of these participants, 1,443 “moderate drinkers” reported having one to three alcohol beverages of some sort each day, while 2,674 said they consumed less than one drink and 165 acknowledged hav- ing four or more drinks per day. Another 1,113 participants abstained altogether.

Over an average follow-up period of 6 years, 146 participants developed Alz- heimer’s disease and another 51 got some other form of age-related dementia. That put overall risk for dementia at 3.7 percent. Risk was about 4 percent among non- drinkers, light drinkers, and heavy drinkers, but only 2.6 percent of the moderate drinkers developed dementia

Once the researchers adjusted their data to account for participants’ sex, age, weight, blood pressure, use of tobacco, and other factors that influence dementia, moderate drinkers showed only 58 percent the risk of dementia calculated for nondrinkers, Breteler‘s team reports in the Jan. 26 Lancet.

Moderate drinkers had an even more marked decrease in vascular dementia, a condition in which blockages in blood ves- sels in the brain cause recurring, minor strokes that gradually erode cognitive abil- ity. The researchers hypothesize that since

and bloodves~ls (SN: 1/5/02,p. 8). Drink-

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- SCIENCE NEWS

than in cancers that remain in remission after initial treatment.

At present, physicians derive a breast cancer prognosis from the tumor’s size, the extent of its spread, the degree to which

tern of gene activity in some of those women, pinpointing who should get further treat- ment, such as chemotherapy, he says.

Although such a genetic profile is cur- rently very expensive to generate, Friend

This Week vascular disorders are linked to dementia in elderly people, alcohol’s benefits to blood ves- sels might indirectly sustain brain function.

Jean-Marc Orgogozo, a neurological epidemiologist at the University of Bor- deaux in France hails the study. He and his colleagues have found that French wine drinkers over the age of 65 have a reduced risk of dementia. The new research sup- ports that finding, shows that beer and hard liquor-not just wine-are protective, and establishes the effect in somewhat younger people, he says.

John R. Copeland, a psychiatrist who’s retired from the University of Liverpool in England, d s the Dutch finding ”very inter- esting but not unexpected.” Although Copeland’s research suggested that heavy, long-term drinking reduces cognitive ability in elderly men, people who show bendts in the new study consumed alcohol in more modest, “therapeutic quantities: he says.

However, Orgogozo questions exactly what quantity constitutes a happy-hour medium. His own past research suggests three to four drinks per day are required to help ward off dementia. The lower threshold for benefit in the Dutch study may reflect participants’ underreporting of alcohol consumption in a country that, unlike France, attaches a stigma to drink- ing, Orgogozo says. -B. HARDER

Ominous Signals Genes may identify the worst breast cancers - Some women with breast cancer respond well to treatment while others succumb to the disease, even when the cancer in both cases appears to have been caught early and was treated similarly. A growing pool of evidence suggests that the genetic nuances of tumor cells account for the con- trasting outcomes.

To turn those genetic traits to medical advantage, several research groups have begun scanning DNA in breast-tumor cells to determine which of thousands of genes are most or least active in aggressive can- cers. A U.S.-Dutch team doing such gene profling reports in the Jan. 31 Nature that certain patterns of activity crop up more frequently in the most deadly breast can- cers-those that spread beyond the breast-

the tumor cells differ from normal cells, molecular character- istics of the tumor cells, and the patient’s age. ’hmor removal and radia- tion therapy cure most women whose cancer is confined to the breast. Nonethe- less, one-fourth of such women subse- quently have cancer crop up elsewhere, says Stephen P. Ethier, a molecular biologist at the Uni- versity of Michigan School of Medicine in Ann Arbor.

says the cost is drop- ping and could be down to “hundreds of dollars” per test in the near future.

Meanwhile, the 70 genes highlighted in this study include many that hadn’t been previously implicated in breast cancer. Researchers might start investi-

GENES IN TUMORS In this microarray, gating these genes each row represents a breast tumor and individually to see if each column, a gene. Black indicates a any presents atarget normally functioning gene, red shows high for therapy, Friend activity, green designates suppressed says. The genes that activity, and gray is indeterminate. Patterns are overactive in in such a grid may reveal aggressive cancers. aggressive cancers

and the proteins To obtain genetic clues to this risk, the

researchers analyzed samples of 78 breast tumors that had been surgically removed from women. All the patients had breast can- certhatwasco~nedtothebreastatthetime of diagnosis. Of these, 34 women had can- cer arise outside the breast within 5 years.

Using microarray analysis-a lab tech- nology that reveals activity in individual genes-the researchers scanned roughly 25,000 genes in the tumor cells. Of the genes, 4,968 showed up as either especially busy or sluggish in at least three tumors.

Next, the researchers used a computer to look for patterns of gene overactivity or underactivity associated with aggressive tumors. Assessed this way, 70 genes stood out. The team tested the accuracy of this genetic profile by using it to determine whether a tumor in a new set of samples came from a woman who had an aggres- sive cancer or had one that remained under control.

Thep~~eenabledthescien~topredict correctly-albeit retrospectively-the fate of 17 of 19 cancer patients, says study coauthor Stephen H. Friend, a molecular biologist at Rosetta Inpharmatics in Kirkland, Wash.

The emerging technology is enabling sci- entists “to think differently about how we dassifjrbreast cancer,” says Ethier. While the technique still doesn’t permit a physician to give all women accurate prognoses, a reiined version “could ultimately. . . change the way a person might be treated,” he says.

The next step for mearchers will be to test the method on hundreds of additional patients, Friend says. Especially good can- didates would be women whose breast can- cer is caught and removed early and who don’t appear to need chemotherapy. M i m - ray analysis could turn up a dangerous pat-

they encode may offer new avenues to slow breast cancer growth. -N. SEPPA

Viral Parts Chemists convert virus into nanoscale tool

Unless they have a cold, most chemists give viruses little thought. That may change now that some researchers are decorating these microbes with avarietyofmolecules-mak- ingthe germs into potential building blocks in electronic circuits and new materials, as well as tools in biomedical therapies.

In recent research, scientists used a virus with a diameter of 30 nanometers, an appropriate choice for eventually control- ling the synthesis of materials on scales that have been difficult to master, says chemist M.G. Finn of the Scripps Research Insti- tute in La Jolla, Calif. W e have to do some things to [the virus to] make it perform, but at least the starting point here is just the right size,” says Finn.

In the Feb. 1 Angewandte C h i ? Inter- national Edition, Finn, Scripps biologist John E. Johnson, and their colleagues report decorating a virus whose genetics and structure are well understood. Called cowpea mosaic virus, it attacks plants including many types of beans. The shell of each virus consists of a geometric tiling of 60 identical protein units.

First, the researchers found that the only sites where the natural virus reacts chem- ically are 60 sulfur-containing chemical groups-one buried within each of its shell- protein units, says Finn. Next, the team created a genetic mutant of the virus in

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