pore and tasting them,” Deamer says. The computer program can differenti-

ate the DNA molecules in a solution of many different types, adds team member Mark Akeson. “We can tell eight to nine different guys apart in one set,” he says. The device can differentiate between hairpin molecules that vary by as little as one base pair in their stem or one un- paired base in their loop, he adds.

Although scientists have been experi- menting with such detectors for several years, “this is the first time that nanopore technology has demonstrated this kind of resolution,” comments Daniel Branton, whose team at Harvard University also experiments with the technique.

Such sensitivity is an important step toward eventually using nanopore de- tectors to rapidly sequence DNA, says Branton. Researchers should now also work toward building stronger, longer- lasting devices, he says, since the cur- rent structures are relatively delicate.

In the current design, DNA molecules move through the pore too quickly to allow identification of individual bases, says Deamer. The team is looking for ways to slow the hairpin molecules, he says. --J. Gorman

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Study reveals male link to preeclampsia Women who suffer a pregnancy com-

plication called preeclampsia seem to pass on the tendency to their daughters, research shows. A new study suggests that women who bear sons after having preeclampsia also convey some risk to their future daughters-in-law.

This seemingly odd conclusion stems from research at the University of Utah School of Medicine in Salt Lake City. There, scientists have found that men who were born of mothers with preeclampsia are twice as likely to father children through preeclamptic pregnancies as are men born of normal pregnancies.

A man can pass genetic flaws on to his offspring at conception. It appears that some still-unidentified genetic traits can contribute to preeclampsia in his mate, says study coauthor M. Sean Esplin, an obstetrician at Utah. The work reinforces the notion that the condition-at least some of the time-is triggered by charac- teristics of the fetus, not the mother, he says. The study appears in the March 22 NEW ENGLAND JOURNAL OF MEDICINE.

“This is a very interesting and poten- tially useful study that provides evi-

dence that males contribute to preeclampsia,” says James L. Mills, a pediatrician and epidemiologist at the National Institute of Child Health and Hu- man Development in Bethesda, Md. By reviewing the medical records of three generations within families, he says, the researchers avoid the imprecision of personal recall.

Preeclampsia, which usually strikes in the third trimester of a pregnancy, is marked by high blood pressure, swelling, and protein in the urine. It sometimes leads to eclampsia, which can include seizures, coma, and death. For preeclamp sia, physicians often prescribe rest and blood pressure medication. In severe cas- es, they will deliver the baby by cesarean section to end the pregnancy, which halts the preeclampsia.

To find a hereditary link between par- ents and offspring, the researchers iden- tified 298 men and 237 women in Utah born of mothers who had preeclampsia. The scientists matched these people with a control group of 596 men and 474 women born of normal pregnancies.

Next, they compared offspring of the men and women in each group. Only 1.3 percent of children in the male control group were born of preeclamptic preg- nancies, compared with 2.7 percent of children fathered by men born of preeclamptic women, the researchers report. Nearly 5 percent of pregnancies among women born of preeclamptic mothers were themselves plagued by preeclampsia, more than triple the control group’s rate. That finding con- firms earlier studies.

Researchers have sought the source of preeclampsia for more than 100 years without success. Some studies have hint- ed that certain genes could play a role, particularly if both parents carry the same recessive gene, Esplin says.

Other research suggests that several gene variations could combine to predis- pose a person to preeclampsia, says Carl A. Hubel, a physiologist at Magee- Womens Research Institute at the Uni- versity of Pittsburgh Medical Center.

Preeclampsia is most common in first pregnancies, with less risk in later preg- nancies. However, when a women changes partners, the risk rises again, says Mills. Also, a 1998 study in Norway tracked men whose mates had preeclamp tic pregnancies. Even with a new partner, these men had nearly twice the average chance of fathering a child through a preeclamptic pregnancy. These factors are all consistent with a paternal link to preeclampsia, Mills says.

Preeclampsia affects about 1 in 20 pregnancies and appears more common in black women than white. The low inci- dences in the new study reflect the large- ly white Utah population. -N Seppa

MARCH 24,2001 SCIENCE NEWS, VOL. 159 181