Science notes: Migration study of North African Jews

  • Updated: August 11, 2012 - 4:58 PM

MIGRATION STUDY OF NORTH AFRICAN JEWS

North African Jews are more closely related to Jews from other parts of the world than they are to most of their non-Jewish neighbors in North Africa, a study has found.

Their DNA carries a record of their migrations over the centuries. Some bits trace back to the Middle Eastern peoples thought to have migrated to North Africa more than 2,000 years ago, while others are linked to Spanish and Portuguese Jews who fled to North Africa after their expulsion from the Iberian Peninsula in the late 15th century, the study's authors said.

The discovery falls in line with other research showing that Jewish people from Europe and the Middle East share more DNA with one another than they do with outside groups, said Dr. Harry Ostrer, a medical geneticist at the Albert Einstein College of Medicine in New York and lead author of the report, published in the Proceedings of the National Academy of Sciences.

DAD'S JOB CAN AFFECT BABY'S HEALTH

It's long been known that the environment of the mother during pregnancy can affect a newborn's health. New research suggests that a father's behavior is important, too.

Scientists at University of North Carolina-Chapel Hill have found that different occupations may bring increased risk of birth defects. For example, photographers seem to have a greater risk of having a child with eye defects. The children of landscapers have a greater risk for gastrointestinal defects.

Yet lead author Tania Desrosiers, an epidemiologist at the university's Gillings School of Global Public Health, cautioned that birth defects are rare and the heightened risks are small. "Dads shouldn't worry or change jobs," she said.

The scientists looked at more than 60 jobs and 60 defects, using data from 10,000 pregnancies with defects and 4,000 live births without defects. The paper was published in Occupational and Environmental Medicine.

Although the study establishes a correlation between jobs and defects, it does not establish the cause. It could be that DNA in sperm is damaged by chemical or radiation exposure.

Different occupations have exposure to different chemicals. Janitors are around cleaning products, and photographers are exposed to developing solvents. Drivers are near diesel fumes, while landscapers are around pesticides. But some surprising jobs, such as mathematicians and computer scientists, had elevated risks for certain defects. Desrosiers said the simple act of sitting might raise the temperature in the genitals and cause sperm changes.

"Dads do play a role," she said. "The next set of studies will try to figure out why."

TEST MAY PREDICT WOMEN'S BONE RISK

A simple urine test before a woman reaches menopause may predict her risk of bone fracture, researchers report. Several indicators of bone deterioration are known to be associated with fracture, but only older women and men are routinely tested for them. Now, researchers report that levels of a substance called cross-linked N-telopeptide of Type 1 collagen, or NTX, which is released into the urine when bones weaken, can predict the risk for future fracture in premenopausal, asymptomatic women.

In a prospective analysis published online in the journal Menopause, the scientists studied 2,305 healthy premenopausal women ages 42 to 52, measuring NTX at the start of the study and following them for an average of more than seven years. During that period, 184 of them suffered at least one fracture. The scientists -- led by Jane Cauley, a professor of epidemiology at the University of Pittsburgh Graduate School of Public Health -- found that women with a baseline NTX above the median were 59 percent more likely to have a fracture than those whose level was below the median.

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