Remember biology class where you learned that children inherit one copy of a gene from mom and a second from dad? There's a twist: Some of those genes arrive switched off, so there is no backup if the other copy goes bad, making you more vulnerable to disorders from obesity to cancer.

Duke University scientists now have identified these "silenced genes," creating the first map of this unique group of about 200 genes believed to play a profound role in health.

More intriguing, the work marks an important step in studying how our environment -- food, stress, pollution -- interacts with genes to help determine why some people get sick and others do not.

The team's findings were published online today by the journal Genome Research. Next comes work to prove exactly what role these genes play.

Usually, people inherit a copy of each gene from each parent and both copies are active, programmed to do their jobs whenever needed. If one copy of a gene becomes mutated and quits working properly, often the other copy can compensate.

Genetic imprinting knocks out that backup. It means that for some genes, people inherit an active copy only from the mother or the father. Molecular signals tell, or "imprint," the copy from the other parent to be silent.


Africa has slashed deaths from measles by 91 percent since 2000 with an immunization drive, a rare success story for the continent, health officials said Thursday.

Measles deaths worldwide have fallen from an estimated 757,000 to 242,000 -- 68 percent -- between 2000 and 2006, according to the Measles Initiative, which includes the American Red Cross, the U.S. Centers for Disease Prevention and Control, the World Health Organization and UNICEF.

In Africa, the deaths dropped from 396,000 to 36,000.

The Measles Initiative vaccinates children 9 months to 14 years old and seeks to vaccinate infants before their first birthday. Trained volunteers reach remote areas on bicycles, horses and even camels, and provide other basic health services, including distributing nets for malaria prevention.