Patterns of DNA

Differences Mapped

Scientists have mapped patterns of tiny DNA differences that distinguish one person from another, an achievement that will help researchers find genes that promote common illnesses such as heart disease and diabetes.

The map represents "a real sea change in how we study the genetics of disease," said David Altshuler, a leader of the project, which included more than 200 researchers from six nations.

Scientists want to find disease-related genes as a means for diagnosis, prediction and developing treatments. Such genes give clues to the biological underpinnings of disease, and so suggest strategies for developing therapies.

Genes that predispose people to common disorders -- heart disease, cancer, diabetes, asthma and others -- are hard to find. But the new "HapMap" -- taken from the genetics term "haplotype" -- opens the door to launching comprehensive searches through the human DNA for those genes, said Altshuler, who works at the Broad Institute of the Massachusetts Institute of Technology and Harvard.

Screening Pares Deaths

As Much as Therapy

Routine screening mammograms contribute just as much as hormone therapy and chemotherapy in slowing the rate of death from breast cancer, a study shows.

The study, based on seven statistical analyses by 43 researchers, found that screening as practiced in the United States reduced the rate of death from breast cancer by 7 percent to 23 percent, depending on the analysis. The study is published today in the New England Journal of Medicine.

Chemotherapy and hormone therapy such as tamoxifen reduced the death rate by 12 percent to 21 percent, according to the study led by Donald Berry of the University of Texas M.D. Anderson Cancer Center in Houston. A combination of screening and other therapy reduced the death rate by an estimated 25 percent to 38 percent.

Study Cites Doctor Loss

From Poorest Countries

Doctors from the world's poorest countries are leaving to pursue jobs in richer nations, draining much of the developing world of critical medical care, a study says.

Sixty percent of international medical graduates in the United States come from poorer countries, researchers at George Washington University found. The rate was 75 percent in Britain, 43 percent in Canada and 40 percent in Australia, the study published in the New England Journal of Medicine said.

"Nine of the 20 countries with the highest emigration factors are in sub-Saharan Africa or the Caribbean," said lead researcher Fitzhugh Mullan.

U.S. Diabetes Cases

Rise by 14 Percent

Almost 21 million Americans have diabetes, a 14 percent jump from two years ago, according to a report by the U.S. Centers for Disease Control and Prevention.

Seven percent of the U.S. population has diabetes, and as many as a third have not yet been diagnosed, the Atlanta-based health agency said. An increase in Type 2 diabetes drove the number of people with the disease up from 18.2 million, or 6.3 percent of the population, in 2003, the CDC said.

Diabetes is the sixth-leading cause of death in the United States, the CDC said.

-- From News Services