science study

Human sperm may 'smell' their way to the egg

A better understanding of the new “smelling” capabilities of human sperm cells may lead to advances in contraception and fertility treatments. A new study identifies a novel odorant receptor on human sperm and shows how activating this receptor causes the sperm to make a beeline for a target. In a study appearing in the 28 March issue of the journal, Science, German and U.S. researchers report that the binding of certain compounds to the new odorant receptor (hOR17-4) found on the surface of sperm cells, triggers a series of physiological events that may result in the directed movement of human sperm. In this chemosensory response, the sperm cells travel toward elevated concentrations of a sperm-attracting substance called “bourgeonal.”

Nation’s brightest increasingly shun science

America’s top college graduates increasingly reject careers in science and engineering, researchers have found, raising concerns about America’s technological future. Faced with the prospect of low-paid apprenticeships and training lasting a decade or more ? and constricted job opportunities even after that ? more of the brightest young Americans are instead pursuing the quicker and surer payoffs offered by business and certain professions, according to the Washington study. “With the notable exception of biological sciences, many of the top U.S. students with potential to become scientists are turning toward other career paths,” said one of the study’s co-authors.

People from distant lands have strikingly similar genetic traits

Scientists have long recognized that, despite physical differences, all human populations are genetically similar to one another. But a new study in the journal Science concludes that populations from different parts of the world share even more genetic similarities than had previously been assumed. At the same time, researchers found that tiny differences in DNA can provide enough information to identify the geographic ancestry of individual men and women.