A new study suggests that the conventional view, which assumes that cells are "instructed" to progress along prescribed signaling pathways, is too simplistic. Instead, it supports the idea that cells differentiate through the collective behavior of multiple genes in a network that ultimately leads to just a few endpoints -- just as a marble on a hilltop can travel a nearly infinite number of downward paths, only to arrive in the same valley. The findings, published in the May 22 issue of Nature, help explain why the process of differentiating stem cells into specific lineages in the laboratory has been highly inefficient.

A protein in plants that could help to reduce the toxic content of crops grown in environments with high levels of arsenic has been discovered. Arsenic is acutely toxic and a highly potent carcinogen, but is widespread in the earth's crust and easily taken up and accumulated in crops. A team of Scandinavian researchers has revealed a set of plant proteins that channel arsenic in and out of cells.