Noted

A team of Yale biologists has identified the molecule that enables a sperm to find its unlikely way to an egg. Reproductive physiologist Jean-Ju Chung and her colleagues isolated a GPS-like protein called EFCAB9 that is critical to finding the whereabouts of the ovum. It acts as a sensor, responding to environmental cues in the female reproductive tract that regulate the activity of the sperm calcium channel (CatsPer)—signalling the apparatus within the sperm that powers the whip-like motions of its tail. The discovery, reported in Cell, may lead to improved fertility therapies and to contraceptives that don’t rely on hormones.

Many astronomers believe the Moon was formed from debris left after a huge object slammed into the Earth. That hypothetical object is named Theia (mother of the Moon goddess in Greek mythology). But there’s a problem:  according to previous studies, a collision of Theia and proto-Earth would form a moon made largely of Theia. In Nature Geoscience, Yale geology and geophysics professor Shun-ichiro Karato, with colleagues in Japan, proposed a solution. If Theia had plowed into a just-formed, hot “proto-Earth while it was covered with a magma ocean,” the result (after the splash) would be a Moon covered with terrestrial minerals—as indeed it is.

View full image

Frogs, salamanders, and other amphibians are often considered the canaries in the environmental coal mine. About 40 percent of the world’s nearly 8,000 amphibian species are known to be at risk of extinction, likely due to pollution, habitat destruction, and climate change. But that estimate may be far too low. An international assessment team led by Pamela González-del-Pliego, a recent postdoctoral ecologist at Yale’s Center for Biodiversity and Global Change, developed techniques to gauge risks to the 2,200 amphibian species for which data is sparse. They found that nearly half of those species, most of them in South America and Southeast Asia, were in serious trouble. The team’s Current Biology article discusses “where urgent conservation is needed to avert their loss.”