ATLANTA — Homo naledi, a rock star among fossil species in the human genus, has made an encore. Its return highlighted debate over whether this hominid was a distinct Homo species that purposefully disposed of at least some of its dead. H. naledi made worldwide headlines last year when researchers announced the discovery of an […]

Iron, says aging expert Naftali Raz, is like the Force. It can be good or bad, depending on the context. When that context is the human brain, though, scientists wrangle over whether iron is a dark force for evil or a bright source of support. Some iron is absolutely essential for the brain. On that, […]

In case there were any lingering doubts, three new studies published May 11 could cement the theory that Zika virus infection in utero causes birth defects. One shows that mice engineered to be susceptible to Zika can pass the virus to offspring via the placenta. In these pregnant mice, which have severely crippled immune systems, […]

A new study sounds a cautionary note for a controversial procedure used in creating “three-parent babies.” That procedure replaces defective mitochondria, the energy-generating organelles in cells, with healthy ones. But even a tiny amount of defective mitochondria may replicate and take over the cell, researchers report online May 19 in Cell Stem Cell. Exactly which […]

A “dirty blizzard” bombarded the Gulf of Mexico seafloor with pollution from the 2010 Deepwater Horizon oil spill for months after workers sealed the leak, new research shows. Marine snow, an organic material that floats down from the ocean’s upper layers, carried the pollution to the seafloor, researchers report the week of May 30 in […]