An escalating confrontation on Native land southwest of Tucson threatens to upend decades of uneasy cooperation between the Tohono O’odham Nation and the United States.

The federal judge denied a Democratic lawmaker’s request for an emergency hearing on the closure, which began on Tuesday.

Scientists have discovered a powerful gene-targeting system in viruses. Billions of years old, VIPR seems to predate CRISPR and may be even more effective.