Bacteria and the viruses that infect them—known as phages—coexist in soils, oceans and living organisms. Scientists have long thought this coexistence reflects a microscopic version of an evolutionary arms race: As parasites and hosts continually adapt to one another, both evolve ways to survive. But a joint study by researchers at the University of Maryland and the University of Exeter shows different pathways to coexistence.

Bacteria and the viruses that infect them—known as phages—coexist in soils, oceans and living organisms. Scientists have long thought this coexistence reflects a microscopic version of an evolutionary arms race: As parasites and hosts continually adapt to one another, both evolve ways to survive. But a joint study by researchers at the University of Maryland and the University of Exeter shows different pathways to coexistence.

Whenever a cell divides, it has to split its chromosomes perfectly between two daughter cells, and even a single mistake can be disastrous. Now, researchers from Japan have found that one of the key structures that makes this possible takes a surprising shape: a hollow sphere.