Marine viruses may use their own photosynthesis genes to enhance their fitness by temporarily boosting the energy production of bacteria they infect, scientists report this week in Nature. The advantages the viruses transfer to their hosts "may have helped enable these bacteria to become the dominant photosynthetic organisms in their habitats," co-author Debbie Lindell at the Massachusetts Institute of Technology at Cambridge told The Scientist. More research into how viruses could temporarily benefit a host's metabolism could shed light on their co-evolution, and what environmental factors most likely impact hosts in their habitats, she added.