An immune system quirk may help anglerfish fuse with mates during sex
For deep-sea anglerfishes, sex resembles an organ transplant. It’s hard to find a partner in the dark depths, so a tiny male anglerfish fuses its tissues to a more massive female during mating, allowing the two to share not only sperm but even blood and skin (SN: 7/26/75). The creatures are the only animals known to mate in this parasitic way. How males and females fuse and avoid being rejected by each other’s immune systems — like a mismatched organ transplant — has been a mystery. Now, a study finds that anglerfish might not have to evade the immune system in the first place. Some species lack key genes involved in the body’s immune response, which may make fusion without deadly consequences possible, researchers report online July 30 in Science. In vertebrates, immune protection typically involves a bodily response called adaptive immunity that identifies and eliminates foreign threats like viruses. Immune cells,...