How a lost gene gave the sea spider its bizarre, leggy body

Scientists have decoded the sea spider’s genome for the first time, revealing how its strangely shaped body—with organs in its legs and barely any abdomen—may be tied to a missing gene. The detailed DNA map shows this ancient creature evolved differently from its spider and scorpion cousins, lacking genome duplications seen in those species. With new gene activity data, researchers now have a powerful tool to explore how sea spiders grow, regenerate, and evolved into some of the oddest arthropods on Earth.