Tiny tardigrades are amazing: the seemingly indestructible animals are the only ones known to survive the vacuum of space, and now researchers publishing in PNAS report one-sixth of their DNA comes from foreign organisms.
Tardigrades, the researchers said, survive extreme temperatures by withstanding desiccation. When they dry out, their DNA breaks into small pieces. When they rehydrate and repair their DNA, they take in foreign DNA through temporary leaky cell membranes. This genetic variation has likely made the tardigrades evolve more tricks to help them withstand harsh environments.