Immunoglobulin genes might have evolved much earlier than previously expected, perhaps even in the common ancestor of Cnidarians and Bilateria, a study suggests.
Researchers find that the protective outer layer that lungfish make to survive extended dry periods—once thought to be a simple mucus shell—contains immune cells that trap bacteria and protect the animals from infection.
The largest study to date of the animals’ genetics provides robust evidence that they are adapting to survive a highly lethal, contagious cancer scientists feared would cause their extinction.