In molecular biology, the microRNA miR-219 was predicted in vertebrates by conservation between human, mouse and pufferfish and cloned in pufferfish.
Members of this family also synthesize tetrodotoxin (TTX), an ancient marine alkaloid and powerful neurotoxin (Na+ pump inhibitor, 1 mg can kill an adult) that serves to protect members of an order of fishes, the Tetraodontiformes (tetras-four and odontos-tooth), which include the puffer fish (see fugu, raw puffer fish served in Japan).