Missouri state law prohibits the transportation of paddlefish eggs that have been removed or extracted from a paddlefish carcass.

State law also prohibits the sale or purchase, or offer of sale or purchase, of paddlefish eggs and restricts the purchase of whole paddlefish.

Using the dossiers as a guide, they created primers-short ,jigsawlikestrands of DNA-eachdesigned to match a specific species of sturgeon or paddlefish DNA.

The American paddlefish is a protected species, while the only other species of the fish, the Chinese paddlefish, is believed to have recently become extinct.

Eight sturddlefish had their genes analysed, and while some appear genetically closer to sturgeon, others are a near perfect mix of sturgeon and paddlefish DNA.

The sturddlefish inherits the sturgeon's mouth and its taste for other animals, while some have gained slightly smaller versions of the paddlefish' fins and snout.

Sturgeon have receptors in the skin of their heads, for example, and the North American paddlefish has 70,000 receptors in its snout and head.