Extra DNA May Make Unlikely Hybrid Fish Possible

Quanta Magazine

Their mothers were Russian sturgeons — large carnivores with creamy bellies, short, rounded snouts, and green, dragonlike scales. Their fathers were American paddlefish — smooth-skinned filter feeders with sensitive, elongated snouts. “Sturddlefish,” as these hybrids have been nicknamed since researchers in Hungary recently announced their creation, go shockingly far beyond classic crossbreeds like mules and ligers, whose parent species sit close together on the tree of life. Sturddlefish result from the merger of different taxonomic families.

“I’m still confused. My jaw is still on the floor,” said Prosanta Chakrabarty, an ichthyologist at Louisiana State University and the curator of fishes at its Museum of Natural Science. “It’s like if they had a cow and a giraffe make a baby.” Then he quickly corrected himself, because the lineages of those two ruminants split only a few dozen million years ago. The evolutionary paths of paddlefish and sturgeons diverged 184 million years ago. For those fish to breed is more like “if a human came out of a platypus egg,” he said.

Hybrids are often shrugged off as freaky living violations of the rules that keep species distinct. But scientific interest in them has grown with mounting evidence that in nature hybrids can be important both in the emergence of new species and in the conservation of species on the brink of extinction.

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