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Tetsuya Nakamura carried out some of this research in the ǧ����Ƶ Whitman Center.

Skates got their wing-like fins with the help of a genetic shuffle that folded different sections of their genomes into physical contact with each other. This created a new pattern of gene activity in the fins of skate embryos, highlighting how changes to the three-dimensional genomic architecture can drive the evolution of new body structures.

Evolutionary biologists are fascinated by fish fins because they represent one of the great innovations in vertebrates: paired appendages. These show an astonishing variety of forms, including our arms. In skates, the equivalent is their front, or pectoral, fins, which have extended forwards and fused with the head.

“Somehow, the pectoral fin and the head is completely combined and integrated in terms of function and the structure,” says , a developmental biologist at Rutgers University in New Jersey. “This is quite a remarkable animal.”