WASHINGTON: Land animals owe the development of their limbs to a gene that helped in the evolution of fins in a primitive fish, a new study by researchers from the Natural History Museum in London has revealed.

The scientists studied the Australian lungfish Neoceradotus and found that one of its fin-sprouting genes also guided the growth of digits in land vertebrates. The gene helped shape the hands, feet and wings of every land animal alive, the researchers said.

"People have found comparable genes and gene-expression patterns in the fins of ray-fin fishes and also sharks, so it seems like the pattern goes very, very deep in vertebrate history," said study team member Zerina Johanson, a palaeontologist. The development of fingers and toes in embryos of land animals is closely linked to a gene called Hoxd13.

This gene orchestrates a series of developmental steps involving the sequential release of certain proteins that affects the outer part of the limb and the digits but not the arm bones. Johanson and her colleagues found that the genes involved in creating the Australian lungfish's fins made proteins in a nearly identical pattern as in tetrapods, by acting on the small fin bones but not the rest of the limb. The findings are scheduled for publication in the Journal of Experimental Zoology.