Study: Genes helped fins evolve into legs

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SEVILLE, Spain, Dec. 10 (UPI) -- The change of fish fins into legs that helped vertebrates move onto land was the result of new DNA elements activating particular genes, Spanish scientists say.

That major event in the history of life, the development of hands and feet, is linked to Hoxd13, a gene known to play a role in distinguishing body parts, the researchers reported in the journal Developmental Cell.

"First, and foremost, this finding helps us to understand the power that the modification of gene expression has on shaping our bodies," said Jose Luis Gomez-Skarmeta of the CSIC-Universidad Pablo de Olavide-Junta de Andalucia, in Seville, Spain.

In an experiment, Gomez-Skarmeta and his colleagues introduced extra Hoxd13 at the tip of a zebrafish embryo's fin, which led to the generation of new cartilage tissue and the reduction of fin tissue, changes that echo key aspects of land-animal development as fins evolved into limbs.

"This result indicates that molecular machinery capable of activating this control element was also present in the last common ancestor of finned and legged animals and is proven by its remnants in zebrafish," researcher Fernando Casares said.