How did digits evolve? While it is clear that they derive from genetic programs already present in fish, their precise origin remains a matter of debate. An international team led by the University of ...

Evolution has adapted the digits of mammals for an enormous range of uses, from our opposable thumbs to the spindly digits that support bat wings to the robust bones that support the hoofs of horses.

To develop their digits, ancestral tetrapods recycled an ancient region of the genome that was initially active in the formation of the fish cloaca. This is illustrated here by the expression of a Hox ...