While there is currently little evidence to support this (and mounting evidence to refute it), some early studies implicated the Ephs to play a part in the signaling of limb development. In chicks, EphA4 is expressed in the developing wing and leg buds, as well as in the feather and scale primordia.
Although there is currently no conclusive proof to support this theory (and a growing body of evidence that refutes it), some early research hinted at the possibility that the Ephs might play a role in regulating limb development. In chicks, EphA4 is expressed in the developing wing and leg buds, as well as in the feather and scale primordia.