The specification of positional values along the proximo-distal axis (shoulder to digits) of the vertebrate limb is an unresolved issue. By using heterochronic transplants of distal mesenchyme, the authors show that the zeugopod and autopod (elbow to digits) are progressively specified in an intrinsically timed manner.
- Patricia Saiz-Lopez
- Kavitha Chinnaiya
- Matthew Towers