http://carm.org/wwwboard3/messages/37384.html
Posted by Paul Rothberg (slip-32-101-64-138.ks.us.ibm.net) on October 02, 1998 at 23:37:31:
In Reply to: Another evolutionary problem... posted by karl on October 02, 1998 at 17:24:26:
Although this does not completely answer Karl's problem, it might help:
Requirement for BMP signaling in interdigital apoptosis and scale formation.
Zou H, Niswander L
Interdigital cell death leads to regression of soft tissue between embryonic digits in many vertebrates.
Although the signals that regulate interdigital apoptosis are not known, BMPs--signaling molecules of
the transforming growth factor-beta superfamily--are expressed interdigitally. A dominant negative
type I BMP receptor (dnBMPR-IB) was used here to block BMP signaling. Expression of
dnBMPR in chicken embryonic hind limbs greatly reduced interdigital apoptosis and resulted in
webbed feet. In addition, scales were transformed into feathers. The similarity of the webbing to
webbed duck feet led to studies that indicate that BMPs are not expressed in the duck interdigit.
These results indicate BMP signaling actively mediates cell death in the embryonic limb.
Sincerely,
Paul