BIO380H5 Lecture Notes - Lecture 10: Melanocyte, Programmed Cell Death, Hoxa11
Document Summary
The outgrowth-promoting signal produced by the aer is fgf; if ectodermal ridge removed at this stage, then the limb will develop only to part of the humerus. In the earliest stages of limb formation, the lateral ectoderm begins to produce fgf-8 as it thickens to form an aer; if removed after the formation of the humerus then it will be no further growth. As the limb bud begins to grow out, the apical ridge also produces fgf-4, fgf-9, and fgf-17 in its posterior half. If the aer is removed, outgrowth of limb bud mesoderm can be supported by the local application of. Yes, the aer is essential, but sometimes if it is removed it can be fine, because the mesenchymal cells of the mesoderm will take over of the local fgf. The formation of two aers on the limb bud leads to a supernumerary limb, as is illustrated by the mutants eudiplopodia in chickens and diplopodia in humans.
