The vertebrate<unk>  arises out of a general morphogenetic area called a<unk>  field. The position of the<unk>  field correlates with the anterior boundary of the Hoxc6 gene expression. Retinoic acid also plays a role in<unk>  positioning. Blocking retinoic acid eliminates<unk>  formation.<unk>  formation occurs out of a reciprocal interaction between the mesenchymal cells and the overlying ectodermal cells. Cells from the lateral plate mesoderm and the myotome migrate to the<unk>  field and proliferate to create the<unk>  bud. The lateral plate cells produce the skeletal portions of the<unk>  while the myotome cells produce the muscle components. The lateral plate mesodermal cells express FGF10 and induce the apical ectodermal ridge (AER) cells to express FGF8 and FGF4 which maintains the FGF10 signal and proliferation in the mesoderm. The position of FGF10 expression is regulated by Wnt8c in the hindlimb and Wnt2b in the forelimb. The forelimb and the hindlimb are specified by their position along the anterior/posterior axis and possibly by two T-box containing transcription factors: Tbx5 and Tbx4 respectively.
Programmed cell death removes the spaces between the digits and joints. BMP signaling induces cell death and Noggin block cell death in the digits.
Limb development
Kidney development
Eye development
Hematopoiesis
Oogenesis
Body shaping
Wound healing
Dynamical system