Tetrapod
four limbed vertebrate
Autopod
Carpals
Stylopod
Humerus
Zeugopod
Radius/Ulna
When does limb formation occur
After most organ systems already developed
Limb bud field
The area of the mesoderm that can form the limb bud
Lateral plater mesoderm
Mesenchymal cells from the LPM undergo EMT to migrate into the limb bud and contribute to the growth
Hox genes
Help specify limb field
How limb bud formation is initiated
RA restricts FGF8 in the field and activates Tbx5
How to detect RA in vivo
RAR-lacZ RA transgene
Limb identity facors
In chicks and FGF soaked bead forms forelimb with tbx5 anteriorly
In mice, Hindlimb initiation is started by Islet1 and Pitx1 contributes to hindlimb character