Teaching MPPSC Assistant Professor Mock Test Series 2025 Life Sciences Developmental Biology Morphogenesis and organogenesis in animals
Which one of the following statements is NOT correct regarding the tetrapod limb development?
1
As the limb grows outward, the stylopod forms first, then the zeugopod and the autopod is formed last. Each phase is characterized by a specific pattern of Hox gene expression.
2
The zone of polarizing activity (ZPA) is maintained by the interaction of the FGFs from the AER and Shh expressed from the mesenchyme.
3
Although cell death in the limb is necessary for the formation of digits and joints, it is never mediated by the BMPs, which is only responsible for differentiating mesenchyme cells into cartilage.
4
The dorsal‐ventral axis is formed in part by the expression of Wnt7a in the dorsal portion of the limb ectoderm, which maintains expression level of Shh in the ZPA and Fgf4 in the posterior AER.