Question #262
Somitogenesis:
Signals from the neural tube and notochord act on the paraxial mesoderm. During the third and fourth weeks the paraxial mesoderm starts to bud off from the cranial end to form somites. The repeating segments express different hox genes, along the long axis of the embryo, that will determine the nature of the tissue formed.
If a somite is transplanted it will continue to make the tissue appropriate for its site of origin.
The somites further divide into:
- Sclerotomes - form skeleton, each sclerotome splits to contribute to the formation of two adjacent vertebrae
- Myotomes – form skeletal muscle
- Dermatomes – form the dermis (not the entire skin)
