Question

1. Summarize the role of Hox genes, neural crest cells, and epidermal: mesenchymal signaling in the patterning of vertebrates. Give an example from each class of vertebrates. How do hox genes, neural crest cells, and epidermal: mesenchymal interactions of the integument give each type of vertebrate their unique and special traits?

Answer 1

The hox genes are instrumental and important is establishing and regulating the body pattern during the development of the body of the vertebrates. It helps in the process of pattern formation. They provide the right kind of signal which helps in controlling the pattern formation in the organisms. The Hox genes consists of the transcriptional factors which are conserved and helps in formation of the skeletal pattern and they are majorly expressed in the mesenchymal steml cells. They pattern the skeleton during the process of the embryonic development. These genes help in the anterior to posterior axis formation and hence they plan the segments of the body. An example where the Hox genes play an important role in the segment and pattern formation is the Drosophlila.

The neural crest cells are important cells which help in the formation of the neural tube and they generally originate from the dorsal part of the body. These cells are unique to the chordate group and are the cells which originate from the ectoderm. The neural plates are produced by the neural crest cels and they undergo as transition from the epithelial cells to the mesenchymal cells. There many transcriptional signals which helps in activating the production of the neural crest cells which ultimately leads to the production of neural plate.

The epidermal cells are responsible for production of the skin and they help in the mesenchymal component of the skin to polarize and become skin. The epidermal cells are one of the most important stem cells and hence proliferate every now and then to replace the old and dead skin cells. with the development of the epidermis it also leads to morphogenesis of appendages like hair follicle or the sweat glands. The epidermal cells are important part of all the vertebrates and they help in regulating and managing various function.