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How can the same ectoderm develop into either skin or neural tissue?
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Animal development
The embryos of many animals appear similar to one another in the earliest stages of development and progress into their specialized forms in later stages.
The differentiation of ectoderm into either skin or neural tissue is primarily governed by a process called embryonic induction. During early development, groups of cells interact through the secretion of signaling molecules, which instruct neighboring tissues to follow specific developmental paths.12
The fate of the ectoderm depends on the presence or absence of these inductive signals:
- Neural Tissue: The dorsal mesoderm (specifically the notochord and somites) acts as an organizer, secreting substances that induce the overlying ectoderm to differentiate into the neural plate. In many vertebrates, this process involves the inhibition of bone morphogenetic proteins (BMPs). When BMP activity is suppressed in the dorsal region, the ectoderm is permitted to develop into the central nervous system.12
- Skin: In regions where the ectoderm is not exposed to these neural-inducing signals—or where lateral mesoderm influences the tissue—the ectoderm differentiates into skin.
Essentially, the ectoderm possesses the potential to become various structures, but its final identity is determined by its spatial relationship to inducing tissues and the resulting concentration gradients of signaling molecules in the embryo.12