TLS Online TPP Program

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#Unit 5. Developmental Biology

Instructive interaction

It occur where the responding cell has a choice of fates and will follow one developmental pathway following induction and an alternative pathway in absence of the inductive signal. 

TLS Online TPP Program

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#Unit 5. Developmental Biology

In Permissive interaction

The responding tissue has already been specified and needs only an environment that allows the expression of these traits. 

TLS Online TPP Program

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#Unit 5. Developmental Biology

Epithelial-mesenchymal interactions

the interactions of sheets of epithelial cells with adjacent mesenchymal cells.

TLS Online TPP Program

#Id: 179

#Unit 5. Developmental Biology

Properties of epithelial-mesenchymal interactions:

Regional specificity of induction

Genetic specificity of induction

TLS Online TPP Program

#Id: 180

#Unit 5. Developmental Biology

Regional specificity of induction:

mesenchyme plays an instructive role, calling into play different sets of genes in the responding epithelial cells.

TLS Online TPP Program

#Id: 181

#Unit 5. Developmental Biology

Genetic specificity of induction:

mesenchyme may instruct the epithelium as to what sets of genes to activate, the responding epithelium can comply with these instructions only so far as its genome permits.