Insufficient research has been done to analyze the effect of FgF2 on presomitic mesoderm. Previous research on the epiblast cells showed that all embryonic tissues are derived from the epiblast cells, including the muscle cells. Myogenic potential develops during gastrulation as epiblast cells enter the primitive streak (stages 3-4). Further development of myogenic precursors occurs within the presomitic mesoderm and the somites. In ovo, differentiation begins by 48 hours within the myotome of the somite. However, previous research also showed that presomitic mesoderm can differentiate in vitroin the absence of axial structures that induce muscle development, if plated as a single cell suspension [2]. Therefore, muscle differentiation is anautonomous process.

Cell-to-cell interactions are crucial for muscle differentiation. In ovo during the stages 3-5 epiblast cells send inhibitory messages to prevent muscle differentiation. In vitro, fewer cells differentiate when plated at low density, because integrin-fibronectin attachment is not achieved. However, when plated at high density, cell-to-cell interactions may play a role in promoting myogenesis [2]. It is not clearly understood, however, what is the effect of theFgF2 on the presomitic mesoderm (stage 14).

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