Carefully distinguish between the terms differentiation and determination. Which phenomenon occurs initially during development?

Key Concepts

Differentiation

Differentiation is the process by which unspecialized cells develop into specialized cells with distinct functions. This process involves changes in gene expression that lead to the formation of various cell types, such as muscle, nerve, or blood cells. Differentiation occurs after cells have been determined, meaning they have committed to a specific fate.

Determination

Determination refers to the process by which a cell becomes committed to a specific developmental pathway, leading to a particular cell type. This commitment occurs before differentiation and is influenced by intrinsic factors (like genetic programming) and extrinsic signals (such as growth factors). Once a cell is determined, it will follow a specific trajectory in its development.

Developmental Sequence

In the context of embryonic development, the sequence of determination followed by differentiation is crucial. Determination occurs first, establishing the cell's fate, while differentiation follows, resulting in the functional specialization of the cell. Understanding this sequence is essential for grasping how complex organisms develop from a single fertilized egg.