What is the term for cells of the same lineage that have not yet differentiated?

The term for cells of the same lineage that have not yet differentiated is progenitor cells. Progenitor cells are considered to be the precursors to differentiated cells and are typically more restricted than stem cells in their potential to develop into specific cell types. They are derived from stem cells and are on the pathway to specialization, which means they have a limited ability to divide compared to stem cells but still retain some capacity for self-renewal.

The concept of progenitor cells is crucial in understanding developmental biology and regenerative medicine, as these cells are pivotal in tissue repair and regeneration. They respond to specific signals in the body that guide them toward becoming specialized cells, like neurons or muscle cells.

In contrast, stem cells are characterized by their ability to divide indefinitely and differentiate into various cell types, making them a more flexible cell type than progenitor cells. Parent cells can refer to various contexts, but it does not specifically denote cells that have yet to differentiate. Specialized cells are fully differentiated and perform specific functions, which distinguishes them entirely from the undifferentiated nature of progenitor cells. So, the best fit for the description of cells that have not yet differentiated from the same lineage is progenitor cells.