Figure 3.

Three broad types of stemness (self-renewal and undifferentiated state) as a relational attribute to stem cell niche and developmental ontogeny of the stem cell undifferentiated state. The idea of the degree of stemness incorporates both stem cell niche and developmental/hierarchical ontogeny of a given stem cell state. Higher the degree of intrinsic stemness, higher is the level of self-sufficiency and the hierarchical position of the stem cell state in the developmental ontogeny of stem cells. In this model, primitive stem cell state such as naïve ES cells exhibit higher degree of intrinsic stemness and are more self-sufficient than lineage committed stem cells such as CD34+ HSCs. The detail discussions on the idea about the degree of stemness and self-sufficiency (including niche modulatory altruistic stem cell state) is given in two book chapters (Das et al., 2009; Das, 2014).