The origination of stem cell research must mention the studies of Dr. Ernest Armstrong McCulloch and Dr. James Edgar Till during the early 1960s (1). These Canadian physician scientists were studying mouse hematopoiesis (blood formation) and identified cells that when transplanted into irradiated mice would give rise to individual cellular colonies on the host spleen. Microscopically, these colonies underwent self-renewal and were differentiating into three different cell lines: erythrocytes (red blood cells), granulocytes and megakaryocytes. These results supported the Unitarian Theory of Hematopoiesis, a hypothesis proposed by a Russian scientist, Alexander A. Maximov, over 50 years earlier, and were heralded as the discovery of stem cells.
While most academicians readily accept McCulloch and Till as the textbook answer, a deeper investigation produces some debate on who first identified stem cells. Specifically, Joseph Altman put forth the question, "Are new neurons formed in the brains of adult mammals?" during 1962 (2), which precedes the seminal "discovery" by McCulloch and Till in 1963 (1). Altman did not merely put forth the question of new neuron formation from stem cells; his data supported his hypothesis that cells adjacent to experimentally induced brain lesions in rats were forming neurons, neuroblasts and glia cells. Unfortunately for Altman, his results contradicted the dogma of "no new neurons" by Dr. Santiago Ramón y Cajal, a Spanish physician scientist and Nobel laureate. This dogma left Altman's work largely ignored, and the dogma held until the early 1990's, when Dr. Reynolds and Weiss first isolated neural progenitor and stem cells in mice (3).
Totipotent: "total power" stem cells that can differentiate into any cell types.
Pluripotent: stem cells that can form any cell type (e.g. embryonic stem cells) EXCEPT extraembryonic cells (i.e. those outside the embryo).
Multipotent: have the power to differentiate into cells in the same family of cells (e.g. hematopoietic stem cell).
Oligopotent: stem cells may only differentiate into a subset of cells in a particular family (e.g. lymphoid or myeloid stem cells).
Unipotent: cells perform self-renewal and are committed to a single cell type (e.g. hepatocytes).
All of the cited cases are actually the originating studies of multipotent stem cells. While these studies were well in advance of the isolation and culture of pluripotent embryonic stem cells in the 1980s, they miss the obvious: fertilized bird eggs are stem cells of "total power." This means stem cell research did nor originate in the laboratory, it actually originated with the study of poultry, reptile, amphibian and fish eggs. Because chickens were one of the earliest domestic species, it is likely that the chicken egg was the subject of much inquiry.
The first people that provided for domestication of the chicken over 10,000 years must have been aware that the fertilized egg had the "total power" to reproduce the entire chicken. Unfortunately, that farmer scientist left no written record of his or her discovery, but the impact of that discovery on science and our diets still resonates as the true origin of stem cell research.