The past few years provided a number of challenges to our expectations regarding hematopoietic stem cell biology. Evidence has emerged that hematopoietic stem cells arise intraembryonally before they can be detected in the yolk sac. A number of genes that may regulate the formation, self-renewal, or differentiation of stem cells have been identified. Although different groups have attributed different properties to hematopoietic stem cells, it now appears that the differences may be explained by the existence of various stem cell populations, each with different potencies ranging from totipotent to more specialized, exist and may persist into adult life. Finally, we propose that the number of hematopoietic stem cells available to an individual is finite and the 'quality', although currently a subjective parameter, is of newly appreciated importance.
|Number of pages||6|
|Publication status||Published - Feb 13 2000|
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