The "LSK" phenotype, consisting of cells expressing Sca-1 and c-Kit, was originally utilized to isolate hematopoietic stem cells (HSCs) in mice. However, further research has revealed the need for additional markers and functional assays to accurately identify and characterize true HSCs. Advanced technologies are aiding in the comprehensive study of HSC heterogeneity and lineage potential.

During fetal development, hematopoiesis occurs in distinct tissues at different stages. The yolk sac is initially significant, producing primitive blood cells. The fetal liver then becomes a major site of blood cell production, followed by the spleen. Ultimately, the bone marrow becomes the primary organ for blood cell production, reflecting changing developmental needs.

Hematopoietic stem cells, found in the bone marrow, continuously produce diverse blood cell types, but are limited to the hematopoietic lineage. They maintain blood system balance, aid in immune response, and have clinical applications, making them crucial in treating blood-related disorders. Their multipotent nature is showcased in their ability to repopulate the blood cell repertoire.