Figure 1: Model of thymus seeding by bone marrow cells and B cell development. Individually labelled stem/progenitor cells were transplanted in NSG mice and thymocyte populations as well as peripheral blood subsets at different time points after transplantation were analyzed for barcode content. The analysis showed clonal restriction in the thymus, while the T cell receptor repertoire was polyclonal. B cell development was more clonal and less restricted.