Fig. 1. Physiological levels of heterozygous mutant IL-7Rα expression consistently originate a B cell precursor pre-leukemic stage.

a Scheme of experimental cross, depicting genotype of progeny. Green (controls) and orange (IL-7R^mut) animals were bled from week 4 and monitored up to week 104, unless disease ensued. A cohort of Cre-toxicity controls (blue) was also monitored that presented no disease. b TCRβ and CD19 fractions within CD45-positive cells in blood from control and IL-7R^mut animals. Each dot denotes an animal and mean value is shown. Two-tailed unpaired t-test. c CD19 fraction (left) and IgM versus IgD subpopulations within CD19 (right) in the blood of one representative animal from each group at 6 weeks of age. Numbers indicate frequencies of each quadrant or region. d CD93 and BP-1 expression within IgM⁻IgD⁻ cells in the blood from the same animals than in c. e Scatter plots summarizing data from all animals analyzed as in c and d. Ctrls: n = 8; IL-7R^mut: n = 10. Each dot denotes an animal and mean value is shown. Two-tailed unpaired t-test. f Scatter plots showing fractions (top) and absolute numbers (bottom) in BM for the indicated populations in 4-week-old animals from Ctrl (n = 7) and IL-7R^mut (n = 4) animals. Two-tailed unpaired t-test. Source data are provided as a Source Data file.