Fig. 5

Gene expression noise increases in LT-HSCs upon ageing. a t-SNE representation of young and aged hematopoietic stem cells [38], sequenced in two batches A and B (see also Additional file 1: Figure S5a). LT-HSC populations identified based on marker gene expression for each condition and batch identity are highlighted (see also Additional file 1: Figure S5b). b t-SNE plot highlighting cellular noise estimates. c Comparison of cellular noise across the four LT-HSC populations identified in a. Boxes indicate inter-quartile range (IQR), and whiskers correspond to ±1.5*IQR of the box limits. Outliers beyond the whisker limits are depicted. Vertical axis limits are manually adjusted for better visualization. A comparison of old versus young cells for each batch was performed, *P  value < 2.2e − 16 (two-sided Wilcoxon test). d Differentially noisy genes identified across LT-HCS populations, comparing aged versus young samples. MA plot shows log₂FC of noise on the y-axis, and average expression on the x-axis. Threshold values: log₂FC > 1.25, padj < 0.001. e Noise \(\varepsilon\) estimates of some example genes detected as highly noisy in aged versus young LT-HSCs in d