Correction to: Nature Genetics https://doi.org/10.1038/ng1937, published online 3 December 2006.

In the version of this article initially published, Supplementary Figs. 2d and 4b contained errors in the representative photographs of organs and cells. In Supplementary Fig. 2d, in the representative photographs of hematoxylin- and eosin-stained longitudinal sections of the spleen in 4-month-old mice of the indicated genotypes, the original photograph for the cohort of iG4 mice showed a spleen sample from a different genotype and age cohort (iF1, Cdkn1a–/–, 12–15 months), which was correctly displayed in Fig. 1d. The corrected Supplementary Fig. 2d contains new representative photographs of the spleens of 4-month-old mice of the indicated genotypes. In Supplementary Fig. 4b, in the representative photographs of SA-βGal staining of hematopoietic stem and progenitor cells (KSL cells) of 12- to 15-month-old iF1 and iG4 mice in the bottom row, the original photographs showed a partially overlapping area of cells from the same image. The corrected Supplementary Fig. 4b contains new representative photographs of KSL cells from 4-month-old mice of the indicated genotypes. The errors have been corrected in the revised Supplementary Figs. 2 and 4 included with this Author Correction online.