(a) The flow cytometry gating strategy using expression of CD27 and CD11b to classify NKp46+ CD3− splenic NK cells of wild and laboratory mice into stages 1–4 of maturity, (b) the proportions of NK cells at each such stage, in wild (shaded) and laboratory (unshaded) mice, and expression of (c) CD69 and (d) KLRG1 by each subset (Table 2). Also shown are (e–h) the gating strategies for Ly49 receptors and the proportions of NK cells expressing, (e) different combinations of Ly49D and Ly49G2, (f) Ly49D, (g) Ly49G2 (Ly49G2+ cells gated into Ly49G2−, Ly49G2low and Ly49G2high cells) and (h) Ly49H. Wild mice are shown as shaded box plots, laboratory mice as unshaded. The box centres are medians, and box limits the 25th and 75th percentiles, the whiskers 1.5 times the interquartile range and outliers are represented by dots and some axes are on a log10 scale. Asterisks denote significant differences as **P<0.01, ***P<0.001 (Mann–Whitney U test; Table 2), and § denotes that there are additional sex effects detailed in Table 2. The gating strategy for NKp46+ CD3− lymphocytes is shown in Supplementary Fig. 1. Sample sizes are shown in Table 2 and Supplementary Data 1.