CAFC frequency in purified Sca-1⁺c-kit⁺Lin⁻cells obtained from young (8-10 weeks) and old (10 months) B6 and DBA mice.

In panel A, cells from young B6 and DBA mice are compared, whereas panel B shows results obtained with cells from old mice of both strains. In panels C and D the same data are shown, but to allow detailed comparison of intrastrain age effects, data for young and old B6 (panel C) and young and old DBA (panel D) are plotted in one graph. Error bars indicate 95% confidence limits for the limiting-dilution analysis.