FIGURE 1. Mutational heritability.
From the following article:
A mutation accumulation assay reveals a broad capacity for rapid evolution of gene expression
Scott A. Rifkin, David Houle, Junhyong Kim and Kevin P. White
Nature 438, 220-223 (10 November 2005)
doi:10.1038/nature04114
Shown are histograms of the mutational heritability 
at the two stages BPF and PF.