Mid-parent / offspring correlation as an estimation of heritability

The red
dots show the correspondence between the phenotype
values of the offspring (Y-axis)
and the mid-parent
(the average of the two parents) (X-axis). The red line is the
calculated regression line,
which corresponds to the heritability
(h^{2}).
Perfect heritability would be indicated by a line with slope =
1.0 (dashed blue line).
Here,
the points are somewhat more scattered, and the slope and
heritability are calculated as h^{2} =
0.5.

Figure ©2002 by Griffiths et al.; all text material ©2013 by
Steven M. Carr