MGA2_18-14.jpg

Mid-parent / offspring regression as an estimation of heritability (h2)


    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 (h2). 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 h2 = 0.5.

    Notice that this analysis is a regression, rather than a correlation, because by the hypothesis the midparent value predicts the offspring value. Absent such a hypothesis, the analysis is mathematically a correlation, because the midparent value is not controlled, that is, chosen for pre-determined values of 1.1, 1.2, 1.3, and so on.



Figure ©2002 by Griffiths et al.; all text material ©2025 by Steven M. Carr