Figure 6 of
Larsson, Mol Vis 2004;
Figure 6. The factor structure underlying the five iris characteristics
This illustrates the genetic and environmental factor structures for the five iris characteristics Fuchs' crypt frequency (Crypts), pigment dot frequency (P. Dots), iris color (Color), extension and distinction of Wolfflin nodules (Wolfflin), and Contraction furrows (Furrows) for one twin only. Each of the five measures of iris characteristics loaded on additive genetic (A1 through A5) and environmental latent factors (E1 through E5).