Correction to: Nature Genetics, published online 1 January 1999.

In the version of the paper initially published, Fig. 5a was inadvertently duplicated and presented as both Figs. 5a and 5f, and the correct image for Fig. 5f was omitted. Images of the original and corrected figure panels are shown in the correction notice.

Fig. 5
figure 1

Original and corrected.