We thank Colin Beechey and Bruce Cattanach for providing information about the origin of deH, Cindy Loomis for communicating unpublished results, and Michael Kuehn for providing Hoxb6-Cre transgenic mice. We are especially grateful to Hirotake Ono for discussion, to Hermie Manuel and to Carla Kroon-Veenboer for technical help, and to David Kingsley for first drawing our attention to the effects of droopy ear on pigmentation. SIC is supported by a grant from The Donald E. and Delia B. Baxter Foundation. GSB is an associate investigator of the Howard Hughes Medical Institute.