Figure 1F. Copyright: Reprinted with permission from Elsevier from [doi:10.1016/j.ydbio.2007.04.034] Dev Biol 307: 421-33, L'honore A; Coulon V; Marcil A; Lebel M; Lafrance-Vanasse J; Gage P; Camper S; Drouin J, "Sequential expression and redundancy of Pitx2 and Pitx3 genes during muscle development." Copyright 2007 [PMID:17540357]