Foxi3CreER mice were mated with ROSA-Ai9 Cre reporter mice and the pregnant females received a single dose of tamoxifen at 6.5 dpc. Mice were analyzed for tdTomato expression at E14.5, together with Sox9 to show developing cartilage. TdTomato cells can be observed in the oropharynx (A), glottis and epiglottis (B), but not the cricoid, arytenoid, or thyroid cartilages (TC; B, C). (D-F) Labeled cells can also be seen in the developing thyroid (Ty), parathyroid (Pt) and thymus (Thy) tissues, as well as the esophagus (Es) and trachea (Tr).