REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
Rabbit polyclonal anti-GFP	Torrey Pines Biolabs	Cat#TP-401; RRID: AB_10013661
Goat anti-Rabbit IgG (H+L) Secondary Antibody, Alexa Fluor Plus 488	Thermo Fisher Scientific	Cat#A32731; RRID:AB_2633280
Chemicals, Peptides, and Recombinant Proteins
Alexa Fluor 555 Phalloidin	Thermo Fisher Scientific	Cat#A34055
Fluoromount-G, with DAPI	Thermo Fisher Scientific	Cat#00-4959-52
RA	Sigma-Aldrich	Cat#R2625
AGN 193109	Tocris	Cat#5758
Alcian Blue 8GX	Sigma-Aldrich	Cat#A9186
Alizarin Red S	Sigma-Aldrich	Cat#A5533
Experimental Models: Organisms/Strains
Fertilized chicken eggs	EARL Morizeau	N/A
Fertilized ostrich eggs	SARL Le père Louis	N/A
Fertilized zebra finch eggs	Laboratory of Marie Manceau	N/A
Transgenic quail: hUbC:memGFP	This paper	N/A
Transgenic quail: hUbC:mEOS2FP	This paper	N/A
Oligonucleotides
Primer Hoxb4 dn Forward: AATAAATCTAGAATGGCCATGAGCT CGTTTTTGATCAACTCC	This paper	N/A
Primer Hoxb4 dn Reverse: TTTTGGCGCGCCTCAGATTTTGATCTGGC	This paper	N/A
Primer Hoxb4 C-terminal Forward: CCAGAACAGGAGGATGAAATGG	This paper	N/A
Primer Hoxb4 C-terminal Reverse: TTATAGGCTGCTGGCTGGTCC	This paper	N/A
Primer Hoxc9 dn Forward: TTTGCTAGCATGTCGGCTTCTGGCCCC ATAAGC	This paper	N/A
Primer Hoxc9 dn Reverse: TTTGGCGCGCCTCAGATTTTGACTTGGC	This paper	N/A
Primer cCyp26a1 Forward: ATCCTGCTGGGCTTCCAGCCC	This paper	N/A
Primer cCyp26a1 Reverse: GGCCGCTGAAACCTATGAATTTGG	This paper	N/A
Recombinant DNA
pCAGGS-H2b-RFP	Laboratory of S. Tajbakhsh	N/A
pFlox-pA-EGFP	[47]	N/A
pCX-Cre	[47]	N/A
pCAG-GFP	[48]	Addgene Cat#11150
pCAGGS-cHoxb4-IRES2-Venus	This paper	N/A
pCAGGS-cHoxb4 dn-IRES2-Venus	This paper	N/A
pCAGGS-cHoxb7-IRES2-Venus	This paper	N/A
pCAGGS-cHoxb9-IRES2-Venus	This paper	N/A
pCAGGS-cHoxc9 dn-IRES2-Venus	This paper	N/A
pBS-Hoxb4	[28]	N/A
pBSKS-Hoxb7	[28]	N/A
pGEMT easy-Hoxb9	[28]	N/A
pSLAX-cTbx5	Laboratory of C. Tabin	N/A
pBSSK-cFgf10	Laboratory of C. Tabin	N/A
pBSSK-cShh	Laboratory of C. Tabin	N/A
pGEMT easy-cCyp26a1	This paper	N/A
pGEMT easy-cHoxb4Cter	This paper	N/A
Software and Algorithms
ImageJ	[49]	RRID:SCR_003070
GraphPad Prism 6	GraphPad Software	RRID:SCR_002798