Table 1.

Summary of expression of Irx genes in the developing digits of mouse and chick embryos.

	Cluster A			Cluster B
	Irx1	Irx2	Irx4	Irx3	Irx5	Irx6
Mouse E12.5	Digit condensations	Digit condensations	Interdigital	Distal	Weak interdigital	Weak proximal
Mouse E13.5	Joints	Joints	Stronger interdigital	Distal edges of digits Interdigital	Edges of digits Interdigital	Interdigital
Mouse E14.5	Joints	Joints	Distal edges of digits	Distal edges of digits	Edges of digits Interdigital	Interdigital
Chick HH27	Digit condensations	Broad distal	Broad distal	Distal rim	N/A	Interdigital (leg)
Chick HH28	Digit condensations Joints	Broad distal	Broad distal	Distal rim	N/A	Interdigital (wing and leg)