TABLE 1.

Effect of retrovirus infection on chicken wing cartilage pattern and feather germ formation

Protein expressed	No. of embryos infected	No. of embryos with phenotype	Proportion with:		Cartilage length indexc
			Feather germ defecta	Altered morphologyb	Humerus	Radius	Ulna	Digit III
Msx1	54	49	0.61	0.49	0.89 ± 0.01	0.88 ± 0.01	0.87 ± 0.01	0.83 ± 0.03
Msx1(R31P)	52	4d	0.08	0	1.00 ± 0.01	1.01 ± 0.01	1.00 ± 0.01	1.01 ± 0.01
Msx1(R31A)	50	45	0.82	0.60	0.93 ± 0.01	0.93 ± 0.01	0.91 ± 0.01	0.86 ± 0.01
APe	6	0	0	0	1.00 ± 0.01	1.03 ± 0.01	1.00 ± 0.01	0.99 ± 0.02
Msx1 + AP	11	10	0.80	0.60	0.89 ± 0.03	0.86 ± 0.04	0.86 ± 0.04	0.85 ± 0.05
Msx1 + Msx1(R31P)	8	8	0.75	0.50	0.92 ± 0.02	0.90 ± 0.03	0.91 ± 0.03	0.83 ± 0.04

^aFeather germs were significantly reduced in size or absent along the posterior wing margin of the right infected wing compared with the contralateral uninfected (control) wing. 

^bThe angle made by the ulna and digit III of infected wings was often ≥180°, compared to the angle made by the ulna and digit III of the uninfected contralateral (control) wing, which was between >90° and <180°. Compare the wings shown in Fig. 7D as an example. 

^cThe cartilage length index is the ratio of the length of the infected right element to the length of the uninfected contralateral element and is expressed as the mean ± standard error. 

^dWing size of the Msx1(R31P)-infected embryos was never observed to change, but in a small number of embryos, there was some difference in the size of feather germs on the right infected wing compared with the contralateral uninfected (control) wing. 

^eAP, human AP.