Table 1.

Comparison of the expression stability of 6 reference genes in fetal sheep liver as calculated by geNorm, Normfinder and BestKeeper

Rank	geNorm		NormFinder		BestKeeper		BestKeeper
	Gene	Stability	Gene	Stability	Gene	Stability*	Gene	Stability**
1	PPIA	0.50	PPIA	0.188	HPRT1	2.17	RNA18S	27.2
2	HPRT1	0.50	HPRT1	0.326	PPIA	2.43	PPIA	32.2
3	RNA18S	0.58	RPLPO	0.349	RNA18S	3.26	HPRT1	33.3
4	RPLPO	0.64	RNA18S	0.410	RPLPO	3.60	RPLPO	40.7
5	TUBB	0.71	TUBB	0.443	ACTB	3.75	TUBB	49.1
6	ACTB	0.75	ACTB	0.454	TUBB	4.45	ACTB	50.0

*% coefficient of variation compared to the mean cycle at the threshold (Ct).

**% coefficient of variation compared to the mean relative abundance (calculated as E^{Ctmin-Ctsample}).