Table 4.

Stability value and ranking of reference genes based on NormFinder

	Circadian
	C57BL/6JOlaHsd		129Pas plus C57Bl/6J-KO		129Pas plus C57Bl/6J-WT		Mouse strain
Gene	liver	adrenal gland	liver	adrenal gland	liver	adrenal gland	liver	adrenal gland
Dataset	A	B	C	D	E	F	G	H
Rn18s	0.118	0.070	0.078	0.068	0.063	0.062	0.020	0.054
Actb	0.196	0.090	0.093	0.104	0.087	0.060	0.555	0.506
Gapdh	0.134	0.088	0.123	0.113	0.106	0.058	0.112	0.080
Hmbs	0.096*	0.058	0.114	0.080	0.095	0.063	0.309	0.088
Hprt1	0.150	0.156	0.062	0.166	0.058	0.187	0.024	0.199
Ppib	0.124	0.057*	0.090	0.062*	0.070	0.025*	0.028	0.028*
Rplp0	0.187	0.081	0.056*	0.099	0.077	0.073	0.021	0.064
Eif2a	0.127		0.112		0.106		0.017*
Tbcc	0.124		0.107		0.081		0.021
Utp6c	0.190		0.060		0.057*		0.027
Best two	Ppib	Ppib	Hprt1	Rn18s	Hprt1	Gapdh	Rn18s	Rn18s
	Hmbs	Hmbs	Ppib	Ppib	Utp6c	Ppib	Eif2a	Ppib
	0.061	0.046	0.044	0.048	0.037	0.032	0.013	0.031

In groups A to F, data was grouped according to tissue, mouse strain and the time point. In groups G and H, data was grouped only according to tissue and time point. *-best candidate reference gene according to NormFinder. (Best two) - the best combination of two reference genes together with their stability value are calculated only if group identifiers (in our case time of sacrifice) are included in the analysis. "Best two" is not always equal to the first and second ranking genes, but represent the two genes with minimal combined inter-and intragroup expression variation [22].