Table 2
Expression stability ranking of 12 candidate reference genes during heavy metal exposures in the gill of different treatment sets

RefFinder		geNorm		NormFinder		BestKeeper		Delta CT
Genes	GRV	Genes	SV (M)	Genes	SV	Genes	SD [±CP]	Genes	Ave. SD
RPL7	1.000	RPL8	0.199	RPL7	0.146	RPL7	0.117	RPL7	0.317
RPL8	1.682	RPL7	0.204	RPL8	0.150	RPL8	0.137	RPL8	0.320
ACTB	3.834	ACTB	0.209	RPL3	0.211	ACTB	0.169	RPL3	0.352
RPL3	4.559	RPL7A	0.236	ACTB	0.215	PPIB	0.188	PPIB	0.353
PPIB	4.681	PPIB	0.250	RPL7A	0.218	RPL7A	0.192	RPL7A	0.353
RPL7A	4.729	RPL3	0.266	PPIB	0.219	EF1A	0.199	ACTB	0.355
EF1A	6.735	EF1A	0.280	EF1A	0.227	RPL4	0.203	EF1A	0.360
RPL4	7.7737	RPL4	0.290	RPL4	0.231	RPL3	0.207	RPL4	0.364
GAPDH	9.000	GAPDH	0.304	GAPDH	0.282	GAPDH	0.280	GAPDH	0.397
RPL5	10.488	RPL5	0.329	UBE2	0.376	RPL5	0.316	UBE2	0.465
UBE2	10.719	UBE2	0.352	RPL5	0.408	B-TU	0.321	RPL5	0.479
B-TU	11.742	B-TU	0.392	B-TU	0.539	UBE2	0.341	B-TU	0.593