Table 2.

Expression stability ranking of previously reported control genes.

Gene	geNorm	Normfinder
rpoC	0.258 (1)	0.310 (6)
map	0.258 (1)	0.331 (8)
alaS	0.299 (2)*	0.301 (5)*
era	0.411 (3)	0.229 (1)
gmk	0.487 (4)	0.295 (4)
rrs	0.522 (5)*	0.278 (3)*
nth	0.559 (6)	0.254 (2)
trpS	0.585 (7)	0.312 (7)
rplI	0.614 (8)	0.426 (10)
gyrA	0.657 (9)	0.525 (9)
recA	0.720 (10)*	0.476 (11)*
coaE	0.786 (11)	0.641 (12)

Ranking of the three control genes previously used in A. ferrooxidans gene expression studies according to their expression stability with respect to the nine candidate reference genes under five different experimental condition using geNorm and NormFinder applications. See Table 1 legend for further detail on the ranking methods and experimental conditions.

* Control genes used in previous studies [28,30,45].

() The ranks of the genes are indicated in parentheses.