Reference genes
This article discusses the specific topic of reference genes. For a more general list of housekeeping genes see housekeeping genes
Reference genes are expressed in all cells of an organism under normal and patho-physiological conditions. Although some housekeeping genes are expressed at relatively constant levels in most non-pathological situations, other housekeeping genes may vary depending on experimental conditions.
Although the terms "housekeeping gene" and "reference gene" are used somewhat interchangeably, caution must be used in selecting genes for reference purposes.
This is a list of recommended housekeeping genes that may be used for reference purposes:
| Gene | Access no. | Description | Chromosome |
| C1orf43 | NM_015449 | Chromosome 1 open reading frame 43 | chr1 |
| CHMP2A | NM_014453 | Charged multivesicular body protein 2A | chr19 |
| EMC7 | NM_020154 | ER membrane protein complex subunit 7 | chr15 |
| GPI | NM_000175 | Glucose-6-phosphate isomerase | chr19 |
| PSMB2 | NM_002794 | Proteasome subunit beta type 2 | chr1 |
| PSMB4 | NM_002796 | Proteasome subunit beta type 4 | chr1 |
| RAB7A | NM_004637 | Member RAS oncogene family | chr3 |
| REEP5 | NM_005669 | Receptor accessory protein 5 | chr5 |
| SNRPD3 | NM_004175 | Small nuclear ribonucleoprotein D3 | chr22 |
| VCP | NM_007126 | Valosin containing protein | chr9 |
| VPS29 | NM_016226 | Vacuolar protein sorting 29 homolog | chr12 |
The following represent genes that should probably not be used for reference purposes: GUSB, RPLP0, TFRC, GAPDH, HSP90, and β-actin. Although they were once considered as "housekeeping genes," recent data suggests that they are not as reliable as once thought.