Housekeeping genes are critical for carrying out basic cell functions and so are expressed at a relatively constant level (constitutively). Since their expression is constant, <answer>housekeeping genes</answer> are used as experimental controls when analysing gene expression. Not all essential genes are <answer>housekeeping genes</answer> since some essential genes are developmentally regulated or expressed at certain times during the organism's life cycle.
When investigating gene expression, what type of genes are used as a control for experiments?
housekeeping genes