Concept development of housekeeping genes in the high-throughput sequencing era.

Housekeeping genes are typically constitutive genes that are required for the maintenance of basic cellular functions, and are stably expressed in all cells of an organism under all conditions and during all developmental stages. The definition and development of housekeeping genes reflect their essence and characteristics at different times. The present study reviews the concept development of housekeeping genes based on the technologies that quantify gene expression levels. We also analyze pig housekeeping genes by RNA-seq data, and discuss conceptual issues raised by the rapid progress of technologies and the growth of data. Our present study summarizes that housekeeping genes should be defined at different levels, and changing times will witness its conceptual development.