Raj, G. DhinakarTANUVAS2018-07-252018-07-252009-09http://krishikosh.egranth.ac.in/handle/1/5810061977Genes are differentially expressed in - Different cell types (e.g. muscle cells, fibbroblasts) - Environmental conditions (e.g. heat shock, nutrient deprivation) - Developmental phases (e.g. embryonic day 10) - Cell-cycle stages (e.g. G1 phase) - Disease states (e.g. tumor cells, virus-infected cells) Gene expression is primarily regulated at the level of transcription. Hence, the number of mRNA copies in a cell for a particular gene is a good indicator of that gene’s expression (number of proteins).enVeterinary ScienceAnimal BiotechnologyBook chapter