Reference no: EM132706489

All cells in a given mammal carry the same genome, yet certain genes are expressed only in a particular tissue, such as in the eye, and not expressed in other tissues, such as in the liver. How is this specificity of gene expression for a particular tissue achieved?

-Different tissues express unique transcription factors that are bound to tissue-specific enhancer elements, thereby achieving tissue-specific gene expression.

-Certain organ and tissue systems, such as the nervous system, form relatively early in the organism's embryonic life, as compared to the epidermis; it is this relative age of the tissue lineage that determines which tissue-specific genes are expressed.

-Each tissue has a unique RNA polymerase holoenzyme that achieves tissue-specific gene expression.

-All different cell types in the organism express all proteins equally and degrade the proteins that they don't need.

-Different tissues inactivate whole swaths of the genome, like a Barr body, thereby achieving tissue-specific gene expression.