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How is gene regulation different in bacteria versus mammalian systems and other higher eukaryotes?
In a bacterial system, there is a proximal relationship between transcription factors and genes with regulatory sequences of a particular gene directly upstream.
In higher eukaryotes, genes can be regulated very far upstream by enhancers 50,000 base pairs away, even beyond adjacent genes. The looping and folding of the DNA brings distant spans into close spatial proximity.