To do this, you transfect various kinds of eukaryotic cells with this DNA and observe how the newly inserted DNA-Z alters the recipient cell's behavior. In each different cell you observe that a different gene is activated after DNA-Z insertion. In each case the activated gene had been expressed at very low levels before transfection, but after DNA-Z is inserted nearby, the gene gets transcribed at a high level. Explain your answer. 6 points It suggests that DNA-Z contains an enhancer.
Enhancers are sequences in DNa that can serve to activate transcription from any nearby promoter.
What appears to be happening in this experiment is that DNA-Z is being inserted into a different place in the genome in each of the cells being examined. Since it has a different location in each transfected cell, it is activating different nearby promoters. Explain how gene duplication and the ability to perform RNA splicing is thought to be one of the factors that allowed eukaryotes to evolve from primitive cells. When these primitive cells developed the ability to splice RNA, large transcripts that spanned more than one of these genes could be spliced to produce a mRNA that contained more than one function and could be of benefit to the cell. Thus, if a gene were duplicated and translocated to another region of the DNA, it might be able to combine with a neighboring gene to produce a novel product.