A DNA library is a collection of clones, each containing a different fragment of DNA, inserted into a cloning vector. What is the difference between a eDNA and a genomic DNA library? You would like to clone gene X, a gene expressed only in neurons, into a vector using a library as the source of insert. If you have the following libraries at your disposal (genomic library from skin cells, eDNA library from skin cells, genomic library from neurons, eDNA library from neurons), which could you use and why?