My text says we have to use expression libraries (cdna libraries) for constructing transgenic animals or for gene therapy,
Now I can't understand why genomic libraries can't because for gene therapy we are going to include the cloned genes after sequencing is completely done.
What other thing is there? Because if it were the promoters, introns which are limiting in the cloning vectors for which cDNA libraries are useful the genes in gene therapy and transgenic animals are used in eukaryotes i.e. human in case of gene therapy, so why can't we use genomic libraries?