A) amplifying DNA segments using cycles of denaturation, annealing to primers, and DNA polymerase-directed DNA synthesis B) transferring DNA fragments from a gel to a membrane filter and used in hybridization experiments C) determining the nucleotide sequence of a DNA molecule D) producing several clones from a single cell by placing the cell in a Petri dish and allowing it to go through several divisions E) detecting mutant genes or differences in the pattern of gene expression