Practice question

Question

A gene from genomic library is screened by using hybridization technique. After hybridizing the probe, usually a stringent washing step is given. The following statements are given to explain the stringent washing step: A. Stringent washing takes care of removing unincorporated and non-specifically hybridized probe molecules B. Stringent washing is done in solution having high salt concentration and lower temperature C. Stringent washing is done in solution having low salt concentration keeping higher temperature D. Salt present in washing solution supports hybrids to stay intact by shielding the interference of water molecules E. Salt reacts with DNA molecules and allows easy dissociation of hybrids F. Stability of hybrid is directly proportional to the temperature Which combination of the above statements is most appropriate for stringent washing, step?