Mouse genomic DNA is treated with a restriction endonuclease and electrophoresed in an agarose gel. A radioactive probe made from the human gene rxr-1 is used to perform a Southern blot. The experiment was repeated three times. Explain the results of these repeated experiments:
Experiment 1. The autoradiogram shows a large smudge at a position corresponding to the top of the lane in which the mouse DNA was electrophoresed.
Experiment 2. The autoradiogram shows a smudge over the entire lane containing the mouse DNA.
Experiment 3. The autoradiogram shows three bands of varying intensity.