A Northern blot is shown here using a DNA probe that is
complementary to the mRNA encoded by a particular gene. The mRNA in
lanes 1 through 4 was isolated from different cell types, and equal
amounts of total cellular mRNA were added to each lane. Explain
these results.
Lane 1: mRNA isolated from nerve cells
Lane 2: mRNA isolated from kidney cells
Lane 3: mRNA isolated from spleen cells
Lane 4: mRNA isolated from muscle cells