Open-ended question 4 You are comparing the expression of four genes (A, B, C and D) in two different cell types (hippocampal and glial cells). Each gene has four exons (1, 2, 3 and 4). You make a small microarray that contains sequences complementary to each exon. You then make cDNA probes from hippocampal and glial cells, labeling them separately as in the legend at the right of the following figure. The results of a microarray hybridization experiment using the two probes is shown below Exon 1 2 3 4 cDNA from cells in hippocampus 50:50 mix cDNA from glial GeneA cells (A)(1 point) Briefly describe how you would make cDNA from your two RNA samples – you will need to mention at least one enzyme, and specify your choice of primer(s). (B) (1 point) Which of these four genes is differentially spliced? (C) (2 points) Draw a schematic of two potential spliced forms (1 pt.) and label them as hippocampal- or glial cell-specific (1 pt.)