You are interested in studying the gene for glucagon, a peptide hormone produced by the pancreas. A colleague in the endocrinology department has purified a milligram of rat glucagon after two years of work. Outline of the steps you would take to isolate the glucagon gene from rats. Several proteins are now being produced in vitro using recombinant DNA technology. Name two of these proteins, and explain what advantage in vitro production of this protein would offer over isolation of that protein from other sources.
Many eukaryotic genes contain large numbers of exons.
Since all 5' splice sites look alike, as do all 3' splice sites, it is remarkable that skipping an exon occurs so rarely during splicing. Some mechanism must keep track of neighboring exons and ensure that they are brought together. One proposal for maintaining exon order during splicing suggests that the splicing machinery binds to a splice site at one end of an intron and scans through the intron looking for a splice site at the other end. Such a scanning mechanism would guarantee that an exon is never skipped. You are intrigued by this hypothesis and decide to test it.