Science Report on Joint Genome Institute.

Essay by EJY345High School, 12th gradeA+, January 2006

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At the JGI--or Joint Genome Institute--I had the opportunity to experience one of the largest dedicated DNA sequencing operations in the world. Basically, I got to see firsthand the machinery and technology involved in the process called whole-genome shotgun sequencing, whereby the order of bases in an organism's genome is determined. One of the tour guides, before the tour, gave us an animated illustration of this process. In this genome-determining-process, DNA from the organism to be sequenced is broken up into pieces about 2,000 to 4,000 bases long through a process called shearing. Then, these fragments of DNA are inserted into the DNA of a bacterium. When grown on an agar plate, only the transformed bacteria with the plasmid containing the fragmented DNA with genes for ampicillin resistance and the lacZ gene interrupted by the inserted DNA can grow on the plate and be white. These white colonies are the ones used in the upcoming steps.

Basically, the plasmid DNA is taken out of the bacterium; the fragments are replicated and the "terminal" base of each fragment is tagged with a fluorescent dye. The tagged fragments are loaded into a high-speed capillary electrophoresis machine, and lasers can read the dyes of the bases as they move through the machine. A computer--at the end--solves the 'puzzle' and determines the organism's genome sequence.

While at the JGI, on our tour, we saw an electroporation machine, which induces the bacteria to open their pores, causing the plasmids to enter into the bacteria. Also, we saw a robotic bacteria picker, which picks specific white bacteria colonies out of the plate. Furthermore, we saw a large number of thermal cyclers and sequencing machines. Overall, the tour was worthwhile because we learned how specialized institutions such as the JGI sequence an organism's DNA and...