What Comes Next?
So now, whether we used the BAC to BAC method or the whole genome shotgun method, we still have DNA broken up into little pieces, and these still need to be sequenced. Until the late 1980's this was done by individuals, painstakingly reading each piece of DNA. As you can imagine, this was a long and tedious job.
Electrophoresis is a process were the DNA to be sequenced is placed at the end of a slab of gel. Electrodes are situated at the ends of the gel slab and an electrical current is sent through the gel. When the current passes through the gel the DNA molecules begin to move with the smaller ones moving faster than the larger ones. This effectively separates the molecules so that they can be identified.
There are now automatic sequencing machines that make the process much faster and more accurate. One of these machines can sequence as much DNA in a few hours as it took an individual to sequence in one year. The machines operate mostly the same as the manual process. 96 rows are filled with gel and the DNA is added. The machine reads the bases as they move through the gel.
Once the DNA has been sequenced it emerges from the automatic sequencing machine in a jumble like pieces in a scrabble game. The next step is the finishing. This is the process of putting 'Humpty Dumpty' back together again and often takes longer to perform than the actual sequencing itself. There are even faster machines out now that are twice as fast as the slab gel machines and these are automatic and do not require much human participation. As time progresses we can be pretty sure that the speed of sequencing DNA will only increase given the speed technology is moving.
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