It has been said that the goal in the genetic sequencing industry is to develop a sequencing method within the next five years that will bring the cost of a human genome to $1000. Crazy cheap considering it was 10 million dollars five years ago. Many believe the technology that will get us there is nanopore sequencing.
With this method of sequencing, single strands of DNA will be forced through a membrane with extremely tiny holes in it, or nanopores. These would be a width small enough to only let one strand of DNA through at a time, about one billionth of a meter!
In the image, the yellow zipper looking object is a DNA strand. It is forced through the membrane due to an electric force. This force is obtained by a positive and negative ionic solution on either side of the membrane. Also, there is a voltage difference across the small pore in the membrane, so electrons will pass from one side of the pore to the other.
To reiterate an earlier post, DNA consists of four nucleotide bases, represented by the letters A, C, G, and T. These four bases are the building blocks of life, or the blueprint if you will. As the DNA strand moves through the membrane, electrons will experience a current change based on the nucleotide base that is passing through, either A, C, G, or T. A device measuring current will allow a computer to determine the exact sequence of bases as they pass through the membrane, and once all of the DNA has passed through, a whole genome will be obtained.
It is anticipated that this technology is likely to succeed and bring the cost of sequencing down significantly. It's really only a matter of time! Check out this link for a 3 minute video explaining nanopore sequencing technology in a slightly more in depth manner.