Cheap and EZ DNA

A new technique combining biology and nanotechnology has enabled the creation of a scanner that can analyze very small scale sequences of DNA, quickly and inexpensively.

The technique could open the door to individualize medicine directed at the genetic roots of such conditions and diseases such as cancer, diabetes, or addiction. Lead author on the study, Jens Gundlach, a UW professor of physics, says that they hope that in 10 years time, people will have all of their DNA sequenced, and this will led to "personalized, predictive medicine."

The technique works by using a nanopore from Mycobacterium smegmatis porin A, which has "an opening of 1 billionth of a meter in size, just large enough to measure a single strand of DNA as it passes through." The size had to be just right in order for only a single strand of DNA to pass through and not an entire series.

The nanopore is then placed within a membrane that is surrounded by a potassium-chloride solution. Then, in order to generate motion for the strand to pass through, a small voltage of electricity was used to create an ion current. This electrical signal was then monitored for fluctuations, each particular change in signature was in result from the varying nucleotides, the essence of DNA, that traveled through the nanopore.

In order for the nucleotides to be isolated long enough to be monitored due to the fast speed that it traveled through the pore, a rate of one every millionth of a second, the researchers had to attach a section of double-stranded DNA between each nucleotide they wanted to measure to act as a net. The second strand would catch for a brief time on the edge of the pore, halting the current of DNA long enough for a single nucleotide to be read.

This simple, yet efficient method, has drastically cut the expense of DNA sequencing. The program, funded by the National Institutes of Health, and its National Human Genome Research Institute, began in 2004 when the cost was $10 million to sequence a human-sized genome. Now, six years later, this new system of sequencing costs up to $1,000. In time, we will see faster, and even more efficient means of sequencing DNA, allowing us to form a literate understanding of the code that forms our organic existence.

Image: "Electron Microscope Coloured DNA Strand On White" by the tjb's on Flickr courtesy of Creative Commons Licensing