Computer giant IBM is the latest company to say it will try to build a DNA sequencing machine. IBM appears to be years behind other companies that are taking similar approaches, but the company’s announcement has caused quite a stir among tech journalists.

PC World says that IBM will “expand the life span of humans,” while the New York Times’ John Markoff predicts that the company will cut the cost of DNA sequencing to under $100, “making a personal genome cheaper than a ticket to a Broadway play.”

Sequencing a whole human genome currently costs tens of thousands of dollars at a minimum.

So what is IBM up to? Its approach involves stacks of semiconducting materials layered onto silicon wafers and pockmarked with tiny holes a nanometer wide, reports MIT’s Technology Review. Since DNA is charged, it flows through these holes, or “nanopores,” when a voltage difference is applied across the semiconducting stacks. Then, somehow, the DNA bases are read as they flow through the pores; IBM hasn’t said yet how it will read the bases.

In other words, IBM appears to be taking a very similar approach to companies such as Oxford Nanopore, points out blogger Daniel MacArthur, who writes, “I certainly expect to see a mature nanopore sequencing platform from Oxford long before I see anything from IBM.”

In IBM’s favor, however, is the fact that sequencing is becoming more and more dependent on storing and interpreting huge amounts of data – something IBM knows a lot about. IBM is also painting this as a sort of exploratory project; a scientist there tells PC World that “We’re in a process in which we will have milestones … [over] three years. At the end of three years we will know if it’s feasible or not.”

It’s hard to imagine what the sequencing market will look like in three years’ time. Companies such as Pacific Biosciences are promising to debut better, faster, cheaper sequencing technologies next year. Complete Genomics has pledged that it will be selling $5,000 genomes in 2010. Established sequencing companies such as Illumina are cranking up their output by the month, it seems. Meanwhile, a host of other earlier-stage companies are plugging away developing new technologies; at the Personal Genomes meeting in Cold Spring Harbor last month, sequencing pioneer George Church listed 17 competitors in the “ultra low-cost sequencing space”.

Where will IBM fit in this mix? It will be fascinating to see how that turns out.