Washington, Dec 21 (IANS) Biomedical engineers have hit upon a way of speeding up genome sequencing by cutting down the amount of DNA required in existing methods, which are costly, time-consuming and error-prone.
A team led by Amit Meller, a Boston University biomedical engineering associate professor, reduced the number of DNA molecules required for such sequencing by 10,000 times, from about one billion sample molecules to 100,000.

“The current study shows that we can detect a much smaller amount of DNA sample than previously reported,” said Meller.

“When people start to implement genome sequencing or genome profiling using nanopores, they could use our nanopore capture approach to greatly reduce the number of copies used in those measurements.”

Currently, genome sequencing utilises DNA amplification to make billions of molecular copies in order to produce a sample large enough to be analysed.

Besides the time and cost DNA amplification entails, some of the molecules come out less than perfect.

Meller and his colleagues at Boston University, New York University and Bar-Ilan University in Israel have harnessed electrical fields surrounding the mouths of the nanopores to attract long, negatively charged strands of DNA and slide them through the nanopore where the DNA sequence can be detected.

They made a counterintuitive discovery: the longer the DNA strand, the more quickly it found the pore opening.

“That’s really surprising,” Meller said. “You’d expect that if you have a longer ’spaghetti’, then finding the end would be much harder. At the same time this discovery means that the nanopore system is optimised for the detection of long DNA strands — tens of thousands base pairs, or even more.

This could dramatically speed future genomic sequencing by allowing analysis of a long DNA strand in one swipe, rather than having to assemble results from many short snippets, says a Boston University release.

The study was published in the Sunday online edition of Nature Nanotechnology.