By Kastalia Medrano 1/29/18

The most extensive and detailed human genome sequence yet has been assembled using a hand-held device roughly the size of a cell phone.

An international team of scientists working at a lab at the University of California, Santa Cruz, created a portable nanopore sequencer that not only used DNA fragments hundreds of times longer than is standard, but closed 12 gaps in the known human genome, according to a UCSC press release. That makes the human genome it assembled the most complete one ever created to date. A paper describing the research was published in the scientific journal Nature Biotechnology.

The sequencer works by identifying changes in the flow of individual molecules of DNA when they pass through a microscopic membrane hole known as a nanopore. The device can read one million letters of DNA at a time, and has now been used to sequence a human individual’s entire genome, according to New Scientist.

This makes it an invaluable breakthrough, because much of the remaining unsequenced human genome involves complex and repetitive strands of DNA, according to the press release. Going off short DNA sequences, or reads, of those regions makes it difficult for scientists to get a sense of what they’re working with. But the ability to used longer sequences, like the new device provides, means much more clarity.

“If you imagine the process of assembling a genome together is like piecing together a jigsaw puzzle, the ability to produce extremely long sequencing reads is like finding very large pieces of the puzzle, which makes the process far less complex,” co-author Nick Loman, a geneticist at the University of Birmingham, said in the press release.

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