Pocket sequencer read the human genome

Scientists were able to read the human genome by means of “pocket”
device for sequencing MinION
the size of a smartphone. In an article published in Nature Biotechnology, also described delivered using the same device record for the longest reading of the DNA molecule to the length of a continuous
reading amounted to 882 thousand base pairs.

Despite the fact that today read genomes
dozens of animal species, and the cost of sequencing has fallen by orders of magnitude for
the first such experiments, the definition of full
the DNA sequences of eukaryotic organisms is still
a non-trivial task. This is mainly due to the fact that a significant part of the genome
is a repeating sequence of microsatellite DNA, tandem
repeats, retroelements, and so on.

The most common technology for high-throughput sequencing
DNA today involves breaking the DNA molecule into small pieces in
a few hundred base pairs, the amplification (multiplication) and reading. From
such small pieces with the help of mathematical algorithms then
restore complete genome sequence (this process is called
Assembly). Many stretches of DNA, especially those containing repeats, all at the same
fall or researchers are unsure of their exact sequence. Even in
the human reference genome, which was first published in 2001, still
then there are gaps.

To avoid this, engineers focused on
the sequencing technologies that allow you to define the sequence as
longer DNA molecules, preferably without amplification. On
today the most popular solution for reading and assembling of large
genomes were technology companies PacBio to continuously read several tens of thousands
couples. For small genomes, e.g., bacterial, company Oxford Nanopore Technologies in 2014
proposed “pocket” sequencer MinION, which is also capable of continuous long read sequencing,
but with limited capacity.

MinION is a
the device is about the size of a smartphone that connects to the computer via USB cable. Its principle of operation is based on
measuring the electrical conductance during the stretching of the DNA molecule via
the pore in the membrane of the device. The cost of the device and starter kit of reagents
is a thousand dollars that in comparison with other existing
technology is quite cheap. The developers have positioned it as a field
sequencer that can be used “in the jungle, in the Arctic, on
space station”. In confirmation of this recently with the MinION on the ISS do I read multiple DNA sequences, such
among the mitochondrial genome of the mouse.

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