Speed record
The read-write speed of DNA was accelerated to 1.9 bits/hour
Maxim Abdulaev, "The Attic"
There have been successful attempts of this kind before, but now the process of writing and reading, firstly, has been automated for the first time, and secondly, accelerated.
Scientists at the University of Washington (USA) and Microsoft Corporation were able to record data on DNA, as on some digital medium. They automated the procedure for encoding digital data into a "genetic alphabet" and spent 21 hours writing the word hello into DNA and reading it.
DNA is a very compact and durable storage of information. One milliliter of DNA can hold up to a billion gigabytes of information that can be stored for thousands of years – today scientists are deciphering the genomes of paleontological finds that are tens of thousands of years old. Other scientists are engaged not in reading, but in recording information in DNA. So far, the record volume of data that the same research group managed to squeeze into DNA is 200 megabytes. The recording process until recently looked like this: first, information in the form of a binary code of ones and zeros was translated into the "alphabet of life" of nitrogenous bases (A, T, G, C), then DNA was synthesized with such a sequence. And in order to read information from DNA, the sequence was sequenced, and then translated back into binary code. At the same time, each step was performed separately, which took a lot of time and was not at all like using a regular file storage.
As one of the authors of an article published in the journal Scientific Reports (Takahashi et al., Demonstration of End-to-End Automation of DNA Data Storage) said, "people should not run around the data center with pipettes." Therefore, scientists have automated the system and created a complex within which all stages of the process take place.
It looks like this:
To test their setup, the scientists translated the word Hello into binary code, obtaining a 5-byte sequence (01101000 01100101 01101100 01101100 01101111), and then translated it into a quaternary code in which A was zero, C was one, G = 2, and T = 3. After that, the setup synthesized DNA in the corresponding sequence. In total, 1 milligram of DNA was synthesized, from which 4 micrograms were sent to the sequencer by a special pump.
The system decodes DNA by nanopore sequencing. This method uses a thin membrane only one and a half nanometers thick, in which proteins-pores are embedded. The membrane bisects the chamber with an electrolyte solution in which DNA floats. When a current is applied through the system, the DNA, which is negatively charged, crawls to the "plus", on the other side of the membrane. On the way, it squeezes through the pores, and the nitrogenous bases of which it consists plug the hole. The trickle of electrolyte ions, which also flows through the pore, becomes narrower, and the strength of the current flowing through the membrane decreases. Different nucleotides have different shapes and plug the passage to varying degrees, therefore, by reducing the current, it is possible to determine which nucleotide is now climbing through the pore.
Sequencers of this type allow you to decode very long pieces of DNA, up to 100,000 base pairs. However, their accuracy is lower than that of the best sequencers of other types – the number of errors can reach up to 10%. But they cost from $ 1,000, are smaller than a smartphone and work quickly – the authors of the article had the decryption process take six minutes. The rest of the process wasn't as fast. It took 21 hours to do everything about everything, and DNA synthesis took the lion's share of the time.
As scientists write, 5 bytes in 21 hours cannot yet be called commercially viable indicators. However, the previous data storage technologies also started with not very impressive results. Now scientists are going to reduce the time of DNA synthesis, as well as make multiple recording and reading of information.
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